HMS MMS 1717 (J517): A Wooden Ship Built to Outsmart a Magnetic Mine

A Wooden Answer to a Magnetic Problem

HMS MMS 1717 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 1717, of the 105-foot type, displaced between 240 and 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.

Genuinely Thin Records for a Genuinely Useful Ship

HMS MMS 1717's individual wartime service record is not well documented in the sources available, a common enough situation for the huge fleet of small auxiliary minesweepers that quietly kept British and Allied coastal waters clear throughout the war without generating the kind of dramatic headlines that followed larger fleet units. What can be said with confidence is that she survived the war and remained in Royal Navy service for years afterward, later carrying the pennant number J517 and previously known as MMS-217.

One of the Last of a Vast Fleet

HMS MMS 1717 was, by 1949, one of only four surviving vessels of her once-huge class still in Royal Navy service, a genuinely striking piece of longevity for a small wooden minesweeper built quickly and cheaply amid the urgent demands of wartime production. Her endurance stands as a quiet testament to the soundness of a simple design, built to solve one specific problem and going on to serve faithfully for years after the immediate crisis that had brought her into being had long since passed.