DUKW

 The DUKW was developed at the direction of the National Defense Research Committee and the Office of Scientific Research and Development for transporting troops and light cargo during amphibious landings.  The initial contract was awarded to General Motors, which designed the prototype around its 6-wheel-drive two-and-one-half (2 ½) ton military truck.  It was basically a heavy duty truck that could also operate in water.  Although constructed out of steel, it had no armor plating.  It could, though, be equipped with a machine gun.  The DUKW had an innovative system enabling the driver to control the tire pressure from inside the cab.  With the tires fully inflated, the DUKW could travel at up to 50 mph on a road.  The tires were partially deflated for operating on softer surfaces, such as beach sand.  When afloat, the DUKW was powered by a propeller at the stern, giving it an effective speed of six knots.  The DUKW designation was assigned by General Motors: D meaning the vehicle was designed in 1942; U meaning utility; K meaning all-wheel drive; and W meaning that the two rear axles were powered.  Thousands of DUKWs were built during World War II and pressed into service by the Army, the Navy/Marine Corps, and various allied forces.  DUKWs were used in landings in the Mediterranean, in the Pacific, and on Normandy Beaches on D-Day.  After the war, many DUKWs were converted to peacetime purposes.  Numerous DUKWs were assigned to the US Coast Guard for use at lifeboat stations.  They remained in use by the Coast Guard as late as 1970.  Others were acquired by fishermen and local fire and rescue departments.  The few DUKWs still in operation are used mostly by tourist transport companies in locations adjacent to harbors, rivers, and lakes.  The US Coast Guard has recently cautioned owners of these vehicles/vessels that they require frequent inspection and maintenance due to their unique operating environment and the fact that passengers on board may be unprepared for emergencies.