Valentine DD tank with screen lowered and gun pointing towards the rear of the vehicle Trials conducted by the British War Office showed that such a tank, propelled by an outboard motor, 'swam' reasonably well. In Britain, the Hungarian-born engineer Nicholas Straussler developed collapsible floats for Vickers-Armstrong that could be mounted on either side of a light tank to make it amphibious. The alternative was to use flotation devices that the tank discarded as soon as it landed–the approach adopted by the Japanese with their Type 2 Ka-Mi and Type 3 Ka-Chi amphibious tanks. Heavier vehicles, such as the experimental, British AT1* had to be so large that the design was impractical. Designs that could float unaided were generally small and light with thin armour, such as the Soviet T-37. Development continued during the interwar period.Īs tanks are heavy for their size, providing them with enough buoyancy was a difficult engineering problem. patent 2,390,747, issued 1945Īmphibious tanks were devised during the First World War a floating version of the British Mark IX tank was being tested in November 1918, just as the war ended. History Early development Diagram of a flotation screen fitted to a Tetrarch tank, taken from Straussler's patent, U.S. The DD tanks were one of the many specialized assault vehicles, collectively known as Hobart's Funnies, devised to support the planned invasion of Europe.

DD tanks would use propellers to move forward through water, then lower the flotation screens once they had reached land and fight as an ordinary tank. The phrase is mostly used for the Duplex Drive variant of the M4 Sherman medium tank, that was used by the Western Allies during and after the Normandy Landings in June 1944.ĭD tanks worked by erecting a canvas 'flotation screen' around the tank, which enabled it to float in water. DD Sherman tank with its flotation screen lowered.ĭD Valentine, DD Sherman, DD M-10 Tank DestroyerĭD or duplex drive tanks, nicknamed ' Donald Duck tanks', were a type of amphibious swimming tank developed by the British during the Second World War.

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