DUKW,
a 2.5-ton, six-wheel amphibious truck used during amphibious operations in World War II by the U.S. Army and Marine Corps. Its primary use was to ferry ammunition, supplies, and equipment from supply ships in transport areas offshore to supply dumps and fighting units at the beach.
The DUKW (an acronym based on D-model year 1942, U-amphibian, K-all wheel drive, W-dual rear axles), called "duck," was shaped like a boat. It had a hollow airtight body for buoyancy and used a single propeller for forward momentum.
It was designed according to Army criteria and was based on the Army's 2.5-ton truck. The vehicle was capable of carrying 25 soldiers and their equipment, an artillery piece, or 5,000 pounds of general cargo. At sea the vehicle could maintain a speed of 5 knots, and on land it could go 50 miles (80 kilometres) per hour.
The United States produced 20,000 DUKWs during World War II. Through lend-lease the British were provided 2,000 of the trucks. The vehicle was first used in "Operation Husky," the invasion of Sicily in 1943.

Above text taken from the Encyclopaedia Britannica, Online

Other great web pages dedicated to the DUKW
http://members.aol.com/twodukw/twodukw.htm

Great Web site dedicated to the LVT (Landing Vehicle Tracked)
http://metalab.unc.edu/hyperwar/USN/ships/LVT/LVT.html

Check out these web pages to see what can be done with a DUKW for fun and recreation!
http://users.belgacom.net/amphib/Dukw-pic.htm
http://my.voyager.net/dukw/dukwpage.htm