MMS-class minesweeper: Difference between revisions

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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 [[Naval trawler|trawlers]].<ref name="bwnp141">{{Harvnb|Brown|2000|p=141}}</ref> The resultant design, the 105&nbsp;ft-class<ref name="wrp56">{{harvnb|Worth|1984|p=56}}</ref> (also known as the ''MMS 1'' series<ref name="jfsww2">{{harvnb|Preston|1989|p=76}}</ref> and later the Type 1501 series<ref name="jfs53p67">{{harvnb|Blackman|1953|p=67}}</ref>) was built between 1940 and 1944.<ref name="wrp56"/>

They were {{convert|105|ft|m|1|abbr=on}} [[length between perpendiculars|long between perpendiculars]],<ref name="wrp56"/> with an [[length overall|overall length]] of {{convert|119|ft|4|in|abbr=on}}, a [[beam (nautical)|beam]] of {{convert|23|ft|5|in|abbr=on}} and a [[Draft (ship)|draught]] of {{convert|8|ft|9|in|abbr=on}}.<ref name="conways22p72">{{harvnb|Gardiner|Chesneau|1980|p=72}}</ref> [[Displacement (ship)|Displacement]] was {{convert|240–255|LT|t|abbr=on}}.<ref name="jfsww2"/><ref name="jfs53p67"/> They were powered by a {{convert|500|bhp|kW|abbr=on}} [[diesel engine]], giving a speed of {{convert|11|kn|mph km/h|abbr=on}}.<ref name="wrp56"/><ref name="lcp583">{{harvnb|Lenton|Colledge|1973|p=583}}</ref> Their major minesweeping equipment was the LL sweep,<ref name="bwnp141"/> 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 {{convert|1|acre}}.<ref>{{harvnb|Cowie|1949|pp=128–129}}</ref> They were later fitted with an SA sweep to deal with acoustic mines, which consisted of aan acoustic hammer box mounted on an A-frame on the ship's bow, which could be lowered into the water when required.<ref name="bwnp141"/> The ships did not have enough towing power to use conventional contact sweeps for dealing with moored contact mines.<ref name="bwnp141"/> Defensive armament consisted of two 0.5 inch machine guns and/or one or two [[Oerlikon 20mm cannon]]s. The ships had a complement of 20 men.<ref name="conways22p72"/>

The coastal minesweepers had [[pennant number]]s ''MMS-1'' to ''MMS-118'', ''MMS-123'' to ''MMS-313'' and ''MMS-1001'' to ''MMS-1090'', the last group measuring 126 feet between perpendiculars. They were nicknamed "Mickey Mouse" from their initials.

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 and were quickly disposed of. By 1949, only four remained in service in the Royal Navy: ''St. David'' (''MMS-1733'', ex-''MMS-233''), ''Venturer'' (''MMS-1761'', ex-''MMS-261''), ''MMS-1717'' (ex-''MMS-217'') and ''MMS-1736'' (ex-''MMS-236''). ''St. David'' and ''Venturer'' were tenders to [[RNVR]] divisions.<ref name="McMurtrie and Blackman 1949, p. 61">McMurtrie and Blackman 1949, p. 61</ref>