HMS MMS 17 (J517): A Wooden Ship Built to Outsmart a Magnetic Mine

A Wooden Answer to a Magnetic Problem

HMS MMS 17 belonged to the Royal Navy's MMS class of motor minesweepers, a wartime programme launched in direct response to Germany's early deployment of magnetic mines, weapons that could be triggered by the mere presence of a steel-hulled ship passing overhead.

The Admiralty's solution was elegantly simple: build the minesweepers themselves out of wood, making them effectively invisible to the very mines they were sent to clear.

Two variants were built between 1940 and 1944, a 105-foot type of which 294 were constructed, and a slightly larger 126-foot type of which a further 102 were built, together forming one of the largest small-ship building programmes of the entire war.

A Modest but Essential Design

HMS MMS 17, of the 105-foot type, displaced around 255 tons, was powered by a single 500 brake-horsepower diesel engine giving her a modest top speed of 11 knots, and carried a small crew of around 20 men.

She was fitted with LL sweep gear, in which two vessels would trail buoyant cables carrying electrodes to detonate magnetic mines at a safe distance, and later with SA sweep equipment to counter acoustic mines as well, defended by a light armament of 0.5-inch machine guns and Oerlikon 20mm cannon, more than adequate for a vessel whose real enemy lay hidden beneath the waves rather than in the air or on the surface.

A Surprisingly Well-Documented 'Mickey Mouse' Boat

Contrary to what you might expect of a mass-produced 255-ton wooden boat, HMS MMS 17's individual record actually survives in reasonable detail. She was built by Wivenhoe Shipyard Ltd on the River Colne in Essex, a small yard that turned out sixteen of the 105-foot 'short' MMS type and eight of the larger 126-foot 'long' type during the war, vessels affectionately nicknamed 'Mickey Mouse boats' simply because, like so many of their kind, they went to war with a number rather than a name. MMS 17 was launched on 15 February 1941 and commissioned that 30 May.

She served under three commanding officers through the war: Lieutenant D G Silcock RNVR held command for the best part of four years, from May 1941 to March 1945, before Robert Murray Johnston and then George Verdon Gare took over as temporary Acting Lieutenant Commanders during the war's final months, seeing her through to victory in Europe and beyond.

A Short, Job-Done Post-War Career

Unlike some of her sisters, who lingered on in reserve or found second careers as fishing boats and workboats for years afterwards, MMS 17's naval service ended fairly promptly: she was sold out of the Royal Navy in 1946, barely a year after the war's end, her job of outsmarting Hitler's magnetic mines no longer required once British and Allied coastal waters had been swept clear.

It was, in its own quiet way, a mission accomplished rather than a story cut short. MMS 17 had done precisely the unglamorous job she was built for, and once magnetic mines stopped being a live threat around Britain's coast, there was simply no need to keep a wooden boat built to dodge them in service any longer.