T - 37A tank The T - 37A was a Soviet light amphibious 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 Two . Early history . In April 1931 , Vickers - Armstrongs conducted several successful tests of light , floating tanks in the presence of the press . Those early models were developed into prototypes by Carden - Loyd Tactors , Ltd . , which was soon purchased by Vickers . Publication of the design and testing by the press attracted the attention of the Department of Motorization and Mechanization of the RKKA ( UMMRKKA ) , because the small tank suited well 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 of 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 ( before the engines could be produced at GAZ plants , they had to be salvaged from imported Ford Model AA ’ s ) , 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 . His Majesty ’ s army refused to implement the Vickers prototype , 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 suck 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 . ” Serial production . Even before the end of 1932 , the high command of the Red Army was planning to order 30 T - 37A ’ s . In order to facilitate faster production , Factory No . 37 ( that is what the No . 2 VATO plant was renamed ) was handed over all OKMO production related to the T - 37 , as well as one British Vickers tank . In 1933 , the No . 37 plant was given an order of 1200 T - 37A ’ s . However , the events that followed showed the excessive optimism shown by the leadership of the trust responsible for the factory . The trust itself was formed as a governing organ for coordinating large - scale efforts to develop new models of armored vehicles in a number of plants across the country , and subsequently played a significant role in the successful carrying out of this task , but at the beginning of 1933 it couldn ’ t overcome the “ antediluvian ” state of equipment at the No . 37 plant , as assessed by M . N . Svirin , purely with organizational measures . Problems with production . By its technological design , the T - 37A was much more complicated than the T - 27 tankette , which immediately caused complications not only at Factory No . 37 , but to its subcontractor – the Podolsk Electric Locomotive Plant , which was producing the hulls of the new T - 37A ’ s . In addition , in 1933 the T - 27 tankette was still being produced , which stressed the lack of adequate resources needed to produce both vehicles simultaneously . This only worsened the situation and slowed the introduction of the T - 37A . The technology for producing stamped cemented armor plates at the Podolsk plant was completely unrefined ; the desired result had to be achieved using improvised and primitive methods . In the end , in the first half of 1933 the Factory No . 37 built 30 amphibious tanks ( 12 of which were T - 41 ’ s ) instead of the 255 needed to fulfill the established plan . The then replacement People ’ s Defense Commissioner Mikhail Tukhochevsky wrote in his report “ of the progress of completion of the tank program in the first half of 1933 ” : The situation didn ’ t change during the second half of 1933 ; the leadership of the Army and Spetzmashtrest , the governing trust , demanded large amounts of T - 37A ’ s to be produced at Factory No . 37 , expecting to receive no more than 800 tanks . In reality , only 126 T - 37A ’ s had been produced by 1 January 1934 , two of which had built - in radios . Some of the tanks participated in a military parade on the 7th of November , 1933 at the Red Square in Moscow . The early T - 37A ’ s did not differ much from the later , series - produced tanks – the earlier ones lacked wave - diffusing shields and floats . In 1934 , the leadership of the Spetzmashtrest lent its attention to improving the conditions in the factories at which the tanks were produced . They purchased foreign equipment for two new wings of the No . 37 Factory , as well as increasing the number of workers and engineering / technical personnel . These measures , however , did not improve the situation ; the number of assembled tanks was significantly lower than planned . The Office of Motorization and Mechanization of the Red Army noted the insufficiency of the technical and general management at the No . 37 plant , and a lack of planning during the production process and " storming through " the operation . As a result , mid 1934 was marked by a change in leadership of the plant , and only towards the end of the year there had been a positive trend in the manufacturing process . Also , in 1934 , slight changes were made to the T - 37A design : the thickness of the sides and the front were increased to 10 mm , the curved stern piece hulls were replaced with stamped ones , and the over - track floats were rolled back and stuffed with cork , and they have become empty on the inside . The production of hulls remained as a limiting factor in the following year of 1935 . The Podolsk Electric Locomotive Plant consistently failed to fulfill the plans for the production of parts in adequate numbers . To solve the problem , a year prior , it was decided to use the T - 37A Izhorsky plant in Leningrad for additional hull production . But this enterprise , although there was considerable capacity , has been directed other orders for armored car rental for the needs of Navy of the Soviet Union , as well as the production of hulls for the Leningrad plants producing armored cars and T - 26 and T - 28 tanks . As a result , most of the hulls of T - 37A were sent to the № 37 plant fr¬om PodolskHulls from different manufacturers had various methods of production : Izhorsk hulls were Welded , and Podolsk hulls riveted . For a permanent solution to the production of hulls for amphibious tanks , engineers restructured them and altered the power plants .