Empire ship the Normandy invasion depended on the successful construction of the Mulberry ports. These were prefabricated ports, constructed at Southampton, Gosport, Portsmouth, Tilbury Docks, and even as far north as Birkenhead and Hartlepool. Two hundred tugs then took three months to tow the components of the harbours from where they were constructed to assembly areas on the South Coast. Between 7 June 1944 and the end of July, the tugs towed the materials across the channel to Normandy. Before D-Day, sixty old merchant ships and four old warships were selected as blockships, to be scuttled in a line to give protection
Erwin Rommel at Calais. Although Hitler himself expected a Normandy invasion for a while, Rommel and most Army commanders in France believed there would be two invasions, with the main invasion coming at the Pas-de-Calais. Rommel drove defensive preparations all along the coast of Northern France, particularly concentrating fortification building in the River Somme estuary. By D-Day on 6 June 1944 nearly all the German staff officers, including Hitler's staff, believed that Pas-de-Calais was going to be the main invasion site, and continued to believe so even after the landings in Normandy had occurred. The 5 June storm in the channel seemed