1942 - 1943 Ford GPA
Provided by Hemmings

The technological and tactical advancements in the manner of waging war from the First to the Second World Wars required innovative thinking and imaginative design application. Having moved from mass battles of opposing armies spread across vast tracts of land to more localized conflicts in which the capture of strategic geographical locations was of more importance than advancing a front line a mile at a time, radically new weapons and tools of war would be needed in order to succeed.

To that end, the National Defense Research Committee, an organization established by order of the Council of National Defense in 1940 with the mission of coordinating and supporting the research of new instruments of war, developed the specifications for a General Purpose vehicle with amphibious capabilities to be designed for the purpose of transporting small numbers of personnel from ship to shore. Hence the popular nomenclature GPA. The NDRC’s Transportation Development division came up with the specifications for the vehicle by 1941. Marmom-Herrington, with the help of the New York yacht building firm of Sparkman & Stevens, and Ford Motor Company soon began actively designing amphibious vehicles based on the _-ton GP chassis. Marmom-Herrington’s prototype, the QMC-4 and Ford’s GPA prototypes were both finished by the Spring of 1942, but it was Ford, based largely upon its proven manufacturing capacity and the comparative ease of its conversion opposed to Marmom-Herrington's, that landed the final production contract. (Both Willys and Ford had already been contracted to build GPs for the military, and Fords Amphibian was based on the basic GP chassis.)

Unfortunately, the Sea Jeep was rushed into production, (its primary target date had been intended to get it into service for use in the Allied invasion of Italy) without the extensive test sessions that its land-going sibling had been subjected to. A bevy of problems cropped up in the field, or shall we say water? The engines were prone to overheating during the trip from ship to shore, they often swamped and sank in rough surf, and on land they were slow and lightly armored, basically easy targets for the enemy.

As to its functionality, it is a case of a sound concept and poor execution. In the water, second gear drove the propeller via a Power Take Off assembly attached to the transfer case. Its small size, in terms of both length and width, meant that it was easily tossed about by waves and its front-mounted splash shield likely did little to keep the water out of its engine compartment, which could be closed off by a hatch. Waterproofing around the propshaft and driveshafts was accomplished via a sealed tube enclosure with a flexible rubber gaiter. Though the top speed in the water was supposed to be 7 mph, they struggled to reach 5, and a capstan winch at the bow allowed the crew to pull themselves onto the beach in case they became stuck in the sand at water’s edge. On land, they were hard pressed to reach more than 50 mph. The part-time four-wheel drive had to be engaged via the transfer case and offered a High and Low range. After being deemed a failure by the military, many of the remaining Sea Jeeps went to the Russian military under the Lend-Lease Act.

Although the initial order had been for some 12,000 units, it is reported that less than half that number were actually built. Apparently, the task of coming up with modifications to solve its many smaller problems consumed much of the time that Ford would have otherwise spent fulfilling the complete order. Today, the GPA or Sea Jeep is a relative rarity; it is seen most often at gatherings of military vehicle collectors. Not many survived the war, and obviously, rust and the lack of parts are factors that make restoring one of these military oddities a major and expensive undertaking.

1942-43 Ford GPA Specifications
Engine: 1,991 cc four-cylinder
Output: 60hp @ 3,600 rpm
Transmission: 3-speed manual with 2-speed transfer case with PTO propshaft drive
Frame: Standard -ton GPW
Body: Welded and bead-rolled stamped steel
Capacity: 2+2
Suspension: Leaf-sprung beam axle front and rear
Brakes: Four-wheel drum
Weight: 3,650 pounds
Length: 182 inches
Width: 64 inches