German_submarine_U-7_(1935)--Karl_Doenitz

German submarine U-7 was a Type IIB U-boat of Nazi Germany's Kriegsmarine, based out of Kiel during World War II. It was one of the smaller versions, and was first launched on 29 June 1935 with a crew of 29. Its first commander was Kurt Freiwald. U-7 would have 16 commanders over the course of its service, the last being Günther Loeschcke.
During the war U-7 was responsible for sinking two vessels.
On 18 February 1944, west of Pillau, U-7 sank in what is believed to have been a malfunction during a diving manoeuvre. There were no survivors.