Destroyer minesweeper was a designation given by the United States Navy to a series of destroyers that were converted into high-speed ocean-going minesweepers for service during World War II. The hull classification symbol for this type of ship was "DMS." Forty-two ships were so converted, beginning with USS Dorsey (DD-117), converted to DMS-1 in late 1940, and ending with USS Earle (DD-635), converted to DMS-42 in mid-1945. The type is now obsolete, its function having been taken over by purpose-built ships, designated as "minesweeper (high-speed)" with the hull classification symbol MMD.
The Clemson-class destroyers and Wickes-class destroyers chosen for conversion were obsolete four-stack destroyers built in 1918 that still had usable power plants; they were nicknamed "four-pipers" on account of their four smokestacks. Although the full conversion process to minesweepers for the original 17 Wickes and Clemson-class destroyers began in October—November 1940, it was not completed for all 17 until around mid-1942. When they were fully converted from destroyers to destroyer minesweepers, the number 4 boiler, the fourth stack from the bow, and the torpedo tubes were removed, the depth charge racks repositioned forward from the stern and angled outboard, and the stern modified to support sweep gear: davits, winch, paravanes, and kites. Two 60-kilowatt turbo-generators replaced the three original 25-kilowatt generators to improve capability for sweeping magnetic and acoustic mines.
The majority of mines left by the Japanese in the Pacific were contact mines which were usually moored and could be removed by a paravane. The Japanese never created their own magnetic or pressure mines, though they captured a very limited number of magnetic mines from the British which they laid off Balikpapan in 1945. Magnetic mines in the European theater were usually disabled by towing a magnetized cable, often swept by wooden-hulled ships, but occasionally swept by iron-clad ships that were degaussed to mask their magnetic properties. Minesweeping in the Pacific theater in World War II consisted primarily in the use of sweep wires suspended between paravanes and kites, particularly among destroyer minesweepers.[1]