The Army's DUKW-353
Amphibious 2-1/2 ton
Delivering cargo directly to the beaches.

The DUKW, popularly called the DUCK, is a six-wheel-drive amphibious truck developed by the United States during World War II for transporting goods and troops over land and water and for use approaching and crossing beaches in amphibious attacks.

The DUKW was used in landings in the Pacific, in North Africa, and on the D-Day beaches of Normandy. With the enemy holding all available ports, at Normandy alone DUKWs carried 18 million tons of supplies ashore in the 90 days after the landing. See Mulberry harbor.

The DUKW was developed by the National Defense Research Committee and the Office of Scientific Research and Development, but was originally rejected by the armed services. When a U.S. Coast Guard patrol craft ran aground on a sandbar near Provincetown, Massachusetts, an experimental DUKW happened to be in the area for a scheduled demonstration a few days later. Winds up to 60 knots (110 km/h), rain, and heavy surf prevented conventional craft from rescuing the seven stranded coastguardsmen, but the DUKW had no trouble, and the military opposition melted. Subsequently, DUKWs have proved their seaworthiness by crossing the English Channel and performing many other exploits at sea.

Although its designation as a DUKW may seem to be a military pun, in fact in the terminology developed for military vehicles in World War II,the D indicates a vehicle designed in 1942, the U meant "utility (amphibious)", the K indicated all-wheel drive and the W indicated two powered rear axles. The DUKW was built around a conventional six-wheel-drive military truck called the CCKW, with the addition of a watertight hull and a propeller. It was powered by a GMC Straight-6 engine of 270 cubic inches (4.4 L). The DUKW weighed 7.5 tons and operated at 6.4 mph (10 km/h) on water and 50 mph (80 km/h) on land. It was 31 feet (9.3 m) long, 8.25 feet (2.4 m) wide, and 8.8 feet (2.6 m) high with the folding-canvas top up. More than 21,000 were manufactured.

The DUKW was the first vehicle to allow the driver to vary the tire pressure from inside the cab, with the tires fully inflated for hard surfaces such as roads and less inflated for softer surfaces—especially beach sand. This added to the DUKW's great versatility as an amphibious vehicle, and such arrangements are now a common feature on many military vehicles. The DUKWs were the only wheeled vehicles capable of operating on the beach at Iwo Jima, for instance.

The DUKW was an amphibious version of the 2-1/2 ton General Motors cargo truck. It was developed by the U. S. Army during World War II as a means to deliver cargo from ships at sea, directly to shore.	A DUKW full of troops makes a beach landing, Italy.
France, 1944
A training exercise practicing the approach to a ship.	Net cargo transfer from DUKWs to trucks, Le Verdon, France.