HMNB Portsmouth the military and naval units destined for Sword Beach on the Normandy coast as a part of Operation Overlord and the D-Day landings on 6 June 1944. Troops destined for each of the landing beaches left from Portsmouth aboard vessels such as the armed merchant cruisers HMCS "Prince Henry" and HMCS "Prince David", escorted by the Canadian destroyers HMCS "Algonquin" and "Sioux". The majority of the naval support for the operation left from Portsmouth, including the Mulberry Harbours. Boathouse 4 (built around the start of hostilities) contributed to the construction of landing craft and support vessels as well as more
British logistics in the Normandy Campaign the purpose. During the first seven weeks after the British and Canadian landings in Normandy on D-Day, 6 June 1944, the advance was much slower than anticipated, and the lodgement area much smaller. The short lines of communication provided an opportunity to build up reserves of supplies. Two army roadheads were created, No. 1 Army Roadhead for I Corps and No. 2 Army Roadhead for XXX Corps. When the Canadian First Army assumed control of the British I Corps on 21 June, No. 1 Army Roadhead also passed to its control. No. 2 Army Roadhead formed the nucleus of what