Saturday 10 June 2017

Renault D1: FT on Steroids

Attempts to modernize the Renault FT, the most numerous tank in WWI, gave unexpected results. Initially, only the low speed was unsatisfactory for the French military, but its tastes grew by the mid-1920s. Now, the thin armour, which was insufficient to protect the tank from high caliber machineguns, was also unsatisfactory. The result was the NC-1 tank, which was 2 tons heavier and had thicker armour, while being twice as fast. The tank was a good replacement for the Renault FT, but the army's appetites grew once more, which led to the creation of a new tank, the Renault D1.

Questionably Light

The military's desires were partially influenced by the development of the 30 ton Char B heavy tank. Renault and Schneider began to develop the SR tank (Schneider-Renault) together. The SRA (Schneider-Renault A, aka Renault JZ) and SRB (Schneider-Renault B) ended up very similar. Both tank used Schneider's cast turret with two Hotchkiss machineguns. The idea of a dual mount was liked by the French, since the tank's firepower doubled. The fact that this system made the commander's life difficult, since he also doubled as the loader and gunner, was not taken into account. The idea of dual machineguns hung around until the mid-1930s.

In 1926, the French infantry command revised its requirements for a light infantry support tank. According to them, the armour had to be thickened to 30 mm tons at a weight of 12 tons. The armament would consist of either two machinguns or a 47 mm cannon. The Renault NC family, meant to replace the Renault FT, did not match those requirements. Renault tried to fit a dual machinegun mount inside the FT turret. The Tanks encyclopedia, published in Munich in 1935, mistakenly calls the tank with this turret the NC-2. It also claims that these tanks were mass produced and exported, but that is not correct.

The only known photograph of the Renault NC-1 STCC, mistakenly also called Renault D3.

Another branch of evolution for this tank is mistakenly called Renault D3. In reality, this was the experimental NC-1 which was converted to test out a new suspension and turret. The design appeared in 1930, and carried a modernized suspension designed by Captain Marie Adrien Joseph Balland. The name STCC meant the Technical Tank Section (section technique des chars de combat) where Balland worked. Aside from the new suspension, the Renault NC-1 STCC had a turret that migrated from the Char B prototype built in 1929. The turret, designed by Schneider, changed shape and received a commander's cupola. This tank remained an experiment, as Renault was already working on a more promising tank.

Renault NC-3. The exhaust pipe coming out of the side is a sign of the more powerful 65 hp engine.

Work on this tank, initially called Renault NC-3, began in January of 1927. Initially, only the armour would be improved, but soon, the design of the hull had to be changed. STCC also wanted to have a radio installed in the tank. Theoretically, it could fit in the turret, but making the commander/gunner a loader as well was considered the peak of sadism. As a result, the crew grew to three men, but the radio operator did not fit into the turret. The most logical solution was to widen the hull by 38 cm, shift the driver to the left, and put the driver on the right.

At the same time, the length of the hull grew by 18 cm, since the increased mass of the tank meant that a more powerful engine was needed. A hull machinegun was added to the right of the driver, so he would not get too bored. The machinegun was fixed in the horizontal plane, but could still be aimed up and down. The special tail to help the tank cross trenches remained. With it, the length of the Renault NC-3 was now 5.3 meters.

Experimental prototype with raised skirt armour, showing the suspension.

The suspension did not change much compared to the NC-1. However, it was covered with removable skirt armour, which protected it from enemy bullets and shrapnel. Despite the increased mass, the NC-3's ancestor was obvious. A prototype of the new infantry tank entered trials in 1928. However, it did not keep the name NC-3 for long. Soon, it was given the name D1, a name it is known by today. In Renault documents, the tank is referred to as Renault UT or TY.


The trials, which ended in 1929, showed that the direction chosen for modernization was correct. Initially, the tank had a 65 hp engine, but it was clearly insufficient. Tanks ordered in 1930 had a new engine. The more powerful 74 hp 6 L Renault 25 CV returned the D1's mobility to the NC-1's levels. Thanks to thicker armour, the D1 was reliably protected from high caliber machineguns, and even anti-tank cannons had problems with 30 mm of armour at the time. A decision to order the first 10 tanks for military trials was made in March of 1929, before trials ended.

82 mm SPG on the Renault TY chassis.

Meanwhile, the tank had one serious issue. The experimental D1 entered trials with a turret from the Renault FT. It did not match the infantry command's requirements, as it could not fit either a 47 mm cannon or two machineguns. Schneider and STCC were still working on the new turret, and nothing existed in metal at the time the contract for 10 tanks was signed. To make things worse, the department that was designing the turret was not in contact with Renault.

As a result, the tanks that were produced had to be equipped with turrets from the Renault FT. Since the turret ring diameter was the same, there were no issues with later replacing the old turret with a new one. The first D1 entered the 503rd Tank Regiment in May of 1931, and the pilot batch was delivered by November. Earlier, on December 23rd, 1930, a new contract for 70 tanks was signed, and these also had to be equipped with turrets from the Renault FT.

An artillery observer vehicle on the Renault D1 chassis, on trials at the 507th RCC.

Several vehicles were designed on the chassis of this tank. In 1930, an SPG was designed that would carry an 82 mm gun. It is still not known what gun this would have been. The initial chassis was used without changes, and the gun was installed with the breech facing forward, which helped fit it into the dimensions of the hull. Compared to the D1, the mass of the SPG dropped from 14 to 12 tons, so there were no issues with mobility. The crew of the SPG consisted of five men. During firing, the driver had to exit the vehicle.

The SPG would take part in the Maginot Line's mobile defenses. The project was cancelled in 1932, even though this vehicle was very realistic. Another project was a vehicle for artillery observers. The turret was removed and replaced with a fixed observation cupola. One such vehicle was made out of tank #1016.

Experimental ST1 turret, tested out on tank #003.

The turret for the new tank, indexed ST1, was produced in 1930. Schneider did not reinvent the wheel, and simply took the Char B turret and modified it. The changes consisted of replacing the right machinegun with a 47 mm cannon and installing a hatch instead of the observation cupola. The thickness of the turret armour gives away what tank the turret came from. It was 40 mm thick, thicker than the hull.

The D1's commander got lucky, since the MAC Mle. 1931 machinegun was used instead of the Hotchkiss, which was more compact and easier to reload. At the same time, the presence of a cannon and a machinegun in a turret with the Renault FT's turret ring diameter, no matter how far apart, was not comfortable for the commander.

Tank #1085 with a reworked ST1 turret (turret serial number 2) in the 508th RCC. A counterweight is installed in the rear of the turret.

The experimental turret was installed on tank #003. It was quickly discovered that the center of mass of the turret shifted, causing many issues. The only way to fix this was to install a large counterweight in the rear of the turret. This was not a long term solution, but, nevertheless, an order for 10 turrets was made. They were installed both on pilot tanks and tanks from the 1930 order. The turrets were severely criticized in the army, as the counterweight could not solve the horribly cramped layout. The hatch in the roof was of questionable value, since it was hard to use.

The only known photograph of the ST3 turret. The only difference is the lack of a cupola and minor details.

After a heap of negative feedback from the army, Schneider and STCC began to design a new turret. Taking the ST1 as the starting point, Schneider's engineers increased the size of the turret bustle, returned the commander's cupola, and slightly reworked the armament mounts. In order to be safe, two turrets were designed (ST2 and ST3), with minor differences. Both turrets were built in 1933 and sent to the long-suffering 503rd Tank Regiment.

It became clear that the improved turret was better than the ST1, since there was more space inside, and the counterweight was no longer needed. The turret was accepted into service in October of 1933, but delivery began in 1936. Meanwhile, on June 12th, 1932, a new batch of 30 D1 tanks was ordered, and another 50 on October 16th, 1933. The last tanks entered service in May of 1935. The tanks only reached their initially envisioned state a year after their production run ended!

Tank #1001 with the ST2 turret. This was the first D1 to receive this turret.

While the new turret was better than the old, it wasn't cause for much praise. A commander's cupola was installed, but it was very uncomfortable to use. The turret became roomier, but the commander's position was still hard to envy. In addition, when open, the rear turret hatch hit the radio antenna. This issue was resolved when the tank was already in service.

Second line fighter

In addition to the 503rd Tank Regiment, where the tanks went through trials, the Char D1 was sent to the 507th, 508th, and 510th regiments. A battalion of 45 tanks was included in each unit. As it often happens with trailblazers, the tank was plagued with defects. The new tanks were used mercilessly, since they were used to work out new tactics. These numbers describe the degree to which the tanks were used. In 1934, out of 110 tanks present, 31 were functional, 62 were broken or undergoing major repairs, and 17 more tanks were in "exhausted" condition.

D1 on exercises in Champagne. The tanks have cannon turrets from the Renault FT.

The situation was made worse due to the tanks being used with old Renault FT turrets. When new turrets were installed in 1936, issues arose, since the old ammunition racks were designed for 37 mm shells. The arrival of the ST2 turret also did not mean that the old and cramped ST1 turrets will be replaced. They remained on tanks, which were later sent to training units. Information that the turrets were replaced by the start of WWII is incorrect. And what would be the point, if the military began to doubt the value of the D1 by 1937? By that moment, 30 mm of armour was not that much, and the tank's other characteristics indicated that it was rapidly becoming obsolete.

At the same time, nobody wanted to remove the D1 from service. France could not afford to replace its tank fleet all at once. Yes, the D1 was no longer suitable for fighting in Europe, but France had many colonies. That's where the obsolete tanks were "exiled" to. In late 1937, the 61st, 65th, and 67th Tank Battalions were formed in Tunisia, and 145 tanks were sent there. These battalions were located in Bizerta. 

The appearance of these tanks in Tunisia was no accident. Having sent the D1s there, France significantly increased its presence in the region, which was getting hotter by the minute. France could not remain indifferent to Mussolini's expansionist policies. The appearance of almost 150 tanks with competitive armour and armament, even for the second half of the 1930s, would cool the Italian dictator's head.

Tanks on exercises, shortly before being sent to Tunisia.

The French remembered that these obsolete tanks were in Africa in late May of 1940, when the Germans penetrated the Franco-British defenses and streamed deep into French territory. The 67th battalion began loading its tanks on May 29th, and on June 2nd, the battalion, now under the command of Captain Valleteau, began unloading in Marseille. The battalion started its journey to the front lines on June 9th. Two days later, it unloaded in Sainte-Menehould. The battalion's objective was to cover the retreat of the 5th Mixed Senegal Infantry Regiment and 6th Colonial Division.

The tankers entered battle on June 12th. The second company moved out towards Suippes at 15:50 to stop the advancing German forces. The D1s had to fight for four hours against German infantry on their own, defending the city. The situation was made difficult by the presence of many anti-tank guns. Each tank received several hits. The turrets were not penetrated, but many tankers were cut up by shattered vision blocks. 11 tanks from the company received this type of damage. The 3rd company, fighting around Souin, also came under fire from German anti-tank artillery and lost 7 tanks.

On the next day, the 1st and 2nd companies covered the retreat of the 6th Colonial Division at Sainte-Menehould. That is where they first met German tanks. Even though the D1 was obsolete in 1940, it was a lot more useful in battle than modern French tanks. The short barreled SA 34 47 mm gun turned out to be more useful than even the long 37 mm SA 38, and not all tanks had that gun to begin with. 30 mm of armour was not a problem for this gun. As for armour, the D1 that was built according to specifications from 1926 and modern light tanks had about the same amount.

As a result, the first meeting between French and German tanks forced the Germans to retreat. However, the 2nd company was down to 4 tanks, and all of them were damaged. The last tank of the company was lost on the next day. The 3rd company was ambushed and lost all of its tanks. As for the 1st company, it mostly lost its tanks to technical breakdowns and a lack of spare parts. Nevertheless, its vehicles still saw action. On the night from June 15th to June 16th, two surviving D1s participated in deflecting a German attack, and were included in the 43rd Tank Battalion the next day, which was armed with Renault R 35 tanks. However, due to technical breakdowns, these tanks did not last long.

Knocked out tanks from the 67th BCC, June 1940.

This was not the end of the Char D1's fighting career.

The Germans received 18 tanks, which were renamed to Panzerkampfwagen D1 732(f). These tanks were not even used as training tanks. Worn out components and battle damage left no chances for further service. In addition, the German trophies contained tanks with ST1 turrets, which were completely useless.

The situation in Africa was different. From 107 tanks left in Tunisia, 77 were returned to warehouses after the surrender of France, where they were given to the Italians. Another 10 tanks were in such poor condition, that they were deemed unsuitable for service. The remaining 20 tanks were secretly moved to Algiers by the French. In the summer of 1941, after several attempts, the French managed to convince the Italians to release 62 D1 tanks, which were also moved to Algiers. That is where they were included in RCA regiments (Régiment de Chasseurs d'Afrique, Regiment of African Hunters), which were subordinate to cavalry. The 2nd RCA, located in Oran, was effectively the 65th Tank Battalion. The French managed to restore an entire tank unit.

The 4th RCA was located in Tunis. It contained 15 tanks. The 5th RCA, in Algiers, officially had 15 tanks, but also had the 20 hidden D1s.

More than two years after the battles in Champagne, the D1 had to fight again. On November 9th, 1942, the Americans began Operation Torch, which included a landing near Oran. One of the priority targets of the operation was the airport at Tafaru. Here, the 601st Tank Destroyer Battalion, armed with 75 mm M3 GMC halftracks, went into battle with what the Americans recorded as French Renault R 35 tanks.

In reality, these were D1s from the 2nd RCA. The battle was uneven, since the 75 mm guns could knock out the French tanks at long ranges. However, the 601st battalion lost one M3 GMC, as well as one Light Tank M3A1. The French losses were much higher: 14 D1s, almost a whole company. There were more damaged tanks, since the remnants of the 2nd RCA were soon included into the Allied forces, and they only had 10 functional tanks.

Tanks of the 2nd RCA in Oran, 1943. These tanks managed to fight against the Germans and the Americans.

At the same time, the 4th RCA in Tunis was between a rock and a hard place. Vichy France was formally neutral, but the Germans from the Africa Corps demanded that its forces should be placed under its control. Meanwhile, the British were on the horizon. This kind of diplomacy could not last for long, and, on November 19th, the 4th RCA began fighting against the Germans. The defending French units began to retreat slowly, but British commandos came to their aid. The 4th RCA continued fighting until February of 1943.

The 5th RCA also had to fight, in the mountainous regions of Tunisia. In late February of 1943, British Valentine tanks came to replace the ageing D1s. By the end of the African campaign, only 10 D1 tanks remained, which were combined into a the EPSM military police unit, subordinate to the Navy.

Despite the fact that the D1 was obsolete in the mid-1930s, its results in battle were surprising. The concept adopted by the French infantry in the mid-1920s was correct. Even with all of its drawbacks, the D1 was a decent infantry tank. Its closest analogue was the British Valentine, which had more armour, but was not as well armed. Alas, in the early 1930s, the French placed their bets on a different class of tanks.

Original article by Yuri Pasholok.


  1. I have read and enjoyed many of your well written historical accounts.

    In this case, though, I thought I might point out an error.

    You have described an action on 9 November, 1942, between French D1s of the 2nd RCA and U.S. M3 Tank Destroyers (75mm SPGs) of the 601st Tank Destroyer Battalion.

    That action, at Tafaraoui Airfield (south of Oran) was against the M3A1 Stuart tanks of CCB (Combat Command B) of the U.S. 1st Armored Division, which had landed at Beach X of the Central Task Force, and driven 25 miles (about 40km) inland by the afternoon of D day (8 November) to overrun the airfield.

    On D + 1 (9 November) when the action occurred, the two companies of 75mm M3 SPGs of the 601st Tank Destroyer Battalion had not yet landed in Algeria. In fact they did not come ashore until December. Only the recon element of the 601st TD Battalion came ashore in November of 1942.

    It is possible that French accounts of this action may have mis-identified U.S. T30 75mm SPHs (self-propelled howitzers), which were also built on the chassis of the M3 halftrack. I have seen this error in French language accounts of the Torch landings. T30s may have been present as assault guns in HQ units of CCB tank formations or in U.S. Armored Cavalry (ie: recon) formations in that area. But T30s were armed with a 75mm pack howitzer, were typically equipped with high-explosive ammunition, and were generally rather ineffective against armored targets.

    For more reading on the forces involved (or not involved), one may examine:

    The U.S. Army account of the Algerian portion of the Torch landings:

    The campaigns of the 601st Tank Destroyer Battalion:

    Other than this minor mis-identification, I found it to be a very interesting and informative article. My thanks for the research and the writing. I remain an avid fan!

    (aka: Mk 1, or Mark2 in WoT)

  2. "Theoretically, it could fit in the hull, but making the commander/gunner a loader as well was considered the peak of sadism."

    This should say, "turret." Doesn't make sense otherwise.