SM UB-90

For other ships with the same name, see German submarine U-90.

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]}

UB-148 at sea, a U-boat similar to UB-90.
History
German Empire
Name	UB-90
Ordered	6 / 8 February 1917[1]
Builder	AG Vulcan, Hamburg
Cost	3,654,000 German Papiermark
Yard number	106
Launched	12 February 1918[2]
Commissioned	21 March 1918[2]
Fate	Sunk 16 October 1918[2]
General characteristics [2]
Class & 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[2]
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[3] 21 March – 16 October 1918
Operations:	2 patrols
Victories:	1 merchant ship sunk (3,575 GRT) 1 merchant ship taken as prize (850 GRT)

On 16 October 1918, UB-90 was hit by a torpedo from HMS L12 at 57°55′N 10°27′E and sunk. All 38 crew members died in the event.^[2]

Construction

Main article: Type UB III submarine

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