German submarine U-863

German submarine U-863 was a long-range Type IXD2 U-boat built for Nazi Germany's Kriegsmarine during World War II.

She was ordered on 5 June 1941, and was laid down on 15 September 1942 at DeSchiMAG AG Weser, Bremen, as yard number 1069. She was launched on 29 June 1943 and commissioned under the command of Kapitänleutnant Dietrich von der Esch on 3 November 1943.

Design
German Type IXD2 submarines were considerably larger than the original Type IXs. U-863 had a displacement of 1610 t when at the surface and 1799 t while submerged. The U-boat had a total length of 87.58 m, a pressure hull length of 68.50 m, a beam of 7.50 m, a height of 10.20 m, and a draught of 5.35 m. The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines plus two MWM RS34.5S six-cylinder four-stroke diesel engines for cruising, producing a total of 9000 PS for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1000 shp for use while submerged. She had two shafts and two 1.85 m propellers. The boat was capable of operating at depths of up to 200 m.

The submarine had a maximum surface speed of 20.8 kn and a maximum submerged speed of 6.9 kn. When submerged, the boat could operate for 121 nmi at 2 kn; when surfaced, she could travel 12750 nmi at 10 kn. U-863 was fitted with six 53.3 cm torpedo tubes (four fitted at the bow and two at the stern), 24 torpedoes, one 10.5 cm SK C/32 naval gun, 150 rounds, and a 3.7 cm Flak M42 with 2575 rounds as well as two 2 cm C/30 anti-aircraft guns with 8100 rounds. The boat had a complement of fifty-five.

Service history
On 20 July 1944, U-863 was attacked with 6pdr (57mm) cannon fire and depth charges from a TseTse flown by Norwegian pilot Rolf Leithe, flying for RAF 333 Squadron. U-863 was forced back to base to repair the minor damage suffered in the attack.

On 29 September; U-863 was sunk by depth charges east southeast of Recife, by two US Navy PB4Y-1 Liberator bomber from VB-107. All 69 of her crew were lost.

The wreck lies at -10.75°N, -25.5°W.