Convoy OB 318

OB 318 was a North Atlantic convoy which ran during the Battle of the Atlantic in World War II. During Operation Primrose Royal Navy convoy escorts , Broadway and captured with an intact Enigma machine and a wealth of signals intelligence, which led to the Allied breakthrough into cracking the German naval Enigma code. By the spring of 1941 the battle of the Atlantic was starting to have an increase in German U-boat losses. This forced Vizeadmiral Karl Dönitz to change his strategy and he now moved his wolf packs further west, in order to catch the convoys without their anti-submarine escort. OB 318 was a west-bound convoy of 38 ships, either in ballast or carrying trade goods, and sailed from Liverpool on 2 May 1941 bound for ports in North America. The convoy commodore was R.Adm. WB MacKenzie in SS Colonial. It was escorted by 7 EG, an escort group led by (Cdr. Bockett-Pugh) and comprising ten warships; these were joined in mid-ocean by 3 EG, a force of eight warships led by HMS Bulldog (Cdr J Baker-Cresswell). Opposing them was a force of nineteen U-boats, though in the event only six were in a position to pose a threat. One of those was U-110 under the command of Kapitänleutnant Fritz-Julius Lemp. Lemp notoriously had been in command of in 1939, which had controversially sunk the 13,581-ton passenger ship . OB 318 was sighted on 7 May 1941 by , which reported its position and commenced shadowing while U-boat Command (BdU) alerted other U-boats in the area. There were six U-boats within striking distance, and these were ordered to close with U-94s position. Meanwhile, during 7 May the escort force was joined by five ships from Iceland and the destroyers of 3 EG, which were to take over escort duties from the Western Approaches to a dispersal point at 34 West, a location south of Greenland. Three ships and the destroyers of 7 EG left for Iceland during 7 May, leaving the escort force still at ten warships. At nightfall on 7 May U-94 attacked the convoy, sinking two ships.