Befehlshaber der U-Boote

The Befehlshaber der Unterseeboote or BdU (Eng: "Commander of the U-boats") was the supreme commander of the German Navy's U-boat Arm (Ubootwaffe) during the First and Second World Wars. The term also referred to the Command HQ of the U-boat arm.

The title was established in June 1917, replacing the role of "Leader of the U-boats" (Führer der Unterseeboote, or FdU) for the High Seas Flotillas. The first incumbent was Kapitan zur See/Kommodore Andreas Michelsen, previously head of the High Seas Fleet’s destroyer force. The post was abolished with the end of the war.

It was revived on 17 October 1939, when Karl Dönitz was promoted to rear admiral (Konteradmiral). His previous title had been FdU, a position he had held from January 1936.

On 31 January 1943 Dönitz was promoted to grand admiral (Großadmiral) and became supreme commander (Oberbefehlshaber der Kriegsmarine) of the entire Kriegsmarine, replacing Erich Raeder. He retained the title, but was replaced as operational commander at BdU by his chief of staff Eberhard Godt.

Godt's successor was Admiral Hans Georg von Friedeburg, who held the position at the end of the war and became commander-in-chief of the German navy when Dönitz became head of Nazi Germany after Hitler's suicide.