The wreck of the Royal Navy’s first long-range diesel-powered submarine has been awarded protected status by the British government.
The ship, known by the name HMS/m D1, was the forerunner of the country’s patrol submarines that guarded its coastlines during the First World War.
Built by shipbuilders Vickers at Barrow-in-Furness in Cumbria, the prototype was launched in secret in 1908. It was larger and more powerful than its C-class predecessor, with innovations including diesel propulsion, twin propellers, and a wireless telegraphy system allowing the submarine to communicate.
At the beginning of the First World War, HMS/m D1 was assigned to protect the coast off Dover from the enemy, later performing a similar service in Portsmouth, as well as other duties. In 1918, HMS/m D1 was deliberately sunk off Dartmouth in Devon and later used to test submarine detection equipment.
The wreck, which remains upright and largely intact, was investigated as part of a project by U-boat historian Michael Lowrey, who is writing a book about First World War U-boat losses. It was identified by a team of skilled technical divers, led by Steve Mortimer of the dive vessel Wey Chieftain IV.
‘Every diver dreams of identifying a historically important wreck,’ said Mortimer. ‘Expecting to find the remains of a German U-boat, we were thrilled to discover a ground-breaking British submarine instead.’
The team subsequently reported their find to Historic England, who recommended to the Department of Digital, Culture, Media, and Sport that it be afforded protected status. This means divers can explore the wreck, but that its contents are protected by law and must remain in situ.