With the complex of floating breakwaters, the sunken block ships and concrete Phoenix units made up most of it. This view of the great floating dry dock at Portsmouth, England, shows the underwater shape of the Phoenix units which were towed slowly at three to four knots across the English Channel.
The "Mulberry" artificial harbor was invented in England and its units were built in Scotland and England. The "Mulberry" was designed to provide a harbor on a coast which had no such natural features. This was critical to the continued arrival and unloading of military supplies and reinforcements from England following the establishment of the D-Day beachhead. Mulberry ‘B’ was the British harbor, while Mulberry ‘A’ served the American landing beaches. British Royal Engineers and U.S. Navy Seabees had the tough assignment of assembling the breakwater and piers on the Normandy side of the British Channel. The whole project was considered to be one of the boldest flights of imagination in history. Note the little window of the crew’s quarters for the trans-channel cruise.