Sunday 10 September 2017

Metamorphoses of an Amphibian Scout

An unusual modification of the T-38 can be seen in the outdoor display of the Central Museum of the Armed Forces of the Russian Federation. This vehicle is distinct from its brothers: instead of one DT machinegun, its turret houses a 20 mm TNSh autocannon and a coaxial DT machinegun. Some Russian historians spread the myth that this tank was experimental. In reality, not only was this not an experimental tank, but these tanks had the chance to fight. This article will cover modifications of T-37 and T-38 amphibious tanks.

Desperate times

The Red Army understood that its amphibious reconnaissance tanks do not fully meet modern requirements in the middle of the 1930s. This became clearer after fighting in Spain. The armour of the T-37 and T-38 only reliably protected from rifle caliber fire at ranges of 400 meters or more, and their DT machinegun was only useful against infantry.

The only advantage of Soviet reconnaissance tanks over armoured cars was superior off-road performance and the ability to cross water obstacles. Realizing this, the GBTU formulated tactical-technical requirements for a new reconnaissance tank, indexed T-39. This tank had improved armour. Later, it transformed into the T-40, which also had improved armament: the 12.7 mm DShK machinegun. This tank was accepted into service on December 19th, 1939, but, for various reasons, only 121 of these tanks were available by June 1st, 1941.

On that date, the Red Army had 2314 T-37 tanks and 1143 T-38 tanks. Like the T-40, they were issued to reconnaissance battalions. From the start of the Great Patriotic War, these tanks often performed the role of infantry support tanks, which they were completely unsuitable for. This must look strange, and even foolish, but, due to enormous losses, any armoured vehicle was worth its weight in gold to the Red Army. The presence of tanks, even these tanks, among infantry bolstered morale.

A number of authors mentions that the idea of applique armour for the T-37 and T-38 came up in July of 1941. Allegedly, it was developed by specialists of the NIIBT proving grounds, a tank with applique armour went through trials, but nothing else happened. For some reason, the NIIBT proving grounds never heard about these experiments. The institute's report for 1941 contains no mention of applique armour. The real story of its appearance is different.

The issue of applique armour for amphibious tanks was raised by the GABTU BTU Chief, Military Engineer 1st Class, N.N. Alamov. Many T-37 and T-38 tanks began piling up at repair factories. His idea was to, instead of simply repairing them, improve their armour and make them into regular land tanks. There was no possibility of improving their armament, as there was barely enough 20 mm ShVAK guns to outfit new T-60 tanks.

The proposal to install applique armour was sent to two people: the Deputy People's Commissar of Tank Production, A.A. Goreglyad, and factory #37 Director, G.R. Frezerov. Factory #37 was the developer and producer of the T-37 and T-38 tanks, and Alymov tasked its design bureau with the development of this applique armour. As you can see, none of this matches up with the story where the applique armour for T-37 and T-38 tanks was performed at the NIIBT proving grounds.

The task for factory #37 was approved, and an inquiry regarding progress already arrived on September 30th. According to Frezerov's response, the factory's design bureau was hard at work, in cooperation with repairs base #2, located in Moscow, at 40 Nizhne-Krasnoselskaya St. N.A. Astrov's department specifically was tasked with the development of applique armour.

Calculations showed that the maximum acceptable mass of applique armour for the T-38 was 400-500 kg. As for the T-37, there was great doubt about improving its armour. The tank already suffered from a weak differential, and additional loads could just cause more problems.

Frezerov warned that the factory's design bureau only has time to design applique armour for one tank. Despite concerns about overloading, it was the T-37 that was submitted for trials on October 1st, 1941. The hull received an extra 7 mm of armour on the hull and 6 mm on the turret. Gunnery trials from 50, 100, 150, and 200 meters showed that bullets fired from that distance could penetrate the applique armour, but not the main armour. The commission came to the conclusion that the tank was bulletproof from all distances.

That was not the end. In the middle of November, factory #2 sent in a description of a converted T-37 land tank. The tank lost its buoys, propeller, rotating gunner's seat, and one DT ammunition rack. In return, the tank received additional armour. 6 mm thick armoured plates were installed on the sides, which covered the space from the bogey carriers to the hull rivets. The front and rear of the tank were also covered in applique armour, as did protruding parts of the hull, including the radiator armour. The turret was also completely covered in applique armour.

Aside from applique armour, the document also discusses the issue of rearmament. In the first variant, the tank retained its DT and an ammunition rack for 15 disk magazines. In the second variant, the front of the turret was altered to be similar to that of the T-40. The new turret received a gun mount for a DShK machinegun, and the commander-gunner received a shoulder stock. There was no coaxial DT in this variant, but there was a firing port for it. The DT was held inside the hull. The tank carried 10 boxes with 60 rounds belts for the DShK.

This T-37 weighed 350 more than the stock T-37: the applique armour weighed 400 kg, the DShK and its ammunition weighed 120 kg, and 170 kg of parts were removed. It took 473 man-hours to convert the T-37 into the DShK model, or 316 man-hours for the DT model. Work on armouring the T-38 was not performed due to the strict time limit.

Later, the issue of applique armour for T-37 and T-38 tanks vanished on its own. By the end of 1941, very few of these tanks remained in the army. The T-38s left on the Leningrad Front were needed for amphibious reconnaissance, and did not need extra armour. It is possible that repair factory #2 did have time to convert some tanks. However, this is only a hypothesis, as the author has not seen the factory's correspondence for that period, or photographs of any tanks with applique armour.

Mass rearmament

There are also questions regarding the rearmament of the T-38, which allegedly took place in 1941. The T-37 and T-38 are absent from the list of tanks that needed rearmament in 1941. The NIIBT proving grounds list of experimental work for 1941 also makes no mention of rearmament of the T-38 or applique armour for it.

The claim that two tanks, allegedly called T-38Sh, were present at the NIIBT proving grounds until the end of the war, is baseless. It is known that the NIIBT proving grounds had two T-37 tanks in March of 1942, and had no T-37 or T-38 tanks at all as of August 8th, 1943. These vehicles returned again by June of 1945, but these tanks had regular DT machineguns. The rumours about these so called T-38Sh tanks are based solely on the imagination of their author.

In reality, the first time the issue of rearming reconnaissance tanks was raised was in November of 1941, and the plan then was to use the DShK, not a 20 mm gun. As mentioned above, the process did not go far, and it is not known whether or not even a prototype of the T-37 with a DShK was ever built.

However, it is known when the topic was revisited: in early 1943. The Far Eastern Front had 288 T-37 and 155 T-38 tanks as of July 1st, 1941. A small part of these tanks went westward with Far Eastern units, but the majority remained where they were.

The idea of improving the firepower of these tanks was inspired by the availability of surplus TNSh guns after T-60 production ended. Repair factory #105 in Khabarovsk was tasked with the project, which was called "L.M. Kaganovich State Automotive Repair Factory #105" until 1941. This organization, which continued its work after the war, is known as PAO "Dalenergomash" today.

Mass produced T-38, rearmed at repair factory #105. There are no differences from the regular T-38 except in armament.

On January 15th, a letter from the GBTU (Main Armoured Directorate of the Red Army, created in 1942 after a reorganization of the GABTU) arrived, addressed to OKB-15 director, B.G. Shpitalniy. According to the letter, repair factory #105 received an order for rearmament of 400 T-37 and T-38 tanks. Since there was a danger that the TNSh belt box would not fit into the T-38's turret, a possibility of using a magazine feed was mentioned. The GBTU asked Shpitalniy to send specialists from OKB-15 to Khabarovsk.

A letter sent by the GBTU to the GAU some time later signifies the seriousness with which this project was treated. In it, Alymov asked for 1.5 million rounds of ammunition for tanks that would be rearmed.

The front of the turret had to be altered to install more powerful armament.

Work on rearming the T-37 and T-38 disappeared from the GBTU's radar for some time. This makes the following request by the Chief of the GBTU TU (Technical Directorate), Major-General Afonin, sent on November 27th, 1943, seem rather strange:

"The GBTU TU was informed that the Armoured and Mechanized Forces of the Far Eastern Front are rearming and equipping their tanks with applique armour. We require information on the amount of work performed.

Please inform the GBTU TU of the following:
1. How many T-37 tanks were reamed with ShVAK guns..."

The gun mantlet was reminiscent of T-30 tanks, equipped with TNSh guns.

Judging by this request, the GBTU simply forgot about the issue of rearming T-37 and T-38 tanks from January to November. In a different place, this could have meant the end of the project, but the Far East was not spoiled by tank supplies that such an important task could be left on its own. Khabarovsk not only adapted the TNSh gun and a coaxial DT machinegun mount for the reconnaissance tank's turret, but put the project into mass production.

Armour of the recoil system from the bottom.

Information from the Far East arrived infrequently, to say the least. Because of this, there is no information about when the design for the installation of the TNSh in the T-37 and T-38 was completed. However, one can say for sure that factory #105 succeeded in this complex task. The new gun increased the mass of the tank by only 100 kg, which allowed it to retain its buoyancy. The repair factory also performed trials, which gave satisfactory results.

Looking into the turret from above.

How many T-37 and T-38 tanks were converted? That question remains unanswered. According to the Assistant Commander of the Armoured and Mechanized Forces of the Far East Front, Engineer-Colonel Rogachev, 97 T-37 and T-38 tanks were converted by January 1st, 1944. 2 additional T-37s and 11 T-38s were converted in January, and 10 T-38s with new armament were delivered in February. After that, repair factory #105's reports vanish once again. Based on these numbers, we can be certain of at least 120 tanks, but it is possible that there were many more.

There was less space in the turret, but it was convenient enough to work with the new armament.

Fears that the ammunition feed system would have to be redesigned were unfounded. Based on the tank that was preserved at the TsMVS, there were no issues with this. There were also no issues with installation, since the width of the front of the turret of T-37 and T-38 tanks was about the same as that of the T-60. The recoil system armour was also similar to the one used on the T-60. The same could be said for the position of the TNSh gun, DT machinegun, and TMFP-1 sight. As for the gun mantlet, it was closer to the one used on the T-30. 

The TNSh, DT, and sight were positioned in the same way as on the T-60.

The smaller dimensions of the turret were partially compensated by the fact that the amphibious tanks lacked bulky aiming mechanisms. Vertical aiming was performed using a shoulder stock. There was also no turret traverse mechanism: as on the regular T-38, the commander rotated the turret without any flywheels. The ammunition capacity of the DT machinegun was reduced to 1260 rounds (20 disk magazines). The tank carried 4 boxes (240 rounds) for the TNSh in a crate behind the turret.

Vehicles from Far Eastern Front units arrived at the repair factory, and returned there after installation. For instance, the 77th Tank Brigade had rearmed T-38 tanks as of January 1945. There is some doubt about the widespread use of these tanks against the Japanese after August 9th, 1945. Formally, the Far Eastern Front still had 52 T-37 and 325 T-38 tanks as of August 5th, but reconnaissance battalions began phasing them out in June. By the time combat started, the 77th Brigade no longer had any of these tanks.

Theoretically, these tanks also could have been included in the 4th Independent Tank Battalion of the Pacific Fleet, which took part in the landing at Chongjin in Korea. However, documents pertaining to this operation only mention T-26 tanks. It is possible that the battalion no longer had rearmed reconnaissance tanks by the time it saw battle.

There is another mystery in the history of the T-38 with a 20 mm gun, the mystery with which this article began: the origin of the tank in the Central Museum of the Armed Forces of the Russian Federation. Fortunately, it can be solved rather easily.

On July 23rd, 1945, a letter was sent to the GBTU Chief, Lieutenant-General Vershinin, from the NIBT proving grounds Chief, Major-General Romanov. In his letter, Romanov asked Vershinin to transfer 9 tanks to his museum, including a T-38 with a ShVAK gun. As you can see, the index T-38Sh was not used in reference to this vehicle. The tank ended up in the NIIBT proving grounds museum, and was passed to the Museum of the Soviet Army in 1965, which is called the Central Museum of the Armed Forces of the Russian Federation today.

Even though the vehicle spent a large amount of time outside, it was well preserved. In 2014, a group of volunteers, led by the article's author, restored the tank.

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