T-40

The T-40 was a Soviet light amphibious tank. At the end of 1938, a design team at Moscow Factory No. 37 under chief engineer N. A. Astrov started work on a replacement for the T-38 under the project name '010'. The crew of two comprised a driver in the front of the hull and a commander in the turret. The transmission was at the front, and the engine could be reached from inside the tank by removing an armoured partition.

Design

For the water, the T-40 had a propeller and two rudders, both armoured against bullets and splinters. It also had an improved hull shape, a water deflector and sealed hatches, so it could cross fast rivers and handle seas up to force 3, though the crew still carried lifebelts. It was much better armed than the T-38, with a 12.7 mm DShK heavy machine gun and a 7.62 mm DT machine gun paired in one mount. Equipment included periscopes for both crew, a magnetic compass for navigating on water and at night, and a 71-TK-3 radio.

Development and production

Four prototypes were built in July 1939 and two more later, fitted with imported Dodge engines for lack of a domestic unit. After trials that summer, the hull was lengthened and widened slightly and the GAZ-202 engine was adopted. The tank was accepted into service in December 1939, and mass production began in October 1940. Only 37 were completed that year against a plan of 100, and another 179 followed by 22 June 1941. To speed output after the German invasion, the amphibious equipment and radio were then deleted (the T-40S). Later tanks had thicker armour, and some carried a 20 mm ShVAK cannon (unofficially 'T-30'). In total, 443 tanks of the three versions were built in 1941.

Service

In 1941 the T-40 was mostly misused as an ordinary battle tank rather than for reconnaissance, and many were lost. It saw most use around Moscow in the winter of 1941-42 and did well in marshland, where heavier tanks could not go. Surviving amphibious tanks gave valuable service at later river crossings. By 1946 the type had been relegated to training.