MMS-class minesweeper
The British Royal Navy operated large numbers of small Motor Minesweepers (MMS) during the Second World War, in two major classes: the first with hulls (of which 294 were built) and the second with hulls (of which 102 were built). Intended to counter magnetic influence mines in coastal waters, they had wooden hulls. 105 ft MMS. In the early months of the Second World War, Germany made extensive use of magnetic mines, which led to a requirement for a wooden minesweeper, less vulnerable than steel trawlers. The resultant design, the 105 ft-class (also known as the  MMS 1 series and later the Type 1501 series) was built between 1940 and 1944. They were long between perpendiculars, with an overall length of , a beam of and a draught of . Displacement was . They were powered by a diesel engine, giving a speed of . Their major minesweeping equipment was the LL sweep, where two minesweepers operating side-by-side each trailed two buoyant cables with electrodes at the end of the cables. Pulsing a high current through the cables generated a magnetic field sufficient to set off mines over an area of about . They were later fitted with an  SA sweep to deal with acoustic mines, which consisted of a hammer box mounted on an A-frame on the ship's bow, which could be lowered into the water when required. The ships did not have enough towing power to use conventional contact sweeps for dealing with moored contact mines. Defensive armament consisted of two 0.5 inch machine guns and/or one or two Oerlikon 20mm cannons. The ships had a complement of 20 men. The coastal minesweepers had pennant numbers MMS1 to MMS312 and MMS1001 to MMS1090. They were nicknamed "Mickey Mouse". Although the motor minesweepers lacked the  power to tow sweeps for contact mines they were suitable for handling equipment for combating magnetic mines and some later models were fitted with an acoustic hammer on a retractable "A" frame over the bow for countering acoustic mines. The motor minesweepers had limited use post-war so they were quickly disposed of. Three were transferred by Lend-Lease to the Soviet Navy.