Anyone Fancy a Swim? The Ford GPA is an amphibious 4-wheel drive vehicle which the US motor giant was commissioned to produce for the US military in April 1942. In addition to the tried and tested GPW engine, its brand new hull-design body was driven through the water by a rear propeller. It took part in a number of landing operations, including the November 1942 invasion of North Africa and the highly significant Normandy landings in June 1944. Production of the GPA had already ceased in June 1943, however, with some 12,800 units manufactured.