Mulberry harbour the armoured vehicles would be able to operate on the beach or become bogged down. The final survey, Operation Bellpush Charlie, occurred on the night of 30-31 January but limited information was gathered due to fog and because German lookouts heard the craft. Further sorties were abandoned. On the afternoon of 6 June 1944 (D-Day) over 400 towed component parts (weighing approximately 1.5 million tons) set sail to create the two Mulberry harbours. It included all the blockships (codenamed Corncobs) to create the outer breakwater (Gooseberries) and 146 concrete caissons (Phoenixes). At Arromanches, the first Phoenix was sunk at dawn
Mulberry harbour Dundas & Whitson, Mowlem, Nuttall, Parkinson, Pauling & Co. and Taylor Woodrow. On completion they were towed across the English Channel by tugs to the Normandy coast at only 4.3 Knots (8 km/h or 5 mph), assembled, operated and maintained by the Corps of Royal Engineers, under the guidance of Reginald D. Gwyther, who was appointed CBE for his efforts. Both locations for the temporary harbours required detailed information concerning geology, hydrography and sea conditions. To collect this data a special team of hydrographers was created in October 1943. The 712th Survey Flotilla, operated from naval base HMS "Tormentor" in