SM UB-90

	UB-148 at sea, a U-boat similar to UB-90.
History
German Empire
Name	UB-90
Ordered	6 / 8 February 1917
Builder	AG Vulcan, Hamburg
Cost	3,654,000 German Papiermark
Yard number	106
Launched	12 February 1918
Commissioned	21 March 1918
Fate	Sunk 16 October 1918 by British submarine
General characteristics
Class and type	Type UB III submarine
Displacement	510 t (500 long tons) surfaced; 640 t (630 long tons) submerged;
Length	55.52 m (182 ft 2 in) (o/a)
Beam	5.76 m (18 ft 11 in)
Draught	3.73 m (12 ft 3 in)
Propulsion	2 × propeller shaft; 2 × MAN-Vulcan four-stroke 6-cylinder diesel engines, 1,085 bhp (809 kW); 2 × Siemens-Schuckert electric motors, 780 shp (580 kW);
Speed	13 knots (24 km/h; 15 mph) surfaced; 7.4 knots (13.7 km/h; 8.5 mph) submerged;
Range	7,120 nmi (13,190 km; 8,190 mi) at 6 knots (11 km/h; 6.9 mph) surfaced; 55 nmi (102 km; 63 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged;
Test depth	50 m (160 ft)
Complement	3 officers, 31 men
Armament	5 × 50 cm (19.7 in) torpedo tubes (4 bow, 1 stern); 10 torpedoes; 1 × 10.5 cm (4.13 in) deck gun;
Service record
Part of:	II Flotilla; 29 June – 16 October 1918;
Commanders:	Oblt.z.S. Gottfried von Mayer; 21 March – 16 October 1918;
Operations:	2 patrols
Victories:	1 merchant ship sunk ; (3,575 GRT); 1 merchant ship taken as prize ; (850 GRT);

SM UB-90 was a German Type UB III submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. She was commissioned into the German Imperial Navy on 21 March 1918 as SM UB-90.^{[Note 1]}

On 16 October 1918, UB-90 was hit by a torpedo from HMS L12 at 57°55′N 10°27′E / 57.917°N 10.450°E / 57.917; 10.450 and sunk. All 38 crew members died in the event.^[1]

Construction

She was built by AG Vulcan of Hamburg and following just under a year of construction, launched at Hamburg on 12 February 1918. UB-90 was commissioned early the next year under the command of Oblt.z.S. Gottfried von Mayer. Like all Type UB III submarines, UB-90 carried 10 torpedoes and was armed with a 10.5 cm (4.13 in) deck gun. UB-90 would carry a crew of up to 3 officer and 31 men and had a cruising range of 7,120 nautical miles (13,190 km; 8,190 mi). UB-90 had a displacement of 510 t (500 long tons) while surfaced and 640 t (630 long tons) when submerged. Her engines enabled her to travel at 13 knots (24 km/h; 15 mph) when surfaced and 7.4 knots (13.7 km/h; 8.5 mph) when submerged.

Summary of raiding history

Date	Name	Nationality	Tonnage^{[Note 2]}	Fate^[4]
29 July 1918	Douro	Denmark	850	Captured as prize
3 October 1918	Eupion	United Kingdom	3,575	Sunk

References

Notes

^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.
^ Tonnages are in gross register tons

Citations

^ ^a ^b ^c ^d ^e ^f Gröner 1991, pp. 25–30.
^ Rössler 1979, p. 61.
^ Helgason, Guðmundur. "WWI U-boat commanders: Gottfried von Mayer". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 8 February 2015.
^ Helgason, Guðmundur. "Ships hit by UB 90". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 8 February 2015.

Bibliography

Bendert, Harald (2000). Die UB-Boote der Kaiserlichen Marine, 1914-1918. Einsätze, Erfolge, Schicksal (in German). Hamburg: Verlag E.S. Mittler & Sohn GmbH. ISBN 978-3-8132-0713-2.
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. ISBN 978-0-85177-593-7.
Rössler, Eberhard (1979). Die deutschen U-Boote und ihre Werften: eine Bilddokumentation über den deutschen U-Bootbau; in zwei Bänden (in German). Vol. I. Munich: Bernard & Graefe. ISBN 3-7637-5213-7.