History
German Empire
NameUC-91
Ordered12 January 1916[1]
BuilderBlohm & Voss, Hamburg[2]
Yard number325[1]
Launched19 January 1918[1]
Commissioned31 July 1918[1]
FateSank while on way to surrender, 10 February 1919[1]
General characteristics
Class and typeGerman Type UC III submarine
Displacement
  • 491 t (483 long tons), surfaced
  • 571 t (562 long tons), submerged
Length
Beam5.54 m (18 ft 2 in) (o/a)
Draft3.77 m (12 ft 4 in)
Propulsion
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 depth75 m (246 ft)
Complement32
Armament
Notes15-second diving time
Service record
Commanders:
  • Kptlt. Bernhard Gerke[3]
  • 31 July – 5 September 1918
Operations: None
Victories: None

SM UC-91 was a German Type UC III minelaying submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I.

Design

A German Type UC III submarine, UC-91 had a displacement of 491 tonnes (483 long tons) when at the surface and 571 tonnes (562 long tons) while submerged. She had a length overall of 56.51 m (185 ft 5 in), a beam of 5.54 m (18 ft 2 in), and a draught of 3.77 m (12 ft 4 in). The submarine was powered by two six-cylinder four-stroke diesel engines each producing 300 metric horsepower (220 kW; 300 shp) (a total of 600 metric horsepower (440 kW; 590 shp)), two electric motors producing 770 metric horsepower (570 kW; 760 shp), and two propeller shafts. She had a dive time of 15 seconds and was capable of operating at a depth of 75 metres (246 ft).[4]

The submarine was designed for a maximum surface speed of 11.5 knots (21.3 km/h; 13.2 mph) and a submerged speed of 6.6 knots (12.2 km/h; 7.6 mph). When submerged, she could operate for 40 nautical miles (74 km; 46 mi) at 4.5 knots (8.3 km/h; 5.2 mph); when surfaced, she could travel 9,850 nautical miles (18,240 km; 11,340 mi) at 7 knots (13 km/h; 8.1 mph). UC-91 was fitted with six 100 centimetres (39 in) mine tubes, fourteen UC 200 mines, three 50 centimetres (20 in) torpedo tubes (one on the stern and two on the bow), seven torpedoes, and one 10.5 cm (4.1 in) SK L/45 or 8.8 cm (3.5 in) Uk L/30 deck gun . Her complement was twenty-six crew members.[4]

Construction and career

The U-boat was ordered on 12 January 1916 and was launched on 19 January 1918. She was commissioned into the German Imperial Navy on 31 July 1918 as SM UC-91.[Note 1] As with the rest of the completed UC III boats, UC-91 conducted no war patrols and sank no ships. She sank after a collision with the steamer Alexandra Woermann on 5 September 1918 in the Baltic Sea. The salvage vessel Vulkan raised the wreck the following day and was repaired. She was en route to surrender on 10 February 1919 when she foundered in the North Sea.[5]

References

Notes

  1. ^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.

Citations

  1. ^ a b c d e Helgason, Guðmundur. "WWI U-boats: UC 91". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 23 February 2009.
  2. ^ Tarrant, p. 174.
  3. ^ Helgason, Guðmundur. "WWI U-boat commanders: Bernhard Gerke". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 20 January 2015.
  4. ^ a b Gröner 1991, pp. 34–35.
  5. ^ Gröner, p. 62

Bibliography

  • Bendert, Harald (2001). Die UC-Boote der Kaiserlichen Marine 1914-1918. Minenkrieg mit U-Booten (in German). Hamburg, Berlin, Bonn: Mittler. ISBN 3-8132-0758-7.
  • Gröner, Erich; Jung, Dieter; Maass, Martin (1991). German Warships 1815–1945, U-boats and Mine Warfare Vessels. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.
  • Gardiner, Robert; Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 978-0-87021-907-8. OCLC 12119866.
  • Tarrant, V. E. (1989). The U-Boat Offensive: 1914–1945. Annapolis, Maryland: Naval Institute Press. ISBN 978-0-87021-764-7. OCLC 20338385.

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