The Marseille was the single vehicle that received a special welded turret made by FCM. Illustration by David Bocquelet, modified by Pavel 'Carpaticus' Alexe
France (1938-1940)
Heavy Infantry Tank – 1 Converted
During the 1930s, the French shipyard of FCM (Forges et Chantiers de la Méditerranée) was a fairly important player in the field of tank development and construction. In a field dominated by manufacturers using casting techniques and a few using riveting and bolting (mainly Renault and its cavalry vehicles), FCM was notable in its use of welding. Though this is mainly known via FCM’s only mass-produced design from the late 1930s, the FCM 36, FCM also studied a variety of heavier designs which used welding, such as the FCM F4 or FCM F1. FCM also took part in the studies to provide an improved version of the B1 Bis tank, of which FCM was one of several manufacturers, the B1 Ter. It is in this context that an experimental welded turret was given to a B1 Bis produced by FCM.
The B1 Bis “Marseille” and its Turret
The tank which received this new turret was the B1 Bis №234. It was assembled by FCM in early 1938 and would be delivered to the 510ème RCC (Régiment de Char de Combat – Combat Tank Regiment) in Nancy, Lorraine. There, it was nicknamed “Marseille”, after France’s second-largest city and a large Mediterranean harbor.
This B1 Bis was given a welded turret that had been designed by FCM. This welded turret appears to not have been an entirely new design, but was instead based on a design studied to provide a second, rear turret for FCM’s F4 tank.
The 47 mm-armed turret design for a variant of the FCM F4. It would have featured in the “variante D”. In all known variants, the FCM F4 had a 75 mm main gun in a rotating front turret. Armed with the 47 mm SA 35, this turret would have given some amount of anti-tank coverage to the rear and sides of the vehicle. Source: GBM 109The only known photo of B1 Bis №234 “Marseille” with its welded turret, likely taken in Nancy. Source: char-français
In comparison to the FCM F4’s turret, the Marseille’s appears to have been merely a slightly simplified version. It remained a welded turret with 7 sides, including the front. The turret was designed to be similar to the APX 4 found on classic B1 Bis tanks in terms of general architecture. It therefore also retained the crew of one, the commander. The turret featured a commander cupola to the rear left, with three vision ports. If this cupola was given the observation devices of the standard B1 Bis, it would have had a PPL RX 160 episcope. However, the turret the Marseille received is known to have been more of a prototype/proof-of-concept, and may have lacked all the advanced features of a standard APX 4.
Vision ports were also found on the sides of the turret. They were more distinctive than on the standard B1 Bis’ APX 4, being more reminiscent of the APX 1 found on the older B1 in this fashion.
The armament of the FCM welded turret was the same as on a standard APX 4, a 47 mm SA 35 main gun to the right, and a coaxial MAC 31 7.5 mm machine gun to the left. The FCM turret featured different mantlets than the APX 4, owing to their use of welding instead of casting. This is particularly distinguishable on the machine gun, which appears to feature some kind of shield protecting it from enemy fire. As for the turret’s armor protection, it was very likely identical in thickness to the APX 4. The welding would have led to less angles and fewer rounded surfaces, but the stronger structural resistance of welded steel in comparison to cast steel would have likely made up for it.
The Point of the FCM Turret
Placing this new welded turret on a production Char B1 Bis which was then issued operationally was obviously a way for FCM to experiment with heavier welded turrets. Several motives can be found behind this.
An obvious one can be found in the form of FCM’s ongoing heavy tanks project. The company was, by 1938, involved in the B1 Ter program, which would later see FCM tasked with manufacturing a serial/pre-production vehicle, which FCM wanted to feature one of their own turrets instead of the APX 4 or even another welded design, the ARL 2. The FCM F4 program was also recent, and in early 1938, had evolved into the FCM F1 – which was also planned to feature a 47 mm-armed turret in addition to a much larger, 90 mm-armed one.
A more discrete but perhaps more realistic or at least short-term motive may also be found in the will to provide some competition to the APX 4 turret which outfitted all B1 Bis produced, including those by FCM. A common issue with French cast turrets (and even the non-cast ones, seeing as this was also an issue with the Panhard 178’s riveted APX 3) was that their production was typically slower than the hull they were to be mounted on, resulting in a backlog of completed hulls with no turret to be outfitted with – not too much of an issue in peacetime, but a much more considerable one in wartime. By proving it could produce its own turret – and likely have it be quicker to produce than the APX 4 for about equal performances – FCM may have hoped to see the army order FCM’s B1 Bis to use an FCM turret instead of those provided by the state manufacturer APX. This would not, however, materialize in any way.
The Fate of B1 Bis “Marseille” and of FCM’s Cast Turret
At the outbreak of the war, in September 1939, the B1 Bis “Marseille” became the tank of the commander of the French 15ème BCC (Bataillon de Char de Combat – Combat Tank Battalion). It was, at this point, retrofitted with the standard APX 4 turret. During the 1940 Campaign, it was passed between the 15th and the 8th battalions, where it again became the battalion commander’s tank in late May 1940. The tank notably took part in the Battle of Abbeville. It broke down on a road on the night of 5th to 6th June 1940. By mid-day on the 7th, it had still not been able to be recovered when it was attacked and captured by German infantry – putting an end to this peculiar B1 Bis’s service within the French Army.
German soldiers in front of the abandoned “Marseille”, north of Beauvais, in Picardy, June 1940. Source: char-français
As for FCM’s welded turret, the B1 Ter, which was to be produced by FCM, very likely had a turret very similar, if not directly based on the design which was found on Marseille. Sadly, no iconographic documents of FCM’s B1 Ter, may it be photos of the assembly process (the tank was being assembled by the time FCM’s facilities fell under Italian occupation) or plans, have survived. Out of the three B1 Ter prototypes, the FL one shares a similar fate, and only a very few photos of the ARL prototype’s hull during the assembly process have survived. The fate of the FCM B1 Ter is also unclear. While the ARL and FL prototypes were sunk during evacuation to North Africa in June of 1940, the FCM was still listed as in existence by an Italian report dated from July 1943. It vanished without a trace after this date, leaving its fate to be a mystery (though the exact nature of its resolution likely lays simply in identifying whether the hands that scrapped it were German during the occupation of Italy and Italy’s French occupation zone, or French, after the liberation of the country in 1944).
The Marseille was the single vehicle that received a special welded turret made by FCM. Illustration by David Bocquelet, modified by Pavel ‘Carpaticus’ Alexe
The first form of the B40, armed with the 47mm SA 37. Hypothetical reconstruction from known aspects of the design. Illustration by Pavel Alexe.
France (1939-1940)
Heavy Tank – Concept Only
When it comes to the various projects in development in France by 1940, the B40 often comes off as both one of the most potentially impressive, but also one of the most mysterious. The last evolution of the Char de Bataille/B1 family before the Armistice cut off the manufacturing arms of France’s military industry, very little is known about this last model which never got the time to jump beyond the drawing board to prototype stage or serial production. In fact, while we have clues to what the vehicle may have looked like, no views of the plans have even reached the modern age.
The unborn heir of the B1 Ter
By late 1939, the most advanced member of the B1 family in development by the French military was the B1 Ter, of which three prototypes were in construction – one by ARL, one by FL and one by FCM. An evolution of the B1 Bis, the B1 Ter reached a heavier weight of 36 tonnes. While it improved on its predecessor in some aspects – featuring a thicker armor protection and some amount of lateral traverse for the hull-mounted 75 mm gun notably – it failed to address some core issues to the design, such as, for example, the one-man turret. This was armed with a 47 mm SA 35, which was still very much decent by 1940, but would realistically become obsolete fairly soon, and with more powerful alternatives in existence in France.
A view of the first B1 Ter prototype, likely in Rueil. Source: World of tanks forums
As such, in either late 1939 or very early 1940, AMX and ARL, two of France’s leading design bureaus, particularly when it came to heavy designs, were approached to design a 40 to 42 tonnes heavy tank which would be given 80 mm of armor. While it would retain the hull 75 mm gun of the B1 Ter, it would swap the 47 mm SA 35 for one of the two more powerful 47 mm anti-tank gun availables by then, the 47 mm mle 1934 RF fortification anti-tank gun or the 47 mm SA 37 field anti-tank gun. AMX’s project would be designed on the base of an artillery-carrying chassis they were working on, resulting in the AMX Tracteur B. Part of the motivation behind AMX and ARL being asked to design this new tank was the belief of the commission tasked to work on the Char de Bataille program that the G1 program would not conclude in a vehicle being adopted for service, and that an alternative – potentially in the form of a new, more modern heavy tank – would be needed.
Meanwhile, ARL had been the leading bureau designing the B1 Ter, under the lead of engineer Lavirotte. To design their version of this new heavy tank, instead of taking a blank state, ARL’s design team would take their well-established B1 Ter design and improve upon it. The AMX and ARL pre-projects would both be presented and judged in the first trimester of 1940. This was merely weeks before the German invasion would come kicking in, and as such, the B40 could never really get any further than plans, though some components would apparently be mounted on ARL’s B1 Ter prototype for experimental purposes.
The rough lines of the B40
Information on the B40 is relatively scarce – the vehicle is mainly known through an article written by its lead designer, Lavirotte, in 1967. Though Lavirotte has gone fairly deep into the vehicle’s suspension design, engine and gearbox, he fails to mention some important aspects of the vehicle.
This is notably the case for the dimensions. The B40 was known to have been widened to an extent in comparison to the B1 Ter in order to accommodate a larger turret ring as well as wider tracks which would help spread the vehicle’s weight more evenly. At its widest, the B40 would have been slightly over 3.10 m, which was the size requirements for the SNCF (Société Nationale des Chemins de Fer – National Railway Company). In order to solve this issue, the large ‘tunnel’ mudguards for the tracks would have a retractable section, suggesting the vehicle was likely very close to this said 3.10 m requirement (for the sake of comparison, the B1 Ter was 2.73 m wide). The main reason to widen the vehicle to such an extent was to vastly expand the turret ring. At 1,280 mm, as on the B1 Ter, it could pretty much not reasonably be expanded further on a vehicle with a fighting compartment the width of the B1 Bis’ or B1 Ter’s. However, the turret ring was widened all the way to 1,680 mm on the B40.
Hull construction
The hull of the B40 was based on the B1 Ter but considerably expanded in terms of the elements that had been first introduced by this previous member of the B1 family.
The B1 Ter had introduced welding to a large portion of the hull’s construction. This was expanded on the B40, which almost entirely moved away from bolting to feature an almost entirely welded hull – a much more modern construction technique that would both quicken construction times and improve the structural resistance of the hull.
The armor layout was to be of 80 mm on the front and sides, and 60 mm to the rear. Additional 40 mm side plates would protect the suspension. The roof was 30 mm thick. The bottom of the hull also received a quite important thickness of 40 mm, as the B40 had been designed with mine protection in mind. This bottom would be constituted of the bottom of the hull itself and the bottom of the 40 mm plates protecting the suspensions, linked by plates inclined at 45°. However, the B40 would forfeit the ‘diamond-shaped’ angled sides, which, at 25°, were thought to provide little additional protection while making the design overcomplicated. The B40 would return to flat sides, similar to the B1 Bis, and likely re-introduce some other features from the B1 Bis (for example, a forward-opening door instead of the B1 Ter’s downward opening ‘drawbridge’ type side door)
Often referred to as a photo of the B40, this is actually the ARL B1 Ter hull during manufacturing. No B40 was ever close to prototype status. The B1 Ter hull had a series of features similar to the B40. The driver’s post, and likely 75 mm hull mount would have been similar, as well as the ventilation for the engine. However, the B40 would have been wider and have lacked the diamond-shape hull sides Source: Tank Archives
The widening of the hull, performed for the sake of including a wider turret ring, would also allow for massively expanded fuel tanks on the B40. From 500 liters on the B1 Ter, these would be expanded all the way to 1,500 liters on the B40, which would massively expand the range of the tank. The engine which would have powered the B40 was a Talbot 500 hp turbo compressed engine, a very considerable upgrade in comparison to the B1 Ter’s 307 hp engine, which also equipped the B1 Bis. Despite the rising weight, the B40 would likely have been more mobile than its predecessor. The air intakes would have been located on top of the engine compartment, as on the B1 Ter. The tank was to use a gearbox installed perpendicularly to the tank’s axis, with six speeds but, thanks to inversion, also six reverse speeds, as well as a main and a secondary differential. Brakes for the tank were inspired by those found on heavy trucks. An immobilization brake acted on the main differential, and two smaller brakes acted on the secondary differential and could also be used when the tank would take a turn.
The widened hull would also likely have improved the conditions for the 3 crew stationed in the hull. In this regard, the vehicle was to remain similar to the B1 Ter. The driver would operate from a driving post of a similar design, and remain the gunner for the 75 mm gun. As on the B1 Ter, the 75 mm gun would have had some degree of lateral traverse in its mount. Interestingly, its servant would also be tasked with reloading the turret’s 47 mm gun from the hull itself. The radio operator remained as the third crew member.
As for the rotation of the hull, two alternative systems to the Naeder present since the SRB were considered for the B40. One, the T.A.H.V, was to be a hydraulic system of simpler construction, and was tested on a testbench, but not on a tank. The other, the B.N., was an electric machine and was actually experimentally mounted on a B1 Bis. In comparison to the Naeder system, it required no radiator, far less maintenance, and required less physical effort when rotating the hull. However, while with the Naeder, the tank would rotate at the same time as the steering wheel associated with the system, with the B.N, the driver would first have to fully rotate the steering wheel, and then progressively rotate it back for the vehicle to rotate with it, due to delays in the transmission of commands. This system was eventually judged to be inferior to the Naeder, and the B40 would retain a simplified and improved version of the classic hydraulic steering system.
Oleo Pneumatic suspension
In order to save weight, the B40 was to replace the suspension used in the previous vehicles with a new oleo-pneumatic one. It would nonetheless retain some elements of the previous suspension, notably the three tender wheels at the front, as well as one at the rear. The size of the road wheels appears to have been retained in general.
What differed were the suspension arms. The B40 got rid of the B1 Bis’ ensemble of three large, coil-spring mounted bogies, each containing two smaller bogies that held two road wheels. Though a similar number of bogies/road wheels appears to have been retained, these instead used a new oleo-pneumatic system. Each bogie group would contain a large cylinder. A piston would be moved by the main boogie, and itself be linked to an additional piston, with an oil-filled reservoir between the two. Between these two pistons, the suspension would also feature a “diaphragm” which would allow for smooth movements. Between the second piston and the cylinder was a “mattress” filled with compressed air, with a variable quantity of air present, which would then act on the boogie.
The tender wheels, originally mounted on leaf springs, also adopted an oleo-pneumatic system, being linked to a piston containing a variable mass of compressed air.
This system was trialed on the ARL B1 Ter prototype. The vehicle could only run for 10 hours before the Armistice but appears to have worked properly with this suspension system.
The B40 would have adopted widened tracks, going from 50 to 60 cm, in order to better spread the vehicle’s weight. The vehicle would have retained large ‘tunnel-like’ track guards on top of the track run. Oiling ports for the B40 would have been located in the same places as the B1 Ter.
A more than one man-turret, at long last
The ARL 2C turret. The B40 would not have used this design, but an enlarged one of fairly similar construction and shape. Source: war-thunder forums
One of the most significant improvements brought to the B40 was the turret. Up to this tank, tanks of the Char de Bataille program had always retained a one-man turret – from the machine gun-armed Schneider turrets of the SRA and SRB, to the cast, 47 mm armed APX 1 and APX 4 of the B1 and B1 Bis, to the welded ARL 2C of the B1 Ter.
The B40 would retain a welded turret. Whatever little information there is on the turret indicates that, generally, it would be roughly similar to the ARL 2C. However, it would be vastly enlarged, with a turret ring expanded from 1,280 mm to 1,680 mm. This would accommodate two major improvements. The first was a far more powerful anti-tank gun in the form of the 47 mm modèle 1934 RF, originally designed as an anti-tank gun for the Maginot Line. The 47 mm mle 1934 was an L/50 gun that fired an armor-piercing capped shell with a magnesium cap. This was a quite heavy 47 mm shell, weighing in at 1.670 kg and propelled by a 610 grams charge of powder, giving it a muzzle velocity of 880 m/s. At an incidence of 30°, it would penetrate 77 mm at 500 m and 56 mm at one kilometer.
A 47 mm model 1934 during trials. In normal operation, the gun would be placed on a beam on the ceiling of the bunker and could be exchanged with a machine gun mount. Source: http://www.lignemaginot.com/
Perhaps even more important than this powerful anti-tank gun was the move away from the one-man turret, with the B40 finally accommodating a second crew member in the turret, the gunner. The loading functions would reportedly not be assumed by the commander but by the 75 mm loader operating from the hull. Such a configuration was still lackluster in comparison to the pure 3-men turret of the German Panzer III and Panzer IV, but was a massive improvement from previous one-man turrets, which left the commander massively overburdened, particularly with a tank as complex as a Char de Bataille, which also contained a hull gun.
The B40 as of May 1940
As the project was before the campaign of France, the B40 would have been yet another incremental improvement in the Char de Bataille family of designs. As the B1 Ter and B1 Bis before it, it would have improved significantly on the previous models. However, one could still claim the design would not have resolved all the previous issues, or have been ideal. Notably, the dual gun configuration, which was retained, would not be optimal, and the vehicle, though now simpler to construct due to the liberal use of welding, would still be heavy and unreliable.
The Char de Bataille they should have built from the start: A turreted 75 mm
The B40 was not to be frozen entirely in its May of 1940 shape though. It is one of the few known instances of an existing French project being amended during the course of the campaign of France itself, using feedback from the units engaged at the front.
By late May 1940, the four DcRs (Division Cuirassée de Réserve – ENG: Reserve Armored Division, with the reserve part indicating the divisions were to be used in exceptional breakthrough operations as a strategic reserve, rather than being divisions formed of reserve servicemen) equipped with the B1 Bis had been heavily engaged in the Campaign of France. In some cases, they saw their B1 Bis fleets almost entirely eliminated. Though the tanks could occasionally prove a significant opponent to their German adversaries, those first combat experiences showed some core issues of the Char de Bataille series of tanks, which the French Army had been effectively blind to up to this point.
One of the major requests of the B1 Bis’s crews was that the 75 mm would have proved much more useful in the turret. Even with the advanced Naedar steering system, a dual gun configuration proved less than ideal, and the solution clearly appeared to have been a weapon that could effectively combine the roles of both the 75 mm and 47 mm – fight both tanks and infantry or fortifications – in a turret. Luckily, such weapons were already in existence within the French Army, notably the 75 mm APX 30 calibers gun featured in the SaU 40 and ARL V39 prototypes as well as a variety of other projects.
The armored vehicle mount of the APX 75 mm gun found on the SaU40 and ARL V39 prototypes, and in a variety of paper projects. Source: Wargaming
The solution that was swiftly devised by ARL’s engineers in late May and early June appears to have been to simply take the turret of one of their projects which would have mounted a turreted 75 mm APX gun, the ARL Char de Forteresse. Its ARL 4 turret, though quite tall, had a two-man crew and a 1,680 mm turret ring, like the turret which was to be mounted on the B40. With its armor thinned from the Char de Forteresse’s 120 mm to the B40’s 80 mm, it could fairly reasonably be mounted in the tank and provide multi-purpose firepower which would prove superior to the dual-gun configuration that had been retained up to this point. In the meantime, the space gained by the elimination of the hull 75 mm gun could potentially be used to accommodate yet another fuel tank, or more ammunition stowage. Without a hull 75 mm gun, the driver would prove vastly less overburdened and require less training, as he had no gun to act as a gunner for. The gun’s servant could also fully concentrate on the role of being a hull-located loader for the turreted main gun, or be removed outright to gain further space.
GBM’s reconstitution of a B40 fitted with the ARL 4 turret from the ARL Tracteur C. Source: GBM n°111 via reddit
Outside of a heightened silhouette and likely gaining a couple of tonnes due to the larger turret, this improved B40 only brought improvements to the previous design, and one could argue that the solution of a turreted 75 mm gun should have been adopted for the Char de Bataille family of vehicles a lot earlier. This is obvious with hindsight, but a lot less so when you consider that whether a 75 mm gun both powerful enough to defeat armor and compact enough to reside in the turret of a vehicle of this size could be developed was uncertain for a long time.
The Char de Bataille is not yet lost: Lavirotte’s work under occupation
By the time the 75 mm-turret B40 was being studied though, it was way too late. The 1940 campaign ended in a hard-fought but disastrous defeat for France, with the country occupied by German forces and divided into a German-occupied zone and the Free Zone of the Vichy Regime in the south, controlled by a French government under strict military limitations.
These limitations being strictly enforced by all of France’s Army men and engineers were little more than a pipe-dream though. Quickly after the armistice, a secret service for the stockpiling of material as well as the refitting of incomplete armored vehicles and eventually the production of new ones would be formed as the CDM (Camouflage du Matériel – Material Camouflage). The CDM’s own design bureau would produce two different vehicles, the Panhard 178 CDM and CDM armored car. At the same time, it would work to provide Lavirotte and the remaining members of his team with resources to continue studying tanks that could be manufactured abroad or after the liberation of France. The most mature work to emerge out of this bureau would be the SARL 42. However, Lavirotte would continue work on the B40 and some of its elements, with the idea of a 30-tonnes tank which would take some elements of the B40, such as the oleo-pneumatic suspension and Talbot turbo compressed engine, would emerge. After the liberation of France, these early studies would evolve into the first new French post-war tank design, the ARL 44 – the direct heir of the mysterious B40.
Conclusion – The missing link
The B40’s obscure status – far more than any known member of the Char de Bataille family, to the point no imagery of the vehicle survives – has led to it being wildly fantasized about. This, coupled with a misinterpretation of a page of François Vauvillier’s Tous les blindés de l’Armée Française 1914-1940, which showed the B40 on the same page as the ARL B1 Ter along with a photo of the ARL B1 Ter hull in construction, has lead some to actually believe a B40 prototype was in construction or finished by May 1940, which was not the case. Nothing but plans of the vehicle and some elements tested on the B1 Ter ever existed, and whatever did likely disappeared along with the FL, ARL and B1 n°101-based B1 Ter prototype when their ship was sunk by German aviation in the estuary of the French river Gironde in June 1940.
Nonetheless, the B40 remains a significant member of the Char de Bataille family. It is effectively the link between the pre-war designs formed by the B1, B1 Bis and B1 Ter, and their final evolution, the ARL 44 of the first post-war years, France’s first new tank, still studied under the lead of the same Lavirotte who led work on the B1 Ter and B40.
The mock-up of the ARL 44, presented in mid-1945. Work on the vehicle would have been impossible was it not for what had already been achieved on the B40 project. Source: RedditThe first form of the B40, armed with the 47 mm SA 37, hypothetical reconstruction.The second form of the B40, armed with a 75 mm gun in a turret, hypothetical reconstruction Both illustrations created by Pavel “Carpaticus” Alexe.
B40 specifications (original project)
Weight
40 to 42 tonnes
Engine
Talbot 500 hp turbo compressed engine
Transmission
6 forward + 6 reverse
Track width
60cm
Crew
5 (Commander, gunner, driver/hull gunner, loader for both pieces, radioman)
Main armament
75 mm SA 35 infantry support gun; 47 RF mle 1934 anti-tank gun
Secondary armament
Very likely coaxial MAC 31E 7.5 mm machine gun
Hull armor
80 mm (front and sides)
60 mm (rear)
40 mm (floor, suspension protection)
30 mm (roof)
Turret armor
Unknown, but likely same layout as the hull
Fuel tanks
1,500 liters
Sources
Char d’assaut & Blindés n°13 to 15, Lavirotte, 1967
GBM n°111, January-February-March 2015, “Les derniers Chars B”, Stéphane Ferrard, pp 83-96, Histoire & Collections editions
Notice provisoire sur les matériels de 47 et de 37 de casemate mle 1934 du 4 mars 1939 via Wikimaginot
Trackstory n°13: Le Char B1, Editions du Barbotin, Pascal Danjou Wikimaginot
An hypothetical view of what a B1 Ter may have looked like in service, circa 1941
France (1935-1942)
Heavy Infantry Tank – 1 Mock-up Prototype Complete, 3 Incomplete Pre-production Prototypes
In the early 1920s, France launched a program for the development of a “Char de Bataille” (ENG: Battle Tank). This tank would learn from the lessons of the First World War and provide a powerful machine able to break through enemy defensive lines, while being more reasonable and affordable than the gigantic FCM 2C. This would be the start of an extremely long development process, of which the first result to reach production, the B1, would only enter production in 1935, with the first production tank only delivered in December of that year. After just a battalion’s worth of B1s were manufactured (32 production vehicles, plus two of the three prototypes being converted to production standard), production switched to a more advanced model, the B1 Bis.
The key improvement brought by the B1 Bis was increasing the B1’s armor. The original model was “only” protected by 40 mm, which would still leave it vulnerable to a variety of anti-tank guns. Firepower was also increased by mounting a more powerful turret armament. As it presented itself, the B1 Bis was a long and somewhat narrow heavy tank. It featured a 75 mm gun mounted on the right side of the hull, without lateral traverse, intended to target fortifications and entrenched positions. Anti-tank protection was assured by a turret-mounted 47 mm SA 35 anti-tank gun. The vehicle benefited from a maximum of 60 mm of armor. This was a considerable improvement from the 40 mm found on the B1, but was still not absolutely impenetrable. French tank designers generally compared the armor protection of their armored vehicles with the penetration capacities of their own anti-tank gun. The 1930s had seen the adoption of some very powerful 47 mm anti-tank guns which could have reasonably penetrated the B1 Bis. Such guns were the model 1934 APX fortification anti-tank gun, and the future SA 37 field anti-tank gun. These guns were very powerful for the time – likely the most powerful medium-caliber anti-tank guns to be found in service anywhere in the late 1930s, in fact – but it remained likely foreign production would likely start to compare to these in the following years. Up-armoring the B1 Bis to face these threats more effectively was a necessity in order to keep its assaulting capacities intact, and this could also serve as an occasion to solve some problems of the tank, such as its lack of hull gun lateral traverse.
The under-budgeted birth of the B1 Ter
There had, in the past, already been some projects for heavier variants of the Char B. There had been a B2 project dating back to the early 1930s, which would have been a 35-ton vehicle, but have retained an armor protection of merely 40 mm. Though seemingly still ongoing at the time, this project would not have taken much of the B1 Bis and would have mostly been a different vehicle, even if up-armored. Instead of introducing a whole new tank, producing an improved model of the already improved B1 Bis was seen as the preferable alternative.
There was still skepticism surrounding up-armoring the B1 Bis though. The tank was already an incredibly complex machine and its production had some major complications. This was in large part due to the old industrial diplomacy agreements called the “Accord Estienne”. These were signed back in the 1920s and were coming to haunt the tank’s production, as all the companies involved in the old Char de Bataille program had their right to be deeply involved in the resulting vehicle’s production and have their own assembly chain. For these reasons, the mass-production of the B1 Bis or one of its evolutions was seen as hazardous in time of war, and its old rival, the D2, was still coming back to offer a competition or alternative to the B1. Many in the French army’s CCA (Conseil Consultatif de l’Armement – ENG: Armament Consultative Council) preferred to consider an up-armored and upgraded variant of the D2 instead. Nonetheless, in April of 1935, the council agreed to launch the study of an improved variant of the B1 which would feature 75 mm of armored protection. Studies on the B2 continued at that time, but it quickly appeared this would not be going anywhere – by December of 1935, the council cancelled all work on the B2.
The project of the B1 Ter was centered around the design bureau of ARL (Arsenal de Rueil), under the lead of engineer Lavirotte. Lavirotte appears to have started work on a parallel version of the B1 Bis as early as 1935 – notably wanting to try and reduce the tank’s dependency to the advanced but complex and expensive Naeder steering system which was used to precisely aim the 75 mm hull gun.
The first prototype/mockup: Recycling the first B1 prototype
A prototype of the B1 Ter was “manufactured” in 1937 in order to test the variety of technical solutions considered for the improved model of the B1 Bis. However, due to a lack of budget, this would not be an entirely new vehicle. Instead, the hull of B1 n°101 – the first B1 prototype that had been manufactured by Renault all the way back in 1929 – was used. The difference between a now more than half-a-decade old prototype and the features of a contemporary B1 series tank were tremendous. As such, a huge quantity of new components were added to the tank. In general, what remained of the original prototype was little more than the body and a few of the basic elements of the n°101, such as the drive sprockets, with the vast majority of other components being newly built and added to the vehicle. Nonetheless, the use of an older hull still made deep structural changes a struggle, and this prototype would still be massively different from a production B1 Ter. As such, it would be best described as somewhere between a true prototype and a mockup proof-of-concept.
A view of the first B1 Ter prototype, likely in Rueil. As can be seen, the vehicle differed significantly from the previous B1 Bis. However, unlike what many may imagine, the production B1 Ter would have looked vastly different. Source: World of Tanks forums
Changes to the hull
The hull of B1 n°101 underwent a very large number of changes to create the B1 Ter prototype. First, the 40 mm plates were up-armored to 60 mm, identical to the B1 Bis, but not at the 75 mm level desired for the Ter. The vehicle also received weights to raise its mass to 33 tons ( B1 n°101 appears to have weighed around 25.5 tons originally).
The hull was given the powerplant of a B1 Bis, in the form of a Renault 6-cylinders 16,625 cm3, 307 hp at 1,900 rpm petrol engine. This engine was coupled to a new ARL-designed gearbox. This was a smaller gearbox design, 22 cm shorter than on the B1 Bis, designed to slightly improve the internal space allocated to the crew. This new gearbox also had new differentials, with notably the change from first to second gear which had to be accomplished at a slightly higher speed.
The drivetrain also underwent some changes. The B1 Ter prototype would retain the 50 cm-wide tracks of the B1 Bis, but its suspension was reinforced in order to accommodate the heavier weight which would be associated with the up-armored model. The suspension’s attachment to the hull was also different. On the B1 Bis, the suspension arms were attached to a series of different plates. These were changed for a single unified plate on the B1 Ter. The vehicle also adapted a single unified lubrication system for maintenance, instead of a variety of different ports, simplifying the maintenance work.
Most significantly, the hull sides received a new armored superstructure. The specified 75 mm of armor to be found on the B1 Ter applied not only to the front, but to the sides as well. ARL’s engineers decided to study a solution in order to use plates slightly thinner than those specified 75 mm to provide equivalent protection. This would be performed by using 70 mm plates folded at the center, which would give them an angle of 25°. This folded side armor is the easiest element allowing the differentiation of the B1 Ter in comparison to another vehicle of the B1 series. It ought to be noted that the first prototype only had 40 mm thick versions of these plates. The adoption of this peculiar side armor required some significant changes. The side grills of the vehicle’s radiator were brought to the top of the hull. These grills were occasionally brought up as a weakness of the B1 Bis during the 1940 campaign, which remains questionable, but would have been solved by the B1 Ter. More clearly and significantly, this gave the vehicle much better fording capacities, going from 1.30 to 1.80 m. A new side door also had to be designed. Compared to the original laterally-opening door, the B1 Ter instead went with a vertically opening “drawbridge”-type door on the vehicle’s right. This door option appears to have been subpar in comparison to the solution found on the B1 and B1 Bis, in which the armored door would provide cover to the crew during evacuation, and would generally be more practical. However, with the diamond-shaped side plates of the B1 Ter, such an option would in no way be practical. The tunnel-type mudguards of the top of the B1 Ter’s hull also benefited from 40 mm of armored protection.
A side photo of the B1 Ter prototype during trials, showing the downward-opening side door adopted on the design. It was a much less practical design than found on the previous B1 Bis and B1. Source: Tank Archives
A number of changes were applied to the vehicle’s hull constructions in order, once again, to improve production. Most significantly, it appears ARL’s engineers opted to reduce the bolting method, which was widely used on the B1 Bis’s hull, to a minimum, and instead switch to welded construction as much as possible. The floor of the vehicle was 20 mm thick and now entirely welded in order to reduce the threat of mines. Bolts were used to link it to the drivetrain. This switch to welded construction was generally viewed as positive, as it would improve the hull’s rigidity, protection from mines, and would eventually be quicker and cheaper than mass use of bolting.
At last, the prototype received an APX 4 turret, the same as found on the B1 Bis. This was in no way a definitive turret to be mounted on the B1 Ter, and was mostly used here for the sake of experimentation and functionality.
New 75 mm mount
One of the more complex features found on the B1 Ter prototype was the new gun mount. As said previously, Lavirotte and ARL’s engineers had been studying a way to make the B1 Bis less reliant on its Naeder steering system for a while, and the most obvious solution was to give some form of lateral traverse to the hull gun. This was performed by adding two lateral trunnions, allowing for the lateral traverse of the gun, in addition to the already existing vertical ones. The resulting traverse would be of 10° in theory, but only 9° in practice. These were 5° to the right, but only 4° to the left, as the dimensions of the hull’s crew compartment did not allow the gun to traverse the last degree.
The new 75mm gun mount as well as the associated armor plate. While the introduction of lateral traverse was a welcome change, this temporary newly-designed mount would considerably hinder the driver’s vision to the right. Source: Tank Archives.
The front plate that mounted this gun was vastly modified, and was much less integrated into the overall shape of the hull than on the B1 Bis. This resulted in it being a lot higher. As such, it reduced the driver’s field of view to the right on the B1 Ter prototype – a major issue which was quickly identified and planned to be fixed on further studies of the B1 Ter. The front plates around the gun had the same thickness as the rest of the hull front, at 60 mm.
The prototype enters trials
The B1 n°101-based prototype entered trials following its completion in 1937. In the following months, a variety of different trials would be performed, though these would generally not be satisfactory.
The vehicle’s first road journey, from ARL’s facilities in Rueil to the French army’s testing facilities in Satory, resulted in issues with the cooling system which would forcibly stop the vehicle. At Satory, the vehicle was presented to the at-the-time War Minister, future Président du Conseil (ENG: Council President – The leader of French governments under the 3rd and 4th Republic, with a role roughly similar to a British PM) Edouard Daladier. Though it appears this first presentation may have been when orders for pre-production B1 Ter prototypes were secured, the B1 Ter prototype would continue going through a variety of trials in the following months – which would generally not be glorious for the new heavy tank.
In December 1937, a 200-km long trip from Rueil to Bourges was planned, in three different steps. During the first step, the vehicle suffered oil and water leakages, as well as to the exhaust collection system. During the second step, starting up the vehicle proved difficult, while the exhaust collection had to be replaced. Finally, during the third step, the same exhaust collection system deteriorated again. The vehicle had suffered a number of breakdowns which required replacement of parts and emergency repairs during the trip, and had overall proved to be very unreliable.
At Bourges, the vehicle underwent firing trials. A hundred 75 mm shots were fired before the gun mount was dismounted for examination and tweakings.
Further trials in 1938 were once again met with difficulties. Intensive trials started in April of 1938 with the goal of determining whether the vehicle would be worth adopting or not by late May. During those, the prototype once again performed terribly. The air and oil cooling proved poor, with both reaching worryingly high temperatures at various points. The exhaust collection system was once again deteriorated. Starting up the engine was also difficult. The trial commission’s report on this B1 Ter prototype ended up very critical. The vehicle was found not only unable to solve most issues of the B1 and B1 Bis, but also to create several of its own. Notably, it had lackluster cooling and braking systems, problems with the exhaust collection, but also fragility of the new gearbox and drivetrain, which, despite being reinforced, struggled with the heavier weight. The commission’s report ended in a very dry comment:
“Dans ces conditions, la commission émet les avis suivants:
Le char B1 Ter présente peu d’intérêt dans son état présent;
Sa fabrication ne peut être envisagée actuellement, même à assez longue échéance”
In these conditions, the commission emits the following opinion:
The B1 Ter tank offers little interest in its current state
Its production cannot currently be considered, even at relatively long term.
Saved from the brink of cancellation
Luckily for the B1 Ter, the report of the trials commission did not end up in the tank being cancelled. A series of different reasons can be found that allowed the ARL tank to survive its terrible trials.
The first can be found in the very nature of the B1 Ter prototype. Based on the hull of the very old n°101, it could in no way, shape of form conform to what a more mature version of the design would have been like, and remained little more than a demonstrator or mule for experimentation of different systems which would be mounted into more mature B1 Ter prototypes.
In order to provide more mature B1 Ter prototypes, three different pre-production prototypes were ordered from three different manufacturers: one from ARL, one from Fives-Liles (FL) and one from FCM. When exactly this order was passed is unclear, but it appears to potentially have been as early as the B1 Ter being presented to Daladier in 1937.
A number of additional factors made the need for a more heavily armored version of the B1 Bis apparent at this time. This meant that, even if the B1 Ter was far from being ready for production, continuing to study it would be a worthy endeavour. Notably, the adoption and beginning of mass-production of the 47 mm SA 37 gun for the French army, demonstrated that field anti-tank guns powerful enough to defeat a B1 Bis could be somewhat commonplace in militaries fairly soon.
Two crewmen in front of the B1 Ter prototype during trials in 1939, showing the diamond-shape folded side armor plates as well as the general structure of the vehicle. Source: Tank Archives
Trials of the B1 Ter thus continued beyond May of 1938, with the prototype undergoing further trials. In June, it even received additional weights, as it was found that a mature B1 Ter would likely weigh more than 33 tonnes, and went through mobility trials with these, with, unsurprisingly, poor results. The suspension was not strong enough, with the coils of the tender wheels’ suspension arms breaking. After running for 35 km, the gearbox was damaged. As a result of these trials, a number of additional modifications were performed, and the prototype slowly but steadily became more reliable. Towards the end of its trials service in the autumn of 1939, 500 km were run without failures of the gearbox, for example. The B1 Ter prototype was finally returned to ARL in early 1940, after running through 2,038 km in a variety of trials. Though imperfect, it had vastly improved in terms of reliability. By this point though, a whole new generation of B1 Ter prototypes was on the way.
The pre-production prototypes
As said previously, the first B1 Ter prototype was more of a mish-mash of the very old hull of the B1 n°101 with a variety of modern components, with no newly-built prototype made at first due to lack of funds. However, it was obvious that such a solution would not translate the actual capacities of the B1 Ter design as accurately as a prototype made to resemble a production standard. Even then, manufacturing just one prototype was judged as insufficient. For a vehicle as complex as the B1 Ter, it would be preferable to have several, simplifying trials and experimentation. As such, three prototypes were ordered, each from a different manufacturer: one from the original designer, ARL, one from FL, and one from FCM.
This photo is a particularly interesting iconographic document. While it looks different from the first B1 Ter prototype, it does not represent one of the pre-production vehicles. This actually is a retouched version of a photo of the B1 n°101-based prototype. This retouching is not a recent photoshop, but one which was performed at the time to give an idea of what the gun mounting on the B1 Ter would have looked like before the pre-production vehicles were completed. Source: Tank ArchivesAnother retouched and simplified photo of B1 n°101, attempting to show the new, lowered mounting for the hull 75 mm gun. Source: Tank Archives
All prototypes incorporated the same changes from the original B1 Ter, though some would also differ in their own way. All would notably feature a vastly redesigned hull gun mount which would enable much more visibility for the driver. The top-mounted grills for the radiator would obviously be retained on all vehicles. All vehicles would have a similar driving position designed by ARL, made of three 70 mm-thick plates of laminated steel. This was a very square-shaped driving position. To the front, it featured a coverable vision port twice as large as that on the B1 Bis. The shutter featured a PPL episcope which would provide a field of view of +5 to -22° vertically, and 34° on each side horizontally. A backup vision port could be found behind the episcope in case it was disabled. On the driving position’s side, similar PPL episcopes could be found, but had somewhat reduced fields of view due to their position. The left one had an identical field of view with the exception of only going down to -18° vertically. The right one was more limited due to the presence of the gun mount, though it had nonetheless been vastly reduced in size. Its field of view was +5 to -10° vertically and 22.5° on each side horizontally. A panoramic periscope was present on the driving position’s roof.
In terms of powerplant, all three prototypes would be given the same engine as the B1 Bis and the B1 Ter first prototype at first. However, more powerful engines were at prototype stage by 1940 and were considered to be refitted later. These would either be a 350 hp, 6-cylinders 155×165 Renault engine, or a 400 hp, 12-cylinders, 130×130 Renault engine. Two prototypes of the first and three of the latter were in construction by June of 1940, with one of each on test benches.
The tank’s drivetrain was also to undergo some considerable changes. Dampeners were added between the coil springs. A rubber block was added to further dampen the tensioning wheel’s coils.
When it came to turrets, the FCM prototype would receive one of their own design, while the ARL and FL would receive the ARL 2 welded turret. Similar to the one found on the S40, this up-armored version would offer the same 70 mm of protection as the rest of the vehicle, with the angled roof being 40 mm thick. It would be present on a larger, 1,218 mm turret ring, in comparison to 1,022 mm for the APX 4; however, it was still a one-man turret. The turret’s large cupola featured three PPL episcopes which would highly improve the commander’s vision in comparison to the APX-4. 67 47mm shells were to be found, 7 within the turret and 60 within the hull. The hull 75 mm gun would be provisioned by 90 75 mm shells, while 30 150-rounds 7.5 mm magazines were to be found for the coaxial MAC 31 machine-gun. The tank would retain the ER 51 model 1938 radio. It ought to be noted that the FL and ARL prototypes may perhaps still have retained the APX 4 turret, though this appears unlikely.
The welded ARL 2C turret, the lighter version of the ARL 2, which was to be mounted in the S40. The ARL 2 would have had the same layout, but with an armor thickness similar to the rest of the B1 Ter. Source: war-thunder forums
Overall, the pre-production B1 Ters were to weigh in at 36,600 kg, giving them a power-to-weight ratio of 8.19 hp/ton. The fuel tanks were slightly enlarged, going from 400 litres on the B1 Bis to 500 on the B1 Ter, which would further the range from 160 to 180 km on average.
The Fives-Lilles prototype: the most obscure one
One of the three prototypes was to be manufactured by Fives-Lilles, in a suburb of the large French city of Lille. Far in Northern France, close to the Belgian border, this location would become highly vulnerable in case of a German invasion going through Belgium and North-Eastern France – exactly what happened. By the point of the German invasion in May of 1940, the prototype appears to have been somewhere on the assembly chain, and swiftly evacuated. It was sent to ARL’s facilities in Rueil, in Paris’s suburbs, with hopes of continuing work on the prototype with FL engineers, but on ARL’s assembly lines and its facilities. From late May onward, the FL prototype shared the same fate as ARL’s.
The ARL prototype: the most documented one
The ARL prototype is by far the most documented of the three pre-production vehicles, as well as the one that was the closest to completion. Two photos taken of the vehicle’s hull during manufacturing give us the best view known of what a pre-production or production B1 Ter hull would have looked like, with the new gun mount, driver’s post, enlarged turret ring, and top-mounted radiator grills.
Often referred to as a photo of the B40, this is actually the ARL B1 Ter hull during manufacturing – with no B40 ever being close to prototype status. This photo shows the hull front has little to nothing to do with the B1 n°101-based prototype, with redesigned driver’s position and gun mount. The turret ring is wider than on the previous B1-series vehicle, and the radiator grills at the rear-right of the vehicle can be clearly seen. Source: Tank ArchivesA rear view of the same hull during construction. It notably shows the very thick tunnel-like mudguards as well as 70 mm-thick folded steel side plates. Source: Tank Archives
The ARL B1 Ter appears to have been fully completed and trialed on the trial grounds for tanks in Rueil. The vehicle was only able to run for about 10 hours before the course of the French campaign forced the hand of fate. These trials were at some point interrupted by issues with the Naeder system and changing gears. Those were quickly fixed, and after these, the vehicle appears to have run fairly well and to have behaved quite well on road. With its 300 hp engine, it was only planned to reach a maximum speed of merely 26.5 km/h. The limited lengths of these trials remain insufficient to identify whether the changes applied from the first B1 Ter prototype would have made the pre-production prototypes sufficiently reliable in practice though.
In late May of 1940, with German forces approaching ever closer to Paris, the three vehicles present at ARL’s facilities – the ARL and FL pre-production vehicles, as well as the original, n°101-based prototype – were evacuated to the harbor of Saint-Nazaire, on the estuary of the river Loire and the western coast of France. Trials were to be continued there. A variety of futures for the B1 Ter appear to have been pondered there, for example sending the vehicles to the United States to set up production there if France was to continue the war. Eventually, on the 17th of June 1940, all three vehicles were loaded onto a ship, the Mécanicien Principal Carvin, a cargo ship on its way to French North Africa, also carrying either one or two 380 mm guns for the battleship Jean Bart as well as two of her propellers. German bombers sunk the ship on the estuary of the Gironde river, way before it could hope to reach Africa. The transport sank in the estuary mud, where it remains to this day – carrying in its hold three of the four B1-ter-related vehicles ever manufactured.
The FCM prototype: The surviving one
Not all B1 Ter tanks ended up in the Gironde’s estuary though, for one was never loaded on the transport ship to be expedited to French North Africa.
The third pre-production prototype was indeed to be manufactured by FCM, in its facilities of La-Seyne-Sur-Mer, on France’s Southern Mediterannean coast – way further south than German Panzers ever reached in 1940.
The FCM prototype was also different from the two others in one major element: the turret. FCM had indeed been designing a welded turret for a while by 1940, and had been given the right to outfit its B1 Ter with a turret design of its own. This turret would have been similar to the ARL 2 in terms of overall structure but remained different. Notably, while the ARL turret would still use cast turret masks, the FCM turret would likely have been entirely welded. While no view of the FCM B1 Ter nor its turret appear to have survived, FCM experimentally mounted a welded turret on a B1 Bis, n°234 “Marseille”, in 1938, and the turret found on the B1 Ter would likely have had a similar design.
The only known photo of B1 Bis n°234 “Marseille” with its welded turret, likely taken in Nancy. A similar turret would likely have been featured on FCM’s B1 Ter pre-production vehicle. Colorized by Jaycee “Amazing Ace” Davis. Source: char-français
By June of 1940, the FCM B1 Ter appears to have been in the early stages of assembly. At the time of the armistice, FCM’s facilities ended up in the unoccupied part of France, entirely under the rule of the Vichy regime. However, with studies on further armored vehicles restricted, there was seemingly no further work performed on the B1 Ter. Lavirotte is known to have continued operations during the occupation, working on some covert projects such as the SARL 42. It has been theorized he and his team may have used the B1 Ter as a reserve of spare parts or for some experimentation, but there has never been any evidence of this.
When German and Italian forces entirely occupied Southern France in November of 1942, FCM’s facilities ended up in Italian hands. An Italian report from June of 1943 mentions, alongside a small number of B1 Bis in various stages of completion, the presence of a “36-tons prototype tank” in FCM’s facilities. This was likely the FCM B1 Ter pre-production vehicle. This report is also the last evidence of it being in existence. The report requested the vehicle to be moved to Genoa, Italy, to the Ansaldo Fossati factory, in order to be studied there. This does not appear to have been performed before Italy signed an armistice and was then occupied by Germany in September of 1943.
What would a production B1 Ter have been like?
The B1 Ter never reached production status, its development and manufacturing process interrupted by the German invasion of France in the spring of 1940. By 1939, it had been agreed that the type would succeed the B1 Bis on the assembly lines after the 715th example was produced. This ended up being pushed back to the 1,133rd example produced, which was scheduled for March of 1941 (though actual production was always late in comparison to the schedules, meaning the actual date would likely have been a couple of months later.)
Had it entered service, the B1 Ter would have been a 36-tons tank, fitted with a 350 or 400 hp engine. The comparison between it and its previous B1 model is mostly positive. The B1 Ter would have featured better armor protection, gun traverse, and with the more powerful engines, would have been similar mobility-wise, while featuring better vision than the B1 Bis.
In practice though, the B1 Ter failed to attend to many of the core issues of the B1 Bis, which would be much harder to solve. Most notably, the crew overtasking that plagued the previous tanks was still the same. The commander in the turret would still operate the 47 mm entirely on his own, in addition to commanding the rest of the crew, the 75 mm and its targets, and making tactical decisions for the tank. The driver would also still have been the gunner for the 75 mm gun, requiring additional training and vastly complicating his task. The presence of better-designed episcopes may have given both of these crewmen an easier time when looking outside of the vehicle, identifying targets or simply driving, but this remained only a detail, a drop of water taken out of the ocean of crew-tasking issues found in the vehicles.
The armament remained the same as on the B1 Bis, but by 1941, its capacities would be starting to become more and more subpar. The 47 mm SA 35, notably, while it was a powerful gun by 1940, would be less and less relevant against up-armored versions of German vehicles, with an armor penetration of 40 mm at an incidence of 30° and a range of 400 m. The tank’s armor protection would be an improvement from the B1 Bis, but remained vulnerable to German 88 mm and 105 mm guns. It would likely be a tough nut to crack even for the new 50 mm Pak 38 though.
Lastly, the B1 Ter would remain an overly complex and expensive design. In this regard, it may actually have proven somewhat easier to mass-produce than the B1 Bis, thanks to the wider use of welding – but this did not prevent the vehicle from making use of a variety of different complex systems, the Naeder notably, and two entirely different guns. In comparison, the G1R, which would likely be at prototype stage by this point, would offer a much more attractive alternative, notably thanks to its turreted 75 mm gun.
Conclusion – At the bottom or at the scrapyard
The B1 Ter remains a somewhat obscure vehicle. Its plans have not survived the war, and as such, the information about it remains limited to whatever information its engineer, notably Lavirotte, left, alongside the few photos of the vehicle – much more numerous for the n°101-based demonstrator than the actual pre-production vehicles.
The fate of the FCM prototype is unknown, but it has not survived to this day. The vehicle very likely ended up scrapped, though it is unknown if this was done by the Germans after they occupied the formerly Italian-occupied French territories in September of 1943, or by the French after the end of the war. As for the three other vehicles, they remain, to this day, in a sunken ship somewhere in the Gironde estuary. Though the position of the ship is known, it rests in an area full of currents making exploration dives hard to perform – though some have been attempted in the past few years. A successful one likely remains the only way the quantity of information available on the B1 Ter could be expanded – but it remains uncertain whether or not that will ever happen.
The first prototype of the B1 Ter, based on the hull of old B1 N°101.A view of what the ARL B1 Ter prototype, with a redesigned hull front and ARL 2C turret, may have looked likeAn hypothetical view of the FCM B1 Ter, with the turret based on the one found on B1 Bis “Marseille”An hypothetical view of what a B1 Ter may have looked like in service, circa 1941A similarly hypothetical view of a FCM B1 Ter in service. All illustrations created by Pavel “Carpaticus” Alexe
B1 Ter specifications (Pre-Production model)
Dimensions (L-H-W)
6.37 x 2.73 x 2.86 m
Weight
36,600 kg
Engine
Renault 6-cylinders 16,625 cm3, 307 hp at 1,900 rpm petrol
Perhaps the most famous B1 Bis, Pierre Billotte's B1 Bis n°337 "Eure", 41ème BCC, 3ème DcR, 1940
France (1935-1940)
Heavy Infantry Tank – ~369 Built
The B1 Bis is arguably the most famous and popular French tank of the 1940 campaign. A very notable design, featuring thick armor and a combination of anti-tank and anti-infantry firepower with the turreted 47 mm and hull-mounted 75 mm guns, the vehicle has a considerable reputation as the most potent vehicle of the French Army of 1940 and a major headache for the Germans. However, as often with the French military of 1940, the reality is more complex and less glamorous, with the B1 Bis proving to be a troublesome beast to operate, maintain and produce.
B1 Bis “Chambertin” of the 3ème DcR, France, May 1940. Source: EPCA D
Early 1930s: toying with a heavier Char B
A major program of French armor through both the 1920 and 1930s was the Char de Bataille. From four prototypes presented in 1924 – the Char de Bataille FAMH, FCM, SRA and SRB, the Char de Bataille program evolved towards the B1, of which the first prototype, mild steel n°101, was completed by Renault in 1929.
At the time, the B1 was a 25.5 tonnes vehicle with a hull-mounted 75 mm and two turret-mounted machine-guns, and envisioned to have 40 mm of maximum armor Though this was already considerable for the time (and during the development of the B1, the Geneva Conference, which discussed banning tanks over 20 tons, was a major hustle to overcome), a program calling for an even heavier tank was formulated in October of 1930. Three different designs were presented at paper or mock-up stage: the B2 (35 tonnes, 40 mm of armor), B3 (45 tonnes, 50 mm of armor) and BB (50 tonnes, 60 mm of armor). Though studies on those concepts were continued until 1935, none would end up being adopted, or even have a prototype be ordered.
A mock-up of the very odd Char BB. Designed by FCM, this design was to feature two hull-mounted 75 mm guns frontally, and two turrets armed with a 7.5 mm MAC 31 on the top of the hull. Source: Tous les blindés de l’armée française 1914-1940 via Rita status report.
While further studies of those vehicles had been abandoned by 1935, the B1 itself had progressed considerably in the meantime. Now reaching 27 tonnes and with a new APX 1 turret armed with both a 47 mm gun and a 7.5 mm machine gun having replaced the twin machine gun Schneider turret, the tank was in the process of entering production. However, its armor protection of 40 mm was now proving to be weaker than expected for a breakthrough tank. French designers typically compared the protection of their tanks to what French anti-tank gun designs of the time could penetrate to evaluate the protection, and the B1 proved very vulnerable to new anti-tank ordnance by 1934. In that year, France had adopted both the Hotchkiss 25 mm SA 34 field anti-tank gun and the APX 47 mm AC mle 1934 fortification anti-tank gun. The APX design would have little trouble penetrating the B1 even at considerable ranges, and even the light 25 mm Hotchkiss could have been able to go through the 40 mm of armor. A solution was needed quite urgently to upgrade the B1’s armor to the standards which would have been required to survive the modern battlefield.
Up-armoring the B1
The B1 N°101 prototype being trialed with a number of additional weights, such as an FCM 36 turret, in order to test the capacities of a heavier B1, 1935. Source: char-français
The solution which emerged would prove to be very straight-forward: it would simply be to thicken the B1’s armor protection. As early as 1935, tests of higher weight loads were performed on B1 n°101, the first mild steel prototype, which had become somewhat of a “mule” to experiment on. After finding out that the B1 was still viable with a higher weight load, thicker plates were added to the design. The front hull went from 40 to 60 mm of thickness, with this upgrade requiring some changes, notably, the upper front plate had to be angled differently, at 45° instead of 57° on the B1. The sides were up-armored to 55 mm, the rear was 50 mm thick, and the engine deck 25 mm.
In order to keep the tank’s mobility decent, a more powerful version of the engine used on the B1 had to be adopted. Though the engine design was the same overall, it was boosted to produce up to 307 hp instead of 272. The first order for 35 B1 bis did still use the older B1 engine though, and was later given a retrofit kit to upgrade their engines.
The turret was another major difference between the B1 and the B1 Bis. While the B1 used the APX 1, the B1 Bis had the APX 4. While largely based on the APX 1, the APX 4 was, notably, up-armored to 56 mm on all sides, from 40 mm on the original design. The cupola was uparmored to 48 mm, and the roof to 30 mm. This turret’s main armament was the new 47mm SA 35, which offered a higher muzzle velocity and far better anti-tank performances in comparison to the B1’s SA 34. The APX 4 also featured different vision slots on the sides of the turret.
A number of other changes were also made from the experience gathered with the B1. The large towing hook mounted to tow the Schneider supply trailers on the B1 was removed from the B1 Bis, which used a much smaller hook design. The idler wheel’s placement was seemingly changed by a few centimeters, being slightly lower and further back. All these changes to the B1 led to the weight rising by about 4 tonnes, reaching 31.5 tonnes on the B1 Bis.
Orders and beginning of production
The design process of the B1 Bis was straightforward, and a first order of 35 vehicles was placed in October of 1936. This would be enough to equip a battalion with B1 Bis. The B1 Bis was to be manufactured by a large number of different entities. As stipulated by the Estienne Agreements all the way back in the early 1920s, all manufacturers involved in the development of the Char de Bataille, which was supposed to be a common effort not affiliated to a single company, would receive orders to produce the vehicle. This meant that the four companies involved in the Char de Bataille – Renault, Schneider, FCM and FAMH/Saint-Chamond – would all be producing the B1 Bis. In addition to those, the newly formed state-owned armor producer of AMX, formed by the nationalization of Renault’s design bureau, would receive orders for the tank as well, bringing the number of B1 Bis manufacturers to five. The first B1 Bis to be completed, n°201 “France”, would come out of Renault’s facilities in February of 1937 (several months before the last B1 was completed by FCM in July of the same year).
Design
Hull
The B1 Bis’ hull was largely retained from the B1 with a few notable changes. It was a quite narrow and elongated design, as a result of being designed with crossing capacities, particularly trenches, in mind. The vehicle had a length of 6.35 m. The tank was 2.58 m wide, 2.79 m high including the turret, and had a ground clearance of 0.48 m. The tank was 8 cm wider than the B1, as a result of thicker side armor and wider tracks. While of similar design, the tracks used on the B1 Bis were 500 mm wide instead of 460 mm.
The B1 Bis’ hull front was composed of 60 mm bolted steel plates. Below the driver’s post and around the center of the gun mount, it was angled at about 42°. The driver’s post itself was angled at around 20°. The plate over the gun mount was angled at around 60° backward. The lower plates were angled at about 48° on the side of the driver’s post and 32° on the side of the gun mount. The most notable feature of the hull front, outside of the 75 mm gun, was the driver’s post. Placed to the vehicle’s left, it was a large armored box which stuck out of the general shape of the hull. This post featured a number of vision devices: two L.710 sights for the 75 mm SA 35 gun, an adjustable slit fitted with a PPL RX 160 episcope at the front, and two vision slits at the sides. The armor plates were 55 mm thick on the sides and 50 mm thick at the rear.
The B1 Bis’ driver post, seen from the right. Source: Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
The hull also featured the B1 Bis radio. Able of both receiving and transmitting, it was at first a morse key-only ER 53, but was replaced through production by a far more modern ER 51, able of morse communication at up to 10 km and voice communications at 2-3 km. A crewman was tasked with operating this radio and was also tasked with handing 47 mm shells from the hull racks to the commander.
A view of the B1 Bis’ hull arrangement. Source: char-français
This radio was installed on the crew compartment side of the bulkhead which separated it from the engine compartment. A particularly interesting feature of the B1 and B1 Bis is that a door existed to enter this engine compartment. It led to a small corridor on the right side of the vehicle, which allowed access to the engine, and even the transmission and Naeder steering system, all the way at the back of the hull. The engine used was an upgraded version of the one fitted to the B1, of which the roots go all the way back to the SRA and SRB prototypes of 1924. It produced 307 hp (at 1,900 rpm) and was a 6-cylinder, 140×180 mm, 16,625 cm3, water-cooled petrol engine. The B1’s transmission had 5 forward and 1 reverse speed. The 31,500 kg B1 Bis was slower than the lighter B1, with 25 km/h instead of 28 km/h. The 400 litres fuel tanks arrangement was maintained, which meant that the range was reduced due to the upgraded engine having a higher consumption. Fuel capacity limited the B1 Bis to 6 to 8 hours of autonomy, in comparison to 8 to 10 on the B1. The maximum range of the B1 Bis was of around 160 km, in comparison to 200 km for the B1.
Hull gun: The 75 mm SA 35
The gun mounted on the B1 Bis’ hull was a 75 mm short gun mounted on the right side of the hull, in a mount that allowed an elevation of -15° to +25° degrees, but no lateral traverse. This was unchanged from the B1. The gun was a 75 mm modèle 1929 ABS gun, also sometimes known as the 75 mm SA 35. This gun was designed by the Arsenal de Bourges.
The 75 mm gun was a short design (L/17.1). The shells it fired were 75×241 mm Rimmed, based on the larger 75×350 mm shells fired by the 75 mm mle 1897, the French Army’s standard field gun in WW1 and, to an extent, also WW2.
A reproduction of the B1 Bis’s gun mount on exposition at the MM Park museum, France. Source: Theatrum Belli
Two shells were standard-issue for the 75 mm ABS. The first was the Obus de rupture Mle.1910M (ENG : Rupture Shell model 1910M), which was an armored piercing high-explosive shell. The shell had a weight of 6.4 kg, and contained 90 grams of explosives. It was fired at a muzzle velocity of 220 m/s. It offered an armor penetration of 40 mm at an incidence of 30° and a range of 400 meters. Though this was a respectable performance by the 1930s, it should be noted that this shell was designed to engage fortifications, and not tanks. The traverse-less hull mounting of the 75 mm meant it was generally a poor weapon against armor, except perhaps at close range.
The other shell was the Obus explosif modèle 1915 (ENG: Explosive Shell model 1915), a high-explosive shell. It weighed 5.55 kg, and contained 740 grams of explosive. It was fired at a muzzle velocity of 220 m/s.
Sights provided for the 75 mm gun were two L.710s, which formed prismatic binocular sights. This gave a field of view of 11.5°. Range ladders were provided for up to 1,600 m with HE and 1,560 m for APHE shells.
Two crew members were involved in the operation of the 75 mm gun. To the left of the hull, the driver also assumed the role of gunner, aiming the gun (both laterally by traversing the tank, as he controlled the Naeder traverse system, and vertically) and fire it. Behind the 75 mm gun, seemingly sitting on the floor, as no seat appears to have been provided, was the loader of the gun. The 75 mm shells carried within the hull of the B1 Bis were in slightly lower numbers than on the B1, with 74 shells instead of 80. Typically, 7 rupture/APHE and 67 high-explosive shells would be carried into battle. The theoretical rate of fire of the gun was quite high, at 15 rounds per minute, however, within the constraints of an enclosed armored vehicle with a limited crew (the driver/gunner was quite overtasked, though this was nowhere near as bad as the commander), the rate of fire would be closer to 6 rounds per minute with APHE shells and the first 6 HE shells. After that, as the fuses would have to be inserted into the shells for HE, the rate of fire would decrease to 2 to 4 rounds per minute.
The hull armament also featured a 7.5 mm MAC31E machine gun mounted to the right of the gun, in a fixed mount. The machine gun was invisible from the outside of the tank, and with absolutely no traverse, would have been a weapon of very little use, far more situational and less practical than the coaxial machine gun in the turret.
Diagram of the mount for the hull machine gun on the B1/ B1 Bis. Source: ATF40 forum
The Naeder steering system
The gun mount of the B1 Bis’ 75 mm did not allow for any lateral traverse, meaning aiming the gun horizontally was assured by rotating the hull itself. This required precise traverse to be possible. This was assured by a system called the Naeder, which had been experimented on from the SRB prototype onward.
The Naeder used the engine’s movement to either suck in or out castor oil heated to 80°C, which was used to traverse the hull with great accuracy. The Naeder system consisted of a generator, a receptor which received the movement from the steering wheel, and a distribution system for the castor oil. 23 to 35 litres of castor oil were stored within the radiator of the Naeder, and 12 within the machine itself. The system was operated by an independent steering wheel at the front, handled by the driver, which transmitted the command to the Naeder via a Brampton transmission chain.
Cut-through of the Naeder system. This is taken from the B1 Bis manual, though the machine was identical on the B1. Source: Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
The Naeder system had a weight of 400 to 450 kg, depending on the actual model, and was mounted at the rear of the engine compartment.
The Naeder was a quite complex piece of machinery, which was expensive and time-consuming to produce. 1,000 were ordered in 1935, in order to satisfy both the B1 and the B1 Bis, though only 633 would be completed by the time of the fall of France. The Naeder system was not immune to breakdowns, which could often immobilize the whole tank. At the same time, it provided a very accurate traverse for the era, and its bad reputation may have somewhat been overestimated. While, as most complicated pieces of machinery, the system was indeed vulnerable to breakdowns, it appears that the system was purposefully given a bad reputation by the Ministry of War, which wrongly put out the idea that the Naeder was only a temporary solution kept for lack of a better option in order to give the idea that it was inefficient, and not worth copying.
One of, if arguably the worst issue the Naeder had was with crew training and castor oil. The Naeder system indeed used castor oil, however, automotive castor oil was not identical to pharmaceutical castor oil, with the latter being unable to be used properly at 80°C, causing breakdowns. However, this significant difference between automotive and pharmaceutical castor oil was not mentioned at any point in the manuals of the B1 or B1 Bis. While professional crews, which had long-time experience with their machines, had usually been informed of the difference, newly-formed recruit crews were not. This resulted in many emptying drug stores of their castor oil to put into their B1 Bis during the campaign of France, only to cause the system to break down and often bring the whole tank along with it. The Naeder was also criticized for causing excessive fuel consumption, as it required the engine to be turned on in order to operate. This was particularly an issue with newly-formed crews, which were very common in the B1 Bis, as a large quantity of the vehicles produced had been delivered in the months or weeks preceding the campaign of France, and the very complex tank required some extensive training before it could be operated optimally.
Drivetrain, suspension and crossing capabilities
The B1 Bis carried on the hull architecture of the B1, and therefore, its elongated hull design and tracks going around the hull, optimised not for maximum speed, but rather all-terrain and crossing capacities. The suspensions used three large bogies mounted on coil springs, which each contained two smaller bogies with two road wheels. Three independent wheels using leaf springs were featured in front of the bogies, and another one at the rear, the purpose of which was track tensioning. A large frontal pulley also assured the track tensioning.
A view of the B1 Bis’s suspension. Two of the three large bogies are cut so as to allow all elements of the drivetrain to fit on one page. Source: Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
This suspension was entirely protected by large side skirts, designed to protect it from mud, firearms and artillery shell splinters. A large central door was featured on the B1 Bis’ right side. It had an enlarged opening radius in comparison to the B1’s, going from 90 to 150 mm. This door would also provide some moderate protection while the crews would evacuate the vehicle, being as thick as the sides of the vehicle at 55 mm, though it would not cover the evacuating personnel’s legs.
The B1 Bis used large, welded track links. There were 63 individual track links per side, with a pitch of 213 mm. These were 500 mm wide, instead of 460 on the B1. Each weighed 18.2 kg. The tank had a ground pressure of 13.9 kg/cm² on solid, horizontal soil, 3.7 kg/cm² on a terrain of medium hardness, and 0.80 kg/cm² on softer soil. The tracks went all around the hull, with large mudguards protecting them at the top of the hull.
The B1 Bis had been designed with crossing capacities in mind, and was identical to the B1 in those regards. It was able to cross a 2.75 m wide trench, or a slope of up to 30°, vertical obstacles up to 0.93 m in height, and ford 1.05 m without preparation.
The APX 4 cast turret
The B1 Bis used an APX 4 cast turret. It was directly based on the APX 1 used on the B1, but incorporated a number of changes.
Schematics of the B1 Bis’ APX 4 turret. Source: Notice du char B1 Bis
A single crewman sat in the turret, the commander. He entered the tank through the side hatch, as did the three other crew members, but the APX 4 turret featured a hatch at the back, meant to allow the removal of the gun. However, it could be opened and then serve as a seat for the commander looking over the turret. This allowed him to observe the battlefield more efficiently, as well as evacuate the tank if needed. In comparison to the APX 1, the APX 4 went up from 40 to 56 mm of armor on all sides, at an angle of 20° on the sides and rear of the turret. The observation cupola was 48 mm thick, while the roof was 30 mm. The turret ring diameter was the same, at 1,022 mm. Under electric rotation, the turret could rotate at 10° per second, and would therefore do a complete rotation in 36 seconds. When rotated by hand, either for fine adjustments or as a backup, a full rotation of the wheel would move the turret by 2.21°; a full 360° rotation would on average be performed in about 60 seconds by a trained and focused commander.
The APX 4’s vision optics can be divided into two: those present within the main turret’s body, and those present in the observation cupola. Within the turret itself were two PPL observation devices, one on each side of the turret, as well as the L.762 sights for the 47 mm gun. The observation cupola was fully rotatable independently from the turret, being rotated by hand, with a full rotation being performed in just 12 seconds on average. It included the most observation devices: a periscopic binocular providing a field of view of 8.91° and a 4x magnification and a PPL RX 160 episcope similar to the one found in the hull giving an horizontal field of view of 68°, and a vertical field of view of +2 and -22°. The last was a vision slit 120 mm wide and 10 mm high, giving a field of view of 114°, and coverable with a 24 mm thick armored shutter when not in use.
Anti-tank firepower: The 47 mm SA 35
The B1 Bis turret’s main armament was the 47 mm SA 35 L/32 main gun. Newly developed by APX, it offered far better performances than the 47 mm SA 34 used on the B1.
The 47 mm SA 35 gun used, in the APX 4 turret, a L.724 sight, with a 4x magnification, a field of view of 11.84°, and range drums of up to 1,600 m for AP shells. The reticle used was first V-shaped, later +-shaped.
A view of the 47 mm SA 35 gun used on the refitted B1 as well as B1 Bis, S35 and second-series D2. Source: http://www.dws-xip.pl/encyklopedia/brpoj47sa35-fr/
The standard issue shells for the 47 mm SA 35 were the Obus de rupture modèle 1935, and the Obus explosif modèle 1932, both 47×193 mm. At first, 50 would be carried within the tank; from n°306 to 340, the ammunition stowage would accommodate 62 shells, and from n°340 onward, 72 would be carried within the vehicle.
The Obus de Rupture modèle 1935 was an Armor Piercing Capped (APC) shell. It weighed 1.62 kg, and was fired at 660 m/s. German testing of the shell showed an armor penetration of 40 mm at an incidence of 30° and a range of 400 m. This was far superior to the penetration capacities of the SA 34.
The Obus explosif modèle 1932 was a High Explosive (HE) shell. It weighed 1.41 kg, including 142 grams of explosives, and was fired at a muzzle velocity of 590 m/s.
A view of a MAC 31E, the tank version of the MAC 31. This example is fed from the left, with both a right and left-fed existing in the French Army. Source: armesfrançaises.free
Secondary armament was provided in the form of a coaxial MAC31 Type E machine gun, the shorter, tank version of the MAC 31 which had been designed for fortification use. It used the new standard French cartridge, the 7.5×54 mm. The MAC31 Type E had a weight of 11.18 kg empty and 18.48 kg with a fully loaded 150-round drum magazine. The machine gun was gas-fed, and had a maximum cyclic rate of fire of 750 rounds per minute. It had a muzzle velocity of 775 m/s. This coaxial machine gun had independent elevation from the main gun. 4,800 7.5 mm rounds were carried within the B1 Bis prior to n°340, and 5,200 from N°340 onward.
How to differentiate a B1 from a B1 Bis
Differentiating the B1 from its later, much more common evolution, the B1 bis, can be somewhat of a hard task. When looking at photos of B1 pre-1940, the difference is particularly easy to make. The B1s feature the SA 34, a shorter gun with a recoil cylinder, while the B1 Bis feature the longer and cylinder-less SA 35. However, as the B1s were refitted with the SA 35 during the Phoney War, identifying them becomes a much harder task. However, some elements can still give it away, but they are typically quite dependent from the angle at which the tank is viewed.
The tracks on the B1 Bis were wider than on the B1, with 500 mm for the Bis and 460 mm for the base model. This, however, is typically quite hard to see. Easier to distinguish is that the mount for the 75 mm gun as well as driver’s post are a lot more distinct from the rest of the front plates in the B1 than in the B1 Bis – mostly as a consequence of the armor being thickened on the Bis model.
A photo of B1 N°111 “Dunkerque” and B1 Bis n°201 “France” (the first B1 Bis completed) at a somewhat similar angle. The gun mount and driver’s post on the B1 stick out from the rest of the hull by a few centimeters, while they are fully integrated for the B1 Bis. Source: char-français
The turrets of the B1 and B1 Bis, while mostly similar, can also be differentiated. The B1 Bis used the APX 4 turret, which mostly was the B1’s APX 1 up-armored to 60 mm, but the vision slots on the side of the turret are quite different. On the APX 1, they stick out from the turret a lot more than on the APX 4, where they appear as little more than small slots.
A view of a B1, N°105 “Strasbourg”, and a B1 Bis, N°396 “Hermitage”. The vision slots are quite different on the APX 1 and APX 4, and provided there is a decent view of the turret side, can give away a B1 from a B1 Bis. Source: char-français
Some other differences also exist, but can typically only be used to differentiate the tank from specific angles. For example, the B1 features a larger rear hook in order to tow the Schneider supply trailer, and it appears the tender wheel is very slightly lower and further back on the B1 Bis, though this is only a question of centimeters.
Slow and complex production
The first B1 Bis was completed by Renault in February 1937. It was numbered as n°201, with the 1XX numbers being taken by the B1s.
The production of the B1 Bis was sluggish, particularly in 1937 and 1938, as production was still setting up. Only 27 B1 Bis were completed in 1937, followed by just 25 in 1938. By September 1939, 84 B1 Bis had been produced in total. Production only really started to rise in 1939, with mobilization efforts seeing more resources pulled into military production. 100 B1 Bis were completed in 1939. Production still proved to be very low in comparison to the mass of tanks ordered At the beginning of the conflict, 350 B1 Bis were already ordered, and 400 more were added in September 1939. In 1940, the number of vehicles produced always remained slightly below the number expected. During one month, 27 were delivered from 41 were expected, for example. March 1940 was the most productive month in the history of B1 Bis production, with 45 examples completed from the 47 expected. Despite France beginning to fall apart in the same month, May was also very productive, with 42 vehicles completed, and overall, the production of the B1 Bis was rising at a respectable pace by the point it was brutally interrupted by German invasion, with the 27 vehicles delivered in June being the last. Overall, around 369 B1 Bis are estimated to have been delivered to the French military. Renault was by far the most productive manufacturer, with 182 B1 Bis, FCM produced 72, FAMH 70, AMX 47 and Schneider a mere 30.
A photomanipulation of Renault’s B1 production chain. Though well known, the fact that this photo is not real, but is instead a photomanipulation made by France’s propaganda services is often ignored. In practice, there was only one assembly chain for B1s in each factory. Source: Tous les blindés de l’armée française 1914-1940
Two photos of the main armor hull during assembly, still lacking most elements such as the hatches and driver post, engine and engine cover, turret, etcetera… Source: char-français
The main reason behind the B1 Bis’ slow production was the high complexity of the tank, and its use of many elements which were typically produced by one manufacturer only but had to be delivered to each of the five assembly chains. The worst offender in that regard was the Naeder steering system, though the APX 4 cast turret was also a major cause of delays.
B1 Bis n°552 on the assembly chains of Renault, June of 1940.It is the latest known B1 Bis, though other tanks bear higher numbers (the highest known being n°859). Source: Char-français
Peacetime service
Due to the sluggish aspect of B1 Bis production prior to the Second World War breaking out, only very few units were outfitted with the B1 Bis at the beginning of hostilities. The first orders for the B1 bis usually comprised 35 vehicles, as each battalion would operate 35 vehicles. The first unit to receive the B1 Bis was the 1st Battalion of 510ème Régiment de Char de Combat (ENG: Combat Tanks Regiment), which was outfitted with its tanks in a period of more than a year, from February of 1937 to March of 1938. Deliveries of the second batch of B1 Bis started in January of 1939, towards the 1st Battalion of the 508ème RCC. Those deliveries were completed in the summer, and deliveries then started towards the 2nd battalion of the 512ème RCC, which was still receiving its tanks by the outbreak of the war, as only 84 B1 Bis were completed by that point. With WW2 starting, the regiments were dissolved, with their battalions being turned into independent units to be integrated into armored divisions in the future: those being the 15ème Bataillon de Char de Combat (ENG: Combat Tank Battalion) for the 1st battalion of the 510th RCC, the 8ème BCC for the 1st battalion of the 508th RCC, and the 28ème BCC for the 2nd battalion of the 512th Regiment.
The B1 Bis’s capacities: An extremely powerful tank…
By the year it was introduced in service in 1937, and even still by 1940, the B1 Bis was a very capable tank when looking simply at its firepower and armor protection.
Armament-wise, the B1 Bis had the most powerful tank gun mounted in any of the serial-produced tanks in French service, the 47 mm SA 35. Besides the B1 Bis itself, there were few vehicles in the world that would prove to be hard targets for it. By 1940, the British were introducing the Matildas, and the Soviets the KV and T-34s, which would have proved mostly invulnerable to the French gun. However, when looking at France’s relevant opponent at the time, Germany, as well as its Italian ally, the 47 mm SA 35 would still prove able to penetrate any vehicle with ease, and was a superior anti-tank gun to what was mounted in tanks such as the Panzer III or 38(t).
The hull-mounted 75 mm gun was also the most powerful infantry support weapon in France’s arsenal save perhaps for the slightly longer 75 mm gun mounted in the very rare FCM 2C super-heavy tanks. Its firepower against fortifications and entrenched positions was considerable.
Looking purely on paper, a B1 Bis combines into one tank and with a crew of four what the German Army would have in two tanks and with a crew of ten, with the combination of the Panzer III and Panzer IV. The B1 Bis’s armor protection was also far superior to those of German tanks of the time. Overall, it was almost invulnerable to German 37 mm guns, and the Panzer IV short 75 mm could occasionally prove a threat, but was neither powerful or accurate enough to be relied upon to knock out the French tank. The major elements of the Wehrmacht which could challenge the B1 Bis were heavier, towed guns – quite famously, the 88 mm Flak guns, notably the 8.8 cm Flak 36, but also 105 mm field guns such as the 10.5 cm leFH 18.
Those theoretical advantages in hard statistics the B1 Bis offered over German tanks of the era, however, paint a far more glamorous reality of the tank than what its operation really was like. Though powerful, the B1 Bis was plagued with a large number of flaws that made it a far from perfect or even great operational vehicle.
… If you’re trained for it
The B1 Bis was a very complex tank for the era, notably due to its combination of different armament system as well as some advanced but complex and not systematically reliable systems, notably the Naeder used for traverse. As a result, it required some extensive crew training to be operated properly. A variety of circumstances resulted in most crews, however, being quite unfamiliar with the vehicle when they had to operate it in combat during the campaign of France.
The first was the inadequacy of French training tank battalions when compared to the complexity of the B1 Bis. By the late 1930s, the standard tank used to initiate conscripts and soldiers to tanks was still the antiquated Renault FT from the First World War. The FT was arguably a decent tank to introduce the crews of two-men light infantry tanks, the likes of the R35/R40, H35/H39 and FCM 36. However, the jump in complexity from the FT to the B1 or B1 Bis was tremendous, with the two machines having little in similarities. Notably, drivers on the FT would be confined to the task of driving, while on the B1 Bis, they would also assume the task of being the gunner of the hull 75 mm gun. The commander on a FT was busier than the driver, but still vastly less so than on the B1 Bis. While FT commanders would spot enemy vehicles and operate the turret armament by themselves, they would also have to command the fire of the 75 mm gun on the B1 Bis. While some training battalions received a very few B1 and B1 Bis tanks during the Phoney War in order to give the crews vehicles much closer to what they would operate, this was done quite late and in small numbers. The 106ème Bataillon d’instruction des chars was created in April 1940 with two B1 and a B1 Bis, and the 108ème the same month with three B1s.
Several Renault FT-31s captured by the German Army in 1940. The type remained widely used by the French military for training, and most tankers which operated the B1 Bis had been initiated to tanks with the old FT. Source: char-français
Another major issue was, simply, that a large quantity of the B1 Bis used in the campaign of France were delivered to their units from a couple months to mere days before they were used during the campaign. In other words, many crews did not even have the time to fully go to the necessarily transitional period that would have been needed to truly get accustomed to the B1 Bis after mainly having been trained on FTs. A US Army attaché to France during the Phoney War had estimated that about six months would be needed to properly train a B1 Bis crew, a time that very few of the operators of the tank had had when they went into combat during the campaign of France.
The results of this poor training were considerable. Notably, poor familiarity with the Naeder steering system had some tragic consequences, with crews not realizing the mechanical castor oil used for the operation of the system did not have the same properties as pharmaceutical castor oil, resulting in the latter sometimes being used in time of need but causing breakdowns that could immobilize the whole vehicle. The very ergonomically discussable configuration of the B1 Bis, with both the commander and driver being utterly overtasked, was an even heavier burden on crews which were not properly trained.
… If you can operate it
Indeed, the commander (typically an officer) assumed in the B1 Bis, though similarly to a large quantity of French tanks, a large quantity of different tasks. The commander was the main spotting force in the vehicle, tasked with identifying enemy targets through the commander’s cupola, as well as making tactical decisions and ordering the crew – a more complicated task than usual due to the presence of an hull-mounted 75 mm gun of which the commander would typically order the firing. At the same time, the commander fully assumed the roles of gunner and loader for the 47 mm SA 35 gun and the machine gun mounted in the turret.
In practice, this meant commanders would regularly have to move position, from looking outside from the cupola to putting themselves behind the gun to load and fire it, while at the same time having to analyze the situation around them and give orders to the hull crew. The difference in comparison to the division of tasks in German Panzer III and IV is more than drastic, and this utter overtasking of the commander had significant consequences on the B1 Bis and its performance. Typically, the awareness of enemy targets and the tactical situation was far worse on French tanks than German one, even if the B1 Bis had the relative privilege of having a radio, something many other French tanks lacked. The operation of the 47 mm SA 35 gun was severely impaired as well. Though in theory, the gun could reach a rate of fire of about fifteen rounds per minute, in practice, it would be much lower – often as little as an abysmal two rounds per minute.
This photo of a destroyed B1 Bis shows the exiguity of the APX 4 turret. The B1 Bis’ poor ergonomics were a major drawback. Source: World War Photos
Though it is almost impossible to equal the overtasking of commanders on the vast majority and French tanks, and particularly the B1 Bis, the driver also assumed a greater variety of tasks than usual in the tank. B1 Bis drivers would not only drive and steer the vehicle, as would usually be expected, but also act as the gunner for the hull-mounted 75 mm SA 35 gun, requiring both more training and giving them a larger range of tasks to accomplish when in combat. The commander would be able to give orders to the driver through both a voice tube, and a set of electric lights codifying simple commands. Though these worked decently, they did not entirely replace the old practice which had been used since the FT: having the commander direct the driver’s steering by foot taps on the shoulders.
The two other hull crew members had somewhat of an easier time, but would typically still require extensive training and be kept busy. Behind the 75 mm gun, the gun’s loader was placed. Officially called a mécanicien aide-pilote (ENG: Mechanic assistant driver), this crew member would also be tasked with trying to repair the engine in case of a potentially repairable breakdown, which would be done through the access corridor without actually leaving the tank. They were also tasked with handing 47 mm shells stored in the hull to the commander. In short, they assumed a variety of roles which would typically be quite occasional but were varied in nature.
The fourth crew member was a radioman, of which the task was limited to operating the B1 Bis’ radio. Though this may seem like a simple task, it should be remembered that the tanks were, at first, fitted with the ER 53 radio, which was only able to communicate through Morse key, typically far more complicated to operate than voice radios, this would require a skilled operator. Only about a hundred B1 Bis were fitted with the ER 53, which was replaced by the more potent ER 51 model 1938, able of voice communications at shorter ranges (two to three kilometers), far more practical for communications between tanks of a platoon or company. Morse key was still retained and could be used for ranges of up to 10 km.
The driver, loader, and radioman were typically all non-commissioned officers. Though the crew of the B1 Bis in operation was four, six to seven crewmen were assigned to the vehicle, with the additional tankers being tasked with helping with maintenance and replacing out-of-action crew members. Some B1 Bis would occasionally carry one of these additional crewmen inside the hull in combat. Though this made the compartment quite cramped, this additional crew member would take on some functions of the loader/assistant driver, typically handing out shells from the hull racks to the commander.
… If you can fuel and maintain it
Not unexpectedly for the heaviest and most complex mass-produced tank of the French Army by 1940, the B1 Bis was quite the high consumer of fuel and required some fairly extensive maintenance work.
The fuel used in the B1 Bis’ engine was 85 octane aviation fuel, reminiscent of the powertrain’s origin as a bisected aircraft engine. It could not run effectively on most other fuels of the French military. Though the availability of the 85 octane fuel was not theoretically a problem in itself, the very poor state of the French logistical services during the 1940 campaign meant that getting fuel to the units often proved hazardous, and a large number of B1 Bis ended up scuttled or left behind in strategic positions after running out of fuel. The B1 Bis had retained the same 400 liters fuel tank as the B1, but with the engine being raised in power to accommodate the additional weight, the consumption raised, with the 400 liters being typically expended in 6 to 8 hours, depending on the conditions of operation. This was quite short, and a solution was to be found in order to allow the B1 Bis to have a better range.
This came in the form of the Lorraine 37L armored supply vehicle. Developed from 1936 onward as part of a call to produce an armored supply tractor for the infantry’s tank, the Lorraine 37L was a fully tracked and armored vehicle that was able to tow a trailer containing 570 liters of fuel, raising the range of the B1 Bis quite considerably. Each company of 10 B1 Bis (with each battalion comprising 3 companies) was to be allocated 6 Lorraine 37L. This was not entirely fulfilled by 1940 though. The 1st and 2nd DcR, the oldest armored divisions of the French infantry, appear to have had a complete or near-complete complement of Lorraine 37Ls, but the newer 3rd and 4th DcR did not.
Two Lorraine 37L with fuel trailers. Sourcel: Panzerserra Bunker
The daily maintenance of the B1 Bis, mostly oiling the various components, such as the transmission, Naeder system, and engine also consumed a number of various oils: 35 liters of castor oil for the engine, 35 liters of that same castor oil for the Naeder system, 60 liters of semi-fluid oil for the gearbox, 2 to 3 liters of thick oil for the radiator, and 15 liters of thick oil for the suspension. Though these oiling operations were performed daily, more complete ones would have to be completed every 150 km. At 300, 600, and 900 kilometers, an extensive emptying and examination of the powertrain would have to be completed. At 1,000 kilometers, the vehicle would have to go through an extensive technical visit. Performing those maintenance operations as planned rarely proved possible in the very fast-paced campaign of France though.
Fists of the DcRs
In operations, the B1 Bis were all to be grouped within the French infantry’s armored divisions – The Division Cuirassée de Réserve or DcR (ENG: Reserve Armored Division, with the reserve being not a description of the units as second-line, but rather of their use as high-value breakthrough divisions to be kept for major offensive or defensive operations). Each DcR would be composed of two battalions of B1 Bis grouped in a half-brigade. Each battalion would feature three companies of 10 tanks, a command tank, and three reserve vehicles. There was an additional command tank for the half-brigade, with the typical complement of B1 Bis in a DcR being 69 or 70 tanks.
Within the DcRs, the half-brigades of B1 Bis would be accompanied by another half-brigade of light tanks – comprising two battalions of H35/H39 light tanks, with 45 tanks and 12 Lorraine 37Ls per battalion. The division would also include a battalion of Chasseurs Portés, which acted as mechanized troops using fairly primitive Lorraine VBCP 38L transports and motorized vehicles. Their artillery would be provided by an artillery regiment part of the division, which included six artillery batteries, comprising a total of 24 105 mm artillery pieces, and an anti-tank battery comprising 8 47 mm SA 37 anti-tank guns, as well as assorted motorized tractors for those batteries. 1 to 2 engineering and transmission companies were also part of the divisions. Overall, the divisions theoretically comprised only about 6,155 men, a far smaller complement than German Panzer-divisions, which had about 13,000. The German divisions also typically had a far larger complement of tanks, with the average being of about 260 and even the less equipped Panzer-Divisions typically had at least 220 tanks at their disposal.
In comparison to the French cavalry’s armored divisions, the DLMs, the DcRs were a fairly new creation, with the French infantry branch having envisioned the use of armored vehicles in large mechanized formations far later than the cavalry, that had been interested in the idea since the late 1920s. The infantry was quite reluctant to stray from the traditional model of the use of tanks in independent battalions reattached to infantry formations for particular operations. As such, the DcRs were all very young units by the time they were thrown into the fray during the campaign of France.
Only the 1st and the 2nd DcRs had their full complement of B1 Bis by 10th May 1940. Both of those divisions had been formed on 16th January 1940. The B1 Bis battalions were the 28th and 37th in the 1st DcR, and the 8th and 15th in the 2nd DcR. As the two fully operational DcRs, they were included in the Dyle-Breda maneuver of the French military aimed at securing Belgium and the Netherlands after those were attacked by the Wehrmacht. This would have been done by entering Belgium towards Charleroi with the 1st DcR going in first and the 2nd DcR second. Ironically, this inclusion of the 1st and 2nd DcR into the Dyle-Breda plan would result in disastrous losses of equipment and personnel.
The 3rd DcR was younger than the 1st and 2nd, having been formed on 20th March 1940. By 10th May, it was still in the last phases of its formation, and its equipment was not complete, with portions of it having been redirected to the 1st and 2nd DcRs in order to get them fully operational faster. Including the H35 and H39s, 138 tanks were in service by 10th May, from an expected total of 160. It appears around 62 B1 Bis were in service in the 3rd DcR’s two battalions equipped with the type, the 41st and 49th, however, many Lorraine 37Ls were yet to be delivered.
The last DcR was the 4th, which vastly differed from the other three in terms of composition. Supposed to begin formation in May of 1940, the division, due to the catastrophic situation of the front, ended up regrouping not only infantry but also cavalry tank battalions as early as its formation began on 15th May 1940. As early as it was created, the division included the B1 Bis-equipped 46th battalion, and the 47th battalion equipped with the type was included in the division on 21st May. Due to availability issues, instead of H35/H39s, the division ended up with three R35-equipped battalions reattached to it – two, the 2nd and 24th battalions, from its inception on 15th May, and a third, the 44th, from 21st May onward. As with the light tank battalions equipped with the H35/H39, each R35 battalion had 45 vehicles. The division also received a company of Renault D2s comprising 14 vehicles and a cuirassiers regiment equipped with 44 Panhard 178 armored cars, as well as a variety of supporting units. This makeshift nature of the 4th DcR, comprising far more tank units and armored vehicle types than the other DcRs, also made it the most numerous in terms of tanks. In theory, it was the only one able to go toe-to-toe with a Panzer-division in terms of the number of personnel and vehicles, though, in practice, not all units would have been fully equipped at the same time as the division was first engaged on 17th May, while several components would only be reattached on the 21st. Under the command of a fairly important proponent of the use of armored vehicles in grouped units, Colonel and later Brigadier General Charles de Gaulle, the 4th DcR, even more so than the others, would be used as a “fireman of the front” unit during the campaign.
B1 Bis of the 46ème BCC on maneuvers. The B1 Bis was thought of as the strongest offensive tool of the DcRs. Source: France 3 régions
1ère DcR: Annihilation at Flavion
The 1ère DcR was led by Brigadier General Christian Bruneau, previously commander of the 511ème Régiment de Char de Combat (ENG: 511th Combat Tanks Regiment). This was the first unit to have received the operational B1, all the way in 1935-1936, as well as arguably France’s most prestigious tank unit. Brig. Gen Bruneau was therefore very much suited to command the first of the French infantry’s tank divisions, particularly as the 1ère DcR did include elements from the 511ème RCC, which was dissolved at the outbreak of the war (the 37ème tank battalion and its B1 Bis being a notable example).
The fully outfitted 1ère DcR was, at the outbreak of hostilities, planned to advance into Belgium, towards the city of Charleroi. The quick German breakthrough through the Ardennes led to the unit being redirected, on 14th May, in efforts by the French to try and destroy the bridgehead which had been secured by the Wehrmacht – the 5th and 7th Panzer Division – across the river Meuse at Dinant, in Belgium.
The 1ère DcR, and its two B1 Bis battalions, the 28th and 37th, were engaged, basically alone and with minimal infantry support, against German troops of the two Panzer Divisions on 15th May. The French situation was, from the start, quite abysmal though. Following the general directions which had been issued to the DcR, most of the logistical and notably refueling elements were all the way at the rear of the division and its convoy – which quickly made the situation disastrous, when the high number of refugees fleeing the German advance on the roads made progressing a hard affair. As a result of this, large portions of the division – and of the B1 Bis – found themselves out of fuel, utterly incapable of maneuvering.
German tanks and troops, supported by their aviation, started advancing on the French positions at around 8:30 am. On the front of the 28th Battalion, the most heavily engaged of the division’s two B1 bis battalions, the first German tanks to attack were seen around 8:30. These were vehicles of the 5th Panzer Division, which faced off against the battalion’s 3rd company first. The German vehicles came close to overrunning the battalion in the morning but were eventually forced back after some considerable losses around 11:00 am. Returning at around 12:00 am, forces of the 5th Panzer-Division, supplemented by the 7th, were engaged with the battalion for all afternoon until it retreated around 18:00 pm.
The tanks of the battalion, despite often being immobilized by lack of fuel, fought quite ferociously, and a fair few did claim the destruction of several German vehicles, as well as resisting a large number of hits. B1 Bis n°283 “Sousse” allegedly claimed to have knocked out 3 enemy vehicles with the 47 mm and 4 with the 75 mm before being put out of operation. N°294 “Tamatave” claimed three, while at the same time resisting about a hundred hits, including a 75 mm high explosive shell to the turret. Those respectable individual successes of some tanks, though likely overestimated to an extent, show the battalion fought bravely, but at the same time, it was hopelessly outclassed. During the day of the 15th, it found itself with no support whatsoever from either infantry, artillery, or aviation – while opposing German tanks were supported by all three. German vehicles also vastly outnumbered the French. In one instance, a B1 Bis, n°415 “Quincy”, reported being engaged by about 15 Panzer III and IVs, the crew escaping miraculously despite a broken radiator thanks to a slope which allowed the vehicle to escape for a moment, long enough for the crew to be rescued by another B1 Bis, n°282 “Tunis”.
The destroyed B1 Bis n°294 “Tamatave”. A vehicle destroyed this way is typically the result of it being scuttled by the crew, though it is likely it was already damaged previously. Source: char-françaisA beautiful photo of N°415 Quincy. Previously a part of the 49th Battalion as Franchet d’Esperey, it was transferred to the 28th battalion in extremis on 10th May and renamed Quincy. Source: char-français
By the point the 28th Battalion retreated on the evening of the 15th, only 7 of its B1 Bis were still in its hands – the rest having been knocked out or abandoned due to a lack of fuel. Unlike the Germans, which may very well have recovered and repaired knocked out but not irreparably damaged vehicles, there was no hope of ever repairing the lightly damaged tanks that were left back. The 37th battalion did not fare particularly better. Also engaged from about 8:30 am, the battalion was also able to push back German advances with losses in the morning but was forced to retreat in the afternoon – a move in which its three companies found themselves isolated, which turned out disastrous. Under orders of General Bruneau, the 2nd Company tried to launch a counterattack towards the south around 13:30 pm, fearing encirclement. The company faced off against Panzer Regiment 31 of the 5th Panzer Division supported by anti-tank guns, a fight it was vastly outclassed in, and suffered very heavy losses, with the company’s commander, Capitaine Gilbert, killed in action. When orders to retreat came in the afternoon, the battalion’s 3rd company took a wrong path, leading it straight into the front elements of the German 8th Infantry Division. The following fight resulted in all of the company’s surviving tanks being lost, and a large number of personnel, including once again the company’s leader, Capitaine Lehoux. Only the 1st company was able to retreat properly with seven tanks. In a single day, the 37th battalion had lost 23 B1 Bis and was reduced to the same complement as the 28th battalion, 7 tanks. The 1ère DcR’s two H35/H39 battalions did not fare particularly better.
The 28th Battalion’s destroyed n°283 Sousse. The 1ère DcR tanks fought ferociously and were able to inflict non-negligible losses, but the consequences of those were minimal in comparison to the complete destruction of one of France’s most well-equipped armored divisions. Source: char-français
The remaining elements of the division were engaged in the desperate defense of the town of Beaumont on the following day. Both battalions and their remaining 14 B1 Bis – less than half of a battalion at full strength – were basically annihilated in the defense of the town. A few elements (by the 17th, 4 H39s formed all that remained of the former 25th battalion, and were accompanied by a single B1 Bis) continued to fight a fighting retreat on the 17th, but by that point, the 1ère DcR had, basically, ceased to exist as an operational unit. General Bruneau and his headquarters were captured on the 18th.
The 1ère DcR was reformed from the ground up from 31st May onward, with two battalions of R35s and a battalion of B1 Bis, the reformed 28th battalion. This attempt to recreate an armored division to desperately try and fend off the tide of German forces that had now encircled most of the French Army’s best elements and cut them off, never reached the full strength a DcR may normally have. The unit was engaged from 8th to 10th June in delaying fights along the River Oise, to try and allow infantry units on the brink of being overrun to retreat behind French lines and recover. By that point, the unit appears to have had about a dozen B1 Bis, perhaps a little less. Two were lost on 9th June, both due to breakdowns. The rest of the campaign for the makeshift DcR was spent in a fighting retreat all the way to the Loire river and beyond until the armistice put an end to the division’s woes.
B1 Bis n°460 Aumale, a newly manufactured vehicle which was given to the reformed 28th BCC, and ended up abandoned due to a breakdown of the drive sprocket throwing off the right track. Source: char-français
2ème DcR: In the path of the German tide
The 2ème DcR was led by Brigadier General Albert Bruché, who had reached this rank in 1938. The division he commanded was, as the 1ère DcR, fully outfitted by the beginning of hostilities in May 1940. Its B1 Bis battalions were the 8ème and 15ème BCCs.
The division had been kept in reserve at the orders of the French North-Eastern headquarters. After the beginning of operations on 10th May, the division was quickly put into alert and was ordered to move north, towards Belgium, to provide assistance to the troops located in the area. This order was given on 13th May around noon. The division’s movement towards the north would prove to be fatal. In order to move north, the tracked and wheeled elements of the division were separated. The wheeled elements, which included pretty much all reconnaissance and logistical means of the division, would move by road, while the tracked vehicles would move by rail. The consequence of this decision could be summed as dislocating the large division into a myriad of small units which did not have the occasion to reform as a large force due to the very quick advance of German armored elements. The German breakthrough at Sedan on the 13th pushed new orders for the division to reform around the forest of Signy from the 14th onward, but this would not prove successful.
Various elements of the 2ème DcR would be unloaded at a variety of railway stations and put to the disposition of various infantry commanders in order to attempt to stop the German breakthrough and crossing of the Meuse. The 8ème BCC’s elements were first engaged on 15th May. The battalion’s three companies were all unloaded at different stations, which highly complicated the coordination of the unit. The companies all operated in several small towns on the Oise River, such as Vervins, Guise, or La Fère, in order to defend bridges on the river and prevent German crossings. The 1st and 3rd companies were further fragmented, with several tanks being sent on individual missions to defend locations separated from the main force of the company. This isolation led to very high losses for the battalion. In the period between 15th and 18th May, all tanks of the 1st company which had been sent on individual missions, five vehicles, were lost, along with large parts of the 2nd and 3rd battalions as well. The French vehicles would typically face much larger and better-organized numbers of German vehicles belonging to several armored divisions involved in the push towards the French coast.
As for the 15ème BCC, it did not fare particularly better. The 1st and 2nd companies of the battalion were able to operate fairly closely with each other, while the 3rd company was almost entirely separated. On the first day of contact with the enemy, 16th May, the first two companies would lose 6 tanks and be considerably slowed down by poor logistical facilities, resulting in the 2nd company being considerably delayed, as it had to refuel with only a single, hand-operated pump. The two companies continued to operate defensively on bridges on other sectors of the Oise River on the 17th and 18th, constantly being flown over by German aircraft. 12 tanks were operational by the 18th, but the first two companies ended up divided into three elements, which operated with various parts of other units, ending with most of the tanks being lost.
The crew of B1 Bis n°204 “Tunisie”, from the 3rd company of the 15ème BCC, standing in front and on top of their tank, resting. Source: char-français
The 3rd company was first engaged a bit later than other units, appearing to meet German troops for the first time on 17th May. Two of its tanks, “Mistral” and “Tunisie”, were engaged in an operation to clean up the village of Landrecies on the 17th. The vehicles ended up encountering, in the village, a large park of German wheeled vehicles, including Sd.Kfz 221 and 222s, liaison vehicles, and according to some French sources, some Panzer I and Panzer II light tanks. This led to the two French tanks destroying the parked vehicles, of which the numbers vary greatly among the sources – from several dozens to up to two hundred vehicles. This success, one of the various anecdotal but impressive successes achieved by small numbers of B1 Bis during the campaign, does little to change the fact the 15ème BCC disappeared while having little impact: most of its tanks, including Mistral and Tunisie, were lost on 18th and 19th May.
By the morning of 20th May, out of the 62 B1 Bis tanks which had been loaded into railway lines on the 13th, 43 had been destroyed or lost to the enemy, and of the remaining 19, only 10 were in operational conditions. The division’s infantry or Hotchkiss light tanks did not fare better; the division, as a combat force, had been wiped from the map and attempts to restructure it would not be successful. The division’s last elements would be consumed in the harsh fighting retreat that was the rest of the campaign of France.
The wreck of B1 Bis n°265 “Mistral”, burned out after being struck by German anti-tank guns on 19th May 1940, two days after it took part in an attack on a park of German light vehicles. Source: char-français
3ème DcR: Stonne’s butchers and cattle
The 3ème DcR was created in March 1940, whilst the first and second DcRs were created in January. It was not entirely outfitted by May 1940, though it appears its B1 Bis complement was complete.
As the other DcRs, the 3ème started its movement around 13th May, and as the two others, the situation on the front led to the 3ème DcR being dislocated into small groups of tanks tasked with defending individual locations as early as 14th May. It was under the orders of General Flavigny, leading the 21st Army Corps, which had been given command of the 3ème DcR (Flavigny had, interestingly enough, been a major instigator of the creation of armored divisions in France).
The division’s two B1 Bis battalions, the 41ème and 49ème BCC, were engaged in one of the most famous tank battles of the Battle of France, the Battle of Stonne, where French and German troops harshly contested the town of Stonne with one another. Located on the southern flank of the German push towards the English Channel, Stonne was a major location which, if retaken by the French, could allow French troops to threaten the German’s logistical lines and their entire push towards the west.
The most intense phase of the battle was from 15th to 17th May, in which most of the 3ème DcR fought with the 67th Infantry Regiment (though cooperation between the tanks and infantry would more often than not be very lacking) against the German 10th Panzer Division and the 16th and 24th Infantry Divisions. The village’s control would change 17 times during this battle.
It is during the Battle of Stonne that the most well-known feat of the B1 Bis happened. On 16th May, B1 Bis N°337 “Eure”, part of the 1st company of the 41ème BCC, entered the main street of the village, only to find itself facing a column of thirteen German tanks, seemingly German Panzer IVs and Panzer IIIs, at very close range. Using its dual weapons, the French tank targeted the front vehicle of the column with the 47 mm and the rear vehicle with the 75 mm, rendering maneuvers very complicated for the German vehicles. The tank then progressed along the column and knocked out all the German tanks within a few minutes. The frontal armor of the B1 Bis proved invulnerable from the German 75 mm and 37 mm shells. Following this action, “Eure” left the town, knocking out two German anti-tank guns (likely 37 mm PaK 36s) on the way. 140 non-penetrating impacts were found on the tank after the action, underlining the very good armor protection of the B1 Bis for the time. This action gained some considerable fame to the tank’s commander, captain Pierre Billotte, who would later become a politician in the post-war era.
The B1 Bis Eure and its crew prior to the Battle of Stonne. This tank arguably stands as the most famous individual French tank of the campaign. Source: char-français
However, the Battle of Stonne was often nicknamed the “Verdun of 1940”. It saw both the German and French forces suffer some considerable losses, with 24 tanks irreparably destroyed for the Germans, and about thirty for the French, including not only the B1 Bis but also some Hotchkiss tanks as well. However, ultimately, German troops remained in control of Stonne, and the French attempts failed to sever the Wehrmacht’s logistical lines.
The 3ème DcR faced some considerable losses not only during the battle but also during the subsequent retreat, which saw many of its vehicles suffer breakdowns, often leading to them being abandoned. Around 10th June, there were only around 30 B1 Bis left. As the other DcRs, the 3ème fought a long fighting retreat during June, in which it lost a large proportion of its equipment. For example, Bilotte”s B1 Bis “Eure” ended up sabotaged by its own crew on 13th June due to breakdowns in the suspension preventing further movement. As with all DcRs, a non-negligible proportion of the 3ème DcR’s fleet of seemingly fearsome B1 Bis ended up lost in breakdowns.
The “Eure’s” undignified end, sabotaged by its own crew after a breakdown of the drive sprocket immobilized the vehicle. Detonating one’s own tank after a breakdown of a small element immobilized the whole tank ended up as a quite common fate for B1 Bis during the campaign of France. Source: char-français
4ème DcR: De Gaulle’s firemen
The 4ème DcR stands as the most peculiar of the four DcRs France engaged during the 1940 campaign. Unlike the 1ère and 2ème DcR, which were completely outfitted, or the 3ème DcR which at least appeared to have had its entire complement of B1 Bis, the 4ème DcR was only in the process of being formed by the start of the campaign of France. The unit quickly became somewhat of a “fireman of the front”; receiving units that did not at all enter the usual composition of a DcR. As it was first engaged on 17th May, it only had a single B1 Bis battalion, the 46ème BCC, with a second battalion of B1 bis, the 47ème, being added to the division on 21st May.
The division was commanded by Colonel Charles de Gaulle, previously commander of the 507ème RCC before the war, as well as a theorist and proponent of the use of tanks in large, armored formations. His actions as the leader of the 4ème DcR would lead to him being promoted to the rank of General on 25th May, a military title he would bear with pride as the future leader of the Free French Forces after the fall of France.
The 4ème DcR’s first battle was the Battle of Montcornet, on 17th May, in which the division attacked a locality that had been seized by the Germans near the Aisne River. As Stonne for the 3ème DcR, Montcornet was another significant location for the logistics of German tank divisions moving further west, and attacking the town was an attempt to prevent the continuation of the German push to the sea. Though the French forces managed to push quite considerably at Montcornet, they faced some considerable resistance in the form of a large number of anti-tank positions the Germans had set up. In the morning and early afternoon, most of the action was performed by the division’s R35s and D2s, with the B1 Bis being unable to engage deep into the action due to problems finding enough fuel. In the late afternoon and early evening, the tanks were engaged. Two B1 Bis were knocked out by an 88 mm FlaK 36 anti-aircraft gun, and another two by Ju 87 Stuka dive bombers. Several suffered breakdowns and could not be recovered. Overall, 24 French tanks were knocked out during the battle (though most were R35s and D2s). Though in terms of human losses, the French suffered less (only 14 killed in action, 9 missing, and 6 wounded in comparison to about 100 German soldiers in total), the material losses were considerable. Despite the 4ème DcR being better organized and cohesive than the other divisions, it lacked aerial and infantry support, which made its vehicles very vulnerable to well-prepared anti-tank defenses.
B1 Bis n°399 “Sampiero Corso” lies, knocked out, on the side of a road, with improvised graves of its crew on the sideway. This tank had become the tank of company commander Bescond after his vehicle, Berry Le Bac, had fallen due to a breakdown. Bescond took the Sampiero Corso as the company command vehicle and had it destroy the Berry Le Bac to avoid capture by German troops. The tank later fell in the early evening of the 17th. A first shot knocked out the drive sprocket and immobilized the tank, before a second shot, 88 or 105 mm in caliber, penetrated in front of the side door, igniting the 75 mm shells and incinerating the crew. Source: char-français
Though the division fought in a number of skirmishes around the Aisne in the following days, the next major battle of the 4ème DcR would be Abbeville. The division was engaged from 28th to 31st May, following a British assault on the previous day. The objective was to manage to link up with the large number of units stuck in the Dunkerque pocket and at least create a safe evacuation route for them.
The B1 Bis’ assault focused first on the village of Huppy on 28th May. The attack, starting in the late afternoon, saw the 47ème BCC’s tanks face off against well-prepared German anti-tank positions. Four tanks were immobilized. French troops managed to seize Huppy, but extending forward, the 47ème BCC encountered two well-placed German 88 mm guns, “Cesar” and “Dora”, which destroyed several B1 Bis.
The offensive continued on the 29th, on the high-place of Mont Caubert, where the two 88 mm guns were located. After a two hours-long exchange of fire in the morning, both guns were knocked out. The B1 Bis continued moving, but were not given any form of infantry support, and their poor quality radios hindered their coordination. Two new German 88 mm guns, “Anton” and “Bertha”, were once again able to stop the French advance. Around noon, several hundreds of German infantrymen charged the heavy tanks, to no avail, as the charge ended in a bloodbath. In the afternoon, the French attacked again with nine B1 Bis, with five ending up being knocked out by the 88 mm guns.
The final B1 Bis offensive, once more consisting of nine vehicles, was performed in the afternoon of the 30th. Though some German anti-aircraft guns were knocked out, the French tanks were once again lacking any effective infantry support and suffered from very poor communications, which made their attacks poorly coordinated. At the end of the day, only four of the nine attacking tanks survived. The division left the front at Abbeville shortly after, leaving its positions to the British 51st Infantry Division. While the division had been able to remain far more organized than the other DcRs, to advance several kilometers into German positions and knock out a number of artillery pieces, it failed to achieve the desired result of a decisive breakthrough against German forces, in no small part due to the inability of French infantry and aviation to properly support their tanks.
The B1 Bis n°423 “Condé”. On 30th May, this vehicle was the only tank still operational within the 47ème BCC. It joined eight tanks of the 46ème in an attack on that day and was knocked out by German 88 mm anti-aircraft guns. Source: char-français
The following weeks saw De Gaulle promoted from the commander of the 4ème DcR to the Undersecretary of War and National Defence in the French Government on 6th June, leaving his functions of commander of the division to Colonel Chaudesolle and General De la Font. After Abbeville, the fate of the 4ème DcR remains similar to the three other divisions. It fought in a long, desperate fighting retreat towards the south, though it managed to remain somewhat more organized and cohesive than the other units.
Autonomous Tank Companies and various other units
Later in the campaign, with the four main tank divisions supposed to operate the B1 Bis either basically nonexistent or in shambles and not necessarily easy to reinforce, a number of typically newly produced B1 Bis were issued to more makeshift and smaller-sized independent units which were engaged in desperate attempts to counter the German tide. These were the 347ème (though it only had 3 B1 Bis, its core being its 10 B1), 348ème and 349ème Compagnie Autonome de Chars de Combat (Eng. Autonomous Combat Tank Companies), formed on 18th May. Another, the 352ème, would be formed on 9th June by separating a company from the 4ème DcR’s 46ème BCC.
The 348ème saw most of its 14 B1 Bis knocked out during the last attempt at Abbeville, in support of British troops, on 4th June. Out of its 14 B1 Bis, only three appear to have survived, the rest being knocked out by German anti-tank guns, mines, or suffering from breakdowns. The 349ème suffered a similar fate, with 5 B1 Bis lost on 4th June, several having already been lost in skirmishes previously. The 352ème, formed much later, suffered a similar fate to the DcRs, fighting in a costly retreat until the end of the campaign.
A number of B1 Bis were, later in the campaign, part of small sections of three, four or five tanks, crewed by whatever crewmen could be gathered, once again fighting in desperate attempts to hold back advancing German forces. On one occasion, one of these units was formed by three turretless tanks, numbers 505, 506 and 507.
German soldiers inspect the abandoned B1 Bis n°505. The vehicle was pressed into service without a turret, nor even a cover for the turret ring which remained wide open. Source: char-français
The B1 Bis in the campaign of France: An analysis
The B1 Bis’ performance during the short campaign of France is a complex subject.
When seeing the vehicle’s combat records, one can hardly claim the B1 Bis was without faults. No tanks in service in the army of one of the belligerents, save perhaps for the British A12 Matilda, could have been able of feats performed by some individual B1 Bis, such as resisting a large number of hits while knocking out a quantity of enemy tanks in a short timespan, as the B1 Bis Eure did at Stonne. The vehicle proved to be, at times, a major headache for German troops, being typically invulnerable to German tank guns. Its firepower was considerable and varied.
At the same time though, a tank as complex, vulnerable to breakdown, and fuel-hungry as the B1 Bis could not reasonably be expected to perform well in an army with poor logistics. The situation of the campaign of France, with French logistical lines being quickly thrown into chaos by a mixture of poor organization and communications, and a very large number of refugees on the roads, meant that more often than not, a mere minor breakdown or fuel shortage would be fatal to the heavy and expensive B1 Bis. And while mighty and powerful, the very poor ergonomics of the tank, combined with the almost systematically lacking coordination with infantry and aviation, meant that B1 Bis were at times very easy targets for the German weapons that could dispose of them, occasionally Junkers Ju 87 Stukas, but much more regularly larger caliber artillery pieces, typically 88 mm anti-aircraft guns but also 105 mm field guns, which could also hope to penetrate or cause high damage to the French heavy tank. Despite its mighty armor and heavy armament, the B1 Bis ended up being no considerable obstacle to Germany’s lightning-fast invasion of France, and while French crews occasionally caused high losses to their adversaries, many of these knocked out vehicles would later be repaired by the Germans – as well as numbers of lightly damaged B1 Bis which would be pressed into service into the Wehrmacht.
It comes as no surprise that the B1 bis suffered very high losses during the campaign of France. An attempt to count the losses places them at 128 B1 Bis lost in combat, and 139 abandoned or scuttled due to breakdowns or fuel shortages. Only 21 vehicles were known to still be operational at the end of the campaign, while 79 had an unknown fate.
In the hands of the occupiers – The B1 Bis in German service
At the end of the campaign, the B1 Bis remaining in the French Army were stored in a variety of facilities, and handed over to the armistice commission and the Wehrmacht. This only comprised a relatively small number of tanks, as the vast majority of the fleet had been lost during the campaign of France. A significant proportion of these lost tanks, sometimes only lightly impaired, would be repaired and put back into operation by the German occupiers, using, notably, Renault’s facilities of Paris-Billancourt. By October 1940, about 161 B1 Bis had been gathered and were operational or in the process of being put back into action. In German nomenclature, the B1 Bis was known as Panzerkampfwagen B2 740(f). They were modified with German FuG radios, and often commander cupolas based on those used on the Panzer III and IV, replacing the original, unopenable commander cupola of the B1 Bis.
The Wehrmacht used the B1 Bis for a variety of roles, for example for the rare 10.5cm leFH 18/3 (Sf) auf Geschützwagen B2(f) self-propelled gun conversion. Most famously, a number of B1 Bis (but also older B1s) were converted into flamethrower tanks, which was done by replacing the hull-mounted 75 mm gun with a flamethrower. Their designation was Flammpanzer B2(f). At least 60 tanks were converted in such a fashion. 12 of those were employed on the Eastern Front, with the others being kept in France and the British Channel Islands. A German unit, Panzer-Abteilung 213, operated only Flammpanzers and standard B1 bis. It comprised 26 unmodified tanks and 10 Flammpanzers. The vehicles were stationed as a garrison on the Channel Islands from May 1942 until the end of the war.
A Flammpanzer B2(f) showcases its flame-throwing capacities. The vehicle retained the 47 mm SA 35 gun, and therefore could typically have more anti-tank capacities than most flamethrower tanks. Seeing as the conversions were performed in 1941-1942 though, the B1 Bis was no longer as powerful as it had been against the tanks fielded by Germany in 1940. Source: beutepanzer.ru
German forces operated B1 Bis on a number of fronts, including, in small numbers, in the Soviet Union. However, the majority of the vehicles remained in France. In total, 125 were still operational in March 1943. During the Liberation of France in 1944, most ended up abandoned or captured by the Free French Forces.
A panel showcasing temporary storage of German Panzer B2(f) seized after the surrender of the Channel Islands in May of 1945. This small archipelago remained a German pocket until the end of the war. The tanks operated by its garrison were very likely the last B1 Bis-type tanks in German hands. Source: Panzer-bau.de
Back in (Free) French hands: capture and salvage of former German B1 Bis tanks
The liberation of France, beginning on 6th June 1944 and intensifying after the breakthrough of Operation Cobra and the fall of the Falaise Pocket in August 1944, saw Germans troops forced to leave most of the country in a hurry to fall back to better defensive positions. At this point, most of the captured B1 Bis were left behind or damaged.
During the uprising which started the Liberation of Paris on 19th August 1944, a B1 Bis was captured by the FFI (Forces Françaises de L’intérieur – ENG: French Forces of the Interior) partisans and put back into action against the German garrison of the city.
The FFI B1 Bis during the liberation of Paris; the vehicle received hand-marked markings of the FFI in order to prevent friendly fire. Source: char-français
On 16th October 1944, in the newly-liberated city of Orleans, a French military regiment was re-created in the form of the 13ème Régiment de Dragons. This regiment was to be composed of three squadrons, each composed of three platoons of five tanks, and all using salvaged pre-1940 tanks. The 1st squadron would use Somua S35s, the 2nd would use the B1 Bis, and the 3rd would use Hotchkiss and Renault light tanks.
The salvaging of the tanks had been organized as early as September of 1944, mere weeks after most of France had been liberated during August. The salvaging was assured by André Gérin of Renault, a veteran of the 28ème BCC who had operated the type. The salvaging teams would search for abandoned vehicles in Normandy. The roads leading to the vehicles would be carefully searched for mines before the abandoned German tanks were towed and placed onto trailers to be driven back to Paris. About forty vehicles were recovered. These were taken to the Somua factories of Saint-Ouen, near Paris, and disassembled in order to find as many components in good condition as possible. 15 operational B1 Bis were refurbished in this fashion and pressed into service with the 13ème Régiment de Dragons, or 13ème RD.
13ème Régiment de Dragons: The B1 Bis’s Swan Song
The B1 Bis of the 13ème Régiment de Dragons were repainted in US Olive Drab paint. The vehicles were typically given hand-painted markings, particularly early ones. These included, most often, allied white stars or Free French crosses of Lorraine.
A B1 Bis of the 13ème RD in front of several vehicles, including a number of S35s and a Loyd Carrier, used by the regiment during the liberation of the German coastal pockets found on the Atlantic. Source: char-français
The 13ème Régiment de Dragons was engaged during operations against remaining German pockets on the French western coast, typically found around U-Boat bases. The unit was notably involved in the liberation of Oleron Island, La Rochelle, and most significantly, the Royan pockets. Though two S35 were knocked out during these operations, no B1 Bis is known to have been damaged in these actions.
The conclusion of the war in Europe in May 1945 did not mean the B1 Bis immediately went out of service. The 13ème RD, with its original equipment, was employed in the occupation of Germany from May 1945 until April 1946, when it was dissolved. In 1946, perhaps for its dissolution, the regiment appears to have returned to its founding city of Orléans. The dissolution of the Regiment on 15th April 1946 saw, coincidently, the removal of the B1 Bis from the French Army’s service.
The 13ème RD’s B1 Bis “Aramis” in 1945, perhaps in Germany. Re-painted in Olive drab and given new markings, in this case, French flags, the B1 Bis were only shortly operated by the French military after the war. In general, pre-1940 armored vehicles were only operated for a few months or a year after the war, though a particular vehicle, the Panhard 178, would see a new model, the Panhard 178B, resume production in 1945. Source: char-français
Surviving Examples
Ten B1 Bis have survived to this day, all being found in either France or Great Britain. It ought to be noted all vehicles surviving have formerly been in German service and incorporate a number of German modifications, even if they are typically showcased in French camouflage.
The British Bovington Tank Museum has one B1 Bis, formerly n°114 of Panzer Abteilung 213 operating in the Channel Islands. The French Saumur tank Museum has three. One, Rhône, is on permanent display within the museum. It has to be noted that ii does not use the typical APX 4 turret, but instead, the Somua S35’s very similar-looking but not identical APX 1-CE. This is likely a modification undertaken by the museum perhaps due to the tank lacking a turret. A second, Rhin, is still in running conditions, and is often showcased at Saumur and also occasionally in Bovington’s Tankfest as well. The third tank was fitted with a demining device and sits in the Museum’s reserves.
The B1 Bis “Rhin” showcasing its running condition at Saumur. The vehicle was fully restored in 2016, in an operation partially funded by gaming company Wargaming, explaining the unhistorical World of Tanks sticker on the vehicle. Source: twitter
Another French museum, the MM Park, possesses three B1 Bis, all in a fairly poor state and awaiting further restoration. Lastly, three B1 Bis are on outdoor display in France: one, Toulal, in Stonne, and two, Héros and Téméraire, at Mourmelon-Le Grand, a major French military base, particularly when it comes to tank regiments.
The B1 Bis on showcase at the French MM Park. The vehicle’s number is unknown. It was formerly used as a target for magnetic mine testing, yet remains in better condition than the two other B1 Bis that sit in this museum’s reserves, awaiting restoration. Source: Theatrum Belli
Conclusion – The most popular French tank?
The B1 Bis has, since the end of the Second World War and the rise in public interest towards tanks, become very likely the most popular French tank of World War Two, and perhaps of all French armor history, marking it one of the other great French tanks, along with the FT or AMX-13. There is indeed a lot to find impressive in the vehicle: its dual gun configuration allowing for optimal anti-armor and anti-infantry firepower condensed into a single armored vehicle was impressive for the time, as was its thick armor able to resist about all German tank guns used in the campaign of France; its unique looks likely factor in as well; and so does the very memorable actions some B1 Bis have been involved in, notably Pierre Billotte’s B1 Bis during the Battle of Stonne.
Looking at the bigger picture, though, peels a lot of the might and quality one may find, at first, in the B1 Bis. Though the vehicle’s firepower was theoretically great, a way overtasked crew made it unable to use it to its full effect, both due to the difficulty of spotting and retaining sight of targets and the slow rate of fire that comes as a consequence of the crew having to perform multiple tasks around the gun. The tank’s armor, though certainly great, was never invincible to 88 or 105 mm rounds, and its reliability made it a very poor vehicle to operate in case of unreliable supply lines. For each B1 Bis that distinguished itself, like the Eure at Stonne or the Mistral and Tunisie at Landrecies, a good dozen laid abandoned at the side of a road due to lack of fuel or a breakdown of a sprocket, radiator, Naeder system, or engine component which could not be replaced. Lastly, the vehicle was a tremendous investment in both time and money, being the conclusion of an about 15-years old program when it entered service in 1937. Being significantly costlier than any other French tank in production by the late 1930s, one could easily argue the B1 Bis was at least somewhat a waste of resources that could have been better spent elsewhere.
The development of the Char de Bataille did not end with the B1 Bis though. In the late 1930s, French engineers continued to work on an improved model, the B1 Ter, which did not go further than the prototype or pre-production stage. All completed or in-completion vehicles disappearing during the war. Even after the war, components of the old B1 Bis, notably around the hull, tracks and suspension, would be used for France’s first new tank produced following the liberation of the country – the ill-fated ARL 44.
An ARL 44 during production. The type stands as the ultimate development of the Char de Bataille program initiated all the way back in 1921, and of which the B1 Bis is the most famous offspring. It would only serve for a few months, plagued by a reliability problem and already being vastly outdated, as a tank designed with close to WW2 principles in a world now entering the Cold War. Source: char-françaisPerhaps the most famous B1 Bis, Pierre Billotte’s B1 Bis n°337 “Eure”, 41ème BCC, 3ème DcR, 1940B1 Bis n°204 “Tunisie”, 15ème BCC, 2ème DcR, 1940.B1 Bis n°492 “Jean Bart” with an unusual gray camouflage, 28ème BCC, 1ère DcR, 1940FFI B1 Bis captured from the German garrison and used during the Paris uprising, August 194413ème Régiment de Dragons B1 Bis “Crouy”, painted in American Olive Drab with basic allied markings, 1945B1 Bis n°251 “Fantasque” with an experimental, forest-like camouflage, Versailles Tank School, December 1939Saumur’s B1 Bis Rhône, currently exposed in France’s largest tank museumSaumur’s B1 Bis Rhin, used by the museum for technical demonstrations as part of its own carrousel as well as, occasionally, Bovington’s Tankfest. All illustrations created by David Bocquelet and modified by Pavel “Carpaticus” Alexe and funded by our Patreon campaign
Char B1 Bis Specifications
Dimensions (l-w-h)
6.37 x 2.58 x 2.79 m
Ground Clearance
0.48m
Total weight
31,500 kg
Engine
Renault 6-cylinders 16,625 cm3, 307 hp at 1,900 rpm petrol
75 mm SA 35 infantry support gun with 74 shells; 47 mm SA 35 anti-tank gun with 50 shells
Secondary armament
2x MAC 31E 7.5 mm machine gun with 5,250 rounds
Hull Armor
60 mm (front)
55 mm (sides)
50 mm (rear)
Turret armor
56 mm (all sides)
48 mm (cupola)
30 mm (roof)
Radio
ER 53
Fuel tanks
400 litres
Range
160 km
Autonomy
6 to 8 hours
Production numbers
~369
Sources:
Trackstory n°13: Le Char B1, Editions du Barbotin, Pascal Danjou
Tous les blindés de l’Armée Française 1914-1940, François Vauvillier, Histoire & Collection editions
GBM N°107 (January-February-March 2014), Histoire & Collections editions, “Les voies difficultueuses du char de bataille”, Stéphane Ferrard
Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels Panzer IV vs Char B1 bis: France 1940 (Duel), Steven J. Zaloga, 2011 Panzer Tracts No.19 Beute-Panzerkampfwagen, Thomas L.Jentz & Werner Regenberg, 2007 Char-français
Journal de Marche de la 1ère Division Cuirassée
Journal de Marche de la 2ème Division Cuirassée
Journal de Marche de la 3ème Division Cuirassée
Journal de Marche de la 4ème Division Cuirassée
Journal de Marche du 28ème BCC
Journal de Marche du 37ème BCC
Journal de Marche du 8ème BCC
Journal de Marche du 15ème BCC
Journal de Marche du 41ème BCC
Journal de Marche du 49ème BCC
Journal de Marche du 46ème BCC
Journal de Marche du 47ème BCC Tbof.us (guns) shadock.free Armesfrançaises (MAC 31)
France (1925-1940)
Heavy Infantry Tank – 3 Prototypes + 32 Production Vehicles Built
The B1 is one of the most famous and recognized French tank designs of the interwar era. The heaviest tank used in the campaign of France outside of the rare FCM 2C, notable for its dual gun configuration mounting a turreted 47 mm anti-tank gun and a hull-mounted 75 mm infantry support gun, the B1 and B1 Bis often have a reputation of strong armor and firepower that largely outclassed their opponents, not so different from the later German Tiger I and II in how they are viewed in the popular imagination. The story and capacities of the B1 are far more complex though and go back all the way to the 1920s.
The Char de Bataille concept: an armored crystallization of France’s WW1 traumatisms
The roots of what would become the B1 go all the way back to the First World War, and how it played out for France. Initially outclassed by a German Army that made more use of machine guns and heavy artillery, France saw Germany’s armies make quick progress through its lands in 1914, seizing some considerable industrial centers and only being stopped and slightly driven back a few dozen kilometers away from Paris at the Battle of the Marne, in September of 1914. From this point onward, despite numerous attempts by both sides, large breakthroughs proved impossible to achieve. The French Army was bled white in numerous offensives launched on the Germans, or defending against German offensives. France suffered the second-highest casualties per population rate during the war, behind only Serbia (as well as Russia if the civil war is counted in addition to WW1).
Armor quickly developed within the minds of engineers of both France and Britain as a way to overcome the power of machine guns, repeating rifles, and artillery, which bogged down infantry offensives. Production of tanks began in 1916 for France, with the Schneider CA1 and the Saint-Chamond, which both proved rather ineffective designs. In 1918, the much lighter Renault FT was deployed en masse, and with its modern features such as a fully-rotating turret (which had been used in armored cars previously, but not in operational tanks, though the Little Willie prototype mounted one) and a separate engine and crew compartment, proved vastly effective. It is often considered the best tank of the war, all nations taken into consideration. However, the FT had light armament: either an 8 mm machine gun or a short 37 mm infantry support gun. The idea of tanks that could combine the FT’s modernity and agility but mount larger, more destructive weaponry, was particularly attractive at the conclusion of the conflict.
In 1921, General Jean Estienne, leader of the subdivision des chars de combat (ENG: Subdivision of Combat Tanks), the branch of the French Army’s infantry which operated tanks (previously known as the AS, Artillerie Spéciale, ENG: Special artillery), formulated requirements for a new tank concept. Known as the Char de Bataille (ENG: Battle Tank), the requirements formulated by Estienne requested a 13-tonne tank, armed with either a 47 mm or a 75 mm gun in the hull, and two machine guns in the turret. It was to be given 25 mm of frontal armor and 20 mm at the sides, have a 120 hp engine and be protected from combat gases. Most importantly, the prototypes which were to be manufactured by the invited companies were not to be adopted and produced as offered. Instead, the most interesting features of each would be taken and combined into a single vehicle. This final design would not be the property of any of the involved manufacturers, but of the French state, with orders then going to each of the manufacturers involved. This organization of the future tank’s production was known as the “Estienne Agreements”. Requirements were sent to five companies, Schneider, Renault, FAMH/Saint-Chamond, FCM and Delaunay-Belleville, though the latter would not offer a new vehicle but a previous prototype that was basically an enlarged FT, and was swiftly rejected.
The Char de Bataille trials: looking for parts to mish-mash
The Char de Bataille prototypes were tested from May of 1924 to March of 1925, starting at Rueil. One had been manufactured by FAMH, and another by FCM, those generally being referred to as the Char de Bataille FAMH or FCM. Schneider and Renault had collaborated to design two different vehicles that shared a turret, engine, and similar hull design. The SRA was manufactured by Renault, and the SRB was manufactured by Schneider. All prototypes had 3 crewmembers and weighed between 15 and 19 tonnes, featured a 75 mm gun in the hull (except the SRB which had a 47 mm), one or two machine guns in a turret, a maximum speed between 15 and 20 km/h, and up to 25 mm or 30 mm of armor.
Though details on what the vehicles went through during their trials are scarce, a number of innovative features were brought into prominence during those. The two Schneider-Renault prototypes were generally the most influential ones, particularly to the future Char de Bataille’s general shape. They also brought some novel features. The SRB, notably, featured the Naeder steering system, an advanced hydraulic steering system that used castor oil and allowed precise movements of the hull required to aim the gun which otherwise had no traverse. It also had metallic track links with a short pitch, while all other vehicles used long pitch tracks with wooden pads which quickly wore out.
Some parts from the other prototypes were also adopted. The FAMH featured a pneumatic suspension system which provided a smooth ride and light controls, while the FCM gave the future Char de Bataille its clutch and gearbox. All said, the two SR prototypes remain by far the most influential.
1925 – 1927: The design takes shape & the Renault mock-up
General Estienne laid the conclusion of the trials in March of 1925. In the end, he requested the future Char de Bataille to use a general configuration based on the Schneider-Renault prototypes, as well as the Renault 180 hp engine used in both. The Naeder steering system was also to be taken from the SRB. While some features were brought on from the FCM and FAMH, the future Char de Bataille’s features were vastly dominated by Renault and Schneider. The two firms, in collaboration with the Sections Technique des Chars de Combat or STCC (ENG: Technical Section of Combat Tanks), assured the design of the future vehicle. A wooden mock-up was manufactured by Renault in 1926.
The Renault mock-up in 1926, note the turret headlights. Source: Tank Archives
The Char de Bataille had obviously been based on the SRA and SRB but had evolved considerably from there. While both had been the heaviest prototypes presented, at about 19 tonnes, the new design appeared even heavier and had a 4-man crew. Though the configuration with the gun mounted to the right was kept, a large, square driver’s post sticking out of the hull at its left, a feature which would be retained on the B1, appeared for the first time on the mockup with the vehicle’s general shape generally closely resembling the future tank. The mock-up was 40 cm longer than the hulls of the SRA or SRB, and the overall dimensions were much bigger. A new suspension system had been devised. It used three large bogies mounted on coil springs, which each contained two smaller bogies of two road wheels. Three independent wheels using leaf springs featured in front of the bogies, and another one at the rear, the purpose of which was track tensioning and handling obstacles. A large frontal pulley also assured track tensioning. The suspension was taller than on previous prototypes, going around all of the hull, a feature somewhat similar to the British rhomboid tanks of WW1, though the suspension’s design in itself was vastly different, and was typical of a tank designed with trench-crossing in mind. This suspension was vastly different from the one of the SR, which used large leaf springs. It allowed the hull to be larger towards the side, extending the internal space of the vehicle, and the crew compartment. Access to the suspension from the vehicle’s interior was possible, while from the exterior, side skirts protected it from mud or damage.
The vehicle’s armor layout also received an upgrade from the Schneider-Renaults. While those had a maximum of 30 mm of armor, the thickest armor plates on the B1’s front were 40 mm thick. These were the unangled plates, as plates which presented a high angle were thinner, at 25 mm. The sides were 30 mm thick, the rear 25 mm unangled, and 20 mm for highly-angled plates. The roof armor was 20 mm thick, and the hull bottom 15 mm. This was a quite impressive armor layout by the standards of the mid-1920s, at a time at which anti-tank weaponry was still in its infancy. This up-armoring also contributed to the vehicle being heavier. A document confirming the Char de Bataille project from 1926 indicates a weight increase from the previous 13 to 19 to 22 tonnes, which actually would still be quite a lot lighter than the weight of the end product.
The turret present on the mockup was designed by Schneider and was an evolution of the previous one featured on the SRA and SRB. It again was planned to receive two machine guns, though which exact model is unknown, as no armament was represented on the mockup’s turret. They may still have been Hotchkiss mle 1914 machine guns firing 8×50 mmR Lebel ammunition, but could instead have consisted of an early model of what would become the MAC 31, as France was already experimenting with its 7.5 mm ammunition by that point, first 7.5×58 mm (FM 24) from 1924 onward, and then 7.5×54 mm (FM 24/29) from 1929 onward. The turret mock-up did, however, feature two headlights, designed to give the commander better visibility at night, but also very vulnerable to any kind of fire (another larger headlight was featured on the hull).
1927: Prototypes are ordered
In 1925, the French Ministry of War decided to order three prototype tanks in order to form an experimental platoon of Char de Bataille, which would allow more in-depth experimentations than with a single prototype. The STCC was given the task of establishing the contracts in November 1925. Three contacts were finally made official in March 1927. One vehicle was ordered from FCM (215 D/L), one from Renault and one from FAMH (which would later be transferred to Renault, the company assuring both the 216 and 217 D/L contracts). Though Schneider may appear to not be favored by those contacts, they were tasked with manufacturing the turrets for each vehicle. In general, each company that designed an element of the Char de Bataille would produce them for the others, which means FCM had to deliver suspensions to Renault, Renault engines to FCM, etcetera…
As for the hull 75 mm guns, it appears they were not newly constructed, but instead taken from the Char de Bataille prototypes, though this is not certain. The first Renault prototype, n°101, would then have used the Schneider-designed 75 mm of the SRA, while n°102 (taken by Renault from FAMH) and 103 (FCM) would have used the FAMH-designed 75 mm guns of the FCM and FAMH Char de Bataille prototypes. The guns used may, however, also have been early models of the 75 mm SA35 gun, designed by the Arsenal de Bourges (ABS) and which would later be featured on the production B1.
Prototype n°101: The first B1
The first prototype of the B1 was manufactured by Renault in its facilities in Billancourt, in the western suburbs of Paris. This first prototype was produced using mild steel, and not military-grade steel, to make changes to the design easier and quicker to perform and to keep costs down. This first prototype was completed in January of 1929 and, shortly after, trials began, though it would only be considered as fully completed in March of the same year, and still undergo various changes throughout its life. It was designated as n°101, though the number 001 was also used at some point of its experimental career. This tank appears to have been the first to use the 6-cylinders, 250 hp bisected aviation engine that would be used on the B1 – an evolution of the 6-cylinders 180 hp aviation engine used on the SRA and SRB. Prototype n°101 appears to have weighed 25.5 tonnes in its original configuration.
The n°101 prototype was mostly similar to the Renault mockup in design, featuring a hull 75 mm gun. As first produced, it appears the prototype was fitted with an evolution of the Schneider dual machine gun turret design. This turret used cast construction and had a flat roof with a command cupola, periscope optics and luminous crosshairs. It was armed with two machine guns, which appear to be early models of the MAC 31, 7.5×54 mm machine gun which would become standard-issue on French tanks during the 1930s. The turret had an armor of 35 mm on all sides and weighed 900 kg. It had a 954 mm turret ring.
Copy of a factory blueprint of n°101, notably showing the significantly revised Schneider turret. Source: Tank ArchivesA side view of prototype nº101 (it is referred to as 102 but actually appears to be of the first prototype), showing the Schneider turret. The barrels are shrouded, which is why they appear larger than on the schematics. Source: Tank Archives
As the first prototype completed, n°101 went through extensive trials, while nº102 and nº103 were still being completed. Changes to the design were still carried on up to April 1930, as the trials put forward a variety of small flaws and issues. In general, the trials were quite often interrupted by breakdowns or failures of parts which had to be replaced, often without a replacement already having been produced to replace the damaged parts. Nonetheless, those first trials were considered to be quite a success. While still in its infancy, the B1 was found to be an impressive design due to its size and theoretical combat capabilities. Driving and traversing the vehicle was also found to be particularly easy for the driver despite its large size, though the Naedar steering system was still found to be fragile and required more work.
Prototypes n°102 & 103: Further experimentations
The two other B1 prototypes, n°102 and n°103, appear to have been completed in 1931, and implemented a number of changes that had been made from the experience with the first B1 prototype. They were made out of military quality steel, instead of mild steel. Prototype n°103 notably presented major differences to 101. It had not been constructed by Renault, as the first two, but by FCM.
The FCM-built prototype had been fitted with a different transmission and traverse system, as a result of worries about the hydrostatic Naeder’s reliability, as well as cost and ease of production. Instead of the Naeder steering system, the vehicle used a hydraulic Winterthur transmission of Swiss design. The Renault 250 hp petrol engine was replaced by a Sulzer 180 hp diesel engine, which was thought to potentially give the vehicle better range and less flammable fuel.
FCM’s n°103 leaves its factory with a dummy turret. Differing quite considerably from the Renault n°101 prototype, the FCM’s vehicle features did not prove satisfactory. Source: Tank Archives
Trials of those features did not go as well as planned though. Trials of the Sulzer engine, produced in Switzerland and performed in the same country, showed it could not produce the desired output of 180 hp, which was already quite low for a vehicle as large and heavy as the B1, while producing excessive smoke. Vibrations also meant some speeds could not be used around the nominal rotation rate of 1200 rpm, which would be incompatible with the proper operation of the tank in combat. The Winterthur transmission was found to not be particularly simpler than the Naeder steering system. Another 180 hp diesel engine designed by an engineer by the name of Clerget was proposed for the B1, but refused by the STCC as it had no guarantees of even reaching this desired horsepower. The diesel and transmission experiments conducted on 103 would therefore not be carried over onto the B1, though they gave experience to FCM on the matter of diesel engines, which would appear in a more reliable form, albeit in a vastly less destructive package than the B1, in the FCM 36 light infantry tank of the late 1930s.
The experimental section and its trials
An experimental section that included the three B1 prototypes was formed in 1931, with the crews beginning operation of their experimental tanks after a test period that went from August to October of 1931, in Rueil. On 23rd October 1931, the experimental section left Rueil, skirting across Paris’s region at an average speed of 12 km/h and a maximum speed of 22 km/h (with supply trailers, a feature studied on the SRA/SRB and retained on the B1). On Christmas Eve 1931, the three prototypes went back to Rueil, in a 23-hours, 225 km-long journey in snowy conditions. While this may not seem particularly impressive by more modern standards, this was quite a lot for an experimental tank in the early 1930s. By the end of 1931, the B1s had each run for about 100 hours, and crossed about 1,000 km in a variety of different terrains. The report concluding on those 1931 trials stated that, while the B1 had some defects that would require fixing, it was a “good mechanic work, its robustness and rusticity making it an impressive battlefield machine.” The trials showed that, after a journey of 50 km, the tanks would be immediately ready to enter combat. 12 hours would be required for maintenance and for the crew to rest after a 100 km journey, and 24 hours after a 200 km one. Trials of the three prototypes continued in the following years, with the vehicles being tested at the base of Mourmelon and trialed in mechanized manoeuvers in 1932.
B1 n°103 during anti-tank obstacles crossing trials. Note the Schneider turret and open driver’s hatch. Source: Tank archives
The trials, however, also showed that the B1 was a complex machine which required extensive maintenance to be kept in working order, more so than most tanks of the era. Greasing the suspension mechanism was necessary every 100 km, and this operation took ten hours. Draining the engine and Naeder steering system was necessary every 500 km, a 15-hour operation. Repairing those was also time consuming, as well as an extensive operation hard to perform for field workshops. A full day was needed to change the engine or hull 75 mm gun, 15 hours to change a Naeder steering system, and those required the use of a 2-tonne overhead crane.
B1 n°101 during trials with a prototype radio antenna, which proved ineffective as reception beyond 50 meters was nil. This photo also shows the vehicle with a large number of headlights: one on top of each weapon, and a large one right of the driver’s post. The B1 prototypes received a number of modifications and experimental features during their trials, particularly the mild steel n°101. Source: Tank Archives
A bigger, meaner turret: Experimenting on n°101
As produced, all three B1 prototypes used the Schneider machine gun armed turret,which only provided a very weak armament. The turret was meant more as a command post for the commander to observe the battlefield and command the crew from, with the machine guns being used in a defensive role while the 75 mm would provide the tank’s offensive firepower. This solution was quite lacking when it came to dealing with enemy armored vehicles. While the 75 mm would have the power to punch through the armor of almost all tanks of the era, with its low velocity and lack of traverse, it would be very challenging to aim against small or moving targets.
As a result of this, more heavily armed turrets were experimented on B1 n°101, seemingly from 1932 onward. The first turret tested was an experimental turret of what would become the ST1, which would be temporarily mounted on the D1 infantry tank. This turret was of cast design. Its armament was a 47 mm gun based on the 47 mm mle 1902 naval gun (originally designed as an anti-torpedo boat gun, but which became a decent gun to base anti-tank gun studies on thanks to its decent velocity and rate of fire). Though the final ST1 design mounted on the D1 featured a coaxial machine gun, the experimental turret mounted on the B1 does not appear to have one.
A formidable view of B1 n°101 with the ST1 turret prototype, showing the turret’s cast construction and its 47 mm naval gun, as well as the hull 75 mm gun and driver’s post. Source: Tank ArchivesA side view of B1 n°101, taken on the same day as the previous one, showing the small size of the turret. Of note, the number “001” on the vehicle’s hull, which was sometimes used interchangeably with 101. Source: Tank Archives
The ST1 was a particularly ambitious concept. It was devised as a “universal turret”, which could be mounted on both the heavy Char B and the lighter Char D. It was even designed to be able to be mounted on the hull of the FT. While this was a theoretically interesting idea, mounting a single turret design across a wide variety of armored vehicles, it resulted in the ST1 being a cramped, one-man turret, with poor balance and vision.
N°101 was later fitted with a more advanced turret design, the ST2. Designed after the failure of the ST1, this turret, while remaining very similar to the ST1 in the sense that it was a one-man, 47 mm mle 1902-armed, cast turret, featured better ergonomics and balance. It would end up being adopted as the standard turret for the D1, though deliveries would only start from 1936 onward.
B1 n°101 with the ST2 turret seemingly lacking its main gun, as well as a variety of spare parts used to simulate extra weight. Source: char-françaisSchematics of the B1 with the ST2 turret. Source: char-français
The ST2 was still a less than ideal design as it was viewed as poorly protected, and lacked an electric motor to allow for quick rotation. Therefore, in December of 1933, studies began on a new turret, which would retain a 47 mm armament (though a different model), used a cast design, and featured independent elevation for the coaxial machine gun. This would become the APX 1 turret, though it does not appear to have been mounted on any of the B1 prototypes while they were at the experimental stage.
The looming specter of… light tanks and international disarmament treaties
Though the B1 progressed slowly but steadily across the late 1920s and early 1930s, the heavy infantry tank was far from being without opposition during this process. As early as the first trials of n°101, some officers expressed their preference for the lighter D1, a derivative of the NC, itself an enlarged variant of the Renault FT. Though far less technologically advanced, the D1 was vastly more economical, and could be produced much earlier and in much larger numbers than the B1 if ordered at a large scale.
The point of view that supported the D1 over the B1 gained considerable leverage when, in the early 1930s, international treaties put the question of a maximum allowed weight for tanks on the table. The most notable was the Geneva Conference of 2nd February 1932. Within the topics treated by this disarmament conference, was the idea of putting a maximum weight limit on tanks. Specifically, the weight of new tanks would have been reduced to 20 tonnes. This was a massive threat to the B1, which had at this point largely exceeded this weight limit, at about 27 tonnes. At the same time, while the D1 appeared increasingly obsolete in comparison to the B1, a new, lighter tank design was being studied by Renault, the UZ, which would become the D2. Studies on it started in January of 1930, with the first prototype manufactured in 1932. The D2 provided a similar armor layout of 40 mm maximum thickness, and its firepower was similar to the one provided by the gun-turret of the B1, seeing as the prototype was first armed with an ST turret, and then an APX 1. However, and crucially, it was lighter, at 19.75 tonnes, just below the limit discussed at the conference. The D2 option was further supported by the fact a 75 mm-armed assault gun based on the chassis of a colonial prototype, the 75 Garnier-Renault based on the D3, was being studied, and could realistically also fit within the 20 tonnes limit. The combination of the two could have offered the same firepower as the B1 (the 75 mm on the Garnier-Renault even being higher-velocity than the B1’s) while remaining safe from international treaties.
The saving grace of the B1 may have come from the rise of the Nationalist Socialist regime in Germany. On 14th October 1933, the new German regime announced it was withdrawing from the discussions of the Geneva Conference, largely putting the legitimacy and usefulness of the conference in question. This pushed the French Army to finally pass a first production order for the B1 in March of 1934 after two years of consideration, and the French government to announce it would assure its security by its own means and withdraw from the conference on 17th April 1934.
Two crewmen sit in front of a D1 fitted with the ST2 turret. Though it may appear ludicrous from a modern lens, the D1 was seriously considered as an alternative to the B1 in the early 1930s. Source: char-françaisFour D2s of the 19ème BCC in a field. A considerable refinement of the D1 design, the D2 appeared as a serious alternative to the B1, less armed perhaps, but lighter and cheaper. Source: char-françaisThe Garnier-Renault 75 mm assault gun. Based on the D3 colonial tank prototype, and armed with a 75 mm gun, this vehicle, which reached prototype stage in 1934, would perhaps have been coupled with the D2 in case the Geneva Conference had made the adoption of the B1 impossible. Source: char-français
Production orders
The first production order for the B1 came on 16th March 1934, motivated by the abandonment of the Geneva Conference, and perhaps by the rise of an increasingly hostile regime in Germany. This contact, 30 D/P, contained seven vehicles, which were to be delivered from September of 1935 to January of 1936. This contract only concerned the hulls of the vehicles, with the turret orders being separate. The production arrangements were also slow and complex. All the way back in 1921, it had been agreed that the production of the Char de Bataille would involve all manufacturers which had taken part in the project, which made the production of this multi-company machine particularly complex. Price was also a considerable concern, with the offer by the manufacturers being 2,500,000 Francs for each hull, which was reduced to 1,400,000 for the first order. A second order for 20 vehicles (14 which were to be assembled by Renault and 6 by FCM) was passed in April 1934 with a price of 1,218,000 francs per unit. In comparison, a D2 hull had a price of 410,000 francs. A last order for 5 vehicles, all to be assembled by FCM, was passed in April of 1935. In the end, 32 production B1s would actually be manufactured. Prototypes n°102 and n°103 were also refitted to the production standard and issued operationally, giving a total of 34 operational B1 tanks. The first production B1, n°104 “Verdun”, was delivered in December 1935.
All orders placed after April of 1935 were for an improved model of the B1, largely similar but featuring, most notably, improved armor and firepower; the B1 Bis, which would immediately follow the B1 on the assembly lines of FCM and Renault. The first B1 Bis, N°201 “France”, would enter service in February of 1937. This was actually earlier than the last B1, n°135 “Morvan”, delivered in July of 1937. The France was manufactured by Renault, while the Morvan was one of the five vehicles of the last B1 order, assembled by FCM.
Hull Design
The B1’s hull was a quite narrow and elongated design, as a result of being designed with crossing capacities, particularly for trenches, in mind. The vehicle had a length of 6.89 m including the towing hook, with length from the front to the rear of the tracks being 6.37 m. The tank was 2.50 m wide, 2.79 m high including the turret, and had a ground clearance of 0.48 m.
The B1’s hull front, sides and rear consisted of bolted 40 mm-thick plates, angled rearward for the front plates. The most notable feature of the hull front outside of the 75 mm gun was the driver’s plate. Placed to the vehicle’s left, it was a large armored box which stuck out of the general shape of the hull. This post featured a number of vision devices: small vision ports on the sides and lower front, closable episcopic sight, telescopic sight, and an openable central hatch.
The driver’s post on the B1. Source: char-français
The hull also featured a radio, placed under the turret ring. This was an ER 53 model 1932 radio. It only operated on a morse key, with no voice option. It had a range of about 15 km, and a weight of 80 kg. A crewman was tasked with operating this radio and with handing 47 mm shells from the hull racks to the commander.
This radio was installed on the crew compartment side of the bulkhead which separated it from the engine compartment. A particularly interesting feature of the B1 is that a door existed to enter this engine compartment. It led to a small corridor on the right side of the vehicle, which allowed access to the engine, and even the transmission and Naeder steering system, all the way at the back of the hull. The engine used was a development of the one featured on the B1 n°101, itself based on those of the SRA and SRB. It was a 272 hp, 6-cylinder, 140×180 mm, 16,625 cm3 petrol engine. The B1’s transmission had 5 forward and 1 reverse speed. The 27,195 kg B1 could reach a maximum speed of 28 km/h on road. With its 400 litre fuel tanks, it had an average range of 8 to 10 hours or around 200 km, with a fuel consumption of 200 litres per 100 km on average. The horsepower per ton ratio was 8.9.
Hull Gun: 75 mm SA 35
The gun mounted on the B1’s hull was a 75 mm short gun, mounted on the right side of the hull, in a mount that allowed an elevation of -15° to +25° degrees, but no lateral traverse. The gun was a 75 mm modèle 1929 ABS gun, also sometimes known as the 75 mm SA 35. This gun was designed by the Arsenal de Bourges.
The 75 mm gun was a short design (L/17.1). The shells it fired were 75×241 mm Rimmed, based on the larger 75×350 mm shells fired by the 75 mm mle 1897, the French Army’s standard field gun in WW1 and, to an extent, also WW2.
Two shells were standard-issue for the 75 mm ABS. The first was the Obus de rupture Mle.1910M (ENG : Rupture Shell model 1910M), which was an armored piercing high-explosive shell. The shell had a weight of 6.4 kg, and contained 90 grams of explosives. It was fired at a muzzle velocity of 220 m/s. It offered an armor penetration of 40 mm at an incidence of 30° and a range of 400 meters. Though this was a respectable performance by the 1930s, it should be noted that this shell was designed to engage fortifications, and not tanks. The traverse-less hull mounting of the 75 mm meant it was generally a poor weapon against armor, except perhaps at close range.
The other shell was the Obus explosif modèle 1915 (ENG: Explosive Shell model 1915), a high-explosive shell. It weighed 5.55 kg, and contained 740 grams of explosive. It was fired at a muzzle velocity of 220 m/s.
Sights provided for the 75 mm gun were two L.710s, which formed prismatic binocular sights. This gave a field of view of 11.5°. Range ladders were provided for up to 1,600 m with HE and 1,560 m for APHE shells.
A view of the interior of a B1. To the left, the driver/gunner’s post, and to the right, the 75 mm SA 35 gun’s breech, and the MAC 31E hull machine gun. Source: Collection Dominique Dumay via char-français
Two crew members were involved in the operation of the 75 mm gun. To the left of the hull, the driver also assumed the role of gunner. He would aim the gun (both laterally by traversing the tank, as he controlled the Naeder traverse system, and vertically) and fire it. Behind the 75 mm gun, seemingly sitting on the floor as no seat appears to have been provided, was the loader of the gun. Eighty 75 mm shells were carried within the hull of the B1. The theoretical rate of fire of the gun was quite high, at 15 rounds per minute, however, within the constraints of an enclosed armored vehicle with a limited crew (the driver/gunner was quite overtasked, though this was nowhere near as bad as the commander), the rate of fire would be closer to 6 rounds per minute with APHE shells and the first 6 HE shells. After that, as the fuses would have to be inserted into the shells for HE, the rate of fire would decrease to 2 to 4 rounds per minute.
The hull armament also featured a 7.5 mm MAC31E machine gun mounted to the right of the gun, in a fixed mount. The machine gun was invisible from the outside of the tank, and with absolutely no traverse, would have been a weapon of very little use, far more situational and less practical than the coaxial machine gun in the turret.
Diagram of the mount for the hull machine gun of the B1/ B1 Bis. Source: ATF40 forum
The Naeder steering system: Centerpiece or Achilles heel?
The gun mount of the B1’s 75 mm did not allow for any lateral traverse, meaning aiming the gun horizontally was assured by rotating the hull itself. This required precise traverse to be possible. This was assured by a system called the Naeder.
The Naeder system’s creation predates the B1, with a first patent filed in 1907, with several additional ones and improvements coming in the following years.
The Naeder used the engine’s movement to either suck in or out castor oil heated to 80° degrees Celsius, which was used to traverse the hull with great accuracy. The Naeder system consisted of a generator, a receptor that received the movement from the steering wheel, and a distribution system for the castor oil. 23 to 35 liters of castor oil were stored within the radiator of the Naeder, and 12 within the machine itself. The system was operated by an independent steering wheel at the front, handled by the driver, which transmitted the command to the Naeder via a Brampton transmission chain.
Cut-through of the Naeder system. This is taken from the B1 bis manual, though the machine was identical on the B1. Source: Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
The Naeder was first mounted on a tank with the SRB and was kept for the B1, except for N°103 which used another system. The machine had a weight of 400 to 450 kg, depending on the actual model, and was mounted at the rear of the engine compartment.
The Naeder was a quite complex piece of machinery, which was expensive and time-consuming to produce. 1,000 were ordered in 1935, in order to satisfy both the B1 and its evolved model, the B1 Bis, which had by this point been ordered, though only 633 would be completed by the time of the fall of France. The Naeder system was not immune to breakdowns, which could often immobilize the whole tank. At the same time, it provided a very accurate traverse for the era, and its bad reputation may have somewhat been overestimated. While, as most complicated pieces of machinery, the system was indeed vulnerable to breakdowns, it appears that the system was purposefully given a bad reputation by the Ministry of War, which wrongly put out the idea that the Naeder was only a temporary solution kept for lack of a better option in order to give the idea that it was inefficient, and not worth copying.
One of, if arguably the worst issue the Naeder had was with crew training and castor oil. The Naeder system indeed used castor oil, however, automotive castor oil was not identical to pharmaceutical castor oil, with the latter being unable to be used properly at 80°C, causing breakdowns. However, this significant difference between automotive and pharmaceutical castor oil was not mentioned at any point in the manuals of the B1 (nor B1 Bis). While professional crews who had long-time experience with their machines had usually been informed of the difference, newly-formed, recruit crews were not. This resulted in many emptying drug stores of their castor oil to put into their B1s during the campaign of France, only to cause the system to break down and often bring the whole tank along with it. The Naeder was also criticized for causing excessive fuel consumption, as it required the engine to be turned on in order to operate.
Drivetrain, suspension and crossing capacities
As the vehicle’s overall long and narrow design suggests, the B1 was designed to have considerable cross-country capacities, potentially at the cost of maximum speed. Those decisions also reflected on the vehicle’s suspension design. It had remained mostly unchanged since the n°101 prototype and Renault mockup. It used three large bogies mounted on coil springs, which each contained two smaller bogies with two road wheels. Three independent wheels using leaf springs were featured in front of the bogies, and another one at the rear, the purpose of which was track tensioning. A large frontal pulley also assured the track tensioning.
A view of the B1’s suspension. Two of the three large bogies are cut so as to allow all elements of the drivetrain to fit on one page. Source: Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
This suspension was entirely protected by large side skirts, designed to protect it from mud, firearms, and artillery shell splinters. A large central door with an opening radius of 90 mm was featured on the center of the B1’s right side, while the left side of the hull had a large radiator grille.
The B1 used large, welded track links. There were 63 individual track links per side. They were 460mm wide. The tracks went all around the hull, with large mudguards protecting them along the top.
With its design’s emphasis on trench crossing, the B1 was able to cross a 2.75 m wide trench, or a slope of up to 30°; vertical obstacles up to 0.93 m in height, and ford 1.05 m without preparation.
The first of the APX cast turrets
The B1 mounted the APX 1 turret. Designed by the Arsenal de Puteaux/APX from December 1933 onward, this turret was a cast, somewhat cylindrical design, which would be fitted on both the B1 and the D2, and serve as basis for the APX 1 CE and APX 4 mounted on the S35 and B1 Bis, respectively.
A view of B1 n°104 Verdun, the first production B1, as well as apparently the first to receive the APX 1 turret, on parade in Paris on 14th July. Source: char-français
This turret was given 40 mm of armor on all sides, as the hull. It had a turret ring of 1,022 mm in diameter. Cast construction was, for the time, an advanced feature, which allowed for some good level of protection and integrity. At the same time, it was expensive and time-consuming to produce, meaning production of cast turrets in general often lagged behind hull production on all French vehicles which used such turrets.
A single crewman sat in the turret, the commander. He could observe the battlefield through an unopenable command cupola. The commander entered the tank through the side hatch, as did the three other crew members, but the APX 1 turret featured a hatch at the back, which could be opened and then serve as a seat for the commander looking over the turret. This allowed him to observe the battlefield more efficiently, as well as evacuate the tank if needed.
Mediocre anti-tank firepower
The turret’s main gun was a 47 mm SA 34 semi-automatic anti-tank gun. It had been designed by APX on the basis of the 47 mm mle 1902 naval gun. Being L/30, it had an average length, though a slow muzzle velocity of 450 to 490 m/s depending on the shell. The theoretical rate of fire was up to 15 rounds per minute, but in practice, in the enclosed environment of a tank, and most significantly as all the operation of the gun was done by a single crewmember, the commander, the rate of fire was closer to 2 to 3 rounds per minute.
The 47 mm SA 34 had an L.671 telescopic sight, which had a magnification of 4x, and a field of view of 11.25°. It had a V-shaped reticle, with adjustable drums up to 1,100 m for the main gun, and 1,600 m for the coaxial machine gun. It had a good depression of -18°, and an elevation of +18°.
View of the 47 mm SA 34 gun which was used on a number of French tanks of the 1930s. Source: Trackstory n°3 “Les chars B”.
Three different shells were standard-issue, all 47×139 mm rimmed. The anti-tank shell was the Obus de rupture Mle1892G. It was a 1.48 kg projectile with 50 grams of explosives and was fired at 450 m/s. This shell had a fairly mediocre armor-piercing capacity, with 31 mm of armor on a straight plate at 100 m, 23 mm at 500 m, and 18 mm at 1 km. Two explosive shells existed, the 1.25 kg Type D and the 1.41 kg Type B model 1932. The latter, which appears to have been the most common, had a 142 grams explosive charge and was fired at 480 m/s.
A view of a MAC 31E, the tank version of the MAC 31. This example is fed from the left, with both a right and left-fed existing in the French Army. Source: armesfrançaises.free
Secondary armament was provided in the form of a coaxial MAC31 Type E machine gun, the shorter, tank version of the MAC 31 which had been designed for fortification use. It used the new standard French cartridge, the 7.5×54 mm. The MAC31 Type E had a weight of 11.18 kg empty and 18.48 kg with a fully loaded 150-round drum magazine. The machine gun was gas-fed, and had a maximum cyclic rate of fire of 750 rounds per minute. It had a muzzle velocity of 775 m/s. This coaxial machine gun had independent elevation from the main gun. 4,800 7.5 mm rounds were carried within the B1.
A unique accessory of the B1: The Schneider supply trailer
An original (and arguably quite archaic, even for the time) accessory which was used alongside the B1 was the Schneider supply trailer. This trailer had been developed by Schneider, seemingly for the time of the Char de Bataille, with a prototype already being featured alongside the SRB prototype in 1924.
The idea was to design a trailer that would be towed for the B1. Its main function would be to carry a large quantity of fuel, which would be used to artificially extend the range of the B1. Additionally, this trailer could carry tools and spare parts. The prototypes used on the SRB and B1 prototypes even had benches for up to eight personnel, though this was not used on the final production model used on the B1s.
A prototype of the Schneider trailer, still featuring benches, being towed by B1 n°101. Source: char-français
The final version of the Schneider trailer that was used by operational B1s weighed 1,400 kg empty and used two wheels with puncture-proof Michelin tires. It featured vision lights, powered by a cable to the B1’s rear electric branching.
When full, the trailer carried 800 liters of fuel, which extended the B1’s range to 21-30 hours, instead of the 8-10 original hours. The trailer also carried two 100 liters water cans, crates containing cans of various types of oils: 30 liters of thick oil, 40 liters of CM oil, and 40 liters of semi-fluid oil. Most notably, one 50 liters can of castor oil used for the Naeder was carried. The trailer also carried a variety of tools (oilers, bulbs, fuses, thermix heaters) and equipment as well as spare parts, from bolts and valves to two track-links.
A view of 4 B1s, at least two of which are towing Schneider supply trailers. Source: http://panzerserra.blogspot.com/2014/02/char-b1-bis-part-01.html
It was originally planned to have 10 trailers for each B1 company, with three companies existing in total. However, the trailers proved unsatisfactory, as they were very vulnerable and could not be reasonably towed anywhere near combat and were abandoned as early as 1936. The lack of a mobile supply of oil and spare parts for the maintenance and fuel-hungry B1s would push the development of the Lorraine 37L tracked and armored supply vehicles, as well as their predecessor, the Renault TRC 36. Some trailers appear to have been brought back into operation in 1940 because of the lack of these mobile supply vehicles.
Slow deliveries and incomplete tanks
The production of the B1 was particularly slow and sluggish, which was to be expected for a new type of tank that was particularly complex and required elements from a large number of different manufacturers. The first serial produced vehicle, n°104 “Verdun”, would be delivered in December 1935, and the last, n°135 “Morvan”, in July 1937.
As they were delivered, the tanks were also not complete. The turrets were delivered separately, as were the guns. This meant that for a while, the B1s were used operationally without the 75 mm hull gun, with a steel plate replacing the large hull mount. All B1s were fully completed to the serial standard by the start of WW2 though. It appears, most, if not all, had the 75 mm gun by 14th July 1937, for the Bastille Day celebrations.
B1 n°110 “Belfort” without the 75 mm gun, likely in 1936 or 1937. Source: char-françaisB1 n°124 “Dauphiné” without the 75 mm gun. A Schneider trailer can be seen in the background. Source: char-français
Peacetime service
A column of B1s led by n°111 “Belfort”, all still lacking the 75 mm gun. Source: char-français
The B1s were delivered to the 511ème Régiment de Char de Combat (ENG: 511th Combat Tanks Regiment). The regiment was created from the 51ème BCL (Bataillon de Char Lourd / ENG: Heavy tank battalion), of fame for operating the super-heavy Char 2Cs. The regiment consisted of a company of Char 2Cs, as well as a 3-company battalion of R35 light tanks, and a 3-company battalion of Char Bs. The tanks were given the names of French regions or cities, especially cities of Alsace-Lorraine or near France’s eastern borders in the latter case.
The companies of the 511ème RCC which operated the B1s were the 4th, 5th and 6th companies. The 4th company was comprised of n°102 Armorique (the transformed second prototype), n°105 Strasbourg, n°115 Ardennes, n°124 Dauphiné, n°125 Provence, n°128 Flandres, n°129 Languedoc, n°133 Nivernais and n°134 Champagne. The 5th company was comprised of n°106 Metz, n°108 Dixmude, n°112 Mulhouse, n°113 Colmar, n°114 Bretagne, n°120 Franche-Comté, n°123 Alpes, n°126 Pyrénées, n°130 Île-de-France and n°135 Morvan. The 6th company was comprised of n° 103 Lorraine (the transformed FCM prototype), n°109 Nancy, n°110 Belfort, n°111 Dunkerque, n°116 Normandie, n°117 Vendée, n°118 Auvergne, n°122 Alsace, n°127 Jura, n°131 Touraine and n°132 Poitou. N°104 Verdun was the command tank of the regiment’s leader, Colonel Bruneau. Tanks n°119 Béarn, n°121 Bourgogne and n°107 Reims were kept in reserve.
B1s of the 511ème RCC preparing for a parade in a French town. Source: Track n°13 “Le char B1”.
While the B1 was now in operational service, its use still was very experimental. The B1 companies of the 511ème RCC were mostly an experiment, in order to prepare for the massive entry in service of the improved model, the B1 Bis.
From 1936 to 1939, the B1s participated in a number of maneuvers and were also sometimes put at the disposal of other services of the French military for training purposes.
B1s of the 511ème RCC on parade in Paris, led by the Dunkerque, 14th July 1937. Source: char-françaisLanguedoc with an experimental anti-aircraft mount for the MAC 31E machine gun. Source: char-français
The Sudeten crisis of September 1938 led to the 511ème RCC being mobilized and being prepared for combat duties if a conflict was to break out with Germany. The regiment was mobilized from 23rd September 1938 to 1st November of the same year, when the regiment was demobilized and came back to normal, peacetime operations.
Mobilization and early wartime service
The month of August 1939 saw the French Army remobilize in a context of renewed international tensions around Poland. On the 20th, soldier leaves were reduced and, on the 22nd, the regiment mobilized, with officers being called back from permissions. The 511ème regiment was dissolved on 27th August, with its different components becoming new units. The 4th, 5th, and 6th companies, which operated the B1, became the three companies of the 37ème Bataillon de Chars de Combat (ENG: Combat Tank Battalion). This battalion remaining close to the R35 and FCM 2C that were part of the 511ème Régiment, as the two other new units, the R35-equipped 9ème BCC and the FCM 2C-equipped 51ème BCC remained part of the Groupe de Bataillons de Chars n°511 (ENG: Tank battalion group) along with the B1-equipped 37ème BCC.
The service of the B1 within the 37ème BCC would be short though. During the so-called Phoney War, they were entirely phased out by the more modern B1 Bis, and distributed to various training units.
B1 n°124 Dauphiné tested with a fascine-carrying mechanism that would have been used to allow the crossing of gaps and trenches. As suggested by the gun being the SA 35, this photo was during the war, showing B1s were still used for a variety of experiments. Source: http://panzerserra.blogspot.com/2014/02/char-b1-bis-part-01.html
The 47mm SA 35 refit
During the Phoney War, the APX 1 turrets of the B1s were re-armed with the 47 mm SA 35 gun, the same fitted in the S35 and B1 Bis. Though only slightly longer than the previous 47 mm SA 34, at L/32, the SA 35 offered far superior performances.
The 47 mm SA 35 gun used, in the APX 1 turret, a L.762 sight, providing a field of view of 11.82°. The reticle used was first V-shaped, later +-shaped.
A view of the 47 mm SA 35 gun used on the refitted B1 as well as B1 Bis, S35 and second-series D2. Source: http://www.dws-xip.pl/encyklopedia/brpoj47sa35-fr/
The standard issue shells for the 47 mm SA 35 were the Obus de rupture modèle 1935, and the Obus explosif modèle 1932, both 47×193 mm.
The Obus de Rupture modèle 1935 was an armor-piercing capped (APC) shell. It weighed 1.62 kg, and was fired at 660 m/s. German testing of the shell showed an armor penetration of 40 mm at an incidence of 30° and a range of 400 m. This was far superior to the penetration capacities of the SA 34.
The Obus explosif modèle 1932 was a high-explosive (HE) shell. It weighed 1.41 kg, including 142 grams of explosives, and was fired at a muzzle velocity of 590 m/s.
A lower frontal view of B1 n°127 Jura re-armed with the 47 mm SA 35 in the winter of 1940, showing the longer barrel. Source: char-français
Refitting the B1 with the SA 35 was a quite simple upgrade, which gave the tank equal anti-tank capabilities to the B1 Bis. It appears the vast majority of B1s were refitted, though it is not certain if a couple of vehicles did not undergo this transformation.
Within the units which received B1s were two BIC, Bataillons d’Instruction des Chars (ENG: Tank Instruction Battalions). These were the 106ème and 108ème BIC, created on 11th and 10th April 1940, respectively. The 106ème BIC received two B1s and a B1 Bis, with the 108ème receiving 3 B1s.
The 106ème BIC received the n°106 Metz and n°113 Colmar, along with a B1 Bis, n°403 Crécy Au Mont. This unit, like other BICs, was used to teach the operation of the vehicles to their crews. Having B1s in BICs was a very welcome evolution, as those units previously only had FTs (24 for the 106ème BIC), which were nowhere near the level of complexity of the B1 Bis the crews would then inherit. The 106ème BIC’s B1 were requisitioned to form an operational section of Char Bs on 17th May 1940. This included the Crécy Au Mont and Metz, however, the Colmar was at this point unoperational, and was awaiting a spare part. It ended up being abandoned.
The 108ème BIC received three B1s; n°102 Armorique, n°107 Reims, and n°108 Dixmude. It was dissolved as early as 15th May 1940, with its B1 forming an independent section of tanks while the FTs formed various protection sections, typically used in second-line tasks such as airfield defenses. This B1 section was tasked with defending the town of Charité-sur-Loire, on the River Loire, on 15th June 1940. It was hoped to form a solid defensive line behind this river, the largest in France. The Reims was abandoned on 17th June after breakdowns, with its armament being scuttled by the crew. The Dixmude appears to have been lost in combat but to have suffered minimal damage. The Armorique was also captured by the Germans after being abandoned by its crew with little damage appearing on the vehicle.
German soldiers inspect the abandoned n°107 Reims on the side of a road, as a motorized column passes. Source: char-françaisA German soldier poses in front of the n°108 Dixmude at the side of an agricultural building. Source: char-françaisTwo German soldiers pose on top of n°102 Armorique, one of the two B1 prototypes to have been converted to production standard. Source: char-français
The B1s of the 106ème and 108ème BICs
11 B1s were in the hands of the PEB 101, Parcs d’Engins Blindés (ENG: Armored Vehicles Park), during the campaign of France. This was a maintenance and storage unit. The B1s it had were n°105 Strasbourg, n°114 Bretagne, n°115 Ardennes, n°120 Franche-Comté, n°123 Alpes, n°124 Dauphiné, n°126 Pyrénées, n°128 Flandres, n°129 Languedoc, n°131 Touraine, and n°135 Morvan.
Little is known about what happened to the B1s of the PEB during the campaign. Photos show a number of them appear to have been engaged during the campaign. Bretagne, Ardenne, and Dauphiné were all photographed abandoned with superficial or absent exterior damage, likely victims of breakdowns.
The n°114 Bretagne abandoned under a tree, with the hatches open. Source: char-françaisN°115 Ardennes abandoned on a road, once again with hatches open and minimal damage. Source: char-françaisGerman soldiers pose in front of the abandoned n°124 Dauphiné, seemingly with 75 mm shells taken from the tank’s racks. Source: char-français
Back into service with the 37ème BCC
The battalion the B1s were originally in at the beginning of the war, the 37ème BCC, replaced all of them with the more advanced B1 Bis during the Phoney War. Part of the 1ère DCR, Division Cuirassée de Réserve (ENG: 1st Reserve Armored Division), the battalion was heavily engaged in Belgium, losing the vast majority of its B1 Bis, up to 23 on a single day on 15th May.
The 37ème BCC, trounced and cut down to size, was transformed into an independent tank company on 17th May, the 3/37 or Gaudet Company. This unit had 14 B1 Bis, as well as 5 B1s that were taken from storage to bolster its numbers. Those five tanks were n°104 Verdun, n°112 Mulhouse, n°122 Alsace, n°127 Jura, and n°132 Poitou.
The 3/37 was heavily engaged during the campaign. Under the command of General De Lattre, it also occasionally left some of its tanks with local infantry units in order to give them support. This was the fate of the Mulhouse and Alsace. The Mulhouse was left to the 31ème BCP, Bataillons de Chasseurs Portés (ENG: Motorized Chasseurs Battalion), on 22nd May. The next day, it had to be sent back behind the frontline in order to be overhauled. The tank appeared again in June of 1940. It was abandoned near Orleans on the 15th of June.
B1 n°112 Mulhouse abandoned near Orleans, in front of a church, 15th June 1940. Source: char-français
The Alsace was given to the 2ème Division d’Infanterie (ENG: Infantry Division) on 31st May, with its further fate unknown, as is the case of the Verdun. The Jura was replaced by a B1 Bis as early as 20th May, with its further fate unknown. The Poitou was still in the hands of company Gaudet in June. On the 17th, it suffered some minor breakdowns, and later, on the 21st, was made entirely inoperable. The crew set the tank alight in order to avoid it being captured intact, in the town of Azay le Perron.
German soldiers inspect the turret of the Poitou through the open hatch, Azay le Perron, June 1940. Source: char-français
B1 of the 347ème CACC: The B1 company
The single largest number of B1 to be found in a single unit in 1940 was the 347ème CACC, Compagnie Autonome de Chars de Combat (Autonomous Tank Company). This unit was created on 17th May 1940, with tanks coming from a variety of different depots and training units. It had 12 B1 tanks: n°103 Lorraine, n°106 Metz, n°109 Nancy, n°110 Belfort, n°111 Dunkerque, n°116 Normandie, n°117 Vendée, n°118 Auvergne, n°119 Béarn, n°121 Bourgogne, n°125 Provence and n°133 Nivernais.
This unit was first attached to the 2ème DCR on 22nd May, then to the 8ème BCC on 28th May. But the mere act of getting the B1s to the frontline took down most of the combat force of the company. The old B1s were exhausted by years of operations and trials and were vulnerable to frequent breakdowns, which would often not be repaired as the logistical services of the French Army had been put into disarray by the speed of the German advance. When the company was first engaged in combat on 3rd June 1940, it had just 3 B1s, the others having been abandoned on the way. A commander of a section of the company, Lieutenant Philibaux, concluded that “the equipment was broken down or exhausted when it arrived to be engaged. The personnel drove at night, and spent the day repairing and maintaining the tanks”.
The company’s service was mostly spent desperately trying to get its used tanks operational. Six tanks were in the hands of a Company d’Échelon (ENG: maintenance company) in early June 1940, in the forest of Eu. Three of those five tanks were able to be repaired before German forces overran the area and got out towing the other two, as well as a B1 Bis of another unit, the Héros. Nancy towed the Héros, Provence the Nivernais, and Vendée the Béarn. Most tanks were lost in the following days, mostly due to breakdowns. The Dunkerque was destroyed on 6th June 1940.
The knocked-out Dunkerque abandoned in a forest, June 1940. Source: char-français
The Vendée fell to a breakdown on 9th June 1940. The crew got out of the tank to try and fix it, but fell under the fire of German motorized vehicles, killing the driver and loader, wounding the radio operator, and capturing the commander.
The broken-down Vendée lying on its side while being inspected by German personnel. Source: char-français
Four tanks were lost on 10th June. Three, the Normandie, Béarn, and Nivernais, had been placed at strategic locations which they had to defend, as their engines were no longer operational. When the order to retreat came to the company, they were scuttled by their crews to avoid capture. A fourth tank, the Provence, was hit by German anti-tank guns which set the tank ablaze. The crew bailed out and was captured.
German soldiers pose in front of the scuttled Nivernais in the forested area where it was abandoned. Source: char-françaisGerman soldier poses in front of the damaged Provence in an armored vehicle park. Source: char-françaisThe Béarn is abandoned in the same forest as the Nivernais. Source: char-français
Though the exact fate of the other vehicles is unknown, it appears most were abandoned as well, and then fell into German hands.
Post-1940: German service
A fair number of B1s were captured with little or no damage by German forces during the invasion of France or handed to them after the armistice of 22nd June 1940.
The B1 appears not to have been differentiated from the B1 Bis in German service, with both models being designated Panzerkampfwagen B-2 740 (f).
The number of B1s used by German troops appears to have been fairly little in comparison to the B1 Bis, for the simple reason that the B1 had a much lower production, and, as such, far fewer were captured by German troops.
At least one individual B1 is known to have been transformed into a flamethrowing tank, by replacing the hull 75 mm gun with a flamethrower. This was B1 n°103, the third prototype, manufactured by FCM and upgraded to production standards. Attached to the 296 Infanterie-Divisione (ENG: Infantry Division), the former Lorraine was sent to assault bunkers of the Molotov Line on 26th June 1941. The bunkers attacked had previously been shot at with 88 mm guns through the openings, before flamethrowing tanks approached under 60 meters to use their main weaponry. The tank formerly known as Lorraine was destroyed by Soviet anti-tank fire during this attack. It is reported that another B1 flamethrowing tank was also destroyed on the same day, though whether it was B1 or B1 Bis based is not known.
The Lorraine, now a flamethrowing tank, in German service. Source: char-françaisGerman soldiers examine the destroyed Lorraine, 1941. With armor of merely 40 mm, the B1 was a lot more vulnerable to anti-tank fire than the B1 bis, particularly by 1941. Source: char-français
Surviving example
Two of the 35 produced B1s have been preserved. One vehicle is referred to as “chassis number 21”, which may suggest it was B1 n°121 “Bourgogne”.
This tank was for a long time at the Fort de Séclin, in a poor, rusted and degraded state. It was taken in by the ASPHM, Association de Sauvegarde du Patrimoine Historique Militaire (ENG: Association for Saving of Historical Military Heritage). The turret appears to have been restored, but the hull has not.
The surviving B1 in the ASPHM’s installations. Source: char-françaisThe same B1 with the restored turret. Source: char-français
The other is in the workshops of MM Park awaiting restoration
How to differentiate a B1 from a B1 Bis
Differentiating the B1 from its later, much more common evolution, the B1 bis, can be somewhat of a hard task. When looking at photos of B1 pre-1940, the difference is particularly easy to make. The B1s feature the SA 34, a shorter gun with a recoil cylinder, while the B1 Bis feature the longer and cylinder-less SA 35. However, as the B1s were refitted with the SA 35 during the Phoney war, identifying them becomes a much harder task; some elements can still give it away, but they are typically quite dependent on the angle at which the tank is viewed.
The tracks on the B1 Bis were wider than on the B1, with 500mm for the Bis and 460mm for the base model. This, however, is typically quite hard to see. Easier to distinguish is that the mount for the 75mm gun as well as driver’s post are a lot more distinct from the rest of the front plates in the B1 than in the B1 Bis – mostly as a consequence of the armor being thickened on the Bis model.
A photo of B1 N°111 “Dunkerque”A photo of B1 Bis n°201 “France” (the first B1 Bis completed) at a somewhat similar angle; the gun mount and driver’s post on the B1 stick out from the rest of the hull by a few centimeters, while they are fully integrated for the B1 Bis. Source: char-français
The turrets of the B1 and B1 Bis, while mostly similar, can also be differentiated. The B1 Bis used the APX 4 turret, which mostly was the B1’s APX 1 up-armored to 60mm, but the vision slots on the side of the turret are quite different. On the APX 1, they stick out from the turret a lot more than on the APX 4, where they appear as little more than small slots.
A view of a B1, N°105 “StrasbourgA view of B1 Bis, N°396 “Hermitage”. The vision slots are quite different on the APX 1 and APX 4, and provided there is a decent view of the turret side, can give away a B1 from a B1 Bis. Source: char-français
Some other differences also exist, but can typically only be used to differentiate the tank from specific angles; for example, the B1 features a larger rear hook in order to tow the Schneider supply trailer, and it appears the tender wheel is very slightly lower and further back on the B1 Bis, though this is only a question of centimeters.
Conclusion: years of development for an underwhelming service life
The B1 is a tank that went through a particularly long design process, which arguably began as early as 1921 with the Char de Bataille, with the B1 itself starting to take shape towards the mid to late 1920s. Due to a long design and correction process, the vehicle would only enter service in late 1935/1936.
By 1940 though, the B1 was outclassed by its own evolution, the B1 Bis, which featured better armor and, as they were far more recently-produced, were not as mechanically worn out as the older vehicles. More vulnerable to both anti-tank weaponry and breakdowns, the tank’s service in the campaign of France was mostly disastrous, with the B1 being sent in small numbers in desperate attempts to turn back the German tide. Most were knocked out not by enemy firepower, but by the breakdowns of their own engines and transmissions used for years of operations. The B1 also had only very limited service beyond 1940. In general, the vehicle is far overshadowed by its evolution, the B1 Bis, in popular memory.
B1 N°101, the first prototype, equipped with the Schneider machine-gun turret, as it was first tested with.B1 n°101 with the 47 mm-armed cast turret it was first experimented with.The projected B1 fitted with the ST-2 turret, which was replaced by the APX 1 before entering productionB1 n°102 Armorique, the second prototype, refitted to serial production standard and pressed into service, pre-WW2The same B1 Armorique, refitted with the SA 35 47mm gun during the Phoney WarB1 n°111 Dunkerque in the late 1930sThe same B1 n°111 Dunkerque with the Schneider supply trailer that was experimented on alongside the B1.B1 n°132 Poitou in the late 1930sB1 n°125 Provence with a colourful, pre-war camouflageThe same B1 n°125 Provence as seen in 1940, refitted with the 47mm SA 35 gun and repainted with a more discreet two-tone paint scheme typically found on AMX and Renault vehicles.B1 n°123 Alpes, notable for its colorful hull but plain green turret, in the configuration it was in 1940. All illustrations produced by Pavel “Carpaticus” Alexe and funded by Tank Encyclopedia’s Patreon campaign.
Char B1 Specifications
Dimensions (l-w-h)
6.37 m (tracks)/6.89 m (hook) x 2.50 m x 2.79 m
Total weight
27.19 tonnes
Crew
4 (Commander/gunner/loader, driver/gunner, loader, radio operator)
Propulsion
Renault 6-cylinders 140×180 mm 16,625 cm3, 272 hp petrol/gasoline engine
Transmission
5 forward + 1 reverse
Speed (road/off road)
28/21 km/h (17/13 mph)
Range
200 km
Armament
75 mm SA 35 infantry support gun with 80 shells; 47 mm SA 34 or SA 35 anti-tank gun with 50 shells
Secondary Armament
2x MAC 31E 7.5 mm machine gun with 4,800 rounds
Maximum armor
40 mm (1.57 in)
Power-to-weight ratio (in hp/ton)
8.9 hp/ton
Sources
Trackstory n°13: Le Char B1, Editions du Barbotin, Pascal Danjou
Tous les blindés de l’Armée Française 1914-1940, François Vauvillier, Histoire & Collection editions
GBM N°107 (January-February-March 2014), Histoire & Collections editions, “Les voies difficultueuses du char de bataille”, Stéphane Ferrard
Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
Char-français: https://www.chars-francais.net/2015/index.php/engins-blindes/chars?task=view&id=6
Tbof.us (guns): http://www.tbof.us/data/tanks/b1bis/b1bis.htm
Axishistory forums (guns): https://forum.axishistory.com/viewtopic.php?t=154362
shadock.free : http://the.shadock.free.fr/Surviving_Panzers.html
Tank archives: http://www.tankarchives.ca/2016/12/char-b-on-frances-backburner.html
Armesfrançaises (MAC 31): http://armesfrancaises.free.fr/Mitr%20MAC%2031%20type%20C%20et%20E.html
Illustration of the Char de Bataille SRB, created by Yuvnashva Sharma and funded by our Patreon campaign
France (1921-1925)
Experimental Infantry Tank – 1 Prototype Built
One of, if not the most famous French tanks of the Second World War was the B1 heavy tank and its improved model, the B1 bis. These large infantry tanks were some of the most heavily armed and armored tanks that existed in the world during the late 1930s. While their production only started in the second half of this decade, they had roots going back as far as 1921, with the Char de Bataille program that started a search for a medium, well-armed tank to fill in the void between the small and numerous Renault FT and the gigantic and rare FCM 2C tanks. Within the proposals offered to this program was one designed by the tank and artillery manufacturer Schneider, in collaboration with the motorized vehicle giant Renault: the Schneider-Renault B, or SRB.
Estienne and the Char de Bataille
Arguably the most important figure of the first years of French tank development was general Jean Estienne. Nicknamed the “Father of Tanks” in France, Estienne, a major proponent of the use of armored vehicles from 1915 onward, was named the director of the AS (Artillerie Spéciale – Eng. Special Artillery), the French armored force, in September of 1916. It is largely thanks to his intervention to the Grand Quartier Général, France’s general headquarters, that the FT light tank reached mass production. Estienne was also a proponent of the Schneider CA1, the first French tank to see service.
Superstructure of Schneider CA1 tanks being manufactured in Le Creusot, December 2 1916. The first French tank to see service, the Schneider CA1 had a production run of 400. It used a 75 mm howitzer on the front-right of the hull and two 8 mm mle 1914 Hotchkiss machine guns in a side-mounted ball mount. The Schneider CA1 was a quite primitive tank design and performed quite poorly in its first combat operation in April of 1917 (though that was also due to a still primitive and untested use of the vehicle), but remains a key vehicle in the development of France’s tank forces. Source: Fonds Académie Bourbon
At the end of the war, Estienne continued in his role as the leading figure of French armored development. He was still at the head of the AS, which was attached to the French infantry and renamed the Subdivision des Chars de Combat (Eng: Combat tank subdivision), and he was also named Inspecteur des Chars de Combat (Eng: Combat Tank Inspector). In this position, Estienne had large amounts of power over the future development of French armored technology. With the French military having large quantities of largely effective light tanks thanks to the mass production of the Renault FT, and with the development of large tank already underway at FCM since 1916, with the FCM 1A and then FCM 2C super-heavy tanks, what the French military lacked in his view was an intermediate vehicle between the dwarves and the giants. A ‘Char de Bataille’ (Eng. battle tank) was desired, thought of as a vehicle of medium weight that would feature a fixed 75 mm gun able to engage enemy fortifications and positions and to move through the devastated terrain typical of trench warfare in an artillery-saturated battlefield. Estienne thought the type would offer the ideal compromise, mounting an armament capable of knocking out enemy fortifications and trenches, something the FT’s armament of either a machine gun or a 37 mm gun struggled with while being vastly more reasonable and easier to mass-produce than a monster the size and weight of the 69-tonne, 10-meter long 2C. If successful, the Char de Bataille would have eventually become the workhorse of France’s armored force.
The Char de Bataille program and the Estienne agreements
In 1921, Estienne gathered five of the largest French industrial companies: Schneider, Renault, FAMH/Saint-Chamond, FCM, and Delaunay-Belleville, and gave them the requirements of the Char de Bataille which he requested them to design. The vehicle was to have a weight of 13-tonnes, and feature a hull-mounted main gun: either a 75 mm howitzer with a muzzle velocity of 350 m/s or the higher velocity 47 mm mle 1902 naval gun, with 750 m/s muzzle velocity. The tank was to have a turret armed with either one or two machine guns. It was to have a power-to-weight ratio of at least 8 hp per ton and be able to run for 8 to 10 hours. The armor was to be 25 mm thick.
Most importantly, the program was not planned to result in the immediate adoption of the product that answered to the specifications the most. The plan was that, once the prototypes were produced, the most interesting features from each would be taken to then be featured in a new tank design that would not be the property of a company, but of the state. The objective of such a move was to reduce competition and encourage the manufacturers to innovate without the risk of a yet not entirely mastered concept leading to the refusal of a proposal. Once the vehicle that combined the best features of each proposal was adopted, each of the manufacturers involved would play a part in the production. This original policy was named the Estienne agreements.
Schneider-Renault Collaboration: Common features, separate designs
While FAMH and FCM went to design and build their own prototypes in complete independence from other firms, Schneider and Renault decided to collaborate to produce two different prototypes. This collaboration mostly consisted of some major elements of the prototypes being shared by both: notably the turret, designed by Schneider, and the powerplant, designed by Renault.
The design of the vehicles and their manufacturing outside of those two major elements, though, remained independent. The second prototype, the SRB, was designed and manufactured by Schneider in its facilities of Le Creusot, in Burgundy, while the SRA was produced by Renault in Billancourt, in the western suburbs of Paris (the SRA is even known to have had an internal designation code, Renault JZ). Still, the hulls of the vehicles in their design appear to be almost identical, though some significant differences exist in the suspension and armament that were fitted to those hulls.
The SRB: Bearer of advanced features
The overall shape of the SRB’s hull was remarkably similar to its SRA sibling, taking the shape of a mostly rectangular vehicle, with two front plates angled backward, the driver’s vision port being featured on the higher one. The first major difference between the two designs was the gun mounted to the right of the vehicle. While the gun mount was identical on both vehicles, the SRB, instead of a short 75 mm howitzer, mounted a 47 mm model 1902 naval gun, a weapon originally designed as an anti-torpedo boat weapon mounted on many French ships of the early 20th century.
A side view of the SRB prototype, showing the vehicle’s hull-mounted 47mm gun. Source: char-français
This weapon was present as an alternative to the 75 mm in the requirements formulated by Estienne, however, all other manufacturers opted for the 75 mm option, which may have appeared as a better option in the anti-fortification role the Char de Bataille was designed for. The 47 mm, however, offered a better velocity than the 75 mm. 750 m/s is generally quoted as the muzzle velocity of the SRB’s gun, which would suggest some modifications to the weapon, as the standard version is known to have had a muzzle velocity of 690 m/s. This was in any case superior to the 350 m/s of the 75mm howitzer. The gun had a semi-automatic action, giving a maximum rate of fire of 15 rounds per minute. While it is likely this would have been lower in the constraints of an armored vehicle, the 47 mm gun retained a better rate of fire than the 75 mm. It also had some decent anti-armor capacity. With the Obus de rupture acier mle 1911 G armor-piercing shell, it could reportedly penetrate, at an incidence of 30°, 40 mm of armor at 500 m, and 30 mm at one kilometer. Whether or not mounting the 47 mm on the SRB was intended to give the vehicle anti-armor capabilities is not known. A problem that has been suggested with the 47 mm’s quite long barrel is that it could possibly hinder the SRB’s crossing capacities, as the barrel extended beyond the hull.
As on the SRA, the mounting of the gun to the right of the hull on the SRB left a great deal of space for the driver. The SRB featured two large hatches on the side of the hull. In comparison to the SRA’s hatches, the SRB’s appeared to be taller, more rectangular, and less square-shaped. The suspension of the SRB is not known in as much detail as its SRA sibling, but it is known to have made use of leaf springs. 14 small wheels can be counted on the bottom of the vehicle. The SRB had a front-drive sprocket and rear idler wheel. The suspension was at its highest point in front of the side hatch of the vehicle. Unlike the three other prototypes, which used wooden pads track with a considerable pitch, the SRB used metallic tracks inspired from the Renault FT’s, which each pad directly linked to the other. The armor of the vehicle was 30 mm at its thickest, on the vehicle’s front. This was an impressive amount for 1925. The SRB was 6 m long, 2.50 m wide and 2.38 m high, making it the longest of the four Char de Bataille prototypes. The ground clearance was 0.41 m, and the tank had a weight of 19 tonnes.
A view of the SRB at a slightly different angle, with the side hatch open. Source: Tank archives
The engine, which was designed by Renault, was a six-cylinder one based on a bisected 12-cylinder aircraft engine. It produced 180 hp at 1500 rpm. This was 60 hp more than the Panhard 120 hp engine used on the FAMH and FCM. Despite being the heaviest tank in the competition, at 19 tonnes, the Schneider-Renault prototypes also had the highest power-to-weight ratio, with 9.5 hp/tonne. The SRB consumed 20 to 35 liters of fuel an hour, and its fuel tanks contained 370 liters, giving an average range of about 125 km. The tank had a maximum speed of 18 km/h on a road and could cross a 2.50 m gap. The transmission was at the rear. Arguably the most advanced feature of the SRB laid within its transmission. The vehicle had been fitted with a Naeder hydrostatic system. The purpose of this system was to allow for precise neutral steering of the hull in order to point the hull gun, which had no lateral traverse in its mount. It consisted of a system that received the movement of the engine and used it to move a fluid (a form of castor oil), sucking it in or out. This was used to operate slow and precise movements of the tracks in order to aim the hull. The hydrostatic system was used thanks to a steering wheel the driver/gunner of the vehicle could use. It allowed for very precise movement but also required the use of both castor oil and regular oil (as the engine was used & it was also necessary to heat up the castor oil at a proper temperature).
The turret featured on the SRB as well as the SRA was of Schneider design. This was a cast design, a particularly modern feature for the early 1920s, with an inclined roof, being at its highest at the rear. The turret had a turret ring diameter of 95 cm, weighed 700 kg, and was armed with two Hotchkiss mle 1914 8×50 mm Lebel machine guns. The crew of the SRB consisted of three, with the commander sat in the turret. The turret was mostly a command post, and the purpose of its armament was to defend the tank against enemy infantry, while the hull gun would engage static fortifications. The driver sat to the left of the hull, and also operated as the hull gunner, which made him quite overtasked. The loader sat behind the 47 mm gun, on the right side of the hull.
Trials: The best impressions
The SRB prototype was trialed along with the three other Char de Batailles starting in Rueil, from May of 1924 to March of 1925. It should be noted that it was tried with a supply trailer designed by Schneider, which had a weight of one tonne and could carry 800 liters of fuel and seat eight men. This was a forerunner to a Schneider trailer which was offered and used on the first B1s in the 1930s.
The SRB prototype towing the supply trailer during the trials, with the side hatch open. Source: Tank archives
The SRB is generally considered as the vehicle which performed the best during those trials. The internal configuration, which it shared with the SRA, with the hull gun pushed to the right of the hull, left the driver/gunner considerably less cramped and more comfortable than on the FCM and FAMH designs. The vehicle’s tracks were also praised. Their metallic and unitary nature left them a lot less worn out than the wooden pad tracks of all other prototypes. Most importantly, the Naedar system featured on the SRB was praised as by far the most effective way of accurately pointing the hull, far superior to the epicyclic transmission used on the SRA.
Conclusion – A deeply influential design on the future B1
Out of all the Char de Bataille prototypes manufactured, the SRB is arguably the one that had the most influence on the future Char B1.
While the SRA may at a first glance seem a little bit more similar to the final product, with its 75 mm hull gun, the SRB’s metallic tracks and Naeder systems were two major features of the B1 which were only featured on the Schneider design. The 47 mm naval gun may perhaps have had some influence as well. The second and third prototypes of the B1, in the early 1930s, were armed with 47 mm naval guns in a fully rotative turret, and the B1 and B1 Bis finally retained the 47 mm anti-tank gun as a feature of their design, albeit replacing the machine gun-armed turret of the Char de Bataille & first B1 prototype, and not the 75 mm hull gun.
The first prototype of the B1, n°101, showing a 47 mm naval gun similar to the SRB’s, but in a fully rotating turret. Source: char françaisIllustration of the Char de Bataille SRB, created by Yuvnashva Sharma and funded by our Patreon campaign
Char de Bataille SRB specifications
Dimensions (L x w x h)
6.00 x 2.50 x 2.38 m
Ground clearance
0.41m
Weight
19,000kg
Engine
Renault six-cylinder producing 180 hp at 1,500 rpm
Maximum speed
18 km/h
Power-to-weight ratio (in hp/ton)
9
Fuel tanks
370 litres
Average hourly fuel consumption
20 to 35 litres
Range
125km
Suspension
Leaf springs
Trench crossing
2.50m
Crew
3 men (Commander/turret gunner, driver/gunner, loader)
Illustration of the Char de Bataille SRA/Renault JZ, created by Yuvnashva Sharma and funded by our Patreon campaign
France (1921-1925)
Experimental Infantry Tank – 1 Prototype Built
One of, if not the most famous French tanks of the Second World War was the B1 heavy tank and its improved model, the B1 Bis. These large infantry tanks were some of the most heavily armed and armored tanks existing in the world during the late 1930s. While their production only started in the second half of this decade, they had roots going back as far as 1921, with the Char de Bataille program that started a search for a medium, well-armed tank to fill in the void between the small and numerous Renault FT and the gigantic and rare FCM 2C tanks. Within the proposals offered to this program was one designed by the industrial giant Renault, with collaboration from Schneider; the Schneider-Renault A or SRA, also known as Renault JZ.
Estienne and the Char de Bataille
Arguably the most important figure of the first years of French tank development was general Jean Estienne. Nicknamed the “Father of Tanks” in France, Estienne, a major proponent of the use of armored vehicles from 1915 onward, was named the director of the AS (Artillerie Spéciale – Special Artillery), the French armored force, in September of 1916. It is largely thanks to his intervention to the Grand Quartier Général, France’s general headquarters, that the FT light tank reached mass production. Estienne was also a proponent of the Schneider CA1, the first French tank to see service.
The assembly sections of Renault’s Boulogne-Billancourt facilities, producing FT light tanks, 1918. The tremendous success of the FT light tank designed by Louis Renault with support from Estienne made the firm a leader of French military development. Source: Renault archives
At the end of the war, Estienne continued in his role as the leading figure of French armored development. He was still at the head of the AS, which was attached to the French infantry and renamed the Subdivision des chars de combat (Eng: Combat tank subdivision), and he was also named Inspecteur des Chars de Combat (Eng: Combat Tank Inspector). In this position, Estienne had large amounts of power over the future development of French armored technology. With the French military having large quantities of largely effective light tanks thanks to the mass production of the Renault FT, and with the development of large tank already underway at FCM since 1916 with the FCM 1A and then FCM 2C super-heavy tanks, what the French military lacked in his view was an intermediate vehicle between the dwarves and the giants. A ‘Char de Bataille’ (battle tank) was desired, thought of as a vehicle of medium weight that would feature a fixed 75 mm gun able to engage enemy fortifications and positions and to move through the devastated terrain typical of trench warfare in an artillery-saturated battlefield. Estienne thought the type would offer the ideal compromise, mounting an armament capable of knocking out enemy fortifications and trenches, something the FT’s armament of either a machine-gun or a 37 mm gun struggled with while being vastly more reasonable and easier to mass-produce than a monster the size and weight of the 69-tonne, 10-meter long 2C. If successful, the Char de Bataille would have eventually become the workhorse of France’s armored force.
The Char de Bataille program and the Estienne agreements
In 1921, Estienne gathered five of the largest French industrial companies: Schneider, Renault, FAMH/Saint-Chamond, FCM, and Delaunay-Belleville, and gave them the requirements of the Char de Bataille which he requested them to design. The vehicle was to have a weight of 13-tonnes, and feature a hull-mounted main gun: either a 75 mm howitzer with a muzzle velocity of 350 m/s, or the higher velocity 47 mm mle 1902 naval gun, with 750 m/s muzzle velocity. The tank was to have a turret armed with either one or two machine guns. It was to have a power-to-weight ratio of at least 8 hp per ton, and be able to run for 8 to 10 hours. The armor was to be 25 mm thick.
Most importantly, the program was not planned to result in the immediate adoption of the product that answered to the specifications the most. The plan was that, once the prototypes were produced, the most interesting features from each would be taken to then be featured in a new tank design that would not be the property of a company, but of the state. The objective of such a move was to reduce competition and encourage the manufacturers to innovate without the risk of a yet not entirely mastered concept leading to the refusal of a proposal. Once the vehicle that combined the best features of each proposal was adopted, each of the manufacturers involved would play a part in the production. This original policy was named the Estienne agreements.
Schneider-Renault Collaboration: Common features, separate designs
While FAMH and FCM went to design and build their own prototypes in complete independence from other firms, Schneider and Renault decided to collaborate to produce two different prototypes. This collaboration mostly consisted of some major elements of the prototypes being shared by both: notably the turret, designed by Schneider, and the powerplant, designed by Renault.
The design of the vehicles and their manufacturing outside of those two major elements, though, remained independent; the second prototype, the SRB, was designed and manufactured by Schneider, while the first, the SRA, was a product of Renault. It even had a two-letters internal designation code, JZ. The prototype was manufactured in Renault’s facilities of Boulogne-Billancourt, in the western suburbs of Paris.
Interestingly enough, two different photos of the SRA’s hull during manufacturing exist, while the production of other prototypes remains a lot more obscure to this day. This notably shows the vehicle’s suspension without the armored skirts that would otherwise hide it, and make the SRA’s suspension the most well-known of all the Char de Bataille prototypes.
The SRA/Renault JZ prototype being manufactured in Boulogne-Billancourt; the suspension still lacks its armored skirts, giving a good look onto its bogies and leaf springs. Source: Tank Archives
The SRA design: A mostly solid proposal
The tank designed by Renault took the shape of a mostly rectangular vehicle, with two front plates angled backward, the driver’s vision port being featured on the higher one. To the right of the hull front, a 75 mm howitzer was fitted but this solution offered no lateral traverse of the gun. It did, however, leave a great deal of space for the driver, who was now more comfortably accommodated than on FCM and FAMH designs. The vehicle featured two almost square-shaped hatches on each side of the vehicle, under the tracks and between the suspension bogies. The armor was 30 mm at its thickest, on the vehicle’s front. This was an impressive amount for 1925. The SRA was 5.95 m long, 2.49 m wide, and 2.26 m high; it had a ground clearance of 0.40 m; the vehicle’s weight was 19 tonnes.
The suspension and tracks were mounted to the side of this hull. Thanks to photos of the SRA during its production, they are a lot more well-known than on other prototypes. The vehicle had a rear-drive sprocket and a front idler wheel; interestingly enough, this rear wheel was mounted higher than the front one, meaning the highest point of the suspension was at the back of the tank. The suspension featured two bogies of six wheels per side, those being mounted on leaf springs. One bogie was in front and one behind the large escape hatch featured at the middle of the hull’s flank. The tracks used had wooden pads with a high track pitch; they were 53 cm wide. The vehicle could cross a 2.50 m-wide gap.
A side view of the SRA prototype during its trial, showing the suspension being higher towards the rear, and the square hatch in the middle of the tank’s hull. Source: char-français
The engine, which was designed by Renault, was a six-cylinder one based on a bisected 12-cylinder aircraft engine. It produced 180 hp at 1500 rpm. This was 60 hp more than the Panhard 120 hp engine used on the FAMH and FCM. Despite being the heaviest tank in the competition, at 19 tonnes, the Schneider-Renault prototypes also had the highest power-to-weight ratio, with 9.5 hp/ton. The SRA consumed 28 to 35 liters of fuel an hour, and its fuel tanks contained 420 liters, giving an average range of about 140 km. The tank had a maximum speed of 17.5 km/h on a road. The transmission was at the rear. It was an epicyclic transmission, which was intended to provide great accuracy in traversing the vehicle’s hull, adjusting for the complete lack of lateral traverse on the gun. The SRA also had hydraulically actuated brake disks.
The turret featured on the SRA as well as the SRB was of Schneider design. This was a cast design, a particularly modern feature for the early 1920s, with an inclined roof, being at its highest at the rear. The turret had a turret ring diameter of 95 cm, weighed 700 kg, and was armed with two Hotchkiss mle 1914 8×50 mm Lebel machine-guns. Out of the three crew members of the SRA, the commander sat in the turret; it was mostly a command post, and the purpose of its armament was to defend the tank against enemy infantry, while the hull gun would engage static fortifications. The driver sat to the left of the hull, and also operated as the hull gunner; the loader sat behind the 75 mm howitzer, on the right side of the hull.
Trials: A good base design with some lackluster features
The SRA prototype was trialed along with the three others Char de Batailles starting in Rueil, from May of 1924 to March of 1925.
Some considerable flaws of the design were made apparent during those trials. Notably, the epicyclic transmission was not effective in ensuring that the SRA’s hull movements were highly accurate, while the lack of traverse of the 75 mm hull gun demanded very precise traverse. The wooden pads tracks, which were a design element shared by all other vehicles except the SRB, ended up being disappointing and promptly worn out as well. In terms of both hull traverse and tracks, the SRA ended up bested by its Schneider sibling, the SRB, which featured the first model of the Naeder hydrostatic transmission/traverse system as well as metallic, FT-based tracks.
A frontal view of the SRA prototype during its trials, showing the opened driver’s hatch, as well as the worn-out wooden trackpads. Source: Tank Archives
The SRA design did have some notable advantages though. The configuration of the main gun being pushed to the right side of the hull made the vehicle far more comfortable for the driver, who was a lot more cramped on the FCM and FAMH designs, particularly the FAMH. While the wooden trackpads were a mediocre feature, the suspension in itself was judged as quite solid. In general, the SRA was one of the more appreciated designs, though the SRB and its advanced Naeder system and metallic tracks brought more novel features.
Conclusion – A forefather to the B1
Of all the four Char de Bataille prototypes trialed in 1924-1925, the SRA, along with its sibling the SRB, was one of the ones which ended up the most influential to the French army’s future infantry breakthrough tank, the B1.
The Char de Bataille during the 1924-1925 trials; from front to back the Schneider-Renault A, the FCM, the FAMH/Saint-Chamond, and an unrelated vehicle, the Renault NC-1 light tank prototype. Not shown on this cut of the photograph is the Schneider-Renault B, leading the column. Source: Tank archives
Most notably, the configuration of the hull, with the gun pushed to the right side, the loader at its rear, and the driver/gunner on the front left, would be the one adopted on the B1, and both vehicles most definitely look related, particularly from the front.
One could argue, though, that the SRA remained overshadowed by the Schneider side of the Schneider-Renault cooperation – the SRB. Indeed, while many of the influential features of the SRA were also present in the SRB – the configuration of the hull was quite similar, notably – the Schneider vehicle featured some advanced elements, particularly the Naeder system, that would be transmitted to the B1. The SRA nonetheless remains one of the most important forefathers of what would become one of the mightiest tanks of France’s army in 1940.
The SRA prototype on the move during its trials, featuring the large frontal headlight on the left of the gun. Source: Tank archivesIllustration of the Char de Bataille SRA/Renault JZ, created by Yuvnashva Sharma and funded by our Patreon campaign
Char de Bataille SRA/Renault JZ specifications
Dimensions (L x w x h)
5.95 x 2.49 x 2.26 m
Ground Clearance
0.40m
Weight
19,000kg
Engine
Renault six-cylinder producing 180 hp at 1,500 rpm
Maximum speed
17.5 km/h
Power-to-weight ratio (in hp/ton)
9
Fuel tanks
420 litres
Average hourly fuel consumption
28 to 35 litres
Range
140km
Suspension
Leaf springs
Trench crossing
2.50m
Crew
3 men (Commander/turret gunner, driver/gunner, loader)
Armament
2 turret-mounted Hotchkiss mle 1914 8 mm machine guns, 1 hull-mounted 75 mm howitzer
Illustration of the Char de Bataille FAMH, created by Yuvnashva Sharma and funded by our Patreon campaign
France (1921-1925)
Experimental Infantry Tank – 1 Prototype Built
The B1 and B1 Bis heavy infantry tanks are some of the most famous and popular of all pre-war French tank designs. Those particularly well-armored vehicles, with their dual configuration featuring a turreted 47 mm anti-tank gun and a hull-mounted 75 mm infantry support gun, and sporting tracks going around all of the hull in a fashion reminiscent of WW1-era rhomboid British tanks with massive individual track links, are some of the most peculiar mass-produced tanks of the late 1930s. Despite their serial production only really starting in the second half of the 1930s, the B1 and its improved version, the B1 bis, have roots going back as far as 1921, with the Char de Bataille program. One of the prototypes of this program which had some influence on the final B1 was produced by the company FAMH (Compagnie des Forges et Aciéries de la Marine et d’Homécourt – Company of Marine Forges and Steelworks and of Homécourt), better known under the name of the city where their main facilities were located, Saint-Chamond.
Estienne and the Char de Bataille
Arguably, the most important figure of the first years of French tank development was general Jean Estienne. Nicknamed the “Father of Tanks” (père des chars) in France, Estienne, a major proponent of the use of armored vehicles from 1915 onward, was named the director of the AS (Artillerie Spéciale – Special Artillery), the French armored force, in September of 1916. It is largely thanks to his intervention to the Grand Quartier Général, France’s general headquarters, that the FT light tank reached mass production. Estienne had also been a proponent of the Schneider CA1, the first French tank to see service.
On the other hand, the Saint-Chamond tank, which entered in service soon after the Schneider, was not at all appreciated by Estienne, though 400 would still be manufactured as the père des chars’s control onto tank production was still incomplete by 1915-1916.
A Saint-Chamond tank in its natural state: struggling due to the massive discrepancy between the length of the tracks and of the hull. On paper, the Saint-Chamond may have seemed like a better vehicle than the CA1 – featuring an axial-mounted 75 mm gun, which was not a mere howitzer but a true field gun, a Saint-Chamond model on the first series and the mighty “French 75”, the model 1897, on the late series. However, the vehicle’s tragic cross-country capacity made it mediocre on the battered terrains of WW1. Source: char-français
At the end of the war, Estienne continued in his role as the leading figure of French armored development. He was still at the head of the AS, which was attached to the French infantry and renamed the Subdivision des chars de combat (Combat tank subdivision), and was also named Inspecteur des chars de combat (Combat Tank Inspector). In this position, Estienne had large amounts of power over the future development of French armored technology. With the French military having large quantities of largely effective light tanks thanks to the mass production of the Renault FT, and with the development of large tank already underway at FCM since 1916 with the FCM 1A and then FCM 2C super-heavy tanks, what the French military lacked in his view was an intermediate vehicle between the dwarves and the giants: a “Char de Bataille” (battle tank), thought of as a vehicle of medium weight, that would feature a fixed 75 mm gun able to engage enemy fortifications and positions, and to move through the devastated terrain typical of trench warfare in an artillery-saturated battlefield. Estienne thought the type would offer the ideal compromise, mounting an armament sufficient to knock out enemy fortifications and trenches, something the FT’s armament of either a machine gun or a 37 mm gun struggled with, while being vastly more reasonable and easier to mass-produce than a monster the size and weight of the 69-tons, 10-meters long Char 2C. If successful, the Char de Bataille would have eventually become the workhorse of France’s armored force.
The Char de Bataille program and the Estienne agreements
In 1921, Estienne gathered five of the largest French industrial companies in France: Schneider, Renault, FAMH/Saint-Chamond, FCM and Delaunay-Belleville, and gave them the requirements of the Char de Bataille which he requested them to design. The vehicle was to have a weight of 13-tons, and feature a hull-mounted main gun – either a 75 mm howitzer with a muzzle velocity of 350 m/s, or the higher velocity 47 mm mle 1902 naval gun, with 750 m/s muzzle velocity. The tank was to sport a turret armed with either one or two machine guns. It was to have a power-to-weight ratio of at least 8 hp per ton, and be able to run for 8 to 10 hours. The armor was to be 25 mm thick.
Most importantly, the program was not planned to result in the immediate adoption of the product that answered to the specifications the most. The plan was that, once the prototypes were produced, the most interesting features from each would be taken to then be adapted to a new tank design that would not be the property of a company, but of the state. The objective of such a move was to reduce competition and encourage the manufacturers to innovate without the risk of a yet not entirely mastered concept leading to the refusal of a proposal. Once the vehicle that combined the best features of each proposal was adopted, each of the manufacturers involved would play a part in the production. This original policy was named the Estienne agreements.
The FAMH vehicle: Smooth drive
In the end, four manufacturers would produce new designs for the Char de Bataille program. Delaunay-Belleville offered a previous design of theirs, an enlarged FT with a 37 mm hull gun and a turret, that had little to do with the program’s requirements and was swiftly thrown out of the equation. Schneider and Renault cooperated to produce two joint prototypes of different designs, while Saint-Chamond and FCM produced their own prototypes individually.
The FAMH design was the one that looked the most different from the other three in terms of general shape. While the FCM and the two Schneider-Renault prototypes were generally long, quite narrow and low vehicles, the FAMH was shorter and a lot bulkier, though it technically was not the highest due to the FCM’s high cupola reaching higher than even the FAMH’s turret The Char de Bataille FAMH had a length of 5.20 m, making it the shortest of the four proposed designs, a width of 2.43 m (which did not make it the widest vehicle, though the two wider ones, the Schneider-Renault, were this way because of their tracks and suspension), and a height of 2.40 m. The ground clearance was 0.45 m.
A side view of the Char de Bataille FAMH prototype, showing the shorter suspension and higher hull when compared to the other Char de Bataille prototypes. Source: Tank Archives
Unlike the three other prototypes, which had tracks pretty much going all around the hull, the FAMH vehicle had a much lower suspension, with the hull reaching out on top of it, unlike the other designs in which the hull was as wide at the top as at the bottom. This hull used riveted construction. The armament of the prototype consisted of a centrally mounted 75 mm howitzer, designed by Saint-Chamond (the industrial also being a prolific artillery manufacturer) and featured in a casemate, the only vehicle using such a configuration. The FAMH Char de Bataille also featured a turret designed by FAMH, which used riveted construction as the hull, and was armed with two Hotchkiss modèle 1914 8 mm Lebel machine guns. This turret’s functions were mostly to serve as a command post, and for close defense of the vehicle, with the commander serving in the turret, while the two other crewmen took place in the hull, which featured the vehicle’s main armament, the 75 mm howitzer. The FAMH is also reported to have been able to be armed with a hull machine gun, but this is not apparent on the prototype, and it is unknown from where this weapon would have been firing from.
A front view of the Char de Bataille FAMH, showing the centrally mounted 75 mm gun fitted in a casemate, the driver’s driving post, the riveted construction and the turret of the vehicle. Source: Tank Archives
As with the other Char de Bataille, the FAMH featured armor skirts protecting the suspension. The exact design which was used for the suspension remains unknown. What is known about it, is that it used six pneumatic systems, each weighing 55 kg, and damping springs. The pneumatic controls are known to have made the vehicle require a lot less physical effort from the driver, unlike other vehicles of the program. The track used wooden pads, as on the FCM and Schneider-Renault A prototype. The pitch was also considerable.
Trials – Estienne’s horse
FAMH’s Char de Bataille was trialed along with the three other vehicles in Rueil, starting with their presentation on 13th May 1924.
The Char de Bataille FAMH was powered by a Panhard engine producing 120 hp at 1500 rpm. This was the same engine as on the FCM, however, the FAMH weighed in at 17,000 kg, whereas the FCM had a weight of just 15,640 kg. This made the FAMH the vehicle with the lowest power-to-weight ratio of the four, with 7 hp/ton – 1 hp/ton under the requirements of 8. The vehicle could reach a maximum speed of 18.2 km/h, which actually appears to have made it the fastest of the Char de Bataille, by 0.2 km/h in comparison to the Schneider-Renault B. However, a domain in which the difference between the FAMH and the other vehicles was notable, and not in a good way for Saint-Chamond’s vehicle, was range. With the smallest fuel tank of all designs, at only 230 l, and a medium hourly consumption of 30 liters, the FAMH had a range of only about 75 km, the second-worst. The Schneider-Renault B had a whole 50 km more, with 125 km. Out of the three vehicles of which we know the trench-crossing capacity, the FAMH also had the shortest one, being able to cross a 2-meters wide gap, a consequence of the shorter suspension which did not fully go around the vehicle’s hull. At the same time though, the pneumatic drive of the FAMH considerably reduced the physical efforts of the driver and was quite appreciated.
A rear view of the Char de Bataille FAMH, showing the rear and side ventilation for the Panhard 120 hp engine. Source: char-français
The vehicle’s armament had both issues and advantages. The central mounting of the 75 mm gun proved mediocre for the driver, as it took a considerable amount of space, and made his position quite cramped. At the same time, the central casemate mounting was praised by Estienne. It was judged as perfectly placed, both in axis and height, to fire through the embrasures of enemy fortifications, where a successful shot would inflict the most damage. In general, out of all the Char de Bataille proposals, the FAMH appeared to be Estienne’s favorite.
Conclusion – The rejected favorite
The FAMH prototype was trialed along with the three others Char de Batailles from May 1924 to March of 1925. Its trials underlined some interesting features, mostly regarding the pneumatic controls.
The Char de Bataille during the 1924-1925 trials. From front to back the Schneider-Renault A, the FCM, the FAMH/Saint-Chamond, and an unrelated vehicle, the Renault NC-1 light tank prototype. Not shown on this cut of the photograph is the Schneider-Renault B, leading the column. Source: Tank archives
The FAMH prototype was not the least influential when it came to the development of what would become the B1. Its pneumatic controls and damping springs ended up being featured on the much less obscure heavy tank, giving it some quite light controls for such a heavy machine. The Saint-Chamond 75 mm gun was also retained for the first two prototypes of the B1, though the third vehicle as well as the serial-produced B1 and B1 Bis would not end up using a FAMH 75 mm howitzer.
The final suspension design of the B1/B1 Bis, featuring a large damping spring. Source: Ateliers de Construction de Rueil – Services des Etudes – Char B1 Bis – Notice sur la description et l’entretien des matériels
Nonetheless, the influence of Saint-Chamond’s designs remains fairly limited. For a vehicle that was dubbed Estienne’s favorite, the FAMH Char de Bataille is indeed overshadowed by the two Schneider-Renault prototypes, which laid the basis for the final architecture of the heavy infantry tank, as well as its complex Naeder hydraulic direction system. The fate of the FAMH prototype, arguably the most unique looking of the four Char de Bataille, is unknown, though ending up scrapped appears to be, by far, the most probable theory.
Char de Bataille FAMH specifications
Dimensions (L x w x h)
5.20×2.43x.2.40 m
Ground Clearance
0.45m
Weight
17,000kg
Engine
Panhard producing 120 hp at 1500 rpm
Maximum speed
18.2 km/h
power-to-weight ratio in hp/ton
7
Fuel tanks
230 litres
Average hourly fuel consumption
30 litres
Range
75km
Trench crossing
2m
Crew
3 men (Commander/turret gunner, driver/gunner, loader)
Armament
2 turret-mounted Hotchkiss mle 1914 8 mm machine gun, 1 hull-mounted 75 mm howitzer, perhaps 1 hull-mounted Hotchkiss mle 1914 8 mm machine gun
Char de Bataille FCM illustration, created by Yuvnashva Sharma and funded by our Patreon campaign
France (1921-1925)
Experimental Infantry Tank – 1 Prototype Built
One of, if not the most famous French tanks of the Second World War was the B1 heavy tank and its improved model, the B1 Bis. These large infantry heavy tanks were some of the most heavily armed and armored tanks existing in the world during the late 1930s. While their production only started in the second half of this decade, they had roots going back as far as 1921, with the Char de Bataille program that started a search for a medium, well-armed tank to fill in the void between the small and numerous Renault FT and the gigantic and rare FCM 2C tanks. One of the proposals to this program was created by the manufacturer of the FCM 2C, Forges et Chantiers de la Méditerranée.
Estienne and the Char de Bataille
Arguably the most important figure of the first years of French tank development was general Jean Estienne. Nicknamed the “Father of Tanks” in France, Estienne, a major proponent of the use of armored vehicles from 1915 onward, was named the director of the AS (Artillerie Spéciale – Special Artillery), the French armored force, in September of 1916. It is largely thanks to his intervention to the Grand Quartier Général, France’s general headquarters, that the FT light tank reached mass production. Estienne was also a proponent of the Schneider CA1, the first French tank to see service.
The Renault FT light tank, armed with a 37 mm gun. A very successful industrial venture by Louis Renault, the light tank received extensive support from Estienne and would become the most successful tank of France, and arguably all belligerents, during the First World War. Colorized by Jaycee “Amazing Ace” Davis. Source: char-français
At the end of the war, Estienne continued in his role as the leading figure of French armored development. He was still at the head of the AS, which was attached to the French infantry and renamed the Subdivision des chars de combat (Combat tank subdivision), and was also named Inspecteur des Chars de Combat (Combat Tank Inspector). In this position, Estienne had large amounts of power over the future development of French armored technology. With the French military having large quantities of largely effective light tanks thanks to the mass production of the Renault FT, and with the development of large tank already underway at FCM since 1916 with the FCM 1A and then FCM 2C super-heavy tanks, what the French military lacked in his view was an intermediate vehicle between the dwarves and the giants. A “Char de Bataille” (battle tank) thought of as a vehicle of medium weight, that would feature a fixed 75 mm gun able to engage enemy fortifications and positions, and to move through the devastated terrain typical of trench warfare in an artillery-saturated battlefield. Estienne thought the type would offer the ideal compromise, mounting an armament capable of knocking out enemy fortifications and trenches, something the FT’s armament of either a machine-gun or a 37 mm gun could struggle with, while being vastly more reasonable and easier to mass-produce than a monster the size and weight of the 69-tons, 10-meters long 2C. If successful, the Char de Bataille would have eventually become the workhorse of France’s armored force.
The Char de Bataille program and the Estienne agreements
In 1921, Estienne gathered five of the largest French industrial companies: Schneider, Renault, FAMH/Saint-Chamond, FCM and Delaunay-Belleville, and gave them the requirements of the Char de Bataille which he requested them to design. The vehicle was to have a weight of 13-tons, and feature a hull-mounted main gun: either a 75 mm howitzer with a muzzle velocity of 350 m/s, or the higher velocity 47 mm mle 1902 naval gun, with 750 m/s muzzle velocity. The tank was to have a turret armed with either one or two machine guns. It was to have a power-to-weight ratio of at least 8 hp per ton, and be able to run for 8 to 10 hours. The armor was to be 25 mm thick.
Most importantly, the program was not planned to result in the immediate adoption of the product that answered to the specifications the most. The plan was that, once the prototypes were produced, the most interesting features from each would be taken to then be featured in a new tank design that would not be the property of a company, but of the state. The objective of such a move was to reduce competition and encourage the manufacturers to innovate without the risk of a yet not entirely mastered concept leading to the refusal of a proposal. Once the vehicle that combined the best features of each proposal was adopted, each of the manufacturers involved would play a part in the production. This original policy was named the Estienne agreements.
The FCM vehicle: Miniature Char 2C
In the end, four manufacturers would produce new designs for the Char de Bataille program. Delaunay-Belleville offered a previous design of theirs, an enlarged FT with a 37 mm hull gun and a turret, that had little to do with the program’s requirements and was swiftly thrown out of the equation. Schneider and Renault cooperated and produced two joint prototypes of different designs, while Saint-Chamond and FCM produced their own prototypes individually.
FCM (Forges et Chantiers de la Méditerranée – Forges and Shipyards of the Mediterranean) was originally a naval shipyard, which became involved in tank production with the FCM 1 heavy tank design that started development in 1916. While it would remain at the prototype stage, the FCM 1 would serve as the basis for the development of the FCM 2C, a 69-tons behemoth. Ordered at first in January of 1918, canceled with the end of the First World War but ordered again by the request of Estienne in April of 1919, albeit only for 10 vehicles, instead of hundreds as originally planned, the FCM 2C took much of FCM’s industrial capacities in the early 20s. The vehicles were completed in 1921, but still received modifications until 1923.
Production of FCM 2Cs at FCM’s factory of La Seyne sur Mer, showing the two turret rings for the forward-firing 75 mm-armed and the rear-mounted 8 mm machine gun-armed turret, the later which would be fitted on the FCM Char de Bataille prototype. Source: Char-français
Therefore, it comes as no surprise that FCM’s Char de Bataille design takes much inspiration and many features from the company’s super-heavy tank design. The turret of the new tank was straight-up the rear machine gun-armed turret of the FCM 2C, which would be armed with a Hotchkiss mle 1914 8×50 mm Lebel machine gun (though the prototype was not outfitted with one). Just like the FCM 2C, the FCM Char de Bataille featured a large engine block protruding from the hull, meaning the turret would only cover the forward firing arc.
Features and trials of the prototype
FCM’s Char de Bataille was trialed along with the three other vehicles in Rueil, starting with their presentation on the 13th of May 1924.
The FCM Char de Bataille prototype, often referred to as “FCM 21” on the Internet, though this designation does not appear to have a historical basis. Source: Tank Archives
The FCM Char de Bataille prototype was a 6.50 meters-long, 2.52 m high, 2.05 m wide tank. It was the longest and highest, but also the narrowest and lightest of the four Char de Bataille designs, though, with a weight of 15,640 kg, it still exceeded the requirements of the program by over two and a half tons. The ground clearance was also the highest, at 0.50 m.
The vehicle was powered by a Panhard engine with an output of 120 hp at 1500 rpm. This was the same engine as the Saint-Chamond prototype, though the FCM’s lower weight meant it had a horsepower per ton ratio of 7.7 hp/ton, almost reaching the requirements of the program. The Saint-Chamond had merely 7 hp/ton, while the two Schneider-Renault featured a more powerful 180 hp engine that gave them both 9.5 hp/ton. This engine allowed the tank to reach a maximum speed of 17.4 km/h, which was quite respectable for early 1920s standards. The FCM had the largest fuel tank of any of the Char de Bataille, 500 liters, though it also had the highest hourly consumption of 35 liters. It had the greatest range of all vehicles, with 175 km. The tank had a suspension of which the exact workings are unclear. It consisted of fifteen small road wheels, with a large front idler and a smaller rear drive sprocket. The suspension was apparently moved by a “Chaîne galle”, a type of mechanical piece usually used in barrages, great at transmitting high efforts at low speeds, which was kept tense by a pneumatic system. The tracks used were inspired by Holt tractor tracks which used wooden pads, with a quite long track pitch. These tracks went all around the hull, as with British rhomboid tanks such as the Mark I and IV. French experience with the CA 1 and particularly Saint-Chamond tanks had shown that tanks with too small of a track run performed far worse in terrain battered by artillery craters.
A side view of the FCM Char de Bataille prototype, showing the 15 road wheels under an armored skirt. Source: CAAPC
The FCM Char de Bataille featured 25 mm of armor. Its main armament was a 75 mm gun located on the right of the hull. Unlike other vehicles, which had the gun in some sort of casemate or mount, the FCM’s gun went straight through the armor plate. Most sources mention a hull machine gun was also featured, though the lack of clear photos of the vehicle’s front makes it hard to confirm that claim. The turret is often claimed to feature two machine guns, but this appears not to be the case as it was taken straight from the FCM 2C, and was of a cylindrical design which would be hard to arm with two forward-firing machine guns. As with other tanks of the Char de Bataille program, this turret was the place from which the commander gave orders to the two other crew members. In combat, the machine gun was to be used mostly to defend the vehicle from enemy infantry. The driver sat to the left of the hull, with the third crewman, tasked with loading the 75 mm gun, sitting to the right; considering the vehicle was the narrowest, it appears the two crewmen sitting in the hull were quite cramped.
Conclusion – A mostly inconsequential design
The trials of the Char de Bataille lasted from May of 1924 to March of 1925. The FCM appeared to have had an unreliable gearbox, and the tracks using wooden pads, used by all prototypes but the Schneider-Renault B, proved to wear down a lot quicker than metallic tracks. Little else is known about the results of the trials.
The Char de Bataille during the 1924-1925 trials. From front to back: the Schneider-Renault A, the FCM, the FAMH/Saint-Chamond, and an unrelated vehicle, the Renault NC-1 light tank prototype. Not shown on this cut of the photograph is the Schneider-Renault B, leading the column. Source: Tank archives
Out of the four Char de Bataille prototypes, the FCM is arguably the one which had the least inspiration taken from for the definitive design, which would become the B1. While the suspension of the final product was mostly inspired by the Saint-Chamond/FAMH, and most of the hull design as well as features, such as the Naeder hydrostatic system allowing for accurate hull movements, were taken from the Schenider-Renault prototypes, the influence of the FCM appears limited to the track-tensioning and clutch systems.
The fate of the FCM prototype beyond the trials is unknown, though the most likely way it ended its life was in a scrapyard.
Char de Bataille FCM illustration, created by Yuvnashva Sharma and funded by our Patreon campaign
Char de Bataille FCM specifications
Dimensions (L x w x h)
6.50 x 2.05 x 2.52 m
Ground Clearance
0.50 m
Weight
15,640 kg
Engine
Panhard producing 120 hp at 1500 rpm
Maximum speed
17.4 km/h
power-to-weight ratio (in hp/ton)
7.7
Fuel tanks
500 liters
Average hourly fuel consumption
35 liters
Range
175 km
Crew
3 men (Commander/turret gunner, driver/gunner, loader)
Armament
1 turret-mounted Hotchkiss mle 1914 8 mm machine gun
1 hull-mounted 75 mm howitzer
Possibly 1 hull-mounted Hotchkiss mle 1914 8 mm machine gun
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France (1938-1940)
