German submarine U-1171 was a Type VIIC/41 U-boat of Nazi Germany's Kriegsmarine during World War II.
She was ordered on 16 July 1942, and was laid down on 5 May 1943, at Danziger Werft AG, Danzig, as yard number 143. She was launched on 23 November 1943, and commissioned under the command of Oberleutnant zur See Otto Heinrich Nachtigall on 22 March 1944.
German Type VIIC/41 submarines were preceded by the heavier Type VIIC submarines. U-1171 had a displacement of when at the surface and while submerged. She had a total length of , a pressure hull length of , an overall beam of , a height of , and a draught of . The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced, two SSW GU 343/38-8 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-1171 was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes or 26 TMA or TMB Naval mines, one SK C/35 naval gun, (220 rounds), one Flak M42 and two C/30 anti-aircraft guns. The boat had a complement of between forty-four and fifty-two.
On 9 May 1945, U-1171 surrendered at Stavanger, Norway, before participating in any war patrols. She was later transferred to Lisahally on 27 May 1945. U-1171 would be spared, for a time, becoming a British N-class submarine, N19, used for testing and then in April 1949, broken up at Sunderland.