Auxiliary motor minesweepers were small wood-hulled

minesweeper A minesweeper is a small warship designed to remove or detonate naval mines. Using various mechanisms intended to counter the threat posed by naval mines, minesweepers keep waterways clear for safe shipping. History The earliest known usage of ...

s commissioned by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

for service during

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

. 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.

Origin of the YMS

The Henry B. Nevins Shipyard, Inc., at

City Island, Bronx City Island is a neighborhood in the northeastern Bronx in New York City, located on an island of the same name approximately long by wide. City Island is located at the extreme western end of Long Island Sound, south of Pelham Bay and east o ...

, designed the YMS and laid the keel of the first one, , on 4 March 1941. Launched on 10 January 1942, ''YMS-1'' was completed two months later on 25 March 1942. From keel-laying to completion, the yard built ''YMS-1'' in one year and three weeks.

The "Y" designation

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 A yacht is a sailing or power vessel used for pleasure, cruising, or racing. There is no standard definition, though the term generally applies to vessels with a cabin intended for overnight use. To be termed a , as opposed to a , such a pleasu ...

-builders; YMSs were built at 35

yards, rather than at larger

shipyards A shipyard, also called a dockyard or boatyard, is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance a ...

, 12 on the

United States East Coast The East Coast of the United States, also known as the Eastern Seaboard, the Atlantic Coast, and the Atlantic Seaboard, is the coastline along which the Eastern United States meets the North Atlantic Ocean. The eastern seaboard contains the coa ...

, 19 on the

United States West Coast The West Coast of the United States, also known as the Pacific Coast, Pacific states, and the western seaboard, is the coastline along which the Western United States meets the North Pacific Ocean. The term typically refers to the contiguous U.S ...

, and four in yards on the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...

Use as minesweepers

Records show that YMSs were used in the

to sweep mines laid by enemy

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

s as early as 1942 off the ports of

Jacksonville, Florida Jacksonville is a city located on the Atlantic coast of northeast Florida, the most populous city proper in the state and is the largest city by area in the contiguous United States as of 2020. It is the seat of Duval County, with which the ...

, and

Charleston, South Carolina Charleston is the largest city in the U.S. state of South Carolina, the county seat of Charleston County, and the principal city in the Charleston–North Charleston metropolitan area. The city lies just south of the geographical midpoint o ...

. Many served in the Pacific. One of their greatest losses occurred on 9 October 1945, when seven U.S. Navy YMSs were sunk in a

typhoon A typhoon is a mature tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere. This region is referred to as the Northwestern Pacific Basin, and is the most active tropical cyclone basin on Earth, accounting for a ...

off

Okinawa is a prefecture of Japan. Okinawa Prefecture is the southernmost and westernmost prefecture of Japan, has a population of 1,457,162 (as of 2 February 2020) and a geographic area of 2,281 km2 (880 sq mi). Naha is the capital and largest city ...

. The wood-hulled YMS proved to be one of the U.S. Navys more durable and versatile types through a quarter-century of service, filling a variety of roles for a number of navies.

Characteristics

All 481 ships of this type had the same general characteristics. The only significant variation within the type was one of appearance; ''YMS-1'' through ''YMS-134'' had two stacks, ''YMS-135'' through ''YMS-445'', ''YMS-480'', and ''YMS-481'' had one, while ''YMS-446'' through ''YMS-479'' had none.

History

Originally rated as service craft, they were used during World War II for inshore sweeping to prepare the way for amphibious assaults. Surviving YMSs were reclassified as AMS in 1947, given names, and re-rated as mine warfare ships; in 1955 they received the new type symbol MSC(O), changed to MSCO in 1967. These ships bore much of the mine warfare burden in Korea, formed a major portion of U.S. Navy minecraft strength through the 1950s, and provided underway training for Naval Reservists in the 1960s. A number of YMSs were transferred to other navies during or after the war. During

Project Hula Project Hula was a program during World War II in which the United States transferred naval vessels to the Soviet Union in anticipation of the Soviets eventually joining the Pacific War, war against Japan, specifically in preparation for planne ...

, the United States secretly transferred 31 of them to the

Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...

between 17 May and 3 September 1945, and some of these saw action in the Soviet Navy during Soviet military operations against the Japanese between 9 August and 5 September 1945. The transfer of five more was canceled when transfers halted on 5 September 1945. One, ''T-610'' (ex-), sank in 1945 while in Soviet service, and the Soviet Union transferred two, ''T-605'' (ex-) and ''T-611'' (ex-), to the

People's Republic of China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

after striking them from the Soviet Navy list in 1955; during 1955 and 1956 the other 28 were scrapped by the Soviet Union or destroyed off its coast by mutual agreement between the two countries.Russell, Richard A., ''Project Hula: Secret Soviet-American Cooperation in the War Against Japan'', Washington, D.C.:

Naval Historical Center The Naval History and Heritage Command, formerly the Naval Historical Center, is an Echelon II command responsible for the preservation, analysis, and dissemination of U.S. naval history and heritage located at the historic Washington Navy Yard. ...

, 1997, , pp. 29, 35, 37-38, 40. Five YMSs served in the

German Navy The German Navy (, ) is the navy of Germany and part of the unified ''Bundeswehr'' (Federal Defense), the German Armed Forces. The German Navy was originally known as the ''Bundesmarine'' (Federal Navy) from 1956 to 1995, when ''Deutsche Mari ...

in different functions for tests, trials, and training; all of them had a civilian crew and were decommissioned between 1975 and 1988.Siegfried Breyer, Gerhard Koop; Die Schiffe und Fahrzeuge der deutschen Bundesmarine 1956 - 1976; München 1978; (German)

''YMS-327'' last YMS in service

, originally ''YMS-327'', the last of her kind in U.S. service, was struck from the

Navy List A Navy Directory, formerly the Navy List or Naval Register is an official list of naval officers, their ranks and seniority, the ships which they command or to which they are appointed, etc., that is published by the government or naval autho ...

in November 1969.

References

External links

Auxiliary Motor Minesweeper (YMS)
{{Project Hula ships Mine warfare vessel classes Minesweepers of the United States Navy Auxiliary City Island, Bronx Ships built in City Island, Bronx