|Ordered:||25 January 1939|
|Builder:||Flender Werke, Lübeck|
|Laid down:||1 October 1940|
|Launched:||25 October 1941|
|Commissioned:||20 December 1941|
|Fate:||Sunk 24 July 1942 in the Northern Atlantic by a Canadian warship|
|Class and type:||Type VIIC submarine|
|Height:||9.60 m (31 ft 6 in)|
|Draught:||4.74 m (15 ft 7 in)|
|Complement:||4 officers, 40–56 enlisted|
|Operations:||30 June – 24 July 1942|
She was laid down at the Flender Werke in Lübeck as yard number 294 on 1 October 1940, launched on 25 October 1941 and commissioned on 20 December with Oberleutnant zur See Hans-Jürgen Oldörp in command.
After training with the 8th U-boat Flotilla, U-90 was assigned to the 9th flotilla on 1 July 1942 for operations. She was a member of one wolfpack in a patrol in which she was sunk by a Canadian warship.
German Type VIIC submarines were preceded by the shorter Type VIIB submarines. U-90 had a displacement of 769 tonnes (757 long tons) when at the surface and 871 tonnes (857 long tons) while submerged. She had a total length of 67.10 m (220 ft 2 in), a pressure hull length of 50.50 m (165 ft 8 in), a beam of 6.20 m (20 ft 4 in), a height of 9.60 m (31 ft 6 in), and a draught of 4.74 m (15 ft 7 in). The submarine was powered by two MAN M 6 V 40/46 four-stroke, six-cylinder supercharged diesel 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, two Brown, Boveri & Cie 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 boat was capable of operating at depths of up to 230 metres (750 ft).
The submarine had a maximum surface speed of 17.7 knots (32.8 km/h; 20.4 mph) and a maximum submerged speed of 7.6 knots (14.1 km/h; 8.7 mph). When submerged, the boat could operate for 80 nautical miles (150 km; 92 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 8,500 nautical miles (15,700 km; 9,800 mi) at 10 knots (19 km/h; 12 mph). U-90 was fitted with five 53.3 cm (21 in) torpedo tubes (four fitted at the bow and one at the stern), fourteen torpedoes, one 8.8 cm (3.46 in) SK C/35 naval gun, 220 rounds, and a 2 cm (0.79 in) C/30 anti-aircraft gun. The boat had a complement of between forty-four and sixty.
Patrol and Loss
Having departed Kiel on 30 June 1942, the boat hugged the southern Norwegian coast before turning west and sailing through the gap separating the Faroe and Shetland Islands. She was attacked and sunk by depth charges from the Canadian destroyer St. Croix in the Northern Atlantic on 24 July.
U-90 took part in one wolfpack, namely.
- Wolf (13–24 July 1942)
- Gröner 1991, pp. 43-46.
- 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. ISBN 1-55750-186-6.
- Busch, Rainer; Röll, Hans-Joachim (1999). Deutsche U-Boot-Verluste von September 1939 bis Mai 1945 [German U-boat losses from September 1939 to May 1945]. Der U-Boot-Krieg (in German). IV. Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0514-2.
- Edwards, Bernard (1996). Dönitz and the Wolf Packs - The U-boats at War. Cassell Military Classics. pp. 75, 79, 82. ISBN 0-304-35203-9.
- 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 VIIC boat U-90". German U-boats of WWII - uboat.net. Retrieved 26 December 2014.
- Hofmann, Markus. "U 90". Deutsche U-Boote 1935-1945 - u-boot-archiv.de (in German). Retrieved 26 December 2014.