Tamiya Military Miniature Series No.43 - 1/35 - U.S. 1/4 Ton 4x4 Amphibian Ford G.P.A. Jeep

The Ford GPA 'Seep' (from Seagoing Jeep), was an amphibious version of the WWII Ford GPW Jeep. Unlike the jeep, the seep was not a successful design being too slow and heavy on land and lacking sufficient seagoing abilities in open water. Similar design features were used in the larger and more successful DUKW amphibious truck.

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".

The War was on at full tilt, and with bridges over Europe's rivers being taken out one after another, it seemed practical if the jeep could swim as well as drive. And so it came to Roderick Stephens Jr. of Sparkman & Stephens Inc. yacht designers, to design a shape for a 2700 lb (1,200 kg) amphibious jeep, in the same vein as his design for the DUKW six-wheel-drive amphibious truck. Not surprisingly Stephens' hull design looked like a miniature version of that of the DUKW, and just like it, the 'Seep' was going to have a screw propellor, driven by a power take-off, operating in a dedicated tunnel faired into the rear end bodywork, as well as a proper rudder.

The construction of the vehicle was developed in competition by Marmon-Herrington and Ford Motor Company. Marmon-Herrington specialised in all-wheel drive vehicles. The Marmon-Herrington prototype's hull formed an integral unibody structure, created by cutting shapes out of steel plate and welding those together, much like the hull or chassis of an armoured vehicle. The Ford entry however used a sturdy chassis and internal frame, to which more or less regular automobile type sheet-steel was welded. This construction made the GPA some 400 lb (180 kg) lighter than its competitor. Also The GPA's design was based on the Willys MB and Ford GPW standard Jeeps as much as possible. When designing and building the GPA, Ford utilized many of exactly the same parts that the Ford GPW did. The GPA had an interior similar to that of the MB/GPW jeeps, although the driver's compartment had almost twice as many control levers: 2WD/4WD, hi-range/lo-range, capstan winch (on the bows), propeller deployment and rudder control. After a direct comparison of the two company's prototypes, Ford received a contract for production starting in 1942.