SM UB-91

	UB-148 at sea, a U-boat similar to UB-91.
History
German Empire
Name	UB-91
Ordered	6 / 8 February 1917
Builder	AG Vulcan, Hamburg
Cost	3,654,000 German Papiermark
Yard number	107
Launched	6 March 1918
Commissioned	11 April 1918
Fate	Surrendered 21 November 1918, broken up in 1921
General characteristics
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 shafts; 6-cylinder MAN-Vulcan diesel engines, 1,100 ihp (820 kW); Siemens-Schuckert electric motors, 788 ihp (588 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; 27 June – 11 November 1918;
Commanders:	Kptlt. Wolf Hans Hertwig; 11 April – 11 November 1918;
Operations:	2 patrols
Victories:	3 merchant ships sunk ; (13,487 GRT); 1 warship sunk ; (1,181 tons);

SM UB-91 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 11 April 1918 as SM UB-91.

On 4 October 1918 UB-91 sank the Hirano Maru, killing among others, Yokohama Specie Bank sub-manager S. Ujie, his wife and three sons, together with bank employee Takashi Aoki and wife Sueko.

History
UB-148 at sea, a U-boat similar to UB-91.
German Empire
Name	UB-91
Ordered	6 / 8 February 1917
Builder	AG Vulcan, Hamburg
Cost	3,654,000 German Papiermark
Yard number	107
Launched	6 March 1918
Commissioned	11 April 1918
Fate	Surrendered 21 November 1918, broken up in 1921
General characteristics
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 shafts 6-cylinder MAN-Vulcan diesel engines, 1,100 ihp (820 kW) Siemens-Schuckert electric motors, 788 ihp (588 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 27 June – 11 November 1918
Commanders:	Kptlt. Wolf Hans Hertwig 11 April – 11 November 1918
Operations:	2 patrols
Victories:	3 merchant ships sunk (13,487 GRT) 1 warship sunk (1,181 tons)