HMS M2

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 were ordered, but 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.

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.

On 26 January 1932, M2 sank during an exercise with the loss of all on board. It is believed that the submarine sank when the aircraft hanger was flooded.