HMS R11

HMS R11 was one of 10 R-class submarine built for the Royal Navy during the First World War. The boat was not completed before the end of the war and was sold for scrap in 1923.

R-class submarine
History
United Kingdom
Name	HMS R11
Builder	Cammell Laird, Birkenhead
Laid down	1 December 1917
Launched	16 March 1918
Commissioned	8 August 1919
Fate	Sold, 21 February 1923
General characteristics
Class and type	R-class submarine
Displacement	410 long tons (417 t) surfaced 503 long tons (511 t) submerged
Length	163 ft 9 in (49.91 m)
Beam	15 ft 3 in (4.65 m)
Draught	11 ft 6 in (3.51 m)
Installed power	240 bhp (180 kW) (diesel) 1,200 hp (890 kW) (electric)
Propulsion	1 × diesel engine 1 × electric motor
Speed	9.5 knots (17.6 km/h; 10.9 mph) surfaced 15 knots (28 km/h; 17 mph) submerged
Range	2,400 nmi (4,400 km; 2,800 mi) at 9 knots (17 km/h; 10 mph) surfaced; 60 nmi (110 km; 69 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged
Test depth	150 feet (45.7 m)
Complement	2 officers and 20 ratings
Sensors and processing systems	Bow hydrophone array
Armament	6 × bow 18-inch (45 cm) torpedo tubes

Design and description

The R-class submarine was designed to meet an Admiralty requirement for a specialised hunter-killer submarine with an emphasis on submerged performance. The boats had a length of 163 feet 9 inches (49.9 m) overall, a beam of 15 feet 3 inches (4.6 m) and a mean draft of 11 feet 6 inches (3.5 m). They displaced 410 long tons (420 t) on the surface and 503 long tons (511 t) submerged. The R-class submarines had a crew of 2 officers and 20 ratings.^[1] They had a diving depth of 150 feet (45.7 m).^[2]

For surface running, the boats were powered by a single eight-cylinder ^[3] 240-brake-horsepower (179 kW) diesel engine that drove the single propeller shaft. When submerged it was driven by a 1,200-horsepower (895 kW) electric motor. They could reach 9.5 knots (17.6 km/h; 10.9 mph) on the surface and 15 knots (28 km/h; 17 mph) underwater. On the surface, the R class had a range of 2,400 nautical miles (4,400 km; 2,800 mi) at 9 knots (17 km/h; 10 mph) and 60 nmi (110 km; 69 mi) at 5 knots (9.3 km/h; 5.8 mph) submerged.^[4]

The boats were armed with six 18-inch (45 cm) torpedo tubes in the bow. They carried six reload torpedoes for a grand total of a dozen torpedoes. They were equipped with an array of five hydrophones in the bow to allow them to locate and engage targets while submerged.^[4]

Construction and career

HMS R11 was laid down on 1 December 1917 by Cammell Laird at Birkenhead, launched on 16 March 1918 and commissioned on 8 August 1919. She came too late to see any combat in World War I, like most of the other R class submarines. R11 was sold on 21 February 1923 to J Smith. The ship's bell is held by the Royal Navy Submarine Museum at Gosport.