Categories
WW2 Republican Spanish tanks

Trubia-Naval

Second Spanish Republic/Autonomous Basque State (1936-1937)
Light Tank/Tractor – 12-45 Built (Light Tank), 2-3 Built (Tractor)

War often creates a desperate situation in which second-rate options are pressed into service. In the world of AFV’s, these may be old designs which resurface when war is on the doorstep. One such example is the Trubia-Naval produced and deployed by the Republican Army of the North during the Spanish Civil War.

Context – A Divided Spain

After the failed General’s coup of July 17th-18th 1936, Spain descended into civil war. The main fighting force of the rebellious Generals (the Nationalist) was in the Spanish colonies of North Africa and was airlifted to peninsular Spain by the German and Italian air forces. Once they gathered with other rebellious forces in Andalucía, they advanced north towards the Republic’s capital, Madrid.
In the central north Spanish plateau, the rebels triumphed with a force made up of Carlist and Falangist militiamen. This meant that the industrial heartlands of the Basque Country and Asturias was cut-off from the main Republican territory.
On October 6th 1936, the Republican Courts (Parliament/Congress) enacted provisions for a statue of autonomy giving the Basque region quasi-de facto independence.
The Partido Nacionalista Vasco (PNV) [Basque Nationalist Party] leader, José Antonio Aguirre, would became ‘Lendakari’ [President] and also took on the Ministry of Defense portfolio.
Given their isolation, the autonomous Basque state created its own army and navy. In the state of war, the Basque military authorities considered building tanks and artillery tractors for their armed forces.

Digging in the Past

The first project to create an indigenous Spanish tank design dated from 1935. Commander Victor Landesa Domenech, an artillery officer attached to the Trubia arms factory in Asturias (Northern Spain), Rogelio Areces, the Trubia arms factory’s Chief Engineer, and Captain Carlos Ruíz de Toledo, a Commander in charge of Batería de Carros de Asalto de Artillería [Artillery Tank Battery] in its first engagements during the Rif War, teamed up to design a tank for the Spanish Army on their own initiative and financed out of their own pockets. The prototype and the serial production version, the Trubia Serie A, would closely resemble the Renault FT, what was considered to be the superior tank in Spain at the time. However, there were some differences. They had improved firepower in an innovative system involving two overlapping turrets with independent movement, each armed with a Hotchkiss M1914 7mm machine gun, a larger size, an additional crew-member (loader) and marginally thicker armor and engine power. It also included an innovative ‘Orion’ suspension system, which was supposed to improve upon traditional systems, in addition to enhancing turning capabilities and minimizing the effects of the tracks on roads. In this integrated track design, the links were suspended from the chassis and held together by a lateral metal wall. This system was designed to prevent the tracks from coming off when maneuvering. Four of these vehicles and a prototype were built with the former seeing service up to the Spanish Civil War.

The first serial Trubia Serie A in the factory it was built. Photo: Artemio Mortera Pérez (2007), p. 8
Landesa Domenech and Areces continued to work together designing a tractor for military use known as the Tractor Landesa [Landesa tractor]. Following a series of trials, 9 would be bought by the Army. They also designed an armored and armed upgrade. Both versions saw service in the Spanish Civil War.
Subsequent to their tractor success, Landesa Domenech and Areces designed a new light tank concept intending it to be used by the Spanish Army. The Carro de Combate Ligero Para Infantería Modelo 1936 as it was known would only be a paper project but it would serve as inspiration for the Trubia-Naval. The main features of this paper tank were: a small size; 2 crewmen; a 80hp engine; and a mix of composite and conventional armor. The sides and front of the vehicle were the composite element of the armor, with the outer layer being 13mm thick and the inner layer a mere 3mm thick. The space between plates was 25mm thick and was most likely filled by wood. The rear, top and bottom of the tank were 3mm thick; a 40mm main gun; and, an improved and smaller version of the suspension used on the Trubia Serie A.

Original blueprints from the Trubia arms factory of the side, top, and front of the Carro de Combate Ligero Para Infantería Modelo 1936 as drawn by Victor Landesa Domenech and Rogelio Areces in which the tank’s key features can be distinguished. Note the striking resemblance to the Trubia-Naval.

A Tank Requirement

The situation in the north of Spain for the Republic in the Summer of 1936 was dire. The Nationalist troops of General Mola (mostly militiamen) were reinforced with troops from General Franco’s Army of Africa and planned to cut the northern regions loyal to the Republic off from the French border, through which tanks and planes were being delivered. At the same time, Republican forces tried repeatedly to take Oviedo (Asturias), which, with its history of revolutionary activities, had surprisingly supported the coup, whilst simultaneously fending off Nationalist troops attacking from the west.
Given this situation, in August 1936, Captain Ignacio Cuartero Larrea was sent to Bilbao (Basque Country) from the Trubia arms factory to discuss the possibility of the production of war materiel for the Asturias Front. Cuartero Larrea was experienced in tank design as he had participated in the construction of the Trubia Serie A.
The Basque authorities convinced Cuartero Larrea to stay in Bilbao (which by October was the seat of government of the Autonomous Basque State) to direct the construction of war materiel, and offered him the installations of Sociedad Española de Construcciones Navales (SECN) [Spanish Society of Naval Constructions] to carry out his task.
Although SECN primarily focused on naval industry, it had, in the years leading up to the Civil War, been building SOMUA lorries and buses under license in its Sestao factory. More importantly, SECN also built the Bilbao Modelo 1932 armored cars, the most advanced pre-Civil War Spanish AFV design. Cuartero Larrea returned to Trubia arms factory with José Rufo Galárraga, the Chief Engineer at SECN, to study the vehicles and documents available there.
After some deliberation, they chose the blueprints of the Carro de Combate Ligero Para Infantería Modelo 1936 to take back to Bilbao.

Photo of the factory assembly line at the SECN in Sestao showing a line of Trubia-Navals being built. The first two, at least, have the driving mechanisms facing the engine, indicating that they are the tractor variant. Photo: SOURCE

Design

The Trubia Naval would be almost a direct copy of the blueprints from Trubia.

External Appearance

The rearmost part of the vehicle had the engine ventilation consisting of a twelve-lat vertical grille, with an additional four lat grille mounted horizontally on each side (unlike the blueprints, which had twelve lats). Those on the side were at a slight inwards angle.
The side hull, which was angled at 65º, had two large hatches on each side for crew access with a small loophole in the upper center. The large size in comparison to the rest of the tank would have most certainly affected armor effectiveness. The side went down and joined the mudguards which covered the entirety of the top tracks.
The turret was placed atop the hull and consisted of a circular structure with a shallow dome covering it welded to it at the top. To the front was the main armament and on each side there appears to be oval-shaped stroboscopes with horizontal turn allowing for continual vision.
The uppermost frontal plate consisted of two hinged plates opening outwards. The right plate had a headlamp, whilst the left one had a vision slit for the driver. From this plate, the armor extended almost horizontally and then almost vertically creating a slightly angled plate which had a machine gun. Below this, the armor took a rounded shape.
The composite armor of the blueprints was replaced by more traditional and simpler riveted chromium-nickel steel plates which were between 8mm and 16mm thick, though exact details are not known.

Armament

The 40mm armament from the blueprints was dropped due to unavailability of guns and was replaced with a machine gun.
The first model of the Trubia-Naval was equipped with two Lewis 7.7mm machine guns which had a cooling jacket, giving the appearence they were a larger caliber gun. There was a large supply of Lewis guns and ammunition as a Soviet ship carrying 200 of these machine guns had docked in Bilbao port on October 1st 1936. The rest of the series would be equipped with two Degtyaryova Tankovy (DT) 7.62mm machine guns. The DT was already carried by the Soviet-supplied BA-6’s and FAI armored cars. This gas-operated machine gun was simple, robust, and ideal for compact spaces, though it had a complex feeding system. The secondary frontal machine gun had limited use due to its position and having to be operated by the driver. The tank carried 9,600 rounds in total.

Series of photos of the first Trubia-Naval built by Sociedad Española de Construcciónes Navales in Sestao. The attention to detail in its construction and features and it being equipped with two Lewis 7.7 machine guns covered with a protector to give the appearance it was armed with a cannon all point to its being the first-built Trubia-Naval. Note the triangle denoting the manufacturer on the side. Photo: Artemio Mortera Pérez (2007), p. 65-66.

Body-on-frame and tracks

Although it had proved to be outdated and ineffective, the ‘Orion’ suspension system was used due to the urgency of the situation.
Each track consisted of a long ellipse-shaped structure formed by two parallel steel sheets and was covered by a mudguard. Between the two sheets, there was a track for the track rollers to travel through. Between the steel sheets, there were drum brakes slightly modified from previous designs.
Unlike in most other vehicles, the track rollers were integrated into the tracks and moved in unison with the track links along the tracks set between the two sheets.
This was an updated copy of the one on the Trubia Serie A and Landesa tractor, albeit, smaller.

Engine and Driving Mechanisms

In the rear of the tank was the engine compartment. Most tanks were equipped with 6 cylinder MAN engines with between 60hp and 100hp, which were plentiful in the Sestao factory where the Trubia-Navals were being produced. These engines had their limitations because of their low elasticity and high revolutions per minute, which meant that with any minor brake, power was lost. It is also stated that two Trubia-Naval were equipped with 6 cylinder Chicago engines and one had a 4 cylinder Chicago engine.
The gearbox, which was situated beneath the driver’s seat at the front, had three forward gears (40km/h, 30km/h, and 10km/h) and one reverse (10km/h).
The vehicle was driven with a steering wheel which activated the brakes and clutch. However, according to Galárraga, some of the tanks were operated by means of two direction levers.

Photo of the unarmored chassis of a Trubia-Naval being driven around the SECN factory in Sestao. Photo: SOURCE

Crew Positions and Responsibilities

The driving and combat compartment at the front of the tank housed the driver, who sat at the front, and the gunner/loader, who was positioned behind him. Given the small size of the tank, the gunner/loader would have had to sit or crouch when inside the tank. The driver also operated the frontal machine gun. Which one of the two was the commander was unspecified.

A Trubia-Naval being tested with the driver’s head emerging out of one of the enormous side doors. Photo: Artemio Mortera Pérez (2007), p. 67.

Photo of three unarmed Trubia-Naval being tested in the area surrounding the SECN factory. Photo: Artemio Mortera Pérez (2007), p. 67.

Name

One of the most controversial issues surrounding the Trubia-Naval is its name. The factory committee which had built them insisted the tank be named Tanque Constructora Naval [Naval Constructora Tank] in homage to the company building it, but Cuartero Larrea gave the name Areces-Trubia instead – Areces in honor of Rogelio Areces, one of the tank’s designers (Landesa Domenech had defected to the Nationalist, so his name was not an option), and Trubia after the arms factory from where the vehicle’s blueprints originated (conveniently, Cuartero Larrea worked at said factory).
The disagreement even reached Lendakari Aguirre, and it was decided that the Chief Engineer at the Trubia factory, Constantino Alzueta Estrada (who had been involved in the Trubia projects since 1925), should check the blueprints and assess the resemblance. Seeing the obvious similarities, a compromise was met, and the official name given was Trubia construido en la Constructora Naval [Trubia built at the Constructora Naval], with ‘Trubia-Naval’ being used for short. However, most tanks only had the Naval crest and shield on them. Again, despite all this, most official documents referred to them simply as Trubia.

The shield on Trubia-Naval no.12 which was captured by Nationalists in April 1936. Despite the fact that an agreement had been reached to acknowledge the involvement of both the Trubia arms factory and SECN in the design and construction of the vehicle, only SECN is represented. Note on the sides of the triangle the initials of Unión General de Trabajadores (U.G.T.), Confederación Nacional del Trabajo (C.N.T.), and Solidaridad de los Trabajadores Vascos (S.T.V.), all of which were trade unions. Photo: Artemio Mortera Pérez (2007), p. 88.
Some sources (such as F.C. Albert, Carros de Combate y Vehículos Blindados de la Guerra 1936-1939 (Barcelona: Borras Ediciones, 1980)) name the vehicle Carro Euskadi [Basque Tank], but this name was never used during the Civil War and is incorrect.
A nickname often associated with the Trubia-Naval is ‘tanque de juguete’ [toy tank] due to its small size.
To add to the confusion, when Trubia-Naval tanks were captured by Nationalist forces, their official documents sometimes referred to them as Carros Rusos [Russian [sic] Tanks].
Another point of interest is that Republican and Basque documents made a distinction between two models of the tank, Modelo 1936 and Modelo 1937. Artemio Mortera Pérez (one of the higher regarded authors on AFV usage in the Spanish Civil War and author of a book dedicated to the Trubia family), theorizes that there is a simple explanation to this.
The Modelo 1936 are the first ones built in Sestao, whilst the Modelo 1937 were a never completed improved version adapted following a series of complaints from Captain Luis Basterretxea de Arendia (Commander of the Trubia-Naval company of the Euskadi Light Tank Battalion in March 1937) and his men.
A last clarification to make is that the Trubia Serie A was not a prototype to this tank.
That is not to say that the two are unrelated. As already explained, the Trubia-Naval was based on and mostly developed from the Carro de Combate Ligero Para Infantería Modelo 1936 designed by Victor Domenech and Areces. This vehicle was influenced by another of the duo’s designs, the Landesa tractor. Landesa Domenech and Areces had also collaborated together to develop the Trubia Serie A. All these vehicles (the Trubia-Naval only partly) were designed with the intention that it be the new light tank for the Spanish Army. A common design feature was the ‘Orion’ suspension system which continued to be used from 1926 to 1937.


A camouflaged Trubia Naval of the Republican forces in the Basque country, 1937.


An unarmed Trubia Naval in hypothetical Nationalist colors. Most captured tanks had the red and yellow Spanish flag painted around the turret. In some cases a St. Andrew cross was painted on the top of the turret for air recognition. The machine guns on this model have been removed and it would have mostly been used for towing, as its combat value was minimal. The one photo that exists of one of these tanks in Nationalist service shows that it indeed had the red and yellow flag painted around the turret, but that it did not have the black St. Andrew cross on top, even though a white background had been painted on. Additionally, an engineer unit emblem is painted on the side in the photo, which is not included in this particular illustration. 

Both of these illustrations were produced by Tank Encyclopedia’s own David Bocquelet.

Numbers Built

Probably the biggest controversy and mystery surrounding these tanks is the total number produced.
The original documents from Departamento de Ferrocarriles de la Naval de Sestao [Naval of Sestao Railway Department], the department within SECN in charge of building the tanks, were lost, a fact that renders an accurate estimation of production almost impossible.
The original idea had been to create an initial series of 20 tanks and 2 tractors [see tractor section below].
Commander Casiano Guerrica-Echeverría, Chief of Industrias Movilizadas de Vizcaya [Mobilized Industries of Vizcaya] (a conglomerate of industrial companies from the Vizcaya province), estimated that only about 12 of the tanks were ever actually built.
When Bilbao was captured by Nationalist forces on July 21st 1937, the documents of the Republican Army of the North were confiscated. Among them was the organization of the Tank Battalion, which was made up of 2 companies of Renault FT’s, 1 company of gun-equipped armored cars, and 3 companies of Trubia-Navals. Each company consisted of three sections with five tanks in each, 15 tanks per company, 45 tanks in total. The document also stated that the battalion had to be ready in Corrales de Buelna (in the middle of Cantabria, northern Spain) before June 25th 1937. This means that the document was referring to available vehicles rather than a template of intended vehicles. However, Mortera Pérez, is skeptical. He does not think that that many tanks were ever built and believes the numbers on the document are a misprint or were compiled with erroneous information. It is also important to note that in a document of listing captured materiel compiled by the Nationalist General Luis Orgaz Yoldi on September 10th 1937, it states that 20 ‘Trubias’ and Renault FT were available. The exact composition of these 20 tanks is hard to tell. The truth will most likely never be known.

Three Trubia-Naval at the grounds of the SECN factory in Sestao with factory workers. Photo: Artemio Mortera Pérez (2007), p. 67.

The Tractor Version

In addition to tanks, the Basque authorities had also shown interest in artillery tractors. The tractor version was an unarmored and unarmed Trubia-Naval but with some modifications. Being a variant of the Trubia-Naval, it also resembled the Landesa tractor.
The driver’s position and that of his assistant were turned around and were now facing the engine, as in the Landesa tractor. Most of the driving mechanisms were relocated. In contrast to the Landesa tractor, seats for passengers were added in the rear.
This tractor is often referred to as Landesa-Naval, but this is a conventional denomination, and as already explained, Landesa Domenech had joined the Nationalist forces. The full name of this tractor was Tractor Landesa fabricado por la Constructora Naval [Landesa Tractor built by Constructora Naval].

Photo of inside the SECN factory showing 4 Renault FT, two improvised armored cars and a Landesa-Naval at the rear right. Photo: Artemio Mortera Pérez (2007), p. 80.

Photo often incorrectly described as a Landesa tractor. The background with the white walls is the Naval installations in Sestao denote that it was built in Bilbao, not Trubia. Furthermore, unlike the Landesa tractor, it has seats for passengers in the rear. Photo: SOURCE

Operational Life

There is not much detail about the operational use of the Trubia-Naval, but there is plenty of information about the campaigns in which it participated.
The first Trubia-Navals were probably ready by January-February 1937, and four were most likely sent to Asturias to take part in the last major offensive there in February. Given that there is no further information about these, it can be assumed that they were destroyed.
On March 23rd 1937, the Euskadi Light Tank Battalion was formed and included a Trubia-Naval company under the command of Captain Luis Basterretxea de Arendia. The Trubia-Naval were numbers 7, 8, 9, 11, and 13 and were given to their crews for training on March 29th. On April 5th, the Battalion Commander, Captain Carlos Tenorio Cabanillas, compiled a report with complaints about the tank, which included: the low engine power, the insufficient track grip to the ground, the fragility of the clutch, the low height of the mudguards over the ground, and the small and uncomfortable space inside. These complaints were noted and the recommendations were adopted for a new improved version of the tank, the Modelo 1937, though exactly how is not known.
On that same day (April 5th), the Trubia-Naval would see combat on the Urquiola road destroying a Nationalist ‘tiznao’ (an improvised armored car) and later taking a hill defended by the Condor Legion and capturing a car. On the 7th, No. 12 was lost to the Nationalists in Barazar. On the 27th, due Nationalist advance, the Trubia-Navals retreated to Durango/Yurreta, 26km from Bilbao, where they were reinforced with BA-6 armored cars. In Yurreta, they covered the infantry retreat and BA-6 assault on the Guernica road, before they themselves retreated.

Nationalist troops belonging to 51 Tabor de Tetuán posing atop the captured Trubia-Naval nº12 in Barazar. Photo: Artemio Mortera Pérez (2007), p. 87.
Throughout May, the Trubia-Naval were divided up and sent to cover different infantry retreats in the fallback to Bilbao.
On June 3rd, several Trubia-Naval with infantry support assaulted Peña Lemona and managed to retake the crag, though this resulted in 5 crewmen being wounded and the unit being taken to Algorta (north of Bilbao) for replenishment. By the 17th, they were back in action again covering a retreat. A day later, the general retreat was ordered and the Trubia-Naval returned to Bilbao to defend the city center whilst the city was being evacuated before the impending Nationalist entry into the city on the 19th. The Trubia-Navals would not be captured though and they retreated towards Santander.

Two photos of the same Trubia-Naval with Basque militiamen in Larrauri, north of Bilbao. In the second photo, the militiamen are posing for the camera. Note the box on the rear of the tank. Photo: Artemio Mortera Pérez (2007), p. 91-94.

The spoils of war following the Vizcaya Campaign. The photo shows two Somua-Naval armored cars, a Soviet BA-6 and the Trubia-Naval captured by the Nationalist at Barazar on October 7th. Photo: Artemio Mortera Pérez (2007), p. 107.
At the beginning of July, all available Trubia-Navals were sent to Laredo, the HQ of the Tank Regiment of the Army of the North. Initially, there were plans to send 11 to Noreña (Asturias) to take part in an offensive, but they were never sent and the offensive did not take place. By August 6th, the Trubia-Naval were incorporated into the Republican Army as the entire Basque region (and consequently the Autonomous Basque State) had fallen. In all, only one Trubia-Naval had been lost since March in the whole of the Vizcaya Campaign.

A Trubia-Naval with Republican troops somewhere in Vizcaya. Note how big the side doors were. Photo: Artemio Mortera Pérez (2007), p. 88.
Back in June, with Bilbao about to fall, it was planned to move tank production to Trubia. On the 15th, the order was given to build a Trubia-Naval Modelo 1937 in the Trubia arms factory, with a second order on July 4th demanding 9 be built. None of these vehicles had been manufactured by September as the factory was busy enough repairing already existing tanks, including 8 Trubia-Naval on September 25th.
On August 10th, the Trubia-Naval were divided into two sections, with one being sent to cover the Reinosa road and the other to Olea, to defend against the southern Nationalist advance on Santander. Not many details are known about the deployment of the Trubia-Naval in the Santander Campaign, but it can be assumed that they were again used to cover the retreat towards Santander. On the 14th, an unspecified number of Trubia-Naval and Renault FT’s were sent to the Escudo mountain pass in support of a section of BA-6’s and FAI’s, allowing for the retreat of the Soviet vehicles. Some would be used two days later in Reinosa. Following the surrender to Italian forces of the C.T.V. (Pacto de Santoña), Santander was taken on the 26th. 4 Trubia-Naval were captured in Santander by the C.T.V. They were divided between the Parque de Artillería de Valladolid [Valladolid Artillery Barracks] and the Fabrica de Artillería de Sevilla [Seville Artillery Factory]. Allegedly, one was kept by the Italians with the intention of sending it to Italy to study it, though it cannot be confirmed if this did indeed happen. However, Spanish figures by the Servicio de Recuperación Nacional [Nationalist Recovery Service] state that only 3 Trubia-Naval were captured, 2 at Muriedas and the other at a warehouse.

The spoils of war following the Nationalist capture of Santander on August 26th. The photo shows a Renault FT, a Soviet BA-6, and two Trubia-Naval (one is almost out of shot at the back). These tanks would be sent to factories to be put back into action. Photo: Artemio Mortera Pérez (2007), p. 144.

A Trubia-Naval pictured next to an Italian C.T.V. trooper. Location unknown, though possibly Santander. Photo: SOURCE
Following the capture of Santander and the collapse of the Republican Army of the North, Nationalist eyes were set on Gijón. The Republican armored forces consisted of a single battalion of Renault FT’s, a Trubia-Naval battalion, and a few armored cars. Due to the terrain and fierce resistance by Republican militiamen, the Nationalist advance was slow. This terrain also meant that tank deployment was limited. On October 20th, a Trubia-Naval was captured alongside a Renault FT in Infiesto, on the Oviedo-Santander railway. Gijón would fall the following day and with it, the War in the North came to an end.

The Trubia-Naval in Nationalist service

What was the exact and common use the Nationalist gave to their captured Trubia-Naval is not fully known, but they generally showed little appreciation of them. By the end of the ‘War in the North’, the Nationalist had plenty of superior tanks and did not need these unreliable and poorly armored machines for tank combat duties. Those which were put back into service were most likely just used to tow artillery pieces or other engineering duties.
The one existing photograph of a Trubia-Naval in Nationalist service supports this argument. The vehicle in question (see photo bellow) has a military engineer’s emblem on its side corresponding to the Arma de Ingenieros (Engineers Branch), and would have probably carried or towed the engineer’s equipment.
This photo also gives us indications as towards any camouflage or marking scheme modifications on the Nationalist vehicles. As with many captured vehicles, the Nationalist painted a red and yellow Spanish flag around the turret. The top of the turret was painted white, but unlike in other vehicles, a black St Andrew cross was not painted on this white background, though that does not mean it was not painted on other vehicles. Another curiosity of this particular picture is that on the front of the hull, just next to the machine gun position, is what appears to be a typical early war Nationalist tank markings which could be a ‘1’, an ‘H’ or an ‘I’, but from this photo it is impossible to tell with complete certainty.
Like many other captured vehicles, the majority were most likely scrapped.

Only known picture of a Trubia-Naval in Nationalist after having been captured. Note the red and yellow Spanish flag painted around the turret, lack of weapons and military engineer’s emblem on the side. Photo: Will Kerrs Private Collection

Trubia Naval specifications

Dimensions 3.55 x 1.70 x 1.80 m (11.65 x 5.58 x 5.9 ft)
Total weight, battle ready 5.5 tons
Crew 3 (commander/gunner, driver, hull gunner)
Propulsion MAN water-cooled, 6 cylinder, 70 hp (52.2 kW)
Max speed 30 km/h (19 mph) on road
Suspension None
Armament 2x 8 mm (0.31 in) Vickers light machine guns
Armor 16 mm (0.63 in)

Sources

Artemio Mortera Pérez, Los Carros de Combate “Trubia” (Valladolid: Quirón Ediciones, 1993)
Artemio Mortera Pérez, Los Medios Blindados de la Guerra Civil Española. Teatro de Operaciones del Norte 36/37 (Valladolid: AF Editores, 2007)
Artemio Mortera Pérez, Los Medios Blindados de la Guerra Civil Española. Teatro de Operaciones de Levante, Aragón y Cataluña 36/39 2.ª Parte (Valladolid: AF Editores, 2011)
Mark Kurlansky, Basque History of the World (London: Vintage Books, 2000)
Special thanks to Mr. Will Kerrs for allowing the author to use his photo.

Categories
WW2 Republican Spanish tanks

Tractor Landesa

Second Spanish Republic (1932-1937)
Tractor/Light Tank – 13-14 Built (Tractor), 2-4 Built (Light Tank), 2-3 Converted From Tractor To Light Tank

Originally intended to be a tractor for military or agricultural use, it was given an armored and armed upgrade which converted it into a tank to attract new markets. In its original tractor form, it would prove to be effective and able to carry out its task reliably. The tank upgrade would see service as a product of circumstance during the Spanish Civil War.

Context – The Tank That Became a Tractor

In 1925, Commander Victor Landesa Domenech, an artillery officer attached to the Trubia arms factory in Asturias (Northern Spain) and Rogelio Areces, the Trubia arms factory’s Chief Engineer, teamed up with Captain Carlos Ruíz de Toledo, a Commander in charge of Batería de Carros de Asalto de Artillería [Artillery Tank Battery] during its first engagements during the Rif War (1911-1927), to design a tank on their own initiative. This tank would become Spain’s first indigenous tank and was to overcome the major faults of the Renault FT, Spain’s most available tank at the time. The prototype improved upon the FT with increased power in an innovative system involving two overlapping turrets moving independently and each armed with a Hotchkiss M1914 7mm machine gun and marginally improved armor and engine power.

The design was considered a success and an improved model was built, the Trubia Serie A. The main difference of the serial version compared with the prototype was its larger size, an additional crew-member, and, most importantly, a new suspension system and engine acquired in Germany. This apparatus was supposed to improve upon traditional arrangements in addition to enhancing turning capabilities and minimizing the effects of the tracks on roads. In this integrated track design, the links were suspended from the chassis and held together by a lateral metal wall. This system was designed to prevent the tracks from coming off when maneuvering.

The first serial Trubia Serie A in the factory it was built – Photo: Artemio Mortera Pérez (2007), p. 8

Four of these tanks would be built and tested in 1926. During the tests, deficiencies in the tank (especially in the new suspension system) were noted and modifications were recommended. At least one of the tanks was modified and re-tested far more successfully in May 1928. Although there was some interest in the tank, political instability, and lack of funding condemned the vehicle.

In this context, Landesa Domenech and Areces embarked on a new project, which would again be a private venture, this time with the aim of creating a tractor for military and agricultural use.

Design

The tractor would be built following the same main principles as the Trubia Serie A, but with updates and modifications.

External Appearance

Between the two tracks, there was a semi-open-topped platform above the engine and driver. The engine itself was covered by steel plates riveted together, with grilles on either side and at the front with eleven blades each. Atop this engine compartment was a headlight. Behind the engine was a steering wheel, the driver’s seat, which carried a small electrical lamp, and space for an additional crewman who acted as the driver’s assistant. The two lamps and the electrical equipment were made by Scinilla and were fed by a Tudor 24 volt battery.

Body-on-Frame and Tracks

Each track consisted of a long ellipse-shaped structure formed by two parallel steel sheets covered by a mudguard. Between the two sheets, there was a track path for the track rollers to travel through. The tracks on either side were joined to each other by 4 u-shaped bars traveling underneath the tank. Between the steel sheets were some sort of drum brakes.

Unlike in most other vehicles, the track rollers were integrated into the tracks and moved in unison with the track links along the tracks set between the two sheets. This was an updated copy of the one on the Trubia Serie A, albeit, smaller.

Engine

The first vehicle was given a Mercedes 60 hp engine. The second and third vehicles used a SEFA engine of unknown horsepower. At least the ones equipped with SEFA engines initially used K.L.G. spark plugs. Some Spanish produced spark plugs from the Toledo arms factory were tested, though, once they proved unsatisfactory, they reverted back to the K.L.G. ones.

At some point between October 1932 and 1934, it was decided that the Mercedes engines were superior to the SEFA, so the command was given to home-build the German engines. Some of the engine components were impossible to copy so they were ordered from Germany, which led to the accusation that Trubia, the factory building the engines, was carrying out an unauthorized copy (which indeed it was).

Fortunately for Landesa Domenech and Areces, this did not amount to anything more. Their justification was that Trubia was creating an experimental series of engines and did not intend to sell them. These new engines would be called Mercedes-Trubia and were presumably 60 hp. The next nine or ten vehicles would be equipped with this engine.

In late 1935 or early 1936, four BOMAG heavy oil engines would be purchased for four new tractors, but only one would be built before the Spanish Civil War broke out in July 1936.

Factory Life

The first tractor was built by Landesa Domenech and Areces with help of factory workers from the Trubia arms factory in the workshop of the Compañía Anónima Basconia in Bilbao, Northern Spain. There it was tested successfully by its inventors on the nearby Malmasín Hill. Landesa Domenech and Areces then decided to take their new tractor to Trubia with the intention of building it in series, despite not having a contract at the time.

An external company, the naval-focused Juliana Constructora Gijonesa S.A., was contacted for the production of more tractors, but Landesa Domenech and Areces wanted to remain in Trubia due to the expertise of the workers there. Therefore, they reached an agreement to lease the factory of Industrial Química de Nalón in Trubia for the production of more tractors. There, the pieces for the tractors were built before they were presumably moved to the Juliana Constructora Gijonesa S.A. factory in Gijón where the two Landesas with SEFA engines were put together, though there is a strong possibility they never left Trubia.

Operational Life

In October 1932, the two Landesa tractors with SEFA engines were sent to Palencia (central north Spain) to take part in the Maniobras del Pisuegra military maneuvers. These were the first military maneuvers of the new Second Spanish Republic (established in April 1931) and as such, attracted lots of interest and attention from the press and military officials from around the globe.

The two tractors were sent for experimental use, but only one was used at the time owing to the lack of crew.

They were attached to Grupo de Artillería nº1 [Artillery Group No. 1] and were put in charge of towing Skoda 76.5mm cannons. The artillery group had eight of these, so the tractors were kept busy. Inclement weather made matters worse, extremely muddy ground meaning that the already busy tractors had to pull immobilised and bogged down vehicles out of the mud.

The overall performance of the tractors during the trials was deemed satisfactory. However, both tractors had breakdowns caused by the snapping of the structure linking the engine to the body-on-frame.
Following the trials, a new Mercedes-Trubia engine was developed and one was installed in a newly built tractor. This tractor would be sent to the Escuela Central de Tiro (the Army’s testing ground) in Carabanchel (Madrid) to test its towing and overcoming obstacle capabilities. The tests were a major success, with the tractor being able to tow 15cm cannons and 155mm howitzers even through the mud of the Jarama River.

As a result, the Army decided to place the order for nine with Mercedes-Trubia engines (it is unclear if these nine included the one tested in Carabanchel or not) to equip the Grupo de Artillería Antiarea nº1 [Anti-aircraft Artillery Group nº1] barracked in Carabanchel.
Once these were built, as a publicity stunt, the nine tractors were intended to cover the 370km (230 miles) distance to Madrid by themselves driven by Trubia arms factory workers.

They managed to cover the first 60km with ease until they reached the Pajares mountain pass (1,378m in height). There, the lead tractor driven by Constantino Alzueta and Zenón Soler (the two men in charge of driving the tractor in all the trials) ventured through the pass and reached the other side. They recommended that due to the other drivers’ inexperience that they take another route. The nine tractors were put on a train to Collado de Villalba, 32km (20 miles) outside Madrid, where they were detrained and finished the trip by road.

They arrived in Madrid in the early hours of October 12th 1935 and were given Skoda guns to tow to take part in the military parade to coincide with the Fiesta de La Raza/Día de la Hispanidad (the national day of Spain, which commemorates the anniversary of Christopher Columbus’s first arrival in the Americas). The Trubia arms factory workers who had driven the tanks to Madrid were given army uniforms and participated in the parade, which went down the Castellana Avenue to the War Ministry, where they were inspected by the War Minister José María Gil-Robles y Quiñones.

It can be assumed that these nine tractors remained in service up to and including the Civil War and were used throughout it by the Republican forces defending Madrid and its surroundings, though any evidence is yet to be found to support this claim.
At the same time, one tractor (it is unknown if it was a newly built one or one of the already existing ones) was exhibited in front of a commission from the Ministry of Agriculture, but no contract was granted.

In late 1935 or early 1936, four new tractors with BOMAG engines were intended to be built, but only one would be before the Spanish Civil War broke out in July 1936. This tractor would later be taken to the Juliana Constructora Gijonesa S.A. factory in Gijón (Asturias) and may have been converted into a tank. When the Nationalist troops took the factory following the fall of Gijón on October 21st 1937, a Landesa tractor (which may or may not have been one which was transformed) was taken, and, by order of Landesa Domenech, sent to the small town of Porriño (Pontevedra) in north west Spain to be used for agriculture.

The Tank Version

Building on their success, at some point before October 1934, Landesa Domenech and Areces, with the assistance of Juliana Constructora Gijonesa S.A., proposed an armed and armored version of the tractor for the Army. Two (most likely the ones with SEFA engines) were converted at this point at the Juliana Constructora Gijonesa S.A. factory or at the Industrial Química de Nalón facilities in Trubia. However, the Army showed no interest and none were purchased.

The Landesa tank. Note the missing machine gun – Photo: Artemio Mortera Pérez (2007), p. 12.

Design

Quite simply, the tank version was the tractor with added armor and a machine gun. The space around the driver and his assistant was covered with slightly inclined steel riveted sheets. Atop this structure was a cone-shaped cupola for entry and access. The front sheet of the crew compartment had to its left a small rectangular hatch which opened to the left. Attached was an oval stroboscope with horizontal turn which allowed for permanent vision. The right side of the frontal plate had a small circular opening with a mount for a Hotchkiss M1914 7mm machine gun. The whole front of the vehicle remained the same with the exception of the headlamp, which had been removed. The overall armor of the tank was 15mm thick chromium-nickel steel plates riveted to each other.

A Revolution and a Civil War

Popular myth and culture have led to an image of the Second Spanish Republic as a radical, progressive, and left-wing state. Whilst there is some substance behind this, it is not entirely true. In the second elections held in November 1933, the centrist Partido Radical Republicano (PRR) of Alejandro Lerroux came to power with the support of the right-wing Confederación Española de Derechas Autónomas (CEDA). Following a crisis of government in September 1934, CEDA removed their support and demanded that the PRR enter a formal coalition with 3 CEDA members to take a ministerial portfolio. Despite opposition from the left, this was done, and as a consequence, the most left-wing elements began to mobilize.

An indefinite revolutionary general strike organized by radical elements of the Partido Socialista Obrero Español (POSE) [left wing social democrat] and Union General de Trabajadores (UGT) trade union with the support of elements of the Anarchist Party and trade union and the Communist Party was called for October 5th 1934.

Following a few days of strike, the revolution was brutally put down, except in Catalonia, where an independent state was declared, only to be toppled by Republican forces a few days later and in Asturias, where the workers, mostly miners, were well armed and mobilized.

By October 6th, the town of Trubia was taken by revolutionary forces consisting of mainly factory workers who commandeered two modified Landesa tractors in the town, though these, apparently, for some reason, lacked their engines. The factory workers fought off the Civil Guard forces, though it is unknown if they used any of the available vehicles (there were also up to three Trubia Serie A in the town).

By the 14th, state forces were putting down the revolution. In a last-ditch attempt to save the revolution, an armored train was sent down the line from Trubia to the neighboring Grado where it defeated the state forces. Another armored train was hastily prepared in Trubia using locomotive number 2544 ‘El Cervera’ of the Northern Railway. The train itself was only minimally armed, but it had two open-topped carriages and upon each a Landesa tank was placed. Until the re-discovery of several photos in the October 1934 edition of Estampa magazine, it was believed that these two tanks on the ‘Cervera’ train were, in fact, Trubia Serie A’s.

Photos showing two converted Landesa tractors onboard flat trucks as part of the ‘Cervera’ armored train during the 1934 October Revolution in Asturias – Photo: Artemio Mortera Pérez (2007), p. 16.

By the 17th, the revolution in Asturias was crushed and what happened to the two Landesa converted tanks is unknown. War has the habit of creating new opportunities for rejected vehicles, and the Spanish Civil War started in July 1936 would be a testament to this.

To most people’s surprise given Oviedo’s history, the coup there was successful and the city would be the only main city in central northern Spain to join the nascent Nationalist forces. Trubia, on the other hand, remained loyal to the Republican government forces, and a Trubia Serie A tank and at least one converted Landesa tractor were pressed into service by the workers and militiamen in the town.

The two Republican tanks were first used in an offensive against Oviedo on September 10th 1936, seeing action in the small town of Las Cruces (north of Trubia and north-west of Oviedo) and Loma del Canto, on the outskirts of Oviedo. In Loma del Canto, both broke-down in no-mans-land apparently because of a burnt-out clutch caused by the inexperience of the crew. Efforts were made to recover the tanks, but this was not possible until October when Loma del Canto was captured.

On October 27th, a converted Landesa tractor was lost to the Nationalists near the Naranco Hill (north of Oviedo), who towed it back with a Trubia Serie A tank. This incident would receive lots of attention from the besieged troops in Oviedo.

Series of photos taken in Escandalera Square (Oviedo) on October 27th, 1936 showing the Nationalist Trubia Serie A nº3 towing a Landesa tank captured at Naranco Hill. The towing through the streets of Oviedo received lots of attention from the besieged Nationalist troops. Note the improvised camouflage on the Trubia Serie A with branches and foliage. Also note that the Landesa seems to be missing the tracks’ side cover – Photo: Artemio Mortera Pérez (2007), p. 41-43.

More photos taken in Escandalera Square (Oviedo) on October 27th 1936, this time with Nationalist troops posing with the captured Landesa tank. Note the cupola and front left hatch openings – Photo: Artemio Mortera Pérez (2007), p. 42-43.

The captured modified Landesa tractor would be repaired and pressed into service with the Nationalist forces. The last knowledge of this vehicle was at some point between the end of 1937 and the beginning of 1938 once the war in the northern part of the country had finished. It was reported to have been seen in the Santo Emiliano Hill, halfway between Mieres and Langero, attached to an artillery unit which was presumably using it for towing.

At the end of 1936 or the very beginning of 1937, the order was made to build four modified tractors in the Juliana Constructora Gijonesa S.A. factory in Gijón for use of the Republican Army of the North. Some days after January 23rd, Santiago Saiz Palacios, the Chief of the Tank Battalion of the Army of the North, visited the factory to assess the progress. It is known from photographic evidence that on January 5th the frame for one had been built and one had an engine but was missing the tracks, armor and machine gun. There is also a possibility that these were just the completion of the four BOMAG engine equipped tractors which had been intended to be built before July 1936, but this time in the tank version.

A document made by the Servicio de Recuperación Nacional [Eng. Nationalist Recovery Service] after the fall of Santander in August 26th 1937 noted that the total of Republican vehicles captured in the final push on Santander were “13 Renault … 3 Trubia … and 2 Trubia/Landesa in Guarnizo”. These ‘Trubia/Landesa’ were most likely modified Landesa tractors which could have been part of those built in Gijón in January 1937. Their ultimate fate is almost impossible to determine, but none survived the Civil War.

Series of photos taken on January 5th 1937 by Constantino Suarez at the Juliana Constructora Gijonesa S.A. factory in Gijón showing different developments in the construction of four Landesa tanks for the use of the Republican Army of the North. Clockwise: the frame of a Landesa tank with the tracks yet to be added; an engine being introduced into the minimally armored frame with tracks of a Landesa tank; a worker finishing the details of a sprocket wheel; a gearbox being built by factory workers – Photo: Artemio Mortera Pérez (2007), p. 73.

Names

The names and designations in the literature for the whole series of vehicles designed or inspired by Landesa Domenech and Areces are inconsistent and full of misinformation.

After the first trial of the tractor in Malmasín, its creators christened the tractor ‘tractor Landesa’, in honor of Landesa Domenech. It is unknown if they ever received an official army denomination once they were pressed into service.

The modified tank version is even more problematic. As it never entered service properly it was never given an official name, and it does not seem that Landesa Domenech or Areces gave it a name. As such, throughout the article, the terms ‘Landesa tank’ or ‘modified Landesa tractor’ have been used. However, Artemio Mortera Pérez (one of the better-known authors on AFV usage in the Spanish Civil War), calls them ‘Carro Areces’ [Areces Tank]. This is not an arbitrary decision. Landesa Domenech had joined the Nationalist side, so naming a vehicle after an officer of the opposition was not a good move. Mortera Pérez uses the name of the other inventor (Rogelio Areces) to designate the tank. Nonetheless, no documents from the period use this designation.

To make matters worse, as stated before, the Servicio de Recuperación Nacional document made after the fall of Santander names them ‘Trubia-Landesa’. This was an easy mistake given the striking resemblance with the Trubia-Naval tanks which were inspired by the Landesa tractor.

It is interesting to note that in the first edition of a booklet created by the Republican authorities to teach the soldiers and militiamen on the front how to read and write, a Landesa modified tractor was featured. This is very odd given how rare these tanks were. By the second edition though, it had been replaced by a Blindado tipo ZIS (UNL 35).

A booklet created by the Republican authorities to teach the soldiers and militiamen on the front how to read and write featuring a Landesa tank – Photo: SOURCE

Conclusion

The Landesa tractor was proof of the determination of Landesa Domenech and Areces, who after the failure of the Trubia Serie A, persevered to create a tractor based on the same principles as their tank. Even though it initially seemed that this new project was going to fail, they convinced the Army authorities to buy their tractor after a series of successful trials.

Despite the design flaws and the unreliability of their suspension, the tractors (including the tank version) managed to perform reliably and their field life-span seems to exceed that of any of the Trubia family.
The Landesa tractor would go on to heavily influence the Trubia-Naval, a light tank which entered service in 1936 and fought in most of the War in the North.


Illustration of the Landesa Tractor tank by Tank Enyclopedia’s own David Bocquelet.

Specifications

Dimensions Approximate values 3.6 x 1.8 x 1.7 m (11.81 x 5.9 x 5.58 ft)
Total weight, battle ready 5,500 kg
Crew 2 (Driver and Gunner/Loader)
Propulsion Mercedes 60hp, SEFA, Mercedes-Trubia 60hp, and BOMAG
Max speed 30 km/h (19 mph) on road
Armament 1 x 7mm M1914 Hotchkiss machine guns
Armor 15 mm (0.59 in)
Production 15-18

Sources

Artemio Mortera Pérez, Los Carros de Combate “Trubia” (Valladolid: Quirón Ediciones, 1993)
Artemio Mortera Pérez, Los Medios Blindados de la Guerra Civil Española. Teatro de Operaciones del Norte 36/37 (Valladolid: AF Editores, 2007)
Artemio Mortera Pérez, Los Medios Blindados de la Guerra Civil Española. Teatro de Operaciones de Levante, Aragón y Cataluña 36/39 2.ª Parte (Valladolid: AF Editores, 2011)

Categories
WW2 Kingdom of Spain Tanks WW2 Republican Spanish tanks

Modelo Trubia Serie A

Kingdom of Spain/Second Spanish Republic/Nationalist Spain (1926-1937)
Light Tank – 4 Built

Spain has mainly depended on foreign technology for its tank forces but there have always been enthusiastic engineers, military commanders, and policy-makers who have wanted to break the mold and create indigenous designs. The first of these initiatives would take place in 1925 in the northern town of Trubia, Asturias. Following the satisfactory completion of a prototype, plans were put in motion to design an improved serial production tank which was to be known as the Modelo Trubia Serie A4, or ‘Trubia tank’ for short.

Context – Lessons from Morocco

Colonial competition and internal politics meant that Spain took possession of large areas of what today is Morocco. The locals loathed the Spanish colonial administrators, leading to the Melilla War (1909) and the Rif War (1911-1927). In the latter, Spain would use for the first time in its history the modern technology of aircraft, armored cars, and tanks. The Spanish brought 11 Renault FT’s and 6 Schneider CA-1’s from France which would take part in multiple actions throughout the war with mixed results. The main shortcomings found in the Renault FT, regarded by the Spanish as their finest tank, were: poor performance, speed, range of operation due to a poor engine, and its vulnerability when its only machine gun jammed.

To overcome these, a team involving Commander Victor Landesa Domenech (an artillery officer attached to the Trubia arms factory), Captain Carlos Ruíz de Toledo (a Commander in charge of Batería de Carros de Asalto de Artillería [Artillery Tank Battery] during its first engagements during the Rif War) and the Trubia arms factory’s Chief Engineer, Rogelio Areces, took it upon themselves to design and build a superior vehicle for the Spanish Army.

The Trubia prototype

Designed and built in 1925 on their own initiative and financed out of their own pockets, the Trubia prototype would be tested in 1926 with a very satisfactory reception. So much so, that, a budget was set for the creation of a tank producing workshop at the Trubia factory and a commission led by Areces and Ruíz de Toledo was established to travel Europe and investigate tank technological innovations they could use for an improved serial version of the prototype.

Appearance-wise, the tank resembled the Renault FT, as it was in the minds of Landesa Domenech and co. the best tank they had knowledge of. However, there were a few differences:
– To surmount firepower concerns, two overlapping turrets with independent movement and each armed with a Hotchkiss 7mm machine gun were adopted.
– At the front of the tank there was a small semi-circular plate attached to an elongated nose of the tank which acted as a ram to break through obstacles such as walls and barbed wire.
– Due to circumstances, armor and engine-power were only marginally improved.

The only known photo of the Trubia prototype, which, in this instance, is mounting a brick wall. Date and location unknown. Note the overlapping turrets, frontal nose ‘ram’ and general resemblance to the Renault FT – source: Artemio Mortera Pérez (2007), p. 6.

The European Expedition, Notions of Tank Design

Areces and Ruíz de Toledo’s European adventure would not be as fruitful as they may have hoped and expected. Tank technology was in its infancy and most tank producing nations were wary of sharing their findings, and the technology they did exhibit and share was mostly outdated. Companies like Vickers did at the time sell custom-made tanks to the buyer’s needs, but it seems that Areces and Ruíz de Toledo did not explore this option as they probably did not want to spend much of their limited budget.

According to Artemio Mortera Pérez, author of the most complete book on the Trubia tanks, in Germany, they were shown a very peculiar suspension inspired by the one intended to be used on the K-Wagen behemoth. However, although the K-Wagen’s suspension was unsprung, the vehicle or suspension system they were shown was probably from or inspired by the earlier Orion-Wagen.

Artist’s impression of the K-Wagen. Apart from the fact it was unsprung, little is known about what is suspension would exactly be – source: The Vintage News
The Orion-Wagen Prototype with its Orion track system of feet treads – source: Landships.info

This undercarriage system was named ‘Orion’ and was supposed to improve upon traditional systems in addition to enhancing turning capabilities and minimising the effects on roads. In this integrated track design, the links were suspended from the chassis and held together by a lateral metal wall. This system was designed to prevent the tracks from coming off when maneuvering.

It is possible that the vehicle they were shown was a totally different vehicle. In 1926, the Leipzig-based firm Wotan-Werke built to test the differences between a suspended and not-suspended tracked chassis. When considering the suspension of this vehicle (see picture below) and the Trubia Serie A (later in the article), the visual similarities are uncanny. The vehicle was known as the Wotan-Werke Type A. The Trubia tank was designated as Serie A (Eng. Series A). Whilst type and series do not mean exactly the same, it is possible that there is some correlation. Notwithstanding, it could just be a coincidence.

The Wotan-Werke Type A tracked tractor, built in 1926 – source: Walter J. Spielberger

At a time when Germany was prohibited from having a standing army, the designers behind the Wotan-Werke Type A may have been eager to find a foreign buyer and saw in Areces and Ruíz de Toledo an opportunity.

Additionally, a few Daimler engines of different horsepower were shown to the commission. As a side note, the Wotan-Werke Type A used a Typ M 1574 100 hp Daimler-Mercedes 4-cylinder Otto engine.

Satisfied with what they saw, the Commission bought at least four ‘Orion’ systems and Daimler 4 cylinder 75 hp engines for the tank series, and two larger undercarriage systems based on the same principle and two Daimler 8 V-shaped cylinder 200 hp engines with the intention of building a large tank recovery tractor.

The team behind the design had several ideas to improve upon the Renault FT:
– Improving firepower and lessening vulnerability when the only machine gun jammed. For this, the same idea as on the prototype was adapted though the lower turret was intended to use a modified Ramírez Arellano 40mm infantry gun. However, this would not materialize.
– Enhancing the FT’s poor speed, range and performance by equipping the more powerful Daimler 75hp engine.
– Avoiding the vulnerability of the crew having to exit the tank to access the engine for repairs by creating a bigger engine compartment which could be accessed from the inside.
– Improvement of the undercarriage, which had caused many headaches. It is possible that early on a wheel-cum-track system was considered, but given the failures of the Chenilletts Saint Chamond in Spanish service which used this system, the idea was quickly abandoned. The ‘Orion’ system bought in Germany was to be used instead.

The design team was willing to sacrifice small size as they felt their improvements were more important.

Design

Blueprints of the Trubia Serie A. Note, not the original – source: Alabarda

Exterior Appearance

The square-shaped central hull part housed the crew compartment and above it was the turret. The back resembled that of an FT – rear tail included – but was much larger and housed the engine. At the front, to each side was a hinged door to access the engine. Behind it only on the right-hand side was a large exhaust pipe. To the front of the central piece was a sheet going down at a 45º angle. On the center-right were two boxes of different shapes. The most central and smaller one had a vision slit for the driver, whilst the larger one to the right had a forward firing machine gun. This position was a detachable piece which allowed the crew to enter and access the tank. The frontal and side pieces sloped inward meeting at the beak of the tank, upon which was a removable small semi-circular plate which acted as a ram to break through obstacles, such as walls and barbed wire. On the earlier version of the tank, there was a mudguard which covered the whole top of the tracks to prevent enemy infantrymen from planting explosives on them.

The side and frontal armor was 20 mm thick and made with chromium-nickel steel plates riveted to an inner frame.

Turret

One of the tank’s most recognizable features, the turret, was made out of two overlapping turrets with independent movement and each armed with a Hotchkiss 7 mm machine gun. Each turret consisted of a truncated cone forged in nickel steel 16mm thick. Each one had a ball machine gun mount which allowed for 65º of vertical and 110º of horizontal fire. On the direct opposite side of the ball mount was a small vision slit, and on either side of the turret there were small sliding windows to improve the gunners’ vision. On the top of the upper turret was a circular outwards opening hinged hatch upon which a cylindrical panoramic visor – a stroboscopic cupola – was fixed. The cylinder had vertical openings around it protected by ‘unbreakable’ glass and turned by means of a small electrical engine, providing a continuous panoramic vision of the exterior by means of the ‘persistence of vision’ phenomenon.

Armament

Armament consisted of three 7 mm Hotchkiss M1914 machine guns. Each turret had one (operated by two different gunners, one of whom was also the commander. The gunners would have to load their own weapons) and the third was at the front and operated by the driver. In total, for the three guns. the tank carried enough ammunition for 8,000 shots. Initially, the lower turret was supposed to carry a modified Spanish-built Ramírez Arellano 40 mm infantry gun, but the project behind this gun would not materialize until a few years later. The machine gun was a stop-gap solution, but with plans to fit the infantry gun in the future, though these never materialized. The sides of the tank also counted with small loopholes through which the crew could fire their personal weapons. Additionally, the first series production vehicle had a ball joint on the right side for a Mauser rifle, the purpose for which is unclear – this was later removed.

Engine

The engine could be started by means of compressed air provided by a compressor, but if this system malfunctioned, it could always be started up manually with a crank and an Bosch electrical system. The engines used were the Daimler MV1574 4 cylinder 75 hp with 900 rpm bought by Ruíz de Toledo and Areces in Germany fitted with Beru spark plugs.

However, these were modified to improve performance. To ensure that enough lubrication was provided for when the tank was at a 45º angle, the oil container was changed. A cogwheel and chain transmission was added to put the air compressor into motion.

Cooling for the motor and the interior was provided by two large ventilators. One was placed in front in the middle of the vehicle sucking air from inside the crew compartment inwards and was expelled to the exterior one through the second ventilator at the back.

The engine and two ventilators were built as one piece and were connected on each side to the body-on-frame.

The manual engine start was situated in front of the frontal ventilator and could be accessed from outside from both sides through the hinged doors.

Beneath the front ventilator was the double cone clutch which was activated by a pedal to the right of the driver.

The tank was capable of traveling at 30 km/h with a range of 100 km, a slight improvement over the Renault FT. The fuel tank held 180 liters.

Driving Mechanisms

The gearbox was beneath the driver and was made from cast steel. It consisted of four speeds with the first speed being used to overcome obstacles and for driving over uneven ground.

Changing direction was possible by means of a mechanism which immobilized or reduced the speed of one of the tracks.

Body-on-Frame and Tracks

Each track consisted of a long ellipse-shaped structure formed by two parallel steel sheets. Between the two sheets there was a track for the track rollers to travel through. The tracks on either side were joined to each other by 4 u-shaped bars traveling underneath the tank. The engine lay over the two furthest to the back. At the front of the tracks, there was an opening to the inside of the tank for the mechanism to connect them to the gearbox. Between the steel sheets were some sort of drum breaks.

Unlike in most other vehicles, the track rollers were integrated into the tracks and moved in unison with the track links along the tracks set between the two sheets. The track links had a cross pressed into them to improve traction.

Name

The tank’s name has caused some controversy over the years. Officially, it was named Carro Ligero de Combate para Infantería Modelo Trubia 75 H.P., Tipo Rápido, Serie A – meaning Infantry Light Tank Trubia Model 75 hp (the engine’s hp), Rapid Type (30km/h was considered quite fast in comparison to the Renault FT and Schneider CA) Series A. Ruíz de Toledo designated the tank Modelo TRUBIA. Serie A. – with this designation being used throughout the article. From the 1930’s onwards, official documents would add ‘A4’ or ‘4A’ at the end, possibly referring to the fact that 4 were built in total. The name Carro Rápido de Infantería [Rapid Infantry Tank] is also used.

It is, however, incorrect to call them Trubia-Naval, as this was a different tank entirely dating from 1936. Furthermore, many sources refer to the tanks as a prototype to the Trubia Naval, including the original Tanks Encyclopedia article on the vehicle. There was a direct connection between the two and they shared multiple features, but that is as far as it went. The tanks were two different projects with two distinct purposes.

The name follows a general Spanish tendency to name tanks and other armored fighting vehicles after the place where they were designed or built, or after one of the engineers behind the project.

The first Trubia Serie A still inside the Trubia arms factory. It was not yet completed, as it was missing its machine guns and mudguards (though the supports for these are visible) – Photo: Artemio Mortera Pérez (2007), p. 7
Photo taken shortly after the one above. The tank now has its three machine guns, mudguards, and Mauser rifle which only this version was equipped with – Photo: Artemio Mortera Pérez (2007), p. 8
The first Trubia Serie A mounted on an open truck bound for Madrid after its completion with all the men involved in its construction. Furthest to the right is the factory’s chief engineer, Rogelio Areces – Photo: Artemio Mortera Pérez (2007), p. 5

Testing

After their construction was rushed by demands coming from Madrid, four vehicles were finished at some point in 1926 as part of a pre-production series. This meant that as soon as they were finished (only one was constructed at each time), they were transported by train to Estación del Norte (modern-day Príncipe Pío) in Madrid. One, most likely the last one, was not even finished when it was transported, and a small workshop garage next to the train station in Madrid had to be hired to finish the vehicle off before it joined the other three at the Escuela Central de Tiro, the Army’s testing ground, in Carabanchel, South Madrid. Due to the hurry imposed from Madrid, the vehicles had not been properly factory tested and a group of factory workers were sent along with the tanks to make sure everything ran smoothly.

The testing of the four tanks would garner lots of interest and many officials would visit during the long demanding tests they were submitted to. These tests included cross-country travel, obstacle demolition, overcoming gradients, pulling heavy artillery and spare armor plates of the same thickness as the tank were fired upon with a 40 mm gun to test the level of protection it offered. The 40 mm gun was the same one as originally planned to be used by the tank. While the tank’s performance was generally considered to be good several important deficiencies were noted.
Pros:
– The engine was considered overall to be an improvement.
– The space and comfort inside.
– The fact that the engine could be accessed from within the tank.
Cons and recommendations:
– The main con was the undercarriage, which broke down several times.
– The ventilator blades and supports snapped because of their excessive weight and were to be replaced with aluminum ones. Changes were made to soften the abrupt halting of the blades when the engine stopped.
– The support for the ventilator at the back was to be changed from cast to forged steel.
– Improvements to the fuel feed.
– The spark plug was unsatisfactory and was first replaced by a Bosch one and later by a K.L.G. one.
– The compressed-air driving system was to be changed by a driving wheel and pedals.
– The vehicle was found to lack rigidity and its main structure had to be reinforced. The top of the vehicle supporting the turrets was of special concern.
– Adding a hinged hatch for the driver’s entry and exit to the left of the detachable boxes on the frontal plate.
– Eliminating the mudguards.
– Recommendations were made for overall improvement to make the undercarriage more durable.
The accompanying factory workers carried out multiple repairs during the tests and made notes of what went wrong. Along with the official recommendations, these would be used on return to Trubia.

One of the Trubia Serie A4 during trials in Escuela Central de Tiro in Carabanchel, Madrid. Note that because the of the hasty construction, this example has the side door to access the engine open, and the machine guns, detachable frontal piece and detachable ‘ram’ piece not yet fitted – source: World of Armor
Another of the Trubia Serie A’s being trialed in Carabanchel. It may well be the same one as in the previous image, but in this photo it now has had the ‘ram’ piece attached – source: Vehículos Blindados de la Guerra Civil

Death of the Project

The four tanks were taken back to Trubia by train to be disassembled and at least one was modified. The modified tanks are often called ‘segunda serie‘ [second series] to distinguish them from the original ones. The idea was to create a production series from the lessons learnt.
A modified tank was tested in the factory grounds in front of the military commanders of the Asturias region, led by General Zuvillaga. During these tests, the vehicle lacked the detachable frontal boxes, ‘ram’ piece, and machine guns.

One of the modified Trubia Serie A (segunda serie) undergoing balance and slope trials. The man next to the tank is thought to be Captain Carlos Ruíz de Toledo – source: Artemio Mortera Pérez (2007), p. 9
The same modified Trubia Serie A (segunda serie) as in the above picture during trials at the factory’s grounds. Note the lack of the detachable frontal boxes, ‘ram’ piece, mudguards, and machine guns – source: Artemio Mortera Pérez (2007), p. 10
The same modified Trubia Serie A (segunda serie) as in the above pictures being inspected by General Zuvillaga and other officers of the Asturias region outside the Trubia arms factory – source: Artemio Mortera Pérez (2007), p. 10

This vehicle was later sent to Madrid in May 1928 for a second round of testing which took place on the 19th under the watchful eye of Lieutenant Colonel Antonio García Pérez, Secretary General of the Estado Mayor Central, the person in charge of supervising military centers.

The results were judged satisfactory and the tank was given ‘A.T.M. 2204’ as its number-plate and was incorporated into the Army. The commission in charge of supervising the tests concluded in a report that [paraphrasing] “the Trubia light tank, had all the required capabilities for a tank of its nature” and the order was made to build one of the heavy tractors envisioned by Ruíz de Toledo and Areces with the larger suspension system and 200 hp engine. As far back as November 1926, plans were made to equip a section within the Tank Group with an undefined number of Trubia Serie A tanks depending on how many could be made available by the Trubia factory.

Unfortunately, none of these projects would materialize. To understand why, it is important to note the context of what had been happening in Spain. In September 1923, the Captain General of Catalonia Miguel Primo de Rivera led a successful coup with King Alfonso XIII’s blessing. Primo de Rivera’s aim was to put an end to the problems associated with the ongoing war in Morocco and labor and trade union unrest. From his position of power, Primo de Rivera attempted to carry out military reforms. These were very unpopular among Army officers, especially those in the artillery section, leading to the dissolution of the latter. The artillery had been up to then responsible for the production of the Trubia Serie A’s and other military vehicles, and without their budget and blessing, the project was all but dead.
The project was never officially canceled, but without the stimuli and finance, it faded away. However, this would not be the end of the Trubia Serie A nor of Landesa Domenech and Areces’ adventures with tank and military vehicle production.

Active Service

Asturias Revolution of 1934

Popular myth and culture has led to an image of the Second Spanish Republic [established in April 1931] as a radical, progressive and left-wing state. Whilst there is some substance behind this, it is not entirely true. In the second elections held in November 1933, the centrist Partido Radical Republicano (PRR) of Alejandro Lerroux came to power with the support of the right-wing Confederación Española de Derechas Autónomas (CEDA). Following a crisis of government in September 1934, CEDA removed their support and demanded that the PRR enter a formal coalition with 3 CEDA members to take a ministerial portfolio. Despite opposition from the left, this was done and as a consequence, the most left-wing elements began to mobilize.
An indefinite revolutionary general strike, organized by radical left-wingers within the Partido Socialista Obrero Español (PSOE) [left wing social democrats] and Union General de Trabajadores (UGT) trade union with the support of elements of the Anarchist party and trade unions (FAI and CNT) and the Communist Party, was called for October 5th 1934. Following a few days of strike, the revolution was brutally put down, except in Catalonia, where an independent state was declared, only to be toppled by Republican forces a few days later, and in Asturias, where the workers, mostly miners, were well armed and mobilized.

Asturias was where the Trubia Serie A’s were, too. On October 6th, the revolutionary forces (in Trubia led by the Communists among the factory workers) took control of the Trubia factory (the revolutionary forces felt that for their success they had to capture the factory with its large weapons deposits) and with up to three of the tanks inside, some or all of which were without engines. It is likely that two Landesa tanks were in a nearby factory also in Trubia and in much better running condition. In the town, the factory workers fought off the Civil Guard forces, though it is unknown if they used any of the available vehicles.

By October 14th, state forces were putting down the revolution. In a last ditch attempt to save the revolution, an armored train was sent down the line from Trubia to the neighboring Grado where it defeated the state forces. Another armored train was hastily prepared in Trubia using locomotive number 2544 ‘El Cervera’ of the Northern Railway. The train itself was only minimally armed, but it had two open-topped carriages. Upon each carriage a Landesa tank, without an engine, was placed. Until the re-discovery of several photos in the October 1934 edition of Estampa magazine, it was believed that these two tanks on the ‘Cervera’ train were in fact Trubia Serie A’s. By the 17th, the revolution in Asturias had been crushed.

Following the revolution, the 3 Trubia Serie A’s which had been left unmodified following the Madrid trials of 1926 were put back into service with a series of modifications, including the removal of the mudguards which covered the top half of the tracks and the addition of the hinged hatch for the driver’s entry and exit to the left of the detachable boxes on the frontal plate. Three of them had ‘Carro Ligero nº’ [Light Tank No.] written on the sides followed by a 1, 2 or 3 and were attached to the Infantry Regiment <<Milán>> nº 32 which was barracked in Oviedo, the capital of Asturias. The vehicles were in a poor condition, but there were plans to continue to carry out tests on them. The fourth vehicle, which may have had a number 4 written on its side, remained in the factory.

Spanish Civil War

The failed General’s coup which drew the country into a bloody civil war gave the Trubia Serie A’s their chance to prove themselves in combat for the first time, ten years after they had left the factory.
To most people’s surprise, given Oviedo’s history, the coup there was successful and the city would be the only main city in central northern Spain to join the nascent Nationalist forces. In Oviedo were the three Trubia Serie A’s of the Infantry Regiment <<Milán>> nº 32 which would serve the war in Nationalist service. On the other hand, Trubia remained loyal to the Republican government forces, and the tanks within the factory, along with a Landesa tractor (which was transformed into a tank), were pressed into service by the workers and militiamen in the town.

The two Republican tanks were first used in an offensive against Oviedo on September 10th 1936, seeing action in the small town of Las Cruces (north of Trubia and north-west of Oviedo) and Loma del Canto, in the outskirts of Oviedo. In Loma del Canto, both broke down in no-mans-land, apparently because of a burnt-out clutch caused by the inexperience of the crew. Efforts were made to recover the tanks, but this was not possible until October when Loma del Canto was captured. No more is known of the fate of the Republican Serie A4 and it was possibly scrapped.

Fortunately, the history of the three in Nationalist service is slightly better recorded; most likely they were used to quell the first attacks by militiamen on the city and helped consolidate Nationalist control of the city.

On August 22nd 1936, the three Trubia Serie A’s, accompanied by two rifle companies and one machine gun company from the Infantry Regiment <<Milán>> nº 32, a Civil Guard detachment, and a battery of Schneider 105/11 guns, were used offensively against Loma del Campón, on the road to Trubia. The objectives were reached, but nº2, under the command of Engineer Brigadier Antonio Morales Elvira broke down. The vehicle was towed back during the night, but because of the general poor condition of the tank and the unevenness of the ground, the turret fell off. It is unknown if the turret was put back, but the vehicle remained in service.

Trubia Serie A nº2 after it broke down in Loma del Campón. The man furthest to the right is Engineer Brigadier Antonio Morales Elvira, the tank’s commander. The other men in the photo appear to be infantrymen or militiamen, though some of them could also form part of the tank’s crew – source: Artemio Mortera Pérez (2007), p. 36
Still from a video showing the rear of a Trubia Serie A4 in Oviedo with Moorish troops of Franco’s army marching past – source: Vehículos Blindados de la Guerra Civil

Following this small offensive, the vehicles were to be deployed defensively in the besieged city of Oviedo. Multiple further breakdowns meant that they were used statically in defensive positions; one defended La Argañosa (the western entrance to the city) and the other two, one of which was now operated by elements of the Civil Guards, were situated between Campo de los Patos street and the arms factory defending the eastern approach along the Santander road.
The one situated in La Argañosa was destroyed at some point before the end of the initial Republican offensive on Asturias in October by Nationalist forces to prevent Republican irregulars from capturing it, as it was broken down and could not be towed to safety due to the crossfire. The remaining two Trubia Serie A’s continued to be used for defensive duties.

The remains of one of the Nationalist’s Trubia Serie A in La Argañosa – source: Artemio Mortera Pérez (2007), p. 38

On October 27th, nº3 was sent to the Naranco Hill to tow back to Oviedo a Republican Landesa tank which had broken through the lines but had broken down.

Series of photos taken in Escandalera square (Oviedo) on October 27th 1936 showing the Nationalist Trubia Serie A nº3 towing a Landesa tank captured at Naranco Hill. The towing through the streets of Oviedo received lots of attention from the besieged Nationalist troops. Not the improvised camouflage on the Trubia Serie A with branches and foliage – Photo: Artemio Mortera Pérez (2007), p. 41-42

In January 1937, the Republican Army of the North planned a major offensive on Asturias with all available men and vehicles. The offensive would properly commence on February 21st with Republican Army forces penetrating the defensive perimeter near Campo de Patos, where the two remaining Trubia Serie A and Nationalist infantrymen managed to fend them off.

Two Nationalists posing next to a Trubia Serie A in Oviedo – source: Vehículos Blindados de la Guerra Civil

It is unknown if the two tanks survived the whole offensive (at least one did), but they were most likely scrapped once the offensive was over and plenty of German Panzer I’s, Italian CV 33-35’s and captured Soviet vehicles were available. It has been subsequently speculated that one was sent to Seville at the end of the War in the North, and was used in victory parades, but there is no evidence to substantiate this claim and no logical reason why this might have occurred. Unless or until firm evidence of their appearance in Seville is produced this has to be considered unlikely at best.

One of the Nationalist Trubia Serie A in Oviedo defending Campo de los Patos and the eastern entrance to the city – source: Artemio Mortera Pérez (2007), p. 76
A Nationalist Trubia Serie A still in its static position defending the weapons factory in Oviedo following the end of the war in Asturias in October 1937 – source: Artemio Mortera Pérez (2011), p. 143

Legacy and Conclusion

Following the unofficial termination of the Trubia Serie A project in 1928-1929, Landesa Domenech, now a Captain, and Areces embarked in a new project, a tractor for military and agricultural use based on the same, but improved and updated, mechanisms as the Trubia Serie A. The tractor, named Tractor Landesa [Landesa Tractor], would also have an armored upgrade which would be used in the Revolution of 1934 and the Spanish Civil War. In the Spanish Civil War, another vehicle, the Trubia-Naval, influenced by the original Trubia Serie A would see service with both Republican and Nationalist forces.

The Trubia Serie A was a brave, but ultimately, unsatisfactory effort to improve upon the existing Renault FT. Had the vehicle worked properly, it would definitely have been a major improvement; it had improved firepower, improved engine performance, which could be accessed from the inside, allowed for higher speed, range and performance, slightly thicker armor, and more comfort for its crew. However, the experimental suspension system used proved to be inefficient and too prone to breakdowns due to its delicate nature. The problem was, that for a variety of reasons, a copy of this suspension system was still being used in new tank designs as late as 1936.
Regardless, the Trubia Serie A was the first example of a Spanish designed tank to overcome the dependency on foreign tanks and valuable lessons were learnt by the designers and engineers.

Modern Reconstruction

In the Museo de la Historia Militar Española, el Cueto, in Asturias, along its impressive collection of Spanish Civil War era reconstructions, is one of the Trubia Serie A. Whilst due to its complexity and obsoleteness the Orion suspensions system has not been replicated, everything else seems to be an accurate reproduction of the vehicle, including the double rotating turret. The vehicle has been given an engine and is used to drive around the museum’s grounds. A video of the vehicle in action can be seen here.

The reproduction of the Trubia Serie A at el Cueto – source: Facebook, Museo el Cueto
Illustration of the Trubia A by Tank Encyclopedia’s own David Bocquelet, with corrections by Jaycee ‘AmazingAce’ Davis.

Specifications

Dimensions Excluding tail 4.36 x 2.8 x 1.8 m (14.3 x 9.19 x 5.9 ft)
Total weight, battle ready 8.1 tonnes
Crew 3 (Driver/frontal gunner; Commander/gunner/loader; and Gunner/loader)
Propulsion Daimler MV1574 4 cylinder 75 hp
Max speed 30 km/h (19 mph) on road
Range 100 km (62.14 miles)
Suspension None
Armament 3 x 7 mm Hotchkiss M1914 machine guns
Armor 16-20 mm (0.63 – 0.79 in)
Production 4

Sources

Artemio Mortera Pérez, Los Carros de Combate “Trubia” (Valladolid: Quirón Ediciones, 1993)
Artemio Mortera Pérez, Los Medios Blindados de la Guerra Civil Española. Teatro de Operaciones del Norte 36/37 (Valladolid: AF Editores, 2007)
Artemio Mortera Pérez, Los Medios Blindados de la Guerra Civil Española. Teatro de Operaciones de Levante, Aragón y Cataluña 36/39 2.ª Parte (Valladolid: AF Editores, 2011)
Chus Neira, “El primer tanque español salió de la Fábrica de Trubia hace 90 años” La Nueva España [Spain], 30 March 2017 (https://www.lne.es/oviedo/2017/03/30/primer-tanque-espanol-salio-fabrica/2081455.html#)