This information was found at http://www.globalsecurity.org/military/systems/ground/dukw-action.htm

The US Navy, responsible for the operation of all boats and ships, simply did not have enough men to train and operate all the various landing craft rolling off assembly lines. In early 1942, the Navy requested that the Army train and man some landing craft and all of the DUKWs. Initially, this mission was assigned to the Corps of Engineers. The First Engineer Amphibian Command was established early in the summer of 1942. Since the military was still segregated by race, African-American troops were typically relegated to support units. Many of the amphibious DUKW drivers were African-American. Army training took place at an Aquatic Park near the San Francisco Port of Embarkation in California. There was not a training model to follow and little time. The Engineer Amphibian Command was required to recruit, procure equipment and develop a training program almost simultaneously. A Boat Training Center was established at Camp Edwards, MA. Local civilian boat and yacht companies taught boat maintenance courses. The initial course of instruction was 3 weeks, but the need for lengthening the course was evident. Even after two months of training, soldiers were still not prepared to operate this complex new vehicle under wartime conditions. Instructors and maintenance officers were sent to General Motors Corporation's War Products School in the fall of 1943. Various civilian companies taught 1,065 instructors about marine diesel engines, harbor operations, and offloading procedures. Before a sufficient number of landing ships were in service, it was necessary to use booms to transport vessels for setting the DUKWs into the water. This procedure was lengthy and difficult. The 2nd Brigade, 87th Engineer Battalion was trained and issued DUKWs and other equipment. At the request of General Douglas MacArthur, they embarked for the Pacific in mid-January 1943. The first training exercise for the DUKW came in March 1943 when the 2nd Brigade landed troops on Noumea, New Caledonia. The land was small and involved only a few DUKWs and other landing craft, but it was successful. The amphibian engineers and the DUKW had proven their merit. DUKW Design The basic GMC model CCKW-353 truck chassis served as the foundation for the Duck. Added to that was a centrally controlled tire pressure system, a 25 inch propeller, a rudder, bilge pumps, and a watertight steel hull. With a crew of 2, it is powered by a GMC Model 270, in-line, 6 cylinder, overhead valve, four cycle, 270 cu in, 91.5 hp gasoline engine coupled with a constant mesh 5-speed forward/1-speed reverse manual transmission and a 2-speed transfer case. The DUKW takes its name from an abbreviation of the Army’s method of identifying vehicles by year and type. The DUKW takes its name from the following: D = built in 1942 U = amphibious 2-1/2 ton truck K = front wheel drive W = rear wheel drive Though coincidental, the abbreviation DUKW (called by the GI’s,"Duck") was an excellent description of the vehicle. The DUKW saw action in all theaters of World War II and Korea as a ship-to-shore transporter of soldiers and supplies. DUKWs proved to be critical to the even flow of supplies from ship to shore. The initial intent was to develop a lighter vehicle that could ferry supplies from ships anchored offshore and drive right up over the beach to support the supply lines.

It is equipped with an integral watertight hull designed in such a way that the truck chassis and drive units are attached to and in the body of the hull. The stripped truck body was wrapped with a steel built hull. A gear box was added to the truck drive train, and propeller, which provided propulsion on the water. For land operation, the vehicle utilizes its six driving wheels and steering-gear assembly. In the water it is propelled with a water propeller. The payload capacity on land was just over 5,000 pounds. On water, it's known to carry in excess of 40 equipped soldiers, and the speed was governed to 50 mile an hour on land, and just over 6 mile an hour on water. A GMC 269.5 cubic inch, in-line, overhead valve, six-cylinder engine powered the DUCK, and a five-speed manual transmission gave it a maximum land speed of 50 miles per hour. A 25-inch diameter propeller, driven by the three lower gears, provided amphibious mobility, giving the DUKW a maximum water speed of 6.4 miles per hour. A permanent rudder provided steering in the water. The first DUKW operations occurred in the Pacific in March 1943; use in the European Theater of Operations (ETO) followed. The DUKW is capable of carrying a 2 1/2 ton payload over land or water. It is equipped with a GMC 270 cubic inch 6 cylinder gasoline engine. It has a 5 speed transmission with a 2 speed transfer case. This gives a total of 10 forward speeds and 2 in reverse. It has 6 wheel drive, a water propeller and a 10 ton winch. All or any of these can be run separately or together in any combination. Top speed on land is 50 to 55 mph while on the water top speed is only 6 mph (land miles per hour not knots). It also has a tire inflation system with a 2 cylinder air compressor and air storage tank. This allows the driver to inflate or deflate any one or all six tires at the same time from the dashboard. The dashboard also has a tire pressure gauge so that air pressure can be monitored. The front brake lines are protected in steel conduit with barbed wire cutters on the outside. The DUKW weighs 7 1/2 tons empty and is 31 feet long. Eventually, the number of DUKW companies grew and the Transportation Corps established 15 Amphibious Truck Battalions and Headquarters Detachments, in order to assemble DUKW companies all under one command. In just a few short months, the Army had come a long way in perfecting amphibious landing techniques and what was needed to put troops ashore. The DUKW proved invaluable during the invasion of Salerno, Italy. Between 9 September and 1 October 1943, 90 landing craft and 150 DUKWs moved 190,000 troops, 30,000 vehicles and 12,000 tons of supplies across the invasion beaches to Salerno. Operation Blue Jay used DUKWs for beaching operations in Sicily. The most important feature of the Marine's assaults upon Betio and Butaritari in the Gilberts during late 1943 was the role of the amphibian tractor [LVT or AMTRAC] as an assault craft. At the time of Operation GALVANIC, an armored amphibian tractor mounting a 37mm gun, the LVT (A), and the amphibious 2 1/2-ton DUKW were in production. Even though neither of these types had undergone an adequate combat test, the Marine Corps recommended that a battalion of armored tractors, two companies of the new DUKWS, and two battalions of ordinary LVTS be assigned each division in future assault landings. A shortage of LCT's, needed to unload Liberty ships, developed in Italy at the beginning of February 1944. Most of these craft had been in service for more than a year without overhaul and they frequently broke down. On 6 February only fifteen were available, a number that was increased to twenty-two by 12 February. As a stop-gap, from ten to twenty LCI's were successfully employed in unloading supplies at the beachhead Anzio in Italy. An effort was made to persuade the Liberty ships to come in closer to shore so that they could be unloaded directly by DUKW's, but ship captains were reluctant to do so in the face of heavy shelling. Between 450 and 490 DUKW's were in use at Anzio. The craft situation greatly eased at the end of February 1944, when sufficient LCT's again became available.

In the fall of 1943, an area on the southwest coast of England at Slapton Sands was ordered evacuated of all civilians. About 3,000 people, livestock, equipment and personal belongings were to be totally evacuated by 20 December 1943. They were sworn to secrecy as to the reason for their movement. Slapton Sands covered about 30,000 acres. The area along the beach had similar characteristics of beach and tide as Utah Beach - the proposed invasion and landing area in Normandy, France. Slapton Sands was used for numerous training and assault exercises. It accustomed the assault troops to the kind of terrain they would be encountering, tested and prepared the equipment with waterproofing, and procedures in demolition of obstacles. Landing craft were assigned from various bases along the south Devon coast, including several DUKW companies, to carry troops and equipment on a sea journey of the same length and time as it would take to cross the English Channel to Normandy, France. Soldiers practiced landing on the beach and loading and unloading supplies. These rehearsals for the most part were very successful, and lessons in coordination were learned, which were applied to the actual invasion. Early lessons by the Engineer Special Brigades were integrated into DUKW use during the Normandy Invasion in 1944. Nineteen companies were allocated to the invasion: 12 assigned to Omaha Beach, and 7 to Utah Beach. All were loaded with ammunition and other cargo, which would be crucial during the early stages of the invasion. The DUKWs embarked on LSTs in Weymouth, England on 5 June 1944, and moved across the channel for the invasion. LSTs offloaded DUKWs 14 miles offshore shortly before the attack began. The DUKWs formed two columns and headed for shore. The 453rd, 458th and 459th Transportation Corps Amphibious Truck Companies were assigned to the initial assault. Their mission was to deliver their cargo, then shuttle between the beach and the ships, offloading supplies and establishing supply and ammunition dumps. Operational difficulties were encountered early. Many DUKW's were sunk or damaged during the landings when they struck enemy-laid mines or other obstacles. Some overloaded DUKW's were swamped, and others, launched too far offshore, ran out of fuel and were lost at sea. Adequate maintenance and repair proved almost impossible because of the shortage of spare parts and the round-the-clock activity. From June 6-7, 1944, the three companies lost 41 DUKWs while delivering supplies from ships to supply dumps established just behind the front lines. The ability to move vital supplies directly to the front lines, and the courage of the crews under enemy fire made the DUKW a vital, integral part of the Normandy Invasion. After D-Day, the DUKW became indispensable in unloading vessels. Until port facilities could be rebuilt, they were crucial for moving supplies. Between June 6 1944 and May 8 1945, DUKWs moved 5,050,000 tons of the 15,750,000 tons unloaded by the allies in Europe during the war, over the course of the 90 days when the enemy held all available ports. Most aspects of the logistical plans for the Marshalls fighting in FLINTLOCK and CATCHPOLE during June 1944 represented improvements over GALVANIC. The DUKW justified the confidence that General Corlett had placed in it, and the “hot cargo” system, as practiced by the 7th Infantry Division, proved a reliable method of getting priority cargo ashore during the early hours of an amphibious operation. hours of an amphibious operation. The Marines also had critical items of supply preloaded in amphibious vehicles, in this case LVTS, ready to be landed at the request of the units ashore. Corps observers were convinced that the amphibian truck was better suited for carrying supplies than the tractor, for the DUKW had a larger cargo compartment and was easier to repair. The DUKWs were used for one last amphibious operation in Europe -- the famous Rhine River crossing in Germany, at the end of March 1945. During this operation, 370 DUKWs were used to move men and supplies. During the early hours of the morning of 26 March 1945, under cloudy skies and protected by clouds of artificial fog, troops of the US 7th Army under General Patch

crossed the Rhine River in Germany. While the DUKWs were busy in Europe, their numbers were increased and their duties expanded in the Pacific Theater. Thirteen full companies were in the invasion of the Philippines. DUKWs were invaluable during the capture of Manila. Although the Japanese had filled the harbor with sunken wreckage, the Army captured the city and supplied the troops using the DUKW. In the final battle on Okinawa, the DUKW was indispensable in moving artillery pieces and ammunition directly to the troops fighting against the Shuri Line, near Naha. Supplying and developing the beachhead had, by Landing plus 3, made substantial progress. Supply ships were run in to the reef's edge, where they unloaded into trucks or DUKWs. At Tacloban (the capital city of Leyte) in April 1945, 20 DUKWs from the 813th Amphibian Truck Company moved 1,847 tons of supplies in a 24-hour period. This required a 9-1/2 mile round trip from the ships, to a supply dump, and back again with each vehicle averaging over 92-tons of cargo. In getting supplies across country to the fast-moving Marines on Tinian in July 1944, the level nature of the island was helpful. Moreover, the Japanese had constructed a good network of roads. Yet, logistically, the Tinian operation was constantly challenged: first by the beaches and then by the weather. When the weather turned, it was the DUKW that saved the day. The tough amphibian truck again demonstrated its usefulness under conditions risky for other craft. Colonel Martyr, who commanded the NTLF Shore Party, said that without the DUKW "supply in this operation would have been practically impossible.” He recommended that henceforth amphibian trucks should be supplied not only to the artillery but also to the shore party—and in greater numbers. Admiral Hill advised that DUKWS, manned by Navy crews, replace the LCVPS then carried on deck by transports and attack cargo ships (AKAs). During the Iwo Jima operation of 19 February 1945 difficulty was experienced in handling DUKW's on the soft sand beaches. The amphibian truck, the DUKW, had the primary mission of bringing the division artillery ashore on D-Day. Personnel to operate these vehicles was furnished both by the Marine Corps and the U.S. Army. The difficulty in landing the artillery resulted from the high surf and the tactical situation ashore. While some of the DUKWs landed without difficulty, others were swamped after exhausting their limited fuel supply or developing mechanical problems. Others that were overloaded, sank almost immediately after disembarking from the LSTs. Many of the DUKWs ran afoul of the steep beaches and broached when the front wheels dug down into the sand or volcanic ash and could not get sufficient traction to pull the vehicles forward. DUKW tires, even when deflated, had a tendency to dig into the sand causing the DUKW to belly. It was usually necessary to tow them clear of the beach, using tractors, until beach matting had been laid or ramps built to the water's edge. On occasion, experienced drivers were unable to negotiate the beaches by putting the vehicle in low gear, deflating tires, and making a slow approach. Many DUKW's were broached; however, a large percentage of them were later salvaged. As sea and surf conditions at Iwo Jima became worse, the operation of DUKW's became increasingly difficult. Following the initial landings, DUKWs hauled supplies, especially ammunition, evacuated the wounded, and performed mail and messenger runs. As in the case of LVT's, it is not possible to embark DUKW's in a rough sea with a heavy swell. If the DUKW is loaded, the difficulties of embarkation are increased. In many instances DUKW's were loaded and sent to the beach when surf conditions were such that DUKW's could not land without serious danger of swamping and broaching. Their recovery by the parent LST was also impracticable. The result was that a number of loaded DUKW's which could neither land nor be reembarked were held off the beaches. As in the case of the LVT, hand pumps were inadequate. The result was that DUKW's which had engine failures or which ran out of gas and were not promptly refueled, sank off the beaches. There was a general tendency to overload these vehicles based on theoretical capacities. A safe load for a DUKW under average operating conditions is about 5,000 pounds, the normal load of an LCVP. Operating conditions off Iwo Jima were not good; however, many DUKW's were loaded with cargo in excess of 7,000 pounds in spite of

DUKW company officers' recommendations to the contrary. These craft usually were the first to swamp, thus losing both vehicle and load. Many of the remarks which had been made in connection with the operation of LVT's at Iwo Jima were equally applicable to the operation of DUKW's. The officers of the DUKW companies should exercise close control over their vehicles. LST's assigned to servicing DUKW's and which are being unloaded by DUKW's must keep the officers of the DUKW companies informed as to their movements and their ability to recover vehicles. The launching of DUKW's should be controlled by an officer who knows their capabilities; they should not be launched if they cannot land. LST commanding officers, control officers, and beachmasters have responsibilities for DUKW operation similar to those with which they are charged for LVT operation. In future operations DUKW it was concluded after Iwo Jima that company officers should ride the control vessels stationed off the beaches to which DUKW's are unloading. It was necessary that all available information be passed to those officers, both afloat and ashore, who were responsible for the successful employment of these vehicles in unloading. The evacuation of casualties during this operation showed a marked improvement over any previous operations of this group. Great care had been taken in thoroughly briefing all medical personnel involved before the operation commenced and in providing special medical equipment such as whole blood, which was used here for the first time. Four LST's were outfitted for use as casualty evacuation ships and a large medical staff placed on board. Shortly after How-Hour these vessels each launched one 3x12 barge and secured it alongside and moved to a position close to the control vessel off each regimental beach. Casualties coming from the beach, principally in DUKW's and LVT's, were taken aboard the barge and thence by crane to the LST where they were given early medical treatment and then evacuated to transports by LCVP's. At Iwo Jima the barges alongside for transferring casualties were usually violently unstable. At times the barges would rise on the swell to the level of the LST deck and on one occasion the barges had to be cut loose. However, the transfer of casualties to transports from LVT's was equally difficult, if not impossible at times, and some means of transferring casualties from LVT's to LCVP's was needed since the LCVP's could be hoisted on the davits to the deck level of the transport and casualties brought aboard this way. LVT's and DUKW's cannot be hoisted in this manner. It is easier to handle casualties in a DUKW than in an LVT, apparently due to the ease of handling the DUKW in a seaway. It has more freeboard, steers easier, and is very roomy. One LST served one beach and evacuated casualties to its transport division or to the hospital ship. With the establishment of hospitals ashore the LST's were withdrawn and at that time more DUKW's were available to facilitate the movement of casualties seaward.