Hans Heidtmann (8 August 1914 – 5 April 1976) was a German U-boat commander in World War II and recipient of the Knight's Cross of the Iron Cross of Nazi Germany U-559 under the command of Heidtmann came under attack by several British warships and an aircraft on 30 October 1942. Fatally damaged and forced to the surface, the U-boat was abandoned after scuttling herself in the Mediterranean. A British boarding party, consisting of Lieutenant Francis Anthony Blair Fasson, Able Seaman Colin Grazier, and Canteen Assistant Tommy Brown, from destroyer HMS Petard recovered the cryptographic materials, but the U-boat sank before the Enigma cipher machine could be brought out. Eight German crewmen and two British seamen were lost, and 37 German survivors were taken prisoner of war.