German submarine U-870
|Ordered:||25 August 1941|
|Builder:||DeSchiMAG AG Weser, Bremen|
|Laid down:||29 April 1943|
|Launched:||29 October 1943|
|Commissioned:||3 February 1944|
|Fate:||Sunk on 30 March 1945|
|Class and type:||Type IXC/40 submarine|
|Height:||9.60 m (31 ft 6 in)|
|Draught:||4.67 m (15 ft 4 in)|
|Test depth:||230 m (750 ft)|
|Complement:||4 officers, 44 enlisted|
German submarine U-870 was a Type IXC/40 U-boat of Nazi Germany's Kriegsmarine built for service during the Second World War. She was ordered on 25 August 1941, and laid down on 29 April 1943 at Bremen, Germany. She was launched on 29 October 1943 and commissioned on 3 February 1944.
German Type IXC/40 submarines were slightly larger than the original Type IXCs. U-870 had a displacement of 1,144 tonnes (1,126 long tons) when at the surface and 1,257 tonnes (1,237 long tons) while submerged. The U-boat had a total length of 76.76 m (251 ft 10 in), a pressure hull length of 58.75 m (192 ft 9 in), a beam of 6.86 m (22 ft 6 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.67 m (15 ft 4 in). The submarine was powered by two MAN M 9 V 40/46 supercharged four-stroke, nine-cylinder diesel engines producing a total of 4,400 metric horsepower (3,240 kW; 4,340 shp) for use while surfaced, two Siemens-Schuckert 2 GU 345/34 double-acting electric motors producing a total of 1,000 shaft horsepower (1,010 PS; 750 kW) for use while submerged. She had two shafts and two 1.92 m (6 ft) propellers. The boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 18.3 knots (33.9 km/h; 21.1 mph) and a maximum submerged speed of 7.3 knots (13.5 km/h; 8.4 mph). When submerged, the boat could operate for 63 nautical miles (117 km; 72 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 13,850 nautical miles (25,650 km; 15,940 mi) at 10 knots (19 km/h; 12 mph). U-870 was fitted with six 53.3 cm (21 in) torpedo tubes (four fitted at the bow and two at the stern), 22 torpedoes, one 10.5 cm (4.13 in) SK C/32 naval gun, 180 rounds, and a 3.7 cm (1.5 in) as well as a 2 cm (0.79 in) anti-aircraft gun. The boat had a complement of forty-eight.
Over her career she claimed two warships sunk, total tonnage 1,960 tons, one warship damaged for a total tonnage 1,400 tons, and two ships a total loss, total tonnage 11,844 gross register tons (GRT). On 20 December 1944, U-870 attacked a small group of landing ships, damaging USS Fogg and sinking the 1,625 ton vessel USS LST-359. The U-boat was then attacked by a British aircraft from No. 220 Squadron RAF but got away, also evading two hunter-killer groups of vessels.
She was sunk on 30 March 1945 at Bremen by US bombs.
Summary of raiding history
|Date||Name of Ship||Nationality||Tonnage[Note 1]||Fate|
|20 December 1944||USS Fogg||United States Navy||1,400||Damaged at|
|20 December 1944||USS LST-359||United States Navy||1,188||Sunk at|
|3 January 1945||Henry Miller||United States||7,207||Sunk at|
|9 January 1945||FFL L´Enjoue||Free French Naval Forces||335||Sunk at|
|10 January 1945||Blackheath||United Kingdom||4,637||Sunk at|
- Busch, Rainer; Röll, Hans-Joachim (1999). Deutsche U-Boot-Verluste von September 1939 bis Mai 1945. Der U-Boot-Krieg (in German). IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
- Helgason, Guðmundur. "The Type IXC/40 boat U-870". German U-boats of WWII - uboat.net. Retrieved 2 February 2015.