German submarine U-805 was a Type IXC/40 U-boat built for Nazi Germany's Kriegsmarine during World War II.
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-805 had a displacement of when at the surface and while submerged. The U-boat had a total length of , a pressure hull length of , a beam of , a height of , and a draught of . The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The boat was capable of operating at depths of up to .
The submarine had a maximum surface speed of and a maximum submerged speed of . When submerged, the boat could operate for at ; when surfaced, she could travel at . U-805 was fitted with six torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one SK C/32 naval gun, 180 rounds, and a Flak M42 as well as two twin C/30 anti-aircraft guns. The boat had a complement of forty-eight.
U-805 was ordered on 10 April 1941 from DeSchiMAG Seebeckwerft in Geestemünde under the yard number 363. Her keel was laid down on 24 December 1942, and the U-boat was launched the following year sometime in October 1943. On 12 February 1944 she was commissioned into service under the command of Kapitänleutnant Richard Bernardelli (Crew 32) in the 4th U-boat Flotilla. She spent the next year as a training boat with the flotilla, then was transferred to the 33rd U-boat Flotilla and deployed on her one and only war patrol in March 1945. At the end of the war U-805 was operating in the West Atlantic as part of the Seewolf group, when she received orders to make for an Allied port in order to surrender. The U-boat reached Portsmouth, New Hampshire on 15 May 1945, where the crew surrendered and handed the boat over to the US Navy.
The US Navy took U-805 on several Victory Visits to ports on the east coast of the United States before sinking her off the coast in position on 4 February 1946.