Ship caption=U-9, a typical Type IIB boat }} German submarine U-23 was a Type IIB U-boat of Nazi Germany's Kriegsmarine, built in Germaniawerft, Kiel. She was laid down on 11 April 1936 and commissioned on 24 September. Design German Type IIB submarines were enlarged versions of the original Type IIs. U-23 had a displacement of when at the surface and while submerged. Officially, the standard tonnage was , however. The U-boat had a total length of , a pressure hull length of , a beam of , a he…