 On 4 February 1941, while at Lorient docks, "U-43" was sunk after a valve was accidentally left open, putting the U-boat out of action for the next three months.After this enforced absence "U-43" began her next patrol on 11 May 1941, still under the command of Wolfgang Lüth, who had been promoted to "Kapitänleutnant" on 1 January.Once again she sailed out into the mid-Atlantic, where she sank three ships.