Name: M2
Location: 50°34.580'N 02°33.770'W
Depth: 32m (sea bed)
Description: GB K class Submarine, 89m, adapted for sea plane, loads of sponges, colourful, great dive
History: Launched 1918, sank 1932. This ship was on of 4 planned and 3 built experimental submarines. She was a K class sub. with the forward gun replaced with an aircraft hanger, catapult and crane. The idea was to have a folding sea plane which could be unfolded, launched using the catapult and the recovered by the crane, folded and stored enabling the submarine to submerge. The plane was intended for observation with a view to launching a torpedo as well.
She sank with all hands for disputed reasons. When they began the salvage operation they found the hanger doors partly open. The known events leading up to her disapearance was that she signalled to command her intention to submerge then nothing was heared again form her. A passing ship signalled that they observed a submarine dive tail first.
One theory is that she began to dive before the crew had fully closed the hanger doors and therefore human error caused her to sink.
The second theory is more complexed in that her operational system for surfacing had changed from blowing the tanks to using the rear hydrofoils to push her to and hold her at the surface. This save a considerable amont of launch/recovery time and enabled the sub to wait underwater for the return of the plane. Based on the observation of the passing ship and the unusual method of surfacing used by the sub, this theory states, that they were closing the hanger doors to prepare for a normal dive, when the rear hydrofoil failed and dragged the sub down by it's rear end.
The salvage attempt lasted two years and failed when a storm blew up causing them to lose her just 6 meters from the surface. She now lies upright, intact and sealed. however the hanger doors are open so the hanger can be entered.