DUKW in World War II action. Photo supplied by Jim Gilmore. Courtesy: U.S. Marine Corps
If there ever was a vehicle that deserved a little love, it would be DUKW, or more affectionately named “Duck.” This amphibious wonder of war has gained little recognition from anyone beyond those who saw it in action, but many people have seen and possibly even ridden in a DUKW. Unbeknownst to them, they were witness to a vehicle that helped to shape the outcome of a World War.
Jim Gilmore, a military vehicle historian, restoration expert and member of the Redball Military Transport Club, recently spoke with Motor Age about this amazing vehicle. He owns 18 restored military vehicles ranging from armored cars to Jeeps, and has served as director and Judging Chairman of the Military Vehicle Preservation Association.
“The DUKW was one of those U.S. military innovations that helped to win World War II,” he confirms. Gilmore explains that Armies have always struggled to land an infantry on a beachhead, and vessels made to do so prior to the war were inadequate. While trucks travelled well over land, and boats navigated the sea, there was no true amphibious vehicle that could bridge the gap between the two.
This proved true during the World War I Allied invasion of the German-influenced Ottoman Empire, in the Turkish peninsula at Gallipoli in 1915. Initial attacks were strictly naval in nature. The first naval attack included 12 British and French ships, which attempted to dislodge forward batteries. Met with light resistance, the Allies deemed the attack a moderate success. Subsequent naval attacks, however, were met with stronger resistance as mines were laid in the peninsula. The final attack was defeated when five Allied ships struck mines, sinking four ships.
It became obvious after the naval attacks that the Allies needed to deploy ground troops. Thinking that they had softened the resistance with naval bombardments, the Allies deployed rowing boats to carry troops ashore. The boats were woefully inadequate for shore landing, and nonstop Turkish attacks inflicted massive Allied casualties.
It was apparent that precious time was lost disembarking boats and wading to shore. More than anything, this battle proved that more suitable craft was needed to expedite the landing of soldiers and supplies.
“The military really needed a craft that could come right out of the water and keep going,” Gilmore says.
Between the Wars
Operators must be thoroughly trained in loading and unloading the DUKW. Photo supplied by Jim Gilmore. Courtesy: U.S. Marine Corps
Remembering the Gallipoli campaign, the British created a vessel called the “Motor Landing Craft” and used it for maneuvers as early as 1926. The craft had a flat bow and was deployed at the onset of World War II. Used until late 1940, it was capable of disembarking troops and equipment from the front, and paved the way for other versions of landing craft. The Motor Landing Craft is said to be the first of its kind.
By the late 1930s, the U.S. Navy’s Bureau of Construction and Repair was requested to build a landing craft that would satisfy the need to disembark on a beach quickly. However, the military grew frustrated with the Bureau’s lack of progress, and contracted boat builder Andrew Higgins to design a suitable landing craft. Higgins’ first design had drawbacks in that the boat had to be unloaded over the sides, exposing men to combat fire.
In 1937, the Japanese built a landing craft with a ramp at its bow — and a picture of that craft provided an example for Higgins’ next design. He quickly contacted his designers and had them develop a prototype similar to the Japanese craft.
Testing proved to be successful, and the boat was dubbed Landing Craft Vehicle Personnel (LCVP), or the “Higgins Boat.” The combination wood-steel landing craft was approximately 36 feet long and carried up to 36 infantrymen. The front or bow of the craft was a ramp, allowing for quick disembarking.
One crucial problem would exist with these traditional landing craft, however: Cargo transfers would still put troops in grave danger, as infantry would have to unload cargo on the beach and then load it onto a truck or other form of transportation, sometimes while under attack. This process was laborious, time-consuming and exposed the infantry to aerial attacks.
The Duck debuts
The DUKW proved to be up to the task when transporting cargo and supplies. Photo supplied by Jim Gilmore. Courtesy: U.S. Marine Corps
After the Dec. 7, 1941 attack on Pearl Harbor and the United States’ subsequent entry into World War II, increased emphasis would be placed on amphibious warfare. The DUKW would be one of the most improbable success stories of the war.
The DUKW was the brainchild of yacht designer Rod Stephens Jr., British sailor Dennis Puleston, and ROTC Lieutenant Frank W. Speir, in cooperation with the National Defense Research Committee and the Office of Scientific Research and Development. DUKW is GMC’s nomenclature description. The D indicates the year the vehicle was designed (1942), U stands for Utility, K indicates all-wheel-drive and W indicates two powered rear axles. Looking at the name DUKW, however, soldiers could not help but use the term “Duck.”
The GMC division of General Motors, known as the Yellow Truck and Coach Co. before the war, was chosen to manufacture the first prototype in April 1942. The prototype was constructed around a GMC ACKWX cab over truck.
“Actually, the military approached Ford Motor Co. first, but they declined,” says Gilmore. “They were already heavily involved mass-producing the Jeep and, unlike GMC, did not have a 6x6 vehicle that could be quickly converted.”
A watertight rectangular hull with a curved bow was welded around the truck, with special attention paid to approach and departure angles. The installation of a propeller and rudder system would complete the amphibious transformation. It was 31 feet long, 8-and-a-quarter feet wide, and just under 9 feet tall.
The DUKW cab was equipped with a folding windshield and side extensions. There was room for the driver and co-driver in front on a plywood cab floor. It was powered by a 270-cubic-inch, 94-horsepower straight-6 engine with five forward gears and high-low range. The DUKW was able to reach speeds of 50 mph on land and 5.6 nautical mph at sea. A high-capacity bilge pump kept the vessel afloat in rough water, and it could carry over 2 tons payload or up to 12 troops, depending on equipment. There was no armament, but it was equipped with a mount for a .50-caliber Browning heavy machine gun.
Proving itself
In the Pacific, two DUKWs are used to transport a Lockheed P-38 Lightning nicknamed by German pilots the “Fork Tailed Devil.” Photo supplied by Jim Gilmore. Courtesy: U.S. Marine Corps
The DUKW performed well on land and at sea during testing, but skeptic military officials considered the vehicle a compromise, being neither a good truck nor a good boat. Surely its ungainly looks would not help its cause, either. Stephens still managed to convince the military to allow him to perform a series of sea demonstrations just off the New England coast.
A few days before testing, a Coast Guard patrol craft ran aground in a sandbar just offshore. Strong wind and heavy rain prevented a traditional rescue. The DUKW was deployed and was successful in rescuing the crew, performing where other craft could not. As word spread of the endeavor, opposition began to dissipate. Soon, the DUKW would be touted as “the last word in mechanized equipment.”
Mass production began in June 1942, with all production versions built around GMC’s CCKW “deuce-and-a-half” 2.5-ton 6-wheel-drive truck, which the military had already been using with great success. This ensured that parts were never in short supply.
More than 20,000 DUKWs were built and distributed to the U.S. Marine Corps and Allied forces. Two thousand were supplied to Britain and more than 500 each to Australia and Russia. According to Gilmore, “Even though it was approved for production, the military was slow to utilize the Duck. Once it became popular, though, demand outweighed supply — and there were never really enough Ducks to satisfy the military need.”
Training was crucial
Because the DUKW was land and seaworthy, it required thoroughly trained operators. It was necessary to equally combine the experience of a truck driver, seaman and maintenance man to handle the vehicle. Relying on one experience over the other could lead to operator error and possible disaster.
Lined up like “ducks in a row” at a government storage depot. Photo supplied by Jim Gilmore. Courtesy: U.S. Marine Corps
The U.S. Navy could not supply enough trainers for the DUKW, so the Army Corps of Engineers First Engineer Amphibian Command created special training schools. Because there was no training template, the First Engineer Amphibian Command had to quickly develop a training program from scratch.
Training was conducted in an aquatic park near Fort Mason (known then as the San Francisco Port of Embarkation), and civilian boat companies were recruited to conduct maintenance training at the General Motors Corp. War Products School. Initial training lasted three weeks, but was later expanded to five weeks because of the extensive preparation that was required.
At the beginning of training, the soldiers practiced driving on land to get used to the vehicle’s handling characteristics. Driving in sand was particularly challenging. In sand, lower tire pressure would be necessary for better traction. Once the vehicle was on a harder road surface, higher tire pressure would be needed.
Seamanship was most important, however, and the list of tasks to be implemented before deploying to water was lengthy. Among many other tasks, bilge plugs had to be checked, guards had to be in place and tire inflation adjusted to meet the demands of the landing destination. After all checks are made, the propeller was engaged and the DUKW had to enter the water squarely with the surf and maintain wheel operation until obstacles were cleared.
When maneuvering the vessel in water, special attention had to be paid to the rear, or stern of the DUKW. Contrary to the operation of a truck, where the front of the vehicle turns when steering, operators of the DUKW needed to get used to steering the Duck with a rudder in the stern.
Because of the exposure to saltwater, routine maintenance had to be performed at all recommended intervals. The DUKW’s lubrication points had to be checked daily and all waterproof areas inspected. Trainees were also instructed on cargo loading and offloading safety. Five weeks of extensive driver, navigation, cargo and maintenance training prepared crews to enter battle.
Ford GPA amphibious Jeep in 1943. Photo supplied by Jim Gilmore. Courtesy: U.S. Army
Initially, the DUKW was equipped with a manual tire inflation system. To adjust tire pressure to meet demands, the operator would have to check the specification for the appropriate driving surface, get out of the vehicle with an air hose, and either use the onboard pump to inflate the tires or manually deflate them. This was seen as putting operators in peril and defeating the purpose of having a true amphibious vehicle.
“Later in production, the DUKW was fitted with a central tire inflation system,” Gilmore explains. It was the first of its kind, and consisted of an onboard compressor that fed air to each of the tires through a series of hoses and tubing. This system proved to be invaluable when landing on a beach, Gilmore adds: “Now, the operator could adjust the tire pressure from inside the DUKW according to the driving surface.”
In the unlikely event that it did get stuck, the DUKW was equipped with tools and an onboard winch to help extricate itself from trouble.
Battle stations
The DUKW was involved in both European and Pacific theaters of operation during World War II. It first saw action during the 1943 invasion of Sicily, code named Operation Husky. The Americans and British used approximately 900 DUKWs for the invasions, which contributed to defeating the Axis Powers in Italy. The DUKW delivered most of the cargo to the shore, and its on-road capabilities enabled it to serve as a regular truck, transporting troops and cargo wherever they were needed. British General Sir Harold Alexander wrote later, “It is not too much to say the DUKW revolutionized the problem of beach maintenance.”
A DUKW would also be used to transport as many as 12 wounded troops back to hospital ships. Special wire cables lifted the Duck to the deck of the ship, where the wounded were removed. Supreme Commander Dwight D. Eisenhower credited the DUKW as invaluable in helping to capture Sicily, and was so impressed that he recommended its creator for a citation.
The Seep alongside its Jeep cousin. Photo supplied by Jim Gilmore. Courtesy: U.S. Army
The DUKW would also be used in landings up to and including D-Day, where nearly 2,000 of the amphibious craft were deployed. Because most ports had been destroyed or still held with token resistance, the DUKW was used to unload supplies on and after D-Day. The last time the vehicle was used in Europe was during Operation Plunder in March 1945, when more than 350 DUKWs were used to move soldiers and supplies across the Rhine River in Germany.
The DUKW saw action in virtually every Pacific assault, including Guadalcanal and the attack on Iwo Jima. The thin hull prevented the vehicle from being used in serious, first-wave combat action, so it was mostly relegated to carrying supplies and transporting wounded troops back to hospital ships. The Japanese were convinced that the barrier reefs would protect against a sustained amphibious attack, but the DUKWs were able to drive over barrier reefs and onto islands with ease. Thirteen companies of DUKWs were used in the invasion of the Philippines.
Seep and Super Duck
As the war progressed in Europe, the Allies consistently witnessed bridges being destroyed — and the idea of an amphibious version of the Jeep arose. Once again, yacht designer Rod Stephens was called upon to design such a vehicle.
Still wanting to take advantage of Ford Motor Co.’s mass-production capabilities, the military contracted with Ford to collaborate with Stephens and military vehicle experts Marmon Harrington to build an amphibious vehicle around the GPW Jeep. Called the “Seep,” which stood for Seagoing Jeep, its underpinnings were essentially the same as the DUKW, only smaller. Not surprisingly, it looked just like a miniature version of the Duck. (Editor’s Note: For the full history of the Jeep, see our Drivability story.)
The Seep was said to have limitations. While it proved to be capable when crossing small rivers and streams, it could be overcome in choppy water and was more difficult than a Jeep to maneuver on land. The U.S., however, used the vehicle with some success during the landing in Sicily.
“This was one of those times when expectations outweighed reality. The GPA was expected to have the same seaworthiness as the Duck, along with the same maneuverability as a Jeep on land,” says Gilmore. It may have been impossible to overcome this perception — and fewer than 13,000 were built by the time production was halted in 1943.
The DUKW, however, kept going on. After the war, the United States, Great Britain, France and Australia kept limited numbers of Ducks in service. The U.S. reactivated and deployed several hundred for use in the Korean War, shuttling supplies ashore during the Battle of Pusan Perimeter and later at Inchon.
In 1953, GMC contracted with the military to produce the XM147 DUKW “Super Duck” prototype. Just like the original DUKW, it was amphibious. Based on the post-WWII GMC M135 series truck, it was capable of carrying up to 4 tons of cargo at 50 mph on land and 5.6 nautical mph at sea.
The Super Duck was produced from 1953 to 1957, but because of mechanical problems, it was never really adopted by the military as a suitable replacement for the original DUKW. The vehicle was said to be underpowered and always suffering from problems with its brake system. The Super Duck was replaced by the Lighter Amphibious Resupply Cargo 5-ton capacity (LARC-V), which was used during the Vietnam War.
Lucky Ducks
“Although the DUKW has not been manufactured since 1945, some are still in use today,” says Gilmore. The end of World War II made DUKWs available for civilian and municipal use. Fire departments and the Coast Guard continue to deploy Ducks today in emergency rescue situations, transporting victims of such disasters as Hurricane Katrina. Many Ducks are owned and restored by private collectors and museums.
Starting as early as 1946, the DUKW was used for amphibious tours. The first Duck tour company, Dells Army Ducks, was established in Wisconsin Dells, Wis., and is still in operation today under the name Original Wisconsin Ducks. According to Gilmore, “Many companies feature duck tours using the original World War II-era boats, but they have been completely gutted and restored, with new engines, drivetrains and enhanced safety features.”
Most Ducks, however, have been replaced by modern variations of the DUKW design. These vehicles are termed “purpose-built” for the intended use of providing amphibious sightseeing. To facilitate tours in all seasons, they can be configured with enclosed or open-air passenger compartments. While the new Duck boats bear a striking resemblance to the classic DUKWs, they are modern, with up-to-date amenities.
Duck boats are now tested and certified by the U.S. Coast Guard using “Guidelines for Certification of DUKW Amphibious Vehicles.” These guidelines contain best practices on the inspection and operation of such vehicles, to ensure that they are certified to meet all modern safety standards. Each vehicle must qualify for on-highway passenger, and passenger-use-boat certifications.
Once again, a vehicle produced for a war demand takes on a new responsibility in civilian life. No one could imagine that the DUKW would become what it is today from what it was yesterday. From its multi-faceted military use, to rescuing stranded flood victims, or providing leisurely tours, this misjudged and underappreciated “Ugly Duck” is one of the most uniquely versatile vehicles of our time.
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