GMC DUKW 353 – 1942

The DUKW was built by Yellow Truck & Coach Manufacturing Co. rebaptisé GMC Truck & Coach Division fin 1943

According to the GMC nomenclature of 1939, his name breaks down as such :

D (initial conception year) = 1942
The (vehicle configuration) = amphibian
K = front axle drive
W = rear axle drive (combination of KW = Model 6×6)

It's a truck 6×6 fitted with an integral welded steel shell, of a marine propeller with a bilge pump and a rudder. The rudder is linked to the steering column, he steers the vehicle in the water when the steering wheel is turned.

It’s not a 6×6 simple because the motor also drives the water propeller and the rear winch. There are also clutch levers for these 2 amenities, in addition to the classic levers.

Very quickly, he took the nickname of duck (duck).
The first test took place on 3 June 1942 in Milford Michigan.
The initial order has been placed for 2.000 vehicles. A total of 21.147 DUKW were built until the end of production in August 1945.
More than 500 changes have been made during his lifetime, of august 1942 to august 1945.

This machine can transport a large amount of various equipment (until 5.000 pounds normally, more 10.000 books in ideal conditions) or 25 soldiers equipped.

On the latest models, a tire pump runs continuously when the engine is running and regulates the pressure of the tires. 6 wheels

Length : 9,45 m
Width : 2,50 m
Height : 2,70 m
Ground clearance : 0,30 m
Unloaded weight : 6.560 kg
gross weight : 9.450 kg
Maximum speed in water : 10 km/h
Maximum road speed : 70 km/h
Maximum autonomy in water : 80 km
Maximum autonomy on land : 385 km
Optional arming : a Browning machine gun from 12,7 mm, There are also versions with rocket launchers
Transport : 25 soldiers equipped or able to embark until 2.500 kg of material
Engine : GMC 270 to 6 cylinders, 4.417 cm3 91,5 horses 2.750 tr/min

Dukw on the Seine in France

Widely used in amphibious exercises, and especially during the Normandy Landings, its maneuverability allows the DUKW to shuttle between transport ships and the beach or even cross rivers.

Personal photo, DUKW in a military depot near Paris (above) and in Reims (below)

Used during the Korean War, les GMC DUKW 353 were greatly appreciated by American soldiers. The DUKW remained in service until the years 1960.

DUKW supplies to an oil tanker

There have been several attempts to replace DUKWs, especially :

In 1950, A DUKW was equipped with hydrofoils to become the “Flying Duck”
Le GM XM147 Super Duck
Le GM XM148 Gull
Lle GM XM157 Drake

The Flying Duck with hydrofoils

When are the Marines most vulnerable ? At the speed of only 5 nodes (9,26 km / h) on the water in a DUKW ...
In 1956, Colonel Frank Speir of the specialized design office proposed to remove the duck from the water. "Lift it on the hydrofoils by considerably increasing the speed". One 1957, the Flying Duck was built.

The two front wings (L-shaped, with a span of 2,74 meters each) and the inverted T-shaped rear wing (swing 3,65 meters, swivel, with a screw) could fall back. And full, the main thing was to know when to fold the wings so that they did not touch the bottom.

Of course, with a native engine of 91,5 ch it was not possible to do much ... So in the hold, they installed a helicopter engine, the powerfull Lycoming T-53 from 860 ch.

A priori foil tests had been done on a boat equivalent in size and weight

This is Miami Shipbuilding Corp. who built the Flying Duck with hydrofoils and according to different sources, the craft went to more than 30 nodes, between 60 km / h and 96,5 km/h. The success was immediate, in a few minutes the DUKW could get out of dangerous situations quickly.

But why was it abandoned so quickly ? The answer is simple, there was no more room in the experimental machine for the payload. The gas turbine took up too much space and the liftable hydrofoil systems too.

Le XM147 DUKW Super Duck

It is an amphibious army vehicle built over a period of two years and tested at Aberdeen Proving Ground from 1956 to 1957. The army needed a vehicle that behaved like a boat in the water and a truck on land. In 1953, the prototype with a motor 145 ch has been tested. He could carry 4 tonnes of freight at a speed of 80 km / h on a road and 12 km / h on water. The cabin was made entirely of metal with sliding side windows and tires 15,50 x 20.

Super DUKW had brake problems, engine steering and cooling. The hull shape posed speed problems in the water. It was manufactured by General Motors and was in service with 1953 to 1980.

This unique vehicle is still on display at the 45th Infantry Division Museum in Oklahoma City.

Le XM148 Gold

At the end of the First World War, JJ company. Brill built the XM148 Gull prototype, 6×6 military amphibian 5 tonnes, whose main feature was a rounded fiberglass body. He used a Hall-Scott gasoline engine from 250 ch, a manual gearbox 5 vitesses Spicer, a Wisconsin transfer box to 2 gears and two propellers with a diameter of 83 cm. The speed on earth was 96 km/h et 13 km / h in water.

Sadly, despite a number of innovative solutions with increased engine power and other innovations, this amphibious with a carrying capacity of 4,53 tonnes was made of very bad plastic which made it very vulnerable and difficult to repair. In addition, despite its greater power it did not match the DUKW and consumed too much gasoline.

Tests also revealed a far too fragile front axle. Despite a slightly improved second version, the XM148E1, the American army did not follow up on the prototype, and Brill then filed for bankruptcy that same year.

Le XM157 Drake

During studies for a new SUPER-DUKW amphibian, designed to replace the good old DUKW, an interesting problem arose, out of the water, on landing, the load distribution was such that the front wheels sank or even instantly entered loose soil. The proposal to install two axes at the front to reduce the load on the train made sense.

Gradually, during construction, a completely different machine began to appear on the GMC designers' drawing board. The large transporter had already received two engines from 145 ch, and not to get into the synchronization of 2 engines, it was decided to distribute them along the axes. In one way, a motor rotated the first and third axle, the other rotates the second and fourth axle. At the same time, each engine had its own automatic transmission, a two-speed transfer box and a two-speed junction box through which rotated two rotary propellers (standing up as they moved ashore) .

The suspension was also interesting, instead of traditional elastic elements, the wheels were suspended from “cushions” inflatable, which changed the pressure, which allowed to modify the ground clearance and to slightly pull the wheels in the hull in the water, thus reducing resistance to movement.

The length of the amphibian was 12,8 m, the width 3,05 m, the height in the cabin 3,3 m. With a maximum mass slightly greater than 22 tonnes, the XM-157 Drake can carry up to 8 tonnes of freight at a speed of 70 km / h by land and at 14,5 km / h by water. For a distance of 700 km (by land). Such an operation required burning 636 liters of petrol, distributed in four tanks.

And now, let's go to the reason why the thing was not produced. Two motors, two automatic gearboxes, twice the maintenance and difficult adjustments and a “bonus” yawing when driving in water (logic, since the motors are not mechanically connected, the synchronization of the propeller rotations is unreal), twice the cost, an overpriced machine, even if it was successful.

Comparison with DUKW on the left, the Super Duck in the middle and the Drake on the right

And today, what about amphibious landing craft ?

Fast amphibious landing craft (EDA-R)
Landing Craft Amphibious Catamaran (LCAT)

Missions :

• Rapid transport and disembarkation of troops and vehicles
• Logistics routing
• Humanitarian operations : assistance to civilian populations and evacuations of nationals

Major assets :

• Innovative concept with shape transformation : catamaran in transit, flat bottom on approach from the coast
• Great maneuverability : 180° in 40 seconds, lateral displacement
• Landing on the beach and on the quay
• Simplified loading and unloading : front and rear doors (RoRo)
• Interoperability according to NATO standards Deployments : Gulf of Guinea, Eastern Mediterranean, Indian Ocean, Atlantic Ocean

The official document : Technical sheet + EDAR

DUKW tourist

Several DUKWs are still in good condition and are used for sightseeing tours in the cities of London., Boston, Philadelphia, Pittsburgh, Baltimore, Wisconsin Dells, Seattle, San Francisco, Santa Barbara, Halifax, Liverpool, Dublin, Rotorua in New Zealand, Koksijde and Blankenberge in Belgium and Kobe.

A pair of DUKW “civilized” serve as ferries and tourist attractions in the Channel Island of Jersey by providing access at any time of tide to Elizabeth Castle, located on a rocky island in the harbor of Saint-Hélier.

More anecdotal has been the use of DUKWs for oyster and mussel farming on the foreshore of the west coast of Cotentin in the years 60 and 70 which was quickly replaced by the use of reformed agricultural tractors, less fuel hungry, more reliable and above all less problematic to repair (disappearance of spare parts).

Other articles on DUKW tourism will be added to this one on SixMania

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I let you watch, but it is not that bad !

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I still have some pictures and plans of the DUKWs

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The LEGO version La version G.I. Joe

And then the real

For enthusiasts, access the DUKW TECHNICAL DOC here !

And finally some videos