T-37A tank

T-37А amphibious scout tank
T-37А, displayed in Kubinka Tank Museum
Type	Amphibious light tank
Place of origin	Soviet Union
Service history
In service	From 1933
Used by	Soviet Union
Production history
Designer	N. Kozyrev, Factory No. 37, Moscow
Designed	1931–33
Produced	1933–36
No. built	~1,200
Variants	T-37A (main production), T-37TU command tank, M1936
Specifications (T-37)
Weight	3.2 tonnes
Length	3.75 m (12 ft 4 in)
Width	2.10 m (6 ft 11 in)
Height	1.82 m (6 ft 0 in)
Crew	2
Armour	3–9 mm
Main armament	7.62mm DT machine gun (585 rounds)
Engine	GAZ-AA 40 hp (30 kW)
Power/weight	13 hp/tonne
Suspension	sprung bogie
Fuel capacity	100 litres
Operational range	185 km
Speed	35 km/h (22 mph)

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-37A’s 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 were used in large numbers during the Soviet invasion of Poland and in the Winter War against Finland. The T-37 A was also used by the Soviets in the beginning of the Great Patriotic War, but most of them were quickly lost. Surviving tanks of that type fought on the front lines until 1944, and were used in training and auxiliary defense until the end of World War II.

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.