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Mulberry Harbor Spud Piers & Whales

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Mulberry Spud Piers


Hospital ship berthed at Spud pierhead. WWII, Normandy.
Hospital ship berthed at Spud pierhead. WWII, Normandy.

Once the Phoenix breakwater and blockship Gooseberry were in place, calm harbor water was available for vessels with cargo. To accommodate this traffic, Lobnitz spud pierheads were put in place and "whale" roadways built to connect the piers to shore.

Each spud pier was a floating barge 200 feet long and 60 feet wide, which could slide up and down on four adjustable posts (spuds) which went through the steel hull and anchored in the harbor bottom. These sixty foot spuds enabled the piers to rise and fall with the twenty-four foot tide, keeping the pier surface level and steady. The pier height could be adjusted for optimum cargo discharge. Royal Navy photo above shows a spud pier to which a small ship is moored waiting to evacuate wounded.


Whale roadway connecting Spud pier to beach in Mulberry artificial harbor.
Whale roadway connecting Spud pier to beach in Mulberry artificial harbor.


It is difficult to grasp the size of a spud pier from the photos, but these self-contained units housed generators, diesel electric winches, a maintenance shop, galley and mess rooms, as well as living quarters, for the men who operated the pier.1 All of this was below deck so is not seen in the photos. The whale roadway can be seen leading from the spud piers in the distance in the U.S. Navy photograph to the right.

Medium sized cargo ships and hospital ships were able to berth and unload at the spud piers where the cargo could be quickly taken to shore over a floating roadway, code named whale. The Whale roadway can be seen in the photo above, leading to the spud pier in the distance. Note the spuds rising above the pier to enable it to rise and fall with the tide.


Whale Roadways (causeways) & Beetle Pontoons


Concrete Beetle pontoon for Whale roadway in Mulberry harbor
Beetle pontoon for Whale roadway in Mulberry harbor.

The steel whale roadways were up to 3,500 feet long and floated on pontoons (code named Beetle) made of steel or concrete which were kept in place by kite anchors. Photo to the right shows a pontoon being launched into the water. Note men standing on top for size reference. Flexible and similar to bridge construction, three Whale causeways were built to bridge the gap from the spud piers to shore, with one whale being strong enough to accommodate heavy armor and tanks over 40 tons.


The construction of the piers and whale roadways was done under war conditions, and the American Mulberry A in particular, was within the range of German snipers.



Notes:

1John P. Taylor, The Prefabricated Port of Arromanches — Mulberry B. London: Shipbuilding and Shipping Record, 1945. p.8.


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