SM UC-90

	O-4 (UC-90) at Yokosuka
History
German Empire
Name	UC-90
Ordered	12 January 1916
Builder	Blohm & Voss, Hamburg
Yard number	324
Launched	19 January 1918
Commissioned	15 July 1918
Fate	Surrendered to Japan, 1 December 1918
Japan
Name	O-4
Acquired	1 December 1918
In service	1920
Out of service	1921
Fate	Dismantled, 1921; used as ASW target, 1924 – 26; scrapped
General characteristics
Class & type	Type UC III submarine
Displacement	491 t (483 long tons), surfaced; 571 t (562 long tons), submerged;
Length	56.51 m (185 ft 5 in) (o/a); 42.20 m (138 ft 5 in) (pressure hull);
Beam	5.54 m (18 ft 2 in) (o/a)
Draft	3.77 m (12 ft 4 in)
Propulsion	2 × propeller shafts; 2 × 6-cylinder, 4-stroke diesel engines, 600 PS (440 kW; 590 bhp); 2 × electric motors, 770 PS (570 kW; 760 shp);
Speed	11.5 knots (21.3 km/h; 13.2 mph), surfaced; 6.6 knots (12.2 km/h; 7.6 mph), submerged;
Range	9,850 nautical miles (18,240 km; 11,340 mi) at 7 knots (13 km/h; 8.1 mph), surfaced; 40 nmi (74 km; 46 mi) at 4.5 knots (8.3 km/h; 5.2 mph), submerged;
Test depth	75 m (246 ft)
Complement	32
Armament	6 × 100 cm (39.4 in) mine tubes; 14 × UC 200 mines; 3 × 50 cm (19.7 in) torpedo tubes (2 bow external; one stern); 7 × torpedoes; 1 x 10.5 cm (4.1 in) SK L/45 or 8.8 cm (3.5 in) Uk L/30 deck gun;
Notes	15-second diving time
Service record
Commanders:	Oblt. Justus Oldekop; 15 – 16 July 1918;
Operations:	None
Victories:	None

SM UC-90 was a German Type UC III minelaying submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. Completed in mid-1918, she saw no action during the war and was transferred to the Imperial Japanese Navy afterwards. The submarine briefly served in the IJN during 1920–1921 before she was partially dismantled and ultimately scrapped in 1926.

History
O-4 (UC-90) at Yokosuka
German Empire
Name	UC-90
Ordered	12 January 1916
Builder	Blohm & Voss, Hamburg
Yard number	324
Launched	19 January 1918
Commissioned	15 July 1918
Fate	Surrendered to Japan, 1 December 1918
Japan
Name	O-4
Acquired	1 December 1918
In service	1920
Out of service	1921
Fate	Dismantled, 1921; used as ASW target, 1924 – 26; scrapped
General characteristics
Class & type	Type UC III submarine
Displacement	491 t (483 long tons), surfaced 571 t (562 long tons), submerged
Length	56.51 m (185 ft 5 in) (o/a) 42.20 m (138 ft 5 in) (pressure hull)
Beam	5.54 m (18 ft 2 in) (o/a)
Draft	3.77 m (12 ft 4 in)
Propulsion	2 × propeller shafts 2 × 6-cylinder, 4-stroke diesel engines, 600 PS (440 kW; 590 bhp) 2 × electric motors, 770 PS (570 kW; 760 shp)
Speed	11.5 knots (21.3 km/h; 13.2 mph), surfaced 6.6 knots (12.2 km/h; 7.6 mph), submerged
Range	9,850 nautical miles (18,240 km; 11,340 mi) at 7 knots (13 km/h; 8.1 mph), surfaced 40 nmi (74 km; 46 mi) at 4.5 knots (8.3 km/h; 5.2 mph), submerged
Test depth	75 m (246 ft)
Complement	32
Armament	6 × 100 cm (39.4 in) mine tubes 14 × UC 200 mines 3 × 50 cm (19.7 in) torpedo tubes (2 bow external; one stern) 7 × torpedoes 1 x 10.5 cm (4.1 in) SK L/45 or 8.8 cm (3.5 in) Uk L/30 deck gun
Notes	15-second diving time
Service record
Commanders:	Oblt. Justus Oldekop 15 – 16 July 1918
Operations:	None
Victories:	None