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 naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

for service during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. 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 Park, and ...

, 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 sail- or marine propulsion, motor-propelled watercraft made 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 ...

-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. Compared to shipyards, which are sometimes more involved ...

, 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 region encompassing the coast, coastline where the Eastern United States meets the Atlantic Ocean; it has always pla ...

, 19 on the

United States West Coast The West Coast of the United States, also known as the Pacific Coast 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. states of Calif ...

, 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 spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...

Use as minesweepers

Records show that YMSs were used in the

to sweep mines laid by enemy

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

s as early as 1942 off the ports of

Jacksonville, Florida Jacksonville ( ) is the most populous city proper in the U.S. state of Florida, located on the Atlantic coast of North Florida, northeastern Florida. It is the county seat of Duval County, Florida, Duval County, with which the City of Jacksonv ...

, and

Charleston, South Carolina Charleston is the List of municipalities in South Carolina, most populous city in the U.S. state of South Carolina. The city lies just south of the geographical midpoint of South Carolina's coastline on Charleston Harbor, an inlet of the Atla ...

. 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 tropical cyclone that develops between 180° and 100°E in the Northern Hemisphere and which produces sustained hurricane-force winds of at least . This region is referred to as the Northwestern Pacific Basin, accounting for a ...

off

Okinawa most commonly refers to: * Okinawa Prefecture, Japan's southernmost prefecture * Okinawa Island, the largest island of Okinawa Prefecture * Okinawa Islands, an island group including Okinawa itself * Okinawa (city), the second largest city in th ...

. 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 Amphibious means able to use either land or water. In particular it may refer to: Animals * Amphibian, a vertebrate animal of the class Amphibia (many of which live on land and breed in water) * Amphibious caterpillar * Amphibious fish, a fish ...

assaults. Surviving YMSs were reclassified as AMS in 1947, given names, and re-rated as

mine warfare Mine warfare refers to the use of different types of explosive devices: *Land mine, a weight-triggered explosive device intended to maim or kill people or to disable or destroy vehicles * Minelaying, deployment of explosive mines at sea **Naval min ...

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 secret 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 war against Japan, specifically in preparation for planned So ...

, the United States secretly transferred 31 of them to the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

between 17 May and 3 September 1945, and some of these saw action in the

Soviet Navy The Soviet Navy was the naval warfare Military, uniform service branch of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy made up a large part of the Soviet Union's strategic planning in the event of a conflict with t ...

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. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

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 part of the unified (Federal Defense), the German Armed Forces. The German Navy was originally known as the ''Bundesmarine'' (Federal Navy) from 1956 to 1995, when ''Deutsche Marine'' (German Navy) became the official ...

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, 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 authorities of a co ...

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