DUKW

The DUKW is a six wheel drive (6×6) amphibious vehicle based on the standard World War II GMC 2 1/2-ton 6×6 truck. Propulsion in the water is by a large propeller driven from a gearbox PTO. The adaption was by naval architects Sparkman and Stephens (who later designed 12-metre racing yachts for the Americas Cup) and is quite sea-worthy. Movie film exists of DUKWs landing on, and leaving from beaches in surprisingly heavy surf.
grean
DUKW
Some DUKWs are fitted with a system where tyre pressure can be varied on the move to improve traction on soft beaches. This is effected by an arm at each wheel which carries an air-pressure line to the outside of the wheel hub where a rotating seal joins with a further line to the tyre valve. -- L. Allison.

DUKW
Loa 372", width 99", height 106", wheelbase 164"=120"+44",
Engine 6-cyl
5-speed gearbox, 2-speed transfer case, 6×4, part-time 6×6
Tyres 11.00×18
yellow
a second life, in 2010

A much smaller amphibious vehicle, the Ford GPA or Seep, was based on the WWII Jeep.