Auxiliary Motor Minesweepers

Auxiliary motor minesweepers were small wood-hulled minesweepers commissioned by the United States Navy for service during World War II. The vessels were numbered, but unnamed. The auxiliary motor minesweepers were originally designated yard minesweepers (YMS) and kept the abbreviation YMS after being re-designated. The type proved successful and eventually became the basis for the AMS type of United States Navy minesweeper.

The Henry B. Nevins Shipyard, Inc., at City Island, New York, designed the YMS and laid the keel of the first one, USS YMS-1, on 4 March 1941. Launched on 10 January 1942, YMS-1 was completed two months later on 25 March 1942. From keel-layng to completion, the yard built YMS-1 in only three months and 18 days.

The first wooden minesweeper of this class was to gain prominence in all theaters during World War II. A total of 561 were built at various U.S. yards. Originally a class of "motor minesweepers" (MS), "Y" was added to distinguish them from other minesweeper types; sources disagree on whether "Y" stood for "yardcraft" – indicating a type of craft assigned for duty within a navy shipyard or naval base and not expected to go beyond waters adjacent to the base – or to indicate they were built by yacht-builders; YMS's were built at 35 yacht yards, rather than at larger shipyards, 12 on the United States East Coast, 19 on the United States West Coast, and four in yards on the Great Lakes.

Records show that YMS'S were used in the United States Navy to sweep mines laid by enemy submarines as early as 1942 off the ports of Jacksonville, Florida, and Charleston, South Carolina. Many served in the Pacific. One of their greatest losses occurred on 9 October 1945, when seven U.S. Navy YMS's were sunk in a typhoon off Okinawa.

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