A successful Allied invasion of mainland Europe relied on a way of rapidly moving vast numbers of troops and supplies ashore for success. Capturing and defending a sizeable French port was seemingly out of the question following the abject failure of the 1942 Dieppe raid, thus the Mulberry harbour concept was born. The two Mulberry harbours comprised a number of different elements aimed at making the Normandy coastline suitable for large scale logistical operations. Furthest out, large chains of floating metal bombardons helped break up waves. Closer to the shore the main breakwaters consisted of lines of sunken ships, known as Gooseberries, and large concrete caisons, known as Phoenixes, which were towed over the Channel and then sunk awaiting D-Day when they would be re-floated. Mulberry A at Omaha beach was irreparably damaged during a storm shortly after construction, so its parts were transferred and used to reinforce Mulberry B.
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