 The design features of the much larger and more successful DUKW amphibious truck were used on the GPA.After having commissioned Willys, Ford and Bantam to build the first 4,500 jeeps (1500 each) in March 1941, the US Motor Transport Board set up a project under the direction of the National Defense Research Committee (NDRC) to be designated "QMC-4 1/4 Ton Truck Light Amphibian".Roderick Stephens Jr. of Sparkman & Stephens Inc. yacht designers was asked to design a shape for a amphibious jeep, in the same vein as his design for the DUKW six-wheel-drive amphibious truck.