HMS L25

History
United Kingdom
Name	HMS L25
Builder	Vickers Limited, Barrow-in-Furness
Laid down	25 February 1918
Launched	13 February 1919
Fate	Sold for scrapping, 1935
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	100 feet (30.5 m)
Complement	38
Armament	4 × bow 21 in (533 mm) torpedo tubes 1 × 4-inch deck gun 14 mines

HMS L25 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 1935.

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. They carried four reload torpedoes for the 21-inch tubes for a grand total of eight torpedoes.^[5] They were also armed with a 4-inch (102 mm) deck gun.^[2] L25 was fitted with 14 vertical mine chutes in her saddle tanks and carried one mine per chute.^[1]

HMS L25 was built by Vickers, Barrow-in-Furness. She was laid down on 25 February 1918 and was commissioned on 13 February 1919.

L25 ran aground off The Needles, Isle of Wight, on 7 April 1924. She was refloated later that day.^[6]

L25 was sold to John Cashmore Ltd for scrapping at Newport, Wales, in 1935. Her ship's bell is in the care of the Royal Navy Submarine Museum.

• 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.