HMS M2 Aircraft-Carrying Submarine
HMS M2 was a Royal Navy aircraft-carrying submarine 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, 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 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 1928. This could carry a small Parnall Peto seaplane, specially designed for the M2 and which could be launched by hydraulic catapult within a few minutes of surfacing. The aircraft would land alongside the submarine on completion of its sortie and be winched aboard using a crane. The submarine was to operate ahead of the battle fleet in a reconnaissance role, flying off her seaplane as a scout.
