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 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.
Deals with Vickers
Meanwhile, an opportunity to fully analyze the British prototype itself appeared. The British Army declined to put the Vickers prototype into service (although they were used as trials vehicles), and so the company decided to look for foreign buyers. Already interested since the April 1931 demonstration, the USSR, on February 5, 1932, made an offer, through Arcos representative Y. Skvirskiy, for the purchase of eight vehicles. Talks about filling the order did not drag on, and by June 1932, Vickers had already produced and shipped two of the first tanks for the Soviets.
It is widely thought that the T-37A was a copy of the Vickers floating tank, with the Soviet purchase of such tanks in mind. However, closer examination of the turn of events leads to the discrediting of such a theory, but it is true that the Soviet T-37A prototypes were heavily influenced by the British models. Nikolai Astrov, a Soviet engineer, having worked hard on the T-37A prototypes, wrote in his memoirs that "peace be unto the T-37A, born “Vickers-Carden-Loyd."