The DUKW prototype was built around the cab over engine (COE) six-wheel-drive military truck GMC ACKWX (a COE version of the GMC CCKW), with the addition of a watertight hull and a propeller. The final production design was based on the CCKW. The vehicle was built by the GMC division of General Motors (called Yellow Truck and Coach at the beginning of the war). It was powered by a GMC Straight-6 engine of 270 in³ (4.416 L). The DUKW weighed 7.5 tons and operated at 6.4 mph (10 km/h) on water and 50-55 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. It was not an armored vehicle, being plated with sheet steel between 1/16" and 1/8" thick to minimize weight. A high capacity bilge pump system kept the DUKW afloat if the thin hull was breached by holes up to 2" in diameter.
The DUKW was the first vehicle to allow the driver to vary the tire pressure from inside the cab, an accomplishment of Speir's device. The tires could be 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. This feature is now standard on many military vehicles.
Although technically a misnomer, DUKWs are often referred to as duck boats. Another popular nickname was old magoo or simply magoo. Though the origin of this term is unknown, it probably refers to the odd shape of the vehicle.
Several were used by abalone fishermen of San Luis Obispo County California to take their catch right off the boats and directly to market, neatly combining the two steps of off-loading onto smaller craft, and then transferring to trucks once they reached the beach.
Britain's Royal Marines still use a small number of these vehicles for training purposes in Scotland.
In the 1950's the USSR copied the DUKW and the Zavod Imeni Likhacheva factory started producing the BAV 485. Production was stopped in 1962.
Whenever a natural disaster or an emergency situation occurs, DUKWs are well equipped for the land and water rescue efforts. One particular duck built in 1945 was loaned to a fire department during the Great Flood of 1993 and in 2005, the vehicle spent 10 days rescuing survivors from Hurricane Katrina. The DUKW maneuvered through flood waters, transporting victims from their rooftops to helicopter pads set up throughout New Orleans.
Although DUKWs were used predominantly for the military, many were used by civilian organizations such as police departments, fire stations and rescue units. Some such as the "Moby Duck" have been adapted as props by local groups such as Seattle's Seafair Pirates to be used in parades and events.
A DUKW is also central to the 2000 AD story Disaster 1990, in which the lead character, London hardman Bill Savage liberates one from a war museum to survive a futuristic flooded Britain.
A DUKW named Scrooge is featured in the 2006 novel Red Lightning by John Varley. Scrooge is used by the main characters to enter a devastated Florida after a tsunami triggered by an object stiking the earth.