 He was transferred to the battleship on 15 June 1939 and was present on the attacking battleship at the Battle of Westerplatte at the beginning of World War II.On 29 April 1940 he was transferred the "U-Boot-Waffe", and on 22 December 1940 he was assigned to , serving under the command of Karl-Friedrich Merten and participating in two missions of the U-boat.On 1 November 1941 he was promoted to "Kapitänleutnant" and assigned to the 24th U-boat Flotilla.