SM UB-31[Note 1] was a German Type UB II submarine or U-boat in the German Imperial Navy (German: Kaiserliche Marine) during World War I. The U-boat was ordered on 22 July 1915 and launched on 16 November 1915. She was commissioned into the German Imperial Navy on 25 March 1916 as SM UB-31.

SM UB-45, a U-boat similar to UB-31
History
German Empire
NameUB-31
Ordered22 July 1915[1]
BuilderBlohm & Voss, Hamburg[1]
Cost1,152,000 German Papiermark[2]
Yard number255[1]
Launched16 November 1915[1]
Completed24 March 1916[1]
Commissioned25 March 1916[2]
FateSunk 2 May 1918 by British warships[2]
General characteristics [2]
Class and typeType UB II submarine
Displacement
  • 274 t (270 long tons) surfaced
  • 303 t (298 long tons) submerged
Length
Beam
  • 4.37 m (14 ft 4 in) o/a
  • 3.85 m (12 ft 8 in) pressure hull
Draught3.69 m (12 ft 1 in)
Propulsion
Speed
  • 9.06 knots (16.78 km/h; 10.43 mph) surfaced
  • 5.71 knots (10.57 km/h; 6.57 mph) submerged
Range
  • 7,030 nmi (13,020 km; 8,090 mi) at 5 knots (9.3 km/h; 5.8 mph) surfaced
  • 45 nmi (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth50 m (160 ft)
Complement2 officers, 21 men
Armament
Notes42-second diving time
Service record
Part of:
  • Baltic Flotilla
  • 16 May 1916 – 24 February 1917
  • Flandern Flotilla
  • 24 February 1917 – 2 May 1918
Commanders:
  • Oblt.z.S. Karl Vesper[3]
  • 18 March – 11 August 1916
  • Oblt.z.S. Thomas Bieber[4]
  • 12 August 1916 – 31 January 1918
  • Oblt.z.S. Wilhelm Braun[5]
  • 1 February – 2 May 1918
Operations: 25 patrols
Victories:
  • 27 merchant ships sunk
    (73,810 GRT)
  • 8 merchant ships damaged
    (34,699 GRT)

The submarine sank 27 ships in 25 patrols. UB-31 was depth charged and sunk by British warships HMS Lord Leitrim, HMS Loyal Friend, and HMS Ocean Roamer in the English Channel on 2 May 1918.[2] Alternatively she may have been sunk by a mine on that date.[6]

Design

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A Type UB II submarine, UB-31 had a displacement of 274 tonnes (270 long tons) when at the surface and 303 tonnes (298 long tons) while submerged. She had a total length of 36.90 m (121 ft 1 in), a beam of 4.37 m (14 ft 4 in), and a draught of 3.69 m (12 ft 1 in). The submarine was powered by two Benz six-cylinder diesel engines producing a total 270 metric horsepower (270 shp; 200 kW), two Siemens-Schuckert electric motors producing 280 metric horsepower (210 kW; 280 shp), and one propeller shaft. She was capable of operating at depths of up to 50 metres (160 ft).[2]

The submarine had a maximum surface speed of 9.06 knots (16.78 km/h; 10.43 mph) and a maximum submerged speed of 5.71 knots (10.57 km/h; 6.57 mph). When submerged, she could operate for 45 nautical miles (83 km; 52 mi) at 4 knots (7.4 km/h; 4.6 mph); when surfaced, she could travel 7,030 nautical miles (13,020 km; 8,090 mi) at 5 knots (9.3 km/h; 5.8 mph). UB-31 was fitted with two 50 centimetres (20 in) torpedo tubes, four torpedoes, and one 8.8 cm (3.5 in) Uk L/30 deck gun. She had a complement of twenty-one crew members and two officers and a 42-second dive time.[2]

Summary of raiding history

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Date Name Nationality Tonnage[Note 2] Fate[7]
9 April 1917 Kittiwake   United Kingdom 1,866 Sunk
24 April 1917 Saint Jacques   France 415 Damaged
28 April 1917 Medina   United Kingdom 12,350 Sunk
21 May 1917 City of Corinth   United Kingdom 5,870 Sunk
15 June 1917 Teesdale   United Kingdom 2,470 Damaged
17 June 1917 Stanhope   United Kingdom 2,854 Sunk
5 July 1917 Ocean Swell   United Kingdom 195 Sunk
6 July 1917 Ariadne Christine   United Kingdom 3,550 Damaged
7 July 1917 Bellucia   United Kingdom 4,368 Sunk
10 July 1917 Hildegard   United States 622 Sunk
11 July 1917 Brunhilda   United Kingdom 2,296 Sunk
1 August 1917 Alcyone   United Kingdom 149 Sunk
1 August 1917 Laertes   United Kingdom 4,541 Sunk
2 August 1917 Newlyn   United Kingdom 4,019 Sunk
3 August 1917 Renee Marthe   France 49 Sunk
8 August 1917 Algerie   France 3,386 Damaged
8 September 1917 Elizabeth   United Kingdom 58 Sunk
9 September 1917 Pluton   Norway 1,449 Sunk
19 October 1917 Waikawa   United Kingdom 5,666 Sunk
20 October 1917 Colorado   United Kingdom 7,165 Sunk
23 October 1917 Lepanto   United Kingdom 6,389 Damaged
19 November 1917 Farn   United Kingdom 4,393 Sunk
13 December 1917 Britannic   United Kingdom 92 Sunk
15 December 1917 Sachem   United Kingdom 5,354 Damaged
18 December 1917 Riversdale   United Kingdom 2,805 Sunk
20 December 1917 Alice Marie   United Kingdom 2,210 Sunk
20 December 1917 Eveline   United Kingdom 2,605 Sunk
20 December 1917 Warsaw   United Kingdom 608 Sunk
22 January 1918 Admiral Cochrane   United Kingdom 6,565 Damaged
22 January 1918 Greatham   United Kingdom 2,338 Sunk
24 January 1918 Elsa   Norway 3,581 Sunk
28 February 1918 Heenvliet   Netherlands 492 Sunk
20 March 1918 Boorara   Australia 6,570 Damaged
24 April 1918 Agnete   United Kingdom 1,127 Sunk
25 April 1918 Joseph   France 42 Sunk

References

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Notes

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  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.
  2. ^ Tonnages are in gross register tons

Citations

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  1. ^ a b c d e Rössler 1979, p. 64.
  2. ^ a b c d e f g Gröner 1991, pp. 23–25.
  3. ^ Helgason, Guðmundur. "WWI U-boat commanders: Karl Vesper (Royal House Order of Hohenzollern)". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 1 February 2015.
  4. ^ Helgason, Guðmundur. "WWI U-boat commanders: Thomas Bieber (Royal House Order of Hohenzollern)". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 1 February 2015.
  5. ^ Helgason, Guðmundur. "WWI U-boat commanders: Wilhelm Braun". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 1 February 2015.
  6. ^ Helgason, Guðmundur. "UB-31". U-Boat.net. Retrieved 8 May 2018.
  7. ^ Helgason, Guðmundur. "Ships hit by UB-31". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 1 February 2015.

Bibliography

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