The T-37A was a Soviet amphibious light tank. The tank is often referred to as the T-37, although that designation was used by a different tank which never left the prototype stage. The T-37A was the first series of mass-produced fully amphibious tanks in the world.
The tank was first created in 1932, based on the British Vickers tankette and other operational amphibious tanks. The tank was mass-produced starting in 1933 up until 1936, when it was replaced with the more modern T-38, based on the T-37A. Overall, after four years of production, 2552 T-37As were produced, including the original prototypes.
In the Red Army, they were used to perform tasks in communication, reconnaissance, and as defense units on the march, as well as active infantry support on the battlefield. The T-37A was used in large numbers during the Soviet invasion of Poland and in the Winter War against Finland. T-37As were also used by the Soviets in the beginning of the Great Patriotic War, but most of them were quickly lost. Surviving tanks fought on the front lines until 1944, and were used in training and auxiliary defense until the end of World War II.
Early history
The Carden-Loyd tankettes by Carden-Loyd Tractors, Ltd., were promising enough that the company was purchased by Vickers-Armstrong. They developed light, floating tanks to General Staff requirements (A4E11 etc). In April 1931, Vickers-Armstrongs conducted several successful tests of these light vehicles in the presence of the press. Publication of the design and testing by the press attracted the attention of the Department of Motorization and Mechanization of the Workers'–Peasants' Red Army (UMMRKKA), because the small tank was well suited to the new armament policies of the Red Army, as well as possibly being able to replace the older T-27 tankette, which never performed well in combat. At the Bolshevik OKMO plant in Leningrad, from the All Russian Co-Operative Society (Arcos), newspapers were handed in containing information about the British tankette, as well as photographs and technical specifications. Based on this information, Soviet engineers found out that the power plant of the Carden-Loyd tankette was originally from a light tractor produced by the company, and thus the overall layout must be similar. Accordingly, the Selezen ("Drake", Ru. Селезень) program was established in order to construct a similar amphibious tank with a layout based on that of the British prototype. The first Selezen prototype, which was designated the T-33, was built in March 1932 and showed good buoyancy during testing. However, the T-33 did not perform satisfactorily in other tests and was too complicated for the existing military-industrial complex to produce. As a result, it was not mass produced or equipped in large numbers.
T-41 and T-37
Even before the construction of the T-33, it was decided to increase the scale of work dedicated to creating an amphibious tank. In addition to the Leningrad OKMO, the Number 2 plant of the All-Soviet Automotive Union (VATO), which was already producing armored vehicles for the Red Army, was relegated to the development and production of amphibious armored vehicles. As a result, at the 2nd VATO plant, under the supervision of N. N. Kozyrev, the T-41 amphibious tank was produced, weighing 3.5 tons and using the GAZ-AA engine, which was based on the T-27 power plant. The transmission was nearly identical to that of the T-27, and to the power take-off for the propeller, they added a rigid gear clutch. Its construction for turning off the propeller demanded stopping the tank and turning off the engine. The chassis was, in part, borrowed from the T-33, and the caterpillar tracks were entirely from the T-27. Leningrad builders likewise continued the development of a more suitable amphibious tank, and they designated their latest model as the “T-37”. It had the same GAZ AA engine as the T-41, the same transmission, wide use of automotive parts, and the Krupp chassis, which Soviet engineers first encountered as a result of a technological partnership with Weimar Germany. Although the T-41 was actually produced for the military in small numbers, after testing and battlefield trials the T-37 was denied production due to various minor faults and an incomplete development process.