Aggressive-class minesweeper explained

The Aggressive-class minesweepers are a class of US-built minesweepers. They are designated as MSO (Mine Sweeper Ocean), distinguishing them from the smaller coastal MSCs and inshore MSIs. Besides the US Navy, this class of vessels has also been used by the Belgian Navy and the Norwegian Navy, among others.

Background

Minesweeping, or the disposal of naval mines, by these vessels is performed in different ways:

Sweeping proper, with an underwater cable cutting the mooring cables of moored mines. The mines then come to the surface and are destroyed by gunfire.
Acoustic sweeping, with a towed device producing noise to trigger acoustic mines.
Magnetic sweeping, with a towed device producing a magnetic field to trigger magnetic mines. To protect the minesweeper itself against magnetic mines, the hull and superstructure of the ship are made of wood. Other components are made of non-magnetic materials, and any magnetic materials are strictly controlled.

Construction and disposition

Of the 53 constructed for the United States Navy, 10 were built at Higgins Corp., New Orleans, Louisiana, 9 at J.M. Martinac Shipbuilding Corp., Tacoma, Washington, 8 at Wilmington Boat Works Inc., Wilmington, California, 6 at Luders Marine Construction Co. of Stamford, Connecticut, 4 at Broward Marine Inc, Fort Lauderdale, Florida, 4 at Martinolich Shipbuilding Co., San Diego, California, 3 at Burger Boat Company, Manitowoc, Wisconsin, 3 at Colberg Boat Works, Stockton, California, 2 at Fulton Shipyard, Antioch, California, 2 at Norfolk Naval Shipyard and 2 at Seattle Shipbuilding and Drydocking Co., Seattle, Washington.

33 of the class were decommissioned before the mid-1970s. Four ex-USN ships were sold to the Republic of China Navy 1994 and re-classed as s. They were still in active service in 2012. was decommissioned 30 September 1994 in Tacoma, Washington and was the last Aggressive-class minesweeper in US Navy active service.

Units

Ship Name	Hull no.	Builder	Commission– Decommission	Fate
	422	Luders Marine Construction Co. of Stamford, Connecticut	1953–1971	Sold for scrap 1980
	423	Luders Marine Construction Co. of Stamford, Connecticut	1954-1970	Destroyed by fire, sold for scrapping 1969
	424	Norfolk Naval Shipyard	1953-1971	Sold for scrap 1981
	425	Norfolk Naval Shipyard	1953-1971	Sold for scrap 1980
	426	Fulton Shipyard, Antioch, California	1954-1973	Sold for scrap 1973
	427	Fulton Shipyard, Antioch, California	1954-1992	Sold for scrap 2001
428 - 431 were US Dash-class minesweepers
	432		1953-1971	Sold or loaned to Spain as Guadalete M41, 1971.
	433		1953-1991	Scrapped 2002
	434		1954-1972	Sold to be scrapped 1976, privately held until scrapped by USACE in 1993.
	435	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1954-1972	Sold for scrap 1973
	436	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1954-1972	Loaned to Philippines 1972 Sold for scrap 1977
	437		1955-1970 1971-1991	Sold for scrap 2000
	438		1955-1970 1971-1991	Sold for scrap 2000
	439		1955-1992	Sold for scrap 2000
	440		1954-1993	Sold for scrap 2002
	441		1954-1993	Sold for scrap 2002
	442		1954-1990	Sold for scrap 1992
	443		1955-1989	Sold for scrap 1990
	444	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1954-1972	Loaned to Philippines 1972 Scrapped 1977
	445	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1955-1973	Sunk after a fire
	446		1954-1992	Scrapped 2002
	447		1955-1972	Sold for scrap 1973
	448		1953-1990	Sold for scrap 1993
	449		1954-1991	Scrapped 2002
450 - 454 built at Bellingham Shipyards Co., Bellingham, Washington for France, not necessarily Aggressive-class ships.
	455	Wilmington Boat Works Inc., Wilmington, California	1954-1994	Sold to Taiwan 1994
	456	Wilmington Boat Works Inc., Wilmington, California	1954-1990	Sold for scrap 1992
	457	Wilmington Boat Works Inc., Wilmington, California	1954-1972	Sold for scrap 1973
	458		1955-1970	Sold for scrap 1976 Currently being restored by the Stockton Historical Maritime Museum as a museum ship
	459		1955-1970	Sold for scrap 1981
	460		1955-1970	Sold for scrap 1971
	461		1955-1972	Sold for scrap 1979
	462		1955-1970	Sold for scrap 1978
	463	Wilmington Boat Works Inc., Wilmington, California	1954-1971	Initially loaned then sold to Spain as Guadalmedina M42, 1974. Decommissioned by Spain 2001.
	464	Wilmington Boat Works Inc., Wilmington, California	1954-1990	Sold for scrap 1992
	465	Wilmington Boat Works Inc., Wilmington, California	1954-1958
	466	Wilmington Boat Works Inc., Wilmington, California	1954-1970	Sold for scrap 1976
	467	Wilmington Boat Works Inc., Wilmington, California	1954-1972	Sold for scrap 1976
	468		1954-1970	Sold for scrap 1971
	469		1955-1970	Grounded at Charleston Harbor then sold for scrap 1970.
	470		1955-1970	Sold for scrap 1971
	471		1950-1970	Sold for scrap 1979, scrapped 1983.
	472		1954-1970	Sold for scrap 1971
	473		1954-1972	Sold to Spain as Guadiana M44, 1972. Scrapped by Spain after 1999.
	474		1955-1972	Sold for scrap 1979
475 - 487 built for France, Portugal, Spain, Belgium and the Netherlands, not necessarily Aggressive-class ships.
	488	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1955-1970 1971-1994	Sold to Taiwan 1994 and decommissioned in 2020.
	489	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1955-1994	Sold to Taiwan 1994 and decommissioned in 2013.
	490	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1955-1970 1971-1991/92	Sold for scrap 1994
	491	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1956-1971	Initially loaned in 1971 then sold to Spain as Guadalquivir M43
	492	J. M. Martinac Shipbuilding Corp., Tacoma, Washington	1956-1994	Sold to Taiwan 1994 and decommissioned 2021.
	493		1956-1966	Caught fire pier side at San Juan, Puerto Rico, sunk 1966. Later raised and sunk as an artificial reef.
	494		1957-1971	Sold for scrap 1978
	495		1957-1971	Sold for scrap 1978
	496	Broward Marine Inc, Fort Lauderdale, Florida	1958-1971	Sold for scrap 1978
MSO-497	497	Cancelled, never built

Aggressive-class minesweeper explained

Background

Construction and disposition

Units

See also

External links