SM U-91
| History | |
|---|---|
 German Empire | |
| Name | U-91 |
| Ordered | 23 June 1915 |
| Builder | Kaiserliche Werft Danzig |
| Yard number | 35 |
| Laid down | 1 August 1916 |
| Launched | 14 April 1917 |
| Commissioned | 17 September 1917 |
| Fate | Surrendered to France 26 November 1918, Broken Up at Brest July 1921 |
| General characteristics [1] | |
| Class and type | Type U 87 submarine |
| Displacement | |
| Length |
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| Beam |
|
| Height | 9.35 m (30 ft 8 in) |
| Draught | 3.88 m (12 ft 9 in) |
| Installed power | |
| Propulsion | 2 shafts, 2 × 1.66 m (5 ft 5 in) propellers |
| Speed |
|
| Range |
|
| Test depth | 50 m (160 ft) |
| Complement | 4 officers, 32 enlisted |
| Armament |
|
| Service record | |
| Part of: |
|
| Commanders: |
|
| Operations: | 8 patrols |
| Victories: | |
SM U-91[Note 1] was one of the 329 submarines serving in the Imperial German Navy in World War I. U-91 was engaged in the naval warfare and took part in the First Battle of the Atlantic.[3]
Design
Type U 87 submarines were preceded by the shorter Type U 81 submarines. U-91 had a displacement of 757 tonnes (745 long tons) when at the surface and 998 tonnes (982 long tons) while submerged.[1] She had a total length of 65.80 m (215 ft 11 in), a pressure hull length of 50.07 m (164 ft 3 in), a beam of 6.20 m (20 ft 4 in), a height of 9.35 m (30 ft 8 in), and a draught of 3.88 m (12 ft 9 in). The submarine was powered by two 2,400 metric horsepower (1,800 kW; 2,400 shp) engines for use while surfaced, and two 1,200 metric horsepower (880 kW; 1,200 shp) engines for use while submerged. She had two propeller shafts. She was capable of operating at depths of up to 50 metres (160 ft).[1]
The submarine had a maximum surface speed of 15.6 knots (28.9 km/h; 18.0 mph) and a maximum submerged speed of 8.6 knots (15.9 km/h; 9.9 mph).[1] When submerged, she could operate for 56 nautical miles (104 km; 64 mi) at 5 knots (9.3 km/h; 5.8 mph); when surfaced, she could travel 11,380 nautical miles (21,080 km; 13,100 mi) at 8 knots (15 km/h; 9.2 mph). U-91 was fitted with four 50 centimetres (20 in) torpedo tubes (two at the bow and two at the stern), ten to twelve torpedoes, one 10.5 cm (4.1 in) SK L/45 deck gun, and one 8.8 cm (3.5 in) SK L/30 deck gun. She had a complement of thirty-six (thirty-two crew members and four officers).[1]
Summary of raiding history
| Date | Name | Nationality | Tonnage[Note 2] | Fate[4] |
|---|---|---|---|---|
| 24 December 1917 | Elmleaf |  United Kingdom
|
5,948 | Damaged |
| 28 December 1917 | Robert Eggleton | United Kingdom
|
2,274 | Sunk |
| 2 January 1918 | Boston City | United Kingdom
|
2,711 | Sunk |
| 4 January 1918 | Otto |  United Kingdom
|
139 | Sunk |
| 5 January 1918 | Knightsgarth | United Kingdom
|
2,889 | Sunk |
| 7 January 1918 | Premier | United Kingdom
|
89 | Sunk |
| 19 February 1918 | Beacon Light | United Kingdom
|
2,768 | Sunk |
| 22 February 1918 | Haileybury | United Kingdom
|
2,888 | Sunk |
| 23 February 1918 | Birchleaf | United Kingdom
|
5,873 | Damaged |
| 23 February 1918 | British Viscount | United Kingdom
|
3,287 | Sunk |
| 24 February 1918 | Renfrew | United Kingdom
|
3,830 | Sunk |
| 2 March 1918 | Bessy | United Kingdom
|
60 | Sunk |
| 20 April 1918 | Florrieston | United Kingdom
|
3,366 | Sunk |
| 21 April 1918 | Landonia | United Kingdom
|
2,504 | Sunk |
| 21 April 1918 | Normandiet | United Kingdom
|
1,843 | Sunk |
| 22 April 1918 | Baron Herries | United Kingdom
|
1,610 | Sunk |
| 26 April 1918 | Ethel | United Kingdom
|
100 | Sunk |
| 27 April 1918 | Gresham | United Kingdom
|
3,774 | Sunk |
| 27 April 1918 | Walpas |  Russia
|
312 | Sunk |
| 28 April 1918 | Damao |  Portugal
|
5,668 | Sunk |
| 28 April 1918 | Oronsa | United Kingdom
|
8,075 | Sunk |
| 28 April 1918 | Raymond |  France
|
109 | Sunk |
| 1 July 1918 | Westmoor | United Kingdom
|
4,329 | Sunk |
| 6 July 1918 | Port Hardy | United Kingdom
|
6,533 | Sunk |
| 9 July 1918 | Silvia |  Italy
|
3,571 | Sunk |
| 13 July 1918 | Badagri | United Kingdom
|
2,956 | Sunk |
| 16 July 1918 | Fisherman | United Kingdom
|
136 | Sunk |
| 25 July 1918 | Tippecanoe |  United States
|
6,187 | Sunk |
| 1 October 1918 | Therese et Marthe | France
|
32 | Sunk |
| 2 October 1918 | Maia | France
|
185 | Sunk |
| 2 October 1918 | Marie Emmanuel | France
|
32 | Sunk |
| 2 October 1918 | Ave Maris Stella | France
|
22 | Sunk |
| 4 October 1918 | Mercedes |  Spain
|
2,164 | Sunk |
| 5 October 1918 | Heathpark | United Kingdom
|
2,205 | Sunk |
| 5 October 1918 | Erindring | United Kingdom
|
1,229 | Sunk |
| 8 October 1918 | Cazengo | Portugal
|
3,009 | Sunk |
| 9 October 1918 | Pierre | France
|
354 | Sunk |
| 11 October 1918 | Luksefjell |  Norway
|
2,007 | Sunk |
| 14 October 1918 | Bayard | France
|
55 | Sunk |
References
Notes
- ^ "SM" stands for "Seiner Majestät" (English: His Majesty's) and combined with the U for Unterseeboot would be translated as His Majesty's Submarine.
- ^ Tonnages are in gross register tons
Citations
- ^ a b c d e Gröner 1991, pp. 12–14.
- ^ Helgason, Guðmundur. "WWI U-boat commanders: Alfred von Glasenapp (Royal House Order of Hohenzollern)". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 21 January 2015.
- ^ Helgason, Guðmundur. "WWI U-boats: U 91". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 25 January 2010.
- ^ Helgason, Guðmundur. "Ships hit by U 91". German and Austrian U-boats of World War I - Kaiserliche Marine - Uboat.net. Retrieved 21 January 2015.
Bibliography
- Gröner, Erich; Jung, Dieter; Maass, Martin (1991). U-boats and Mine Warfare Vessels. German Warships 1815–1945. Vol. 2. Translated by Thomas, Keith; Magowan, Rachel. London: Conway Maritime Press. ISBN 0-85177-593-4.