DD tank

DD tank
DD Sherman tank with its flotation screen lowered.
Service history
In service	1944–1950s
Used by	United Kingdom Canada United States
Wars	World War II
Production history
Designer	Nicholas Straussler
Designed	1941–1944
Variants	DD Valentine, DD Sherman, DD M-10 Tank Destroyer
Specifications
Maximum speed	4 knots (7 km/h) swimming

DD or duplex drive tanks, nicknamed "Donald Duck tanks",^[1] were a type of amphibious swimming tank developed by the British during the Second World War. 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.

DD tanks worked by erecting a canvas 'flotation screen' around the tank, which enabled it to float in water. 'Duplex drive' refers to the fitted propellers allowing propulsion through water, which supplemented the usual track propulsion used when the flotation screens were lowered upon landing to fight as an ordinary tank.

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.