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
D-Day naval deceptions the western flank of the true invasion fleet. This operation was intended to lend confusion as to the extent of the landings in Normandy. Glimmer and Taxable were very similar operations. They were executed in the early hours of 6 June 1944 whilst the invasion fleet was approaching Normandy. Taxable simulated an invasion force approaching Cap d'Antifer and Glimmer threatened Pas-de-Calais. By dropping chaff in progressive patterns, Royal Air Force (RAF) bombers were able to create the illusion of a large fleet on coastal radar screens. Beneath the chaff, small boats towed radar reflector balloons and simulated the radio traffic