German Reich (1939-1941)
Engineering Tank – At Least 8 Built
Deemed obsolete in 1939, the Panzer I chassis was reused for many roles and purposes, creating new variants of the Panzer I. One of these new variants was the Panzer I bridge layer. Using the Panzer I Ausf.A chassis, the engineer battalion of the 2nd Panzer Division converted two of their tanks into bridge layers before the Invasion of Poland in September 1939. During the Polish campaign, more Panzer I bridge layers entered service and these vehicles also took part in the Invasion of France in May 1940. Their service life ended at some point in 1941, during Operation Barbarossa, due to the Panzer I chassis not being able to carry the bridge reliably. Furthermore, the production of Bridge layers on more modern chassis and with greater capacity had already begun in 1940, which replaced the Panzer I bridge layer, the Brückenleger I.
Context: Mobile Bridges for the Wehrmacht
The Panzer I was initially planned as a frontline and stopgap tank for the Panzerwaffe (English: tank force) in case of enemy aggression. However, as more and more modern tanks entered production and the Panzer I, with its thin armor and armed only with machine guns, was outdated as a frontline tank. However, rather than simply scrapping the vehicles, many Panzer I chassis of the Ausf.A and B variants were reused in new roles.
By 1939, the Waffenamt (English: Weapons office) had realized the need for motorizing bridge layers and engineering equipment in general. Normally, engineer bridges would have been carried by engineers, cars, or horses. Motorizing these bridges meant that they could be deployed almost immediately and could then support the advancing tank forces.
The exact production numbers and dates for the Brückenleger are not known. The first 2 Bridge layers were built before the Invasion of Poland in September 1939. These tanks were not simple field conversions carried out by the troops but conversions demanded by the Weapons Office. Alongside the 2 Panzer Is, multiple Panzer IIs were also converted into bridge layers. The conversions were most likely carried out by Krupp or Henschel, since these two companies were the leading companies in Panzer I production. The vehicle had its turret removed and a scaffold built around it, on which the bridge was fitted.
During the Invasion of Poland, an additional unknown number of Panzer I Ausf.As were converted into bridge layers. At least 2 vehicles can be seen with their entire superstructure removed. This would lead to the possibility that these vehicles were field conversions of Fahrschulwagen (Engish: training tanks) carried out by the 2nd Panzer Division’s engineer battalion.
At some point in September 1939, an unknown quantity of Panzer Is (Ausf.As and Bs) were also converted into bridge layers. Photos suggest that at least four additional vehicles (2 Ausf.As. and 2 Ausf.Bs) were built. However, this last variant differed greatly from the previous two bridge layer types. They featured a new bridge and still had their turret mounted. They all participated during the Invasion of Poland and later in France. It is unknown if any further vehicles were converted after 1940.
Officially, there is no record of the vehicle being referred to as Brückenleger I (English: Bridge layer I). However, this is the term the troops used to refer it to. Additionally, the later bridge layer on Panzer II and IV chassis was referred to as “Brückenleger”. Therefore, it can be presumed that this vehicle would have a similar name.
The first two bridge layers used the chassis of the Panzer I Ausf.A. Other than the removal of the turret, no changes were made. On the second version, again two Panzers I Ausf.A chassis were used. On the last version, both Ausf.A and B chassis were used.
Other than the mounting of support beams for the bridge, the superstructure was left unchanged on the first version. On the second version, the entire superstructure appears to be removed or was never mounted, as these vehicles could have been maintenance or training tanks on Panzer I chassis which both featured no real superstructure. Across the mudguards, two wooden beams for holding the bridge were mounted on the rear and front sides. The last version had an unchanged superstructure of the Ausf.A and B. However, multiple iron beams appear to be bolted into the front part of the hull for a bridge support. Furthermore, two iron bars were bolted onto the side of the superstructure on each side.
The suspension of the Ausf.A and B was left unchanged in all parts. It was still the same leaf spring suspension type with the road, idler, frontal wheels, and return rollers. This would later turn out to be a problem, as the already stressed chassis of the Ausf.A and B had problems successfully carrying the bridge in steep areas.
On the Brückenleger I mounted on the Ausf.A and B chassis, two different engines were installed. The bridge layer vehicle on the Ausf.A chassis used the Krupp M 305 4-cylinder air-cooled engine, which was very loud and noisy and could barely handle the Panzer Is lone weight. Adding a heavy bridge and even other tanks could lead to engine breakdowns. Vehicles on the Ausf.B chassis had the new Maybach NL 38 TL 6 cylinder water-cooled installed, which improved the Panzer I’s performance greatly.
On the first two versions, the turret was removed due to an unknown reason. This was presumably done in order for the first bridge type to fit the tank. The last version still mounted the Ausf.A or B turret in its entirety.
Three Different Bridges
Generally, the bridge layers differed mainly in what bridges they were mounting and were all rather primitive in terms of technology. The first version mounted two removable bridge ramps that could be used either as a ramp or additional length for the tank driving onto it. The deck could be removed, but it was not intended to be in combat. The bridge was made out of wooden beams bolted and held together via iron corner brackets. The deck rested on a wooden supporting skeleton mounted around the superstructure, which in turn was attached to the hull and superstructure by wooden beams. In total, the two bridge ramps had a length of 4 meters and a maximum load capacity of around 7 tonnes.
The second version can be seen as more of a bridge carrier and looked rather rudimentary. In photos, the two vehicles seem to be carrying three independent bridging sections which could all be removed easily. They laid on two wooden beams which in turn laid on the mudguards. Not much is known about their load capacity but, due to them solely being made out of wood, without any trace of metal support brackets, it is questionable if these 4-meter-long bridges could carry more than 7 tonnes.
The last version was technically the most advanced and looked more like the later bridge layers, such as the bridge layer IV. It featured three parts. One part could be put behind the tank so another tank could drive onto it. Once again, the deck acted as a part of the bridge itself and the front part would be extended either upwards or downwards. This bridge, although mainly being made out of wood, featured more metal parts that supported the bridge. This upgrade led to an estimated load capacity of around 8 tonnes and the three parts could cover a length of up to 15 meters. However, a new problem occurred. The bridge was now less stable, and rigidity was decreased. The deck was now a single piece with no hole between the tank itself and the bridge. Furthermore, it was now steep and permanently fixed and could not be removed without removing the bolts. Two large iron beams bolted into the hull supported the front part of the deck. Two smaller iron bars were bolted to the side of the superstructure and to the bridge on each side. Lastly, there was an iron bar hanging above the front hull between the turret and the front support beams which held two (presumably) concrete cubes in place, which acted as counterweights for the extended front bridge. The concrete cubes were connected to the extended front bridge via a large iron bar. To elevate the extended front bridge, the concrete cubes could be dismounted from the middle iron bar and moved from the level of the superstructure to a level above the bridge. If the concrete cubes were at the level of the superstructure, the extended front bridge would be pointing upwards. If the concrete cubes were above the deck, the extended front bridge would be pointing downwards. In some photos, the concrete cubes seem to be missing for unknown reasons.
This is what the bridge layer was intended to look like. However, since there were no official regulations for the Brückenleger I, many crews changed the type of bridge that they were carrying or mounted further bridges on it. In some photos, Brückenleger Is with a full metal bridge can be seen or with another type of bridge which was much more narrow and normally mounted on the Sd.Kfz.251 engineer variant.
There is no record of any changes to the armor and the wooden bridge would not upgrade the armor overall. Therefore, the side, frontal and rear armor was still around 13 mm of steel. The turret, if mounted, was also up to 13 mm.
Armament was removed in the early versions due to the absence of the turret. The machine guns presumably would be carried with the rest of the crew in a separate vehicle. In the later version, both machine guns, the MG 13 k, were mounted.
All three versions had a crew of 2. The commander/gunner was relieved of his task of operating the machine guns in the early versions. On the later versions with turrets, the commander was also operating the weapons. The driver would only drive the vehicle. The rest of the crew responsible for managing the bridge would drive alongside in a truck, car, or half-track and deploy if the bridge was needed. The exact number of how many people were needed to deploy the bridge is not known. In multiple photos, more than 3 people are shown (two of these are the actual crew members). This means at least one additional member was needed.
Organization and Doctrine
At first, the bridge layers were organized into the engineer battalions of Panzer Divisions, since the term tank engineer battalions did not exist yet. In 1939, officially, there were no armored bridge laying tanks, these were only unofficially part of the engineer companies. Starting in March 1940, the third company of every Pionier-Abteilung (English: engineer battalion) of all 10 panzer divisions was renamed into Panzer-Pionier-Kompanien (English: tank engineer companies). Within these Companies, there was the bridge platoon. This platoon would have 4 Brückenleger. Officially, these Brückenleger were based on the Panzer II and IV chassis, however, as the photos suggest, the Brückenleger Is were also fitted in these divisions. This also explains why the bridge layers participating in the Polish campaign only feature the tactical symbol for tank battalions and not that of the tank engineer battalions. At some point, an improvised ‘P’ was painted next to the tank battalion’s rhomboid, standing for Pionier (English: Engineer).
Although the bridge layers were superior in terms of mobility in comparison to their counterparts on foot, they were limited in the capacity and length of the bridge that they were carrying. This meant they could only be deployed in specific situations. The bridge layers were used when an obstacle, such as a small valley, trenches, or ditches not crossable by tanks, stood in the way of the advancing forces. The first two versions were able to clear 4-meter-long obstacles. Since their entire hull acted as a part of the bridge, the vehicle would drive into the ditch or trench, and then other tanks could drive over it. However, the bridge layers would always act together, meaning on one bridge layer the ramps were removed and used for additional length on the other one. On the second version, the bridges could be removed completely. On the later version, similar to the previous ones, the other tanks would drive over it but now the length of the covered area was much longer. Furthermore, the bridge (without the support platform) could be removed and used in other places.
Service Life/Test Results
The bridge layers which participated during the invasion of Poland were part of the 38th Engineer Battalion of the 2nd Panzer Division. No information exists on where and how effectively the bridge layers were used. However, one can assume that they were used during the crossing of the river Dunajec and river San in some way or another.
During the Invasion of France, the bridge layers were divided into three possible engineer battalions. Engineer Battalion 38 of the 2nd Panzer Division kept its old bridge layers, whilst Engineer Battalion 58 of the 7th Panzer Division was equipped with new bridge layers. The last potential battalion was Engineer Battalion 39 of the 3rd Panzer Division, however, this is solely a possibility with no photographic evidence.
Although very likely, it is unknown if the vehicles stayed in their battalions during Operation Barbarossa. Some Brückenleger Is can be seen in deep snow. The photos show the later versions with the large bridge.
Before the Invasion of Poland, tests were done to test the weight-carrying capability of the Brückenleger. During the tests, the Brückenleger was driven into a trench and another Panzer I would drive over it in the same manner as the later and better known ‘ARK’ type tanks. The bridge could successfully carry up to 8 tonnes, which was enough for the Panzer I. However, due to the bridge being made out of wood, stability and rigidity was reduced. This led to the tests turning out rather disappointing for the troops. Nonetheless, the vehicles were sent to the frontlines. It is unknown if any further tests were done on the later models. In theory, wooden bridges could turn out to be quite useful, as they were easier to produce, quieter, and are less slippery in wet conditions.
The Practicality of such a Conversion
Being only able to carry very few tanks of the German Army, the bridge layer I would turn out to be useless in its task of carrying tanks once the Panzer I was put out of service. However, during the first years of the war and especially during the Polish campaign, a large proportion of the German tank force consisted of Panzer Is.
Furthermore, one could argue that the bridge rigidity was insufficient when tanks drove over it and that it could only be deployed in very specific areas. But these were areas in which tanks performed much better than motorized vehicles and the bridge layer I could effectively sustain the weight of German trucks and cars, which could therefore transfer through difficult terrain.
Lastly, the Panzer I was available in large quantities around 1939, whilst heavier tanks, such as the Panzer IV, were not yet available in large numbers and, if available, were used as combat tanks and not engineer tanks. This task could be performed by the already obsolete Panzer I. Like many other conversions, the Panzer I could be made useful again in another role, from which the Army could benefit again.
Other Brückenleger Is
The following vehicles were all based on the Panzer I chassis, but do not have anything in common with the initial development of the real Brückenleger I.
The first odd bridge layer appears to be a training tank on the Ausf.B chassis mounting a very small bridge above its crew compartment.
The second vehicle is a Panzer I Ausf.A chassis without a turret but with a bridge put across the tank. It was used to demonstrate a motorcycle driving up steep obstacles during a parade.
Another bridge layer variant was the Panzer I Ausf.A with fascines. This one was not as much of a bridge layer as the other ones, but still has the same general purpose. It was a regular Panzer I Ausf.A mounting iron support beams. Across the support beams, fascines would be laid. The fascines would be used to support infantry walking across unstable ground, such as mud. If tanks could have used these fascines is questionable. Based on photos, at least one vehicle was converted. This one took part during the Invasion of Poland in 1939 as part of Panzer Regiment 35 within the 4th Panzer Division and was destroyed during that time.
The exact fate of these vehicles is not known, but photos show the vehicles during the winter of 1941. After the winter, no photos exist. Therefore, it can be assumed that the vehicles were either lost or pulled off the front because of their obsolescence.
Although the idea of having a mobile and armored bridge-laying vehicle had proven to be successful, the Panzer I was not the right choice for the chassis. It was severely limited with regards to which vehicles it could carry and how long its bridge could be. The later bridge layers, such as the bridge layer IV, were much better fitted for the role. Furthermore, the need for mobile bridges slowly decreased from 1943 onwards, as the Wehrmacht suffered more and more defeats and was on the retreat. However, the Brückenleger I could effectively carry trucks and other motorized vehicles and the obsolete Panzer I was fitted with a new role.
Brückenleger I specifications
|Dimensions (L-W-H)||Early version: 4.02 x 2.06 x 1.5 m, Late version: 4.02-44 (extended bridge 15) x 2.06 x 1.90 m|
|Total Weight||Early version: 6.4 tonnes (bridge load: 7 tonnes), Late version: 7 tonnes (bridge load: 8 tonnes)|
|Crew||At least 3 (commander/gunner, driver, bridge operator)|
|Elevation||-10° to +20°|
|Speed||Ausf.A: max.: 32 km/h, Ausf.B: 35 km/h|
|Range||roads: 140 km|
|Armament (if turret mounted)||2x 7.92 mm MG 13/MG 13k|
|Ammunition||2250 7.92 mm S.m.K. in 25 magazines|
|Engine||Ausf.A: Krupp M 305 4-cylinder air-cooled, Ausf.B: Maybach NL 38 TL 6 cylinder water-cooled|
|Communication||FuG 2 receiver|
|Total Production||At least 8 built|
Janusz Ledwoch, Vol. XI PzKpfw I vol. I (Tank Power)
Lucas Molina Franco, Panzer I The beginning of a dynasty
Peter Chamberlain and Hilary Louis Doyle, Encyclopedia of German Tanks of World War Two
Thomas L. Jentz and Hilary Louis Doyle, No. 14 Gepanzerte Pionierfahrzeuge (Armored Combat Engineer Vehicles) (Panzer Tracts)