German submarine U-857 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine built for service during the Second World War. She was ordered on 5 June 1941, laid down on 16 November 1942, and launched on 25 May 1943. For her operational lifespan, she was commanded by Kapitänleutnant Rudolf Premauer and had a crew complement of 59.
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-857 had a displacement of 1144t when at the surface and 1257t while submerged. The U-boat had a total length of 76.76m (251.84feet), a pressure hull length of 58.75m (192.75feet), a beam of 6.86m (22.51feet), a height of 9.6m (31.5feet), and a draught of 4.67m (15.32feet). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4400PS for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1000shp for use while submerged. She had two shafts and two 1.92abbr=onNaNabbr=on 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-857 was fitted with six 53.30NaN0 torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.52NaN2 SK C/32 naval gun, 180 rounds, and a 3.7cm (01.5inches) Flak M42 as well as two twin 2sp=usNaNsp=us C/30 anti-aircraft guns. The boat had a complement of forty-eight.
She undertook three patrols, the first was for training. She sank two ships for a total tonnage of, and damaged one other ship on her last two patrols.[1] She sank on 14 April 1945, on 18 April 1945 and damaged on 23 April 1945.
U-857 went missing since 30 April 1945 in the North Atlantic Ocean off the east coast of the United States. All hands were lost, and no wreckage was found.
The U-boat had been claimed to have been sunk by depth charge hedgehogs off the coast of Massachusetts on 7 April 1945 by and was also thought to have been possibly sunk by .[2] However more recent commentary surmised that Gustafson had not hit her, and her loss is currently unexplained.[3] [4] U-857 was considered as a possible identity for the wreck that was ultimately determined to be U-869.[5]
| Date | Ship Name | Nationality | Tonnage (GRT) | Fate[6] | |
|---|---|---|---|---|---|
| 14 April 1945 | Belgian Airman |  Belgium | 6,959 | Sunk | |
| 18 April 1945 | Swiftscout |  United States | 8,300 | Sunk | |
| 23 April 1945 | Katy |  Norway | 6,825 | Damaged |