 The boat had a complement of between forty-four and sixty.Despite carrying out 13 war patrols between July 1943 and April 1945, "U-307" sank only two vessels; the 7,176-ton American Liberty ship on 30 April 1944, fifty miles south of Bear Island, and the 50-ton Norwegian Army motor boat "Lennox" in Van Mijenfjorden, Spitsbergen, on 18 August 1944.In September 1944, together with the supply ship "Carl J. Busch", "U-307" transported the men of Operation Haudegen, a German military meteorological mission, to Svalbard.