German submarine U-991 was a Type VIIC U-boat of Nazi Germany's Kriegsmarine during World War II.
Construction The U-991 was laid down on 30 October 1942 at the Blohm & Voss yard in Hamburg, Germany. She was launched on 24 June 1943 and commissioned on 29 July 1943 under the command of Oberleutnant zur See Diethelm Balke. Her U-boat emblem was a diving eagle.
When she was completed, the submarine was long, with a beam of , a height of and a draft of . She was assessed at submerged. The submarine was powered by two Germaniawerft F46 four-stroke, six-cylinder supercharged diesel engines producing a total of for use while surfaced and two BBC GG UB 720/8 double-acting electric motors producing a total of for use while submerged. She had two shafts and two propellers. The submarine was capable of operating at depths of up to , had a maximum surface speed of and a maximum submerged speed of .When submerged, the U-boat could operate for at and when surfaced, she could travel at .
The submarine was fitted with five torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one deck gun (220 rounds) and a Flak M42 anti-aircraft gun. The boat had a complement of 44 to 57 men.
Service history 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.
Training and tests During U-991'''s service as a training ship, she completed a number of trainings and tests for the Kriegsmarine.
Date Place Activity 30 July – 19 August 1943 Keel Trials at UAK 20 August 1943 Sonderborg Auscultation at UAK 22 – 26 August 1943 Swinemünde Flakausbildung at Flakschule 27 – 29 August 1943 Danzig Trials at UAK 30 August – 4 September 1943 Hela Front training at AGRU-Front 5 September 1943 – 5 February 1944 Flensburg School boat 9 February – 11 May 1944 Hela Front training at AGRU-Front 12 – 23 May 1944 Pillau Torpedo shooting at the 26th U-boat Flotilla 24 May – 4 June 1944 Gotenhafen Tactical Training at the 27th U-boat Flotilla 5 – 8 June 1944 Baltic Sea March over Königsberg to Stettin. Equipment for the company Wallenstein 10 June – 14 August 1944 Königsberg Remaining work in F. Schichau yard 15 – 16 August 1944 Danzig Trials at UAK 21 – 26 August 1944 Swinemünde Flakausbildung at Flakschule 29 August – 12 September 1944 Königsberg Installation of a Schnorchel underwater-breathing apparatus 13 – 20 September 1944 Hela Snorkel training at AGRU-Front 21 – 22 September 1944 Rönne Auscultation at AUK 23 – 29 September 1944 Keel Remaining work and equipment to the 1st company
Active Service 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.
Date Port of Departure Port of Arrival Duration 5 – 7 October 1944 Kiel Horten 3 days 11 – 12 October 1944 Horten Kristiansand 2 days 15 October – 26 December 1944 Kristiansand Bergen 73 days (Patrol) 27 – 29 December 1944 Bergen Marviken 3 days 2 – 4 January 1945 Marviken Flensburg 3 days 20 – 27 April 1945 Kiel Horten 8 days 29 April – 4 May 1945 Horten Bergen 6 days
In total, the U-991 spend 98 days at sea during her active service until 9 May 1945.
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).U-991'' was sunk at 12.15am on 11 December 1945 in the North Atlantic, North-West off the coast of Ireland by a torpedo from the British submarine HMS Tantivy. Her wreck still lies at .
References
Bibliography