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Mulberry Artificial Harbors - Normandy, WWII

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Necessity of a Deep Water Harbor

Completed Mulberry harbor

Completed Mulberry harbor - WWII Normandy. September 1944. A - breakwater composed of concrete Phoenixes and blockship Gooseberry. B - Spud pier for unloading. C - floating whale roadways. British government photo.

By June of 1943, nearly a year after the disastrous raid on Dieppe by the British, Europe was still firmly in German hands along with all its ports.

Although the failure at Dieppe showed that a port could not be easily captured, a deep port was essential if the Allies were to begin their assault on the French coast.

The calm waters of a harbor were necessary to allow a continuous supply of troops and equipment to a newly opened front which was being planned as Operation Overlord.

Difficulties of a Captured Harbor

*Artificial Harbor code names

Artificial harbor Mulberry
Concrete breakwater unit Phoenix
Blockship breakwater Gooseberry
Individual blockship Corn Cob
Pier head barge Spud pier
Roadway Whale
Roadway pontoon Beetle
* The Mulberry project had code names for the harbor and its components because of the high level of secrecy kept during this time.

The choices available to the Allies for obtaining a harbor included an attempt to capture a port or build their own. The ports at Cherbourg and Le Havre were closest to England but also the most heavily defended.

It was realized that not only heavy losses could be expected, but if the port could be taken, it would not be particularly operational for some time due to damage incurred during the battle.

Sunken ships would need to be cleared out and harbor repairs, or new construction carried out. It was felt that this could take many weeks to accomplish, all while trying to hold the port without a ready means to receive troops and supplies.

Artificial Harbors: Mulberry A and B


Code named Mulberry, a daring plan was put into action. It included two prefabricated harbors, each containing breakwater, piers and roadways all of which would be built in England. These components would then be towed across the English Channel and set up at two locations, following the initial attack on the Germans at Normandy.

The American Mulberry A harbor would be constructed on Omaha Beach, and the British Mulberry B on Gold Beach. Plans and construction prior to D-Day, would be kept in utmost secrecy in order to gain the element of surprise. It was initially estimated that an artificial harbor could support 12,000 tons of supplies and 2,500 vehicles per day once it was in operation.1


1John P. Taylor, The Prefabricated Port of Arromanches — Mulberry B. London: Shipbuilding and Shipping Record, 1945. p.5.