| HMS C31|
19 November 1909
7 January 1909
| 7 January 1909|
2 September 1909
| Sunk by mine, 4 January 1915|
290 long tons (290 t) surfaced
320 long tons (330 t) submerged
HMS C31 was one of 38 C-class submarines built for the Royal Navy in the first decade of the 20th century. She struck a mine in 1915 and sank with all hands.
HMS C31 Wikipedia
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.
For surface running, the boats were powered by a single 12-cylinder 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. 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).
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.
HMS C31 was built by Vickers, Barrow. She was laid down on 7 January 1909 and was commissioned on 19 November 1909. The boat was sunk by a mine off the Belgian coast on 4 January 1915 whilst patrolling off Zeebrugge. There were no survivors.