HMS M2

HMS M2 retrieving her seaplane
History
Name:	HMS M2
Builder:	Vickers
Laid down:	1916
Launched:	1919
Fate:	Sank during exercise, 26 January 1932
General characteristics
Class and type:	M-class submarine
Displacement:	1,594 long tons (1,620 t) (surfaced) 1,946 long tons (1,977 t) (submerged)
Length:	295 ft 9 in (90.14 m)
Beam:	24 ft 8 in (7.52 m)
Installed power:	2,400 hp (1,800 kW) (diesel engines) 3,200 hp (2,400 kW) (electric motors)
Propulsion:	2 × 12-cylinder Vickers diesel engines 4 × electric motors 2 × 3-blade, 5 ft 10 in (1.78 m) diameter propellers
Speed:	15 kn (17 mph; 28 km/h) (surfaced) 8–9 kn (9.2–10.4 mph; 15–17 km/h) (submerged)
Range:	2,000 nmi (2,300 mi; 3,700 km) at 15 kn (17 mph; 28 km/h) 4,500 nmi (5,200 mi; 8,300 km) at 10 kn (12 mph; 19 km/h)
Endurance:	80 nmi (92 mi; 150 km) at 2 kn (2.3 mph; 3.7 km/h)
Test depth:	200 ft (61 m) - accidentally reached 239 ft (73 m) in 1923
Complement:	62
Armament:	1 × 12-inch (305mm)/40 cal Mark IX gun with 50 rounds (removed 1928) 1 × 3 in (76 mm) Mk II HA anti-aircraft gun 4 × 18-inch (450mm) bow torpedo tubes with 4 reload torpedoes
Aircraft carried:	1 × Parnall Peto seaplane
Aviation facilities:	Hangar and Hydraulic catapult

HMS M2 was a Royal Navy submarine monitor completed in 1919, converted in 1927 into a submarine aircraft carrier. She was shipwrecked in Lyme Bay, Dorset, Britain, on 26 January 1932. She was one of three M-class boats completed.

Four M-class submarines replaced the order for the last four K-class submarines, K17-K21. Although they were similar in size, the M class was an entirely different design from the K class, although it is possible that some material ordered for the K-boats went into them. In any event, the end of the First World War meant that only three were completed.

M2 was laid down at Vickers shipyard at Barrow in Furness in 1916, and launched in 1919. Like the other members of her class, she was armed with a single fixed 12-inch (305mm) gun as well as torpedo tubes. The Mark IX gun was taken from spares held for the Formidable-class battleships.

The M-class submarines were very large for the time at 296 feet (90 m) long. They were designed to operate as submarine monitors or cruisers. They displaced 1,600 long tons (1,600 t) on the surface and 1,950 long tons (1,980 t) when submerged. Two 12-cylinder diesel engines producing 2,400 hp (1,800 kW) drove them on the surface; underwater, they were driven by electric motors producing 1,500 hp (1,100 kW).

After the accidental sinking of M1 in 1925, M2 and her sister M3 were taken out of service and reassigned for experimental use. Her 12-inch gun was removed, replaced by a small aircraft hangar, the work being completed in 1927. This could carry a small Parnall Peto seaplane, specially designed for the M2, which, once its wings had been unfolded, could be lowered onto the sea alongside by a derrick for take off. On landing, the aircraft was hoisted back onto the deck and replaced into the hangar. In October 1928, a hydraulic aircraft catapult was fitted, to enable the seaplane to take off directly from the deck. The submarine was intended to operate ahead of the battle fleet in a reconnaissance role, flying off her unarmed seaplane as a scout.