When she was completed, the submarine was 67.10 metres (220 ft 2 in) long, with a beam of 6.18 metres (20 ft 3 in), a height of 9.60 metres (31 ft 6 in) and a draft of 4.74 metres (15 ft 7 in). She was assessed at 864.7 t (851 long tons) submerged. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder superchargeddiesel engines producing a total of 2,800 to 3,200 metric horsepower (2,060 to 2,350 kW; 2,760 to 3,160 shp) for use while surfaced and two BBC GG UB 720/8 double-acting electric motors producing a total of 750 metric horsepower (550 kW; 740 shp) for use while submerged. She had two shafts and two 1.23 m (4 ft) propellers. The submarine was capable of operating at depths of up to 230 metres (750 ft), had a maximum surface speed of 17.6 knots (32.6 km/h; 20.3 mph) and a maximum submerged speed of 7.5 knots (13.9 km/h; 8.6 mph).When submerged, the U-boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph) and when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph).[1]
U-991 was used as a Training ship in the 5th U-boat Flotilla from 29 July 1943 until 31 August 1944 before serving in the 11th U-boat Flotilla for active service on 1 September 1944.[2]
Training and tests
During U-991's service as a training ship, she completed a number of trainings and tests for the Kriegsmarine.[3]
During her active service, U-991 made 1 patrol and left Kristiansand on 15 October 1944. Her patrol lasted 73 days and U-991 patrolled the North Atlantic from Norway, around the United Kingdom and Ireland and also to France before returning to Bergen. She arrived in Bergen on 26 December 1944, which marked the end of her first and only patrol during World War II.[2][3]
In total, the U-991 spend 98 days at sea during her active service until 9 May 1945.[3]
Capture And End
U-991 surrendered on 9 May 1945 at Bergen, Norway to the Allied Forces. The submarine was transferred from Bergen to Scapa Flow on 2 June 1945 and from Scapa Flow to Loch Ryan on 5 June 1945. She stayed in Loch Ryan for her immersion in Operation Deadlight (post-war Allied operation) until 11 December 1945, when she was towed to sea by the British Navy tug HMS Freedom (W.139).[3]
^ abc"U-991 (+1945)". wrecksite.eu. 29 November 2009. Retrieved 7 April 2016.
^ abcdHelgason, Guðmundur (1995). "U-991". German U-boats of WWII - uboat.net. Retrieved 7 April 2016.
^ abcdHofmann, Markus (23 December 2013). "U-991". Deutsche U-Boote 1935-1945 - u-boot-archiv.de (in German). Retrieved 7 April 2016.
Bibliography
Busch, Rainer; Röll, Hans-Joachim (1999). German U-boat commanders of World War II : a biographical dictionary. Translated by Brooks, Geoffrey. London, Annapolis, Md: Greenhill Books, Naval Institute Press. ISBN1-55750-186-6.
Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN0-85177-593-4.