German submarine U-11 was a Type IIB U-boat built before World War II for service in Nazi Germany's Kriegsmarine. She was commissioned on 21 September 1935, with Kapitänleutnant Hans-Rudolf Rösing in command. She served in several training flotillas in her 10-year career, but sank or damaged no ships.
In 1940, U-11 was the first unit to carry out sea trials of a new anechoic tile, which was developed by the Kriegsmarine for reducing a submarines' acoustic signature. This development project was codenamed Alberich after the invisible sorcerer from Germanic mythology.
German Type IIB submarines were enlarged versions of the original Type IIs. U-11 had a displacement of 279t when at the surface and 328t while submerged. Officially, the standard tonnage was 250LT, however. The U-boat had a total length of 42.7m (140.1feet), a pressure hull length of 28.2m (92.5feet), a beam of 4.08m (13.39feet), a height of 8.6m (28.2feet), and a draught of 3.9m (12.8feet). The submarine was powered by two MWM RS 127 S four-stroke, six-cylinder diesel engines of 700PS for cruising, two Siemens-Schuckert PG VV 322/36 double-acting electric motors producing a total of 460PS for use while submerged. She had two shafts and two 0.85abbr=onNaNabbr=on propellers. The boat was capable of operating at depths of up to 80-.
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for 35- at ; when surfaced, she could travel at . U-11 was fitted with three 53.30NaN0 torpedo tubes at the bow, five torpedoes or up to twelve Type A torpedo mines, and a 2cm (01inches) anti-aircraft gun. The boat had a complement of twentyfive.
The U-boat was scuttled on 3 May 1945 in Kiel. The wreck was broken up.