HMS C27

History
United Kingdom
Name	HMS C27
Builder	Vickers, Barrow
Laid down	4 June 1908
Launched	22 April 1909
Commissioned	14 August 1909
Fate	Scuttled, 5 April 1918, salvaged and scrapped August 1953
General characteristics
Class and type	C-class submarine
Displacement	290 long tons (290 t) surfaced 320 long tons (330 t) submerged
Length	142 ft 3 in (43.4 m)
Beam	13 ft 7 in (4.1 m)
Draught	11 ft 6 in (3.5 m)
Installed power	600 bhp (450 kW) petrol 300 hp (220 kW) electric
Propulsion	1 × 16-cylinder Vickers petrol engine 1 × electric motor
Speed	13 kn (24 km/h; 15 mph) surfaced 8 kn (15 km/h; 9.2 mph) submerged
Range	910 nmi (1,690 km; 1,050 mi) at 12 kn (22 km/h; 14 mph) on the surface
Test depth	100 feet (30.5 m)
Complement	2 officers and 14 ratings
Armament	2 × 18 in (450 mm) bow torpedo tubes

HMS C27 was one of 38 C-class submarines built for the Royal Navy in the first decade of the 20th century.

The C-class boats of the 1907–08 and subsequent Naval Programmes were modified to improve their speed, both above and below the surface. The submarine had a length of 142 feet 3 inches (43.4 m) overall, a beam of 13 feet 7 inches (4.1 m) and a mean draft of 11 feet 6 inches (3.5 m). They displaced 290 long tons (290 t) on the surface and 320 long tons (330 t) submerged. The C-class submarines had a crew of two officers and fourteen ratings.^[1]

For surface running, the boats were powered by a single 12-cylinder^[2] 600-brake-horsepower (447 kW) Vickers petrol engine that drove one propeller shaft. When submerged the propeller was driven by a 300-horsepower (224 kW) electric motor.^[1] They could reach 13 knots (24 km/h; 15 mph) on the surface and 8 knots (15 km/h; 9.2 mph) underwater. On the surface, the C class had a range of 910 nautical miles (1,690 km; 1,050 mi) at 12 knots (22 km/h; 14 mph).^[3]

The boats were armed with two 18-inch (45 cm) torpedo tubes in the bow. They could carry a pair of reload torpedoes, but generally did not as they would have to remove an equal weight of fuel in compensation.^[4]

HMS C27 was built by Vickers, Barrow. She was laid down on 4 June 1908 and was commissioned on 14 August 1909. HMS C27 along with the trawler Princess Louise (ex-Princess Marie Jose) sank U-23 in the Fair Isle Channel between Orkney and Shetland on 20 July 1915 using the U-boat trap tactic. The tactic was to use a decoy trawler to tow a submarine. When a U-boat was sighted, the tow line and communication line was slipped and the submarine would attack the U-boat. The tactic was partly successful, but was abandoned after the loss of two C class submarines. In both cases, all the crew were lost.

HMS C27 was involved in the Baltic operations from 1915 to 1918. The boat was scuttled on 5 April 1918 outside Helsingfors (now Helsinki) south of the Harmaja Light (Gråhara) to avoid seizure by advancing German forces. HMS C27 was salvaged for breaking up in Finland in August 1953.

• 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.

• MaritimeQuest HMS C27 pages