HMS L11

HMS L11 was a L-class submarine built for the Royal Navy during World War I. She was one of five boats in the class to be fitted as a minelayer. The boat survived the war and was sold for scrap in 1932.

History
United Kingdom
Name	HMS L11
Builder	Vickers Limited, Barrow-in-Furness
Laid down	17 January 1917
Launched	26 February 1918
Commissioned	27 June 1918
Fate	Sold for scrapping, February 1932
General characteristics
Class and type	L-class submarine
Displacement	914 long tons (929 t) surfaced 1,089 long tons (1,106 t) submerged
Length	238 ft 7 in (72.7 m)
Beam	23 ft 6 in (7.2 m)
Draught	13 ft 3 in (4.0 m)
Installed power	2,400 bhp (1,800 kW) (diesel) 1,600 hp (1,200 kW) (electric)
Propulsion	2 × diesel engines 2 × electric motors
Speed	17 kn (31 km/h; 20 mph) surfaced 10.5 kn (19.4 km/h; 12.1 mph) submerged
Range	3,800 nmi (7,000 km; 4,400 mi) at 10 kn (19 km/h; 12 mph) on the surface
Test depth	150 feet (45.7 m)
Complement	38
Armament	4 × bow 21 in (533 mm) torpedo tubes 2 × beam 18 in (457 mm) torpedo tubes 1 × 4-inch deck gun 16 mines

Design and description

L9 and its successors were enlarged to accommodate 21-inch (53.3 cm) torpedoes and more fuel. The submarine had a length of 238 feet 7 inches (72.7 m) overall, a beam of 23 feet 6 inches (7.2 m) and a mean draft of 13 feet 3 inches (4.0 m).^[1] They displaced 914 long tons (929 t) on the surface and 1,089 long tons (1,106 t) submerged. The L-class submarines had a crew of 38 officers and ratings.^[2]

For surface running, the boats were powered by two 12-cylinder Vickers^[3] 1,200-brake-horsepower (895 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600-horsepower (447 kW) electric motor.^[1] They could reach 17 knots (31 km/h; 20 mph) on the surface and 10.5 knots (19.4 km/h; 12.1 mph) underwater. On the surface, the L class had a range of 3,800 nautical miles (7,000 km; 4,400 mi) at 10 knots (19 km/h; 12 mph).^[4]

The boats were armed with four 21-inch torpedo tubes in the bow and two 18-inch (45 cm) in broadside mounts. They carried four reload torpedoes for the 21-inch tubes for a grand total of ten torpedoes of all sizes.^[5] They were also armed with a 4-inch (102 mm) deck gun.^[2] L11 was fitted with 16 vertical mine chutes in her saddle tanks and carried one mine per chute.^[1]

Construction and career

L11 was built by Vickers, Barrow. She was laid down on 17 January 1917 and was commissioned on 27 June 1918. The boat was sold for scrap in February 1932.

Notes

1. Gardiner & Gray, p. 93
2. Akermann, p. 165
3. Harrison, Chapter 25
4. Harrison, Chapters 3
5. Harrison, Chapter 27

References

• Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN 1-904381-05-7.
• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
• Gardiner, Robert & Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 0-85177-245-5.
• Harrison, A. N. (January 1979). "The Development of HM Submarines From Holland No. 1 (1901) to Porpoise (1930) (BR3043)". RN Subs. Retrieved 27 September 2022.