Agile-class minesweeper explained

The Agile-class minesweepers are a class of US-built ocean-going minesweepers. 58 ships were built for the United States Navy, 35 ships were built for the allied NATO navies of Belgium, France, Italy, the Netherlands, Norway and Portugal. 13 ships were later transferred to Belgium, Spain, Taiwan, the Philippines and Uruguay.

There is some confusion on how to name this class.^[1] The class is often described as the Aggressive-class, as was the first ship to be commissioned. Sometimes four ships are a Dash-class subclass, although all ships are of the same design.^[2]

Design

As a result of experiences during the Korean War, the United States Navy undertook a large scale construction of a new series of minesweepers. In contrast to the steel-hulled minesweepers built before, the Agile-class minesweepers were built mostly of wood with bronze and stainless steel fittings and engines to minimize their magnetic signature. The ships were equipped with the UQS-1 mine-locating sonar and were capable of sweeping moored, bottom contact, magnetic and acoustic mines.^[3]

Modernization

Although it was planned to modernize all U.S. Navy ship of this class, only 19 ships were modernized starting with Fiscal Year 1968. The modernization cost between 700,000 and 1,500,000 $ per ship and should enable them to operate for another ten years. The ships received new aluminum block Waukesha diesel engines and the superstructure was enlarged aft. The UQS-1 sonar was replaced with SQQ-14. Two PAP-104 cable-guided undersea tools were added. Also, two 40 hp zodiacs were carried for the purpose of mooring the new sonar reflectors. Also, a team of mine clearance divers was added. Additional space on the foc'sle was needed for installation of the SQQ-14 cabling so the 40mm Bofors bow gun was replaced with a mount for a twin 20 mm Mk 68 gun.^[4]

As of 2015, the four ships transferred to Taiwan are still in service.

Construction and disposition

Ship Name	Hull No.	Builder	Commission– Decommission	Fate	Link
	421	Luders Marine Construction Co. of Stamford, Connecticut	1956–1972	Sold for scrap 1980	[{{Naval Vessel Register URL|id=MSO421}}]
	422	Luders Marine Construction Co. of Stamford, Connecticut	1953–1971	Sold for scrap 1980	[{{Naval Vessel Register URL|id=MSO422}}]
	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	[{{Naval Vessel Register URL|id=MSO424}}]
	425	Norfolk Naval Shipyard	1953-1971	Sold for scrap 1980	[{{Naval Vessel Register URL|id=MSO425}}]
	426	Fulton Shipyard, Antioch, California	1954-1973	Sold for scrap 1973	[{{Naval Vessel Register URL|id=MSO426}}]
	427	Fulton Shipyard, Antioch, California	1954-1992	Sold for scrap 2001	[{{Naval Vessel Register URL|id=MSO427}}]
	428	Astoria Marine Construction, Astoria, Oregon	1953-1982	Sold for scrap 1984	[{{Naval Vessel Register URL|id=MSO428}}]
	429	Astoria Marine Construction, Astoria, Oregon	1953-1982	Sold for scrap 1984	[{{Naval Vessel Register URL|id=MSO429}}]
	430	Hiltebrant Dry Dock Co., Kingston, New York	1954-1982	Sold for scrap 1984	[{{Naval Vessel Register URL|id=MSO430}}]
	431	Hiltebrant Dry Dock Co., Kingston, New York	1954-1982	Sold for scrap 1984	[{{Naval Vessel Register URL|id=MSO431}}]
	432		1953-1971 1971-1998	1971 to Spain as Guadalete (M41) 1971, decommissioned 1998	[{{Naval Vessel Register URL|id=MSO432}}]
	433		1953-1991	Scrapped 2002	[{{Naval Vessel Register URL|id=MSO433}}]
	434		1954-1972	Sold to be scrapped 1976, privately held until scrapped by the USACE in 1993.	[{{Naval Vessel Register URL|id=MSO434}}]
	435		1954-1972	Sold for scrap 1973	[{{Naval Vessel Register URL|id=MSO435}}]
	436		1954-1972 1972-1977	1972 to the Philippines as BRP Davao del Norte (PM-91) Sold for scrap 1977	[{{Naval Vessel Register URL|id=MSO436}}]
	437		1955-1991	Sold for scrap 2000	[{{Naval Vessel Register URL|id=MSO437}}]
	438		1955-1991	Sold for scrap 2000	[{{Naval Vessel Register URL|id=MSO438}}]
	439		1955-1992	Sold for scrap 2000	[{{Naval Vessel Register URL|id=MSO439}}]
	440		1954-1993	Sold for scrap 2002	[{{Naval Vessel Register URL|id=MSO440}}]
	441		1954-1993	Sold for scrap 2002	[{{Naval Vessel Register URL|id=MSO441}}]
	442		1954-1990	Sold for scrap 1992	[{{Naval Vessel Register URL|id=MSO442}}]
	443		1955-1989	Sold for scrap 1990	[{{Naval Vessel Register URL|id=MSO443}}]
	444		1954-1972 1972-1977	1972 to the Philippines as BRP Davao del Sur (PM-92), scrapped 1977	[{{Naval Vessel Register URL|id=MSO444}}]
	445		1955-1973	Sunk after a fire	[{{Naval Vessel Register URL|id=MSO445}}]
	446		1954-1992	Scrapped 2002	[{{Naval Vessel Register URL|id=MSO446}}]
	447		1955-1972	Sold for scrap 1973	[{{Naval Vessel Register URL|id=MSO447}}]
	448		1953-1990	Sold for scrap 1993	[{{Naval Vessel Register URL|id=MSO448}}]
	449		1954-1991	Scrapped 2002	[{{Naval Vessel Register URL|id=MSO449}}]
Berneval	450		1954-1987	Built for France, scrapped	http://www.navsource.org/archives/11/02450.htm
Bir Hacheim	451		1954-1970 1970-1979	Built for France, transferred to Uruguay in 1970 and renamed Maldanado (MS 33), scrapped 1979	http://www.navsource.org/archives/11/02451.htm
Garigliano	452		1954-1988	Built for France, struck 1988	http://www.navsource.org/archives/11/02452.htm
Alençon	453		1954-1983	Built for France, struck 1983	http://www.navsource.org/archives/11/02453.htm
Dompaire	454		1954-1983	Built for France, struck 1983	http://www.navsource.org/archives/11/02453.htm
	455		1954-1994	Sold to Taiwan 1994	[{{Naval Vessel Register URL|id=MSO455}}]
	456		1954-1990	Sold for scrap 1992	[{{Naval Vessel Register URL|id=MSO456}}]
	457		1954-1972	Sold for scrap 1973	[{{Naval Vessel Register URL|id=MSO457}}]
	458		1955-1970	Sold for scrap 1976 Currently being restored by the Stockton Historical Maritime Museum as a museum ship	[{{Naval Vessel Register URL|id=MSO458}}]
	459		1955-1970	Sold for scrap 1981	[{{Naval Vessel Register URL|id=MSO459}}]
	460		1955-1970	Sold for scrap 1971	[{{Naval Vessel Register URL|id=MSO460}}]
	461		1955-1972	Sold for scrap 1979	[{{Naval Vessel Register URL|id=MSO461}}]
	462		1955-1970	Sold for scrap 1978	[{{Naval Vessel Register URL|id=MSO462}}]
	463		1954-1971 1974-1999	1974 to Spain as Guadalmedina (M42), scrapped 1999	[{{Naval Vessel Register URL|id=MSO463}}]
	464		1954-1990	Sold for scrap 1992	[{{Naval Vessel Register URL|id=MSO464}}]
	465		1954-1958
	466		1954-1970	Sold for scrap 1976	[{{Naval Vessel Register URL|id=MSO466}}]
	467		1954-1972	Sold for scrap 1976	[{{Naval Vessel Register URL|id=MSO467}}]
	468		1954-1970	Sold for scrap 1971	[{{Naval Vessel Register URL|id=MSO468}}]
	469		1955-1970	Grounded at Charleston, sold for scrap 1970.
	470		1955-1970	Sold for scrap 1971	[{{Naval Vessel Register URL|id=MSO470}}]
	471		1950-1970	Sold for scrap 1979	[{{Naval Vessel Register URL|id=MSO471}}]
	472		1954-1970	Sold for scrap 1971	[{{Naval Vessel Register URL|id=MSO472}}]
	473		1954-1972 1972-1999	1972 to Spain as Guadiana (M44), scrapped 1999.	[{{Naval Vessel Register URL|id=MSO473}}]
	474		1955-1972	Sold for scrap 1979	[{{Naval Vessel Register URL|id=MSO474}}]
Mytho	475	Bellingham Shipyards Co., Bellingham, Washington	1955-1988	Built for France, scrapped 1989	http://www.navsource.org/archives/11/02475.htm
Cantho	476	Bellingham Shipyards Co., Bellingham, Washington	1955-1987	Built for France, struck 1987	http://www.navsource.org/archives/11/02476.htm
Vinh Long	477	Bellingham Shipyards Co., Bellingham, Washington	1955-1988	Built for France, scrapped 1992	http://www.navsource.org/archives/11/02477.htm
São Jorge	478	Bellingham Shipyards Co., Bellingham, Washington	1955-1973	Built for Portugal, scrapped 1973	http://www.navsource.org/archives/11/02478.htm
Pico	479	Bellingham Shipyards Co., Bellingham, Washington	1955-1974	Built for Portugal; transferred to Belgium for spare parts, burned out in 1997, scrapped in 2011	http://www.navsource.org/archives/11/02479.htm
Onversaagd	480	Astoria Marine Construction, Astoria, Oregon	1955-1979	Built for the Netherlands, reclassified A854 in 1965, scrapped 1979	http://www.navsource.org/archives/11/02480.htm
Onbevreesd	481	Astoria Marine Construction, Astoria, Oregon	1955-1988	Built for the Netherlands, reclassified A855 in 1965, scrapped 1989	http://www.navsource.org/archives/11/02481.htm
Onvervaard	482	Astoria Marine Construction, Astoria, Oregon	1955-1984	Built for the Netherlands, reclassified A858 in 1965, scrapped 1984	http://www.navsource.org/archives/11/02482.htm
Onverschrokken	483	Peterson Builders, Sturgeon Bay, Wisconsin	1955-1987	Built for the Netherlands, converted to torpedo retriever Mercuur (A856) in 1973, decommissioned 1987 and preserved as museum ship in Vlissingen	http://www.navsource.org/archives/11/02483.htm
Onvermoeid	484	Peterson Builders, Sturgeon Bay, Wisconsin	1955-1974	Built for the Netherlands, reclassified A857 in 1965, scrapped 1975	http://www.navsource.org/archives/11/02484.htm
Onverdroten)	485	Peterson Builders, Sturgeon Bay, Wisconsin	1955-1984	Built for the Netherlands, reclassified A859 in 1965, scrapped 1985	http://www.navsource.org/archives/11/02485.htm
	486		1955-1973	Built for Portugal, scrapped 1973	http://www.navsource.org/archives/11/02486.htm
Corvo	487		1955-1973	Built for Portugal, scrapped 1973	http://www.navsource.org/archives/11/02487.htm
	488		1955-1994 1994-2020	1994 to Taiwan as Yung Tzu (MSO-1307)	[{{Naval Vessel Register URL|id=MSO488}}]
	489		1955-1994 1994-2013	1994 to Taiwan as Yung Ku (MSO-1308)	[{{Naval Vessel Register URL|id=MSO489}}]
	490		1955-1991	Sold for scrap 1994	[{{Naval Vessel Register URL|id=MSO490}}]
	491		1956-1971 1971-2000	1971 to Spain as Guadalquivir (M43), scrapped	[{{Naval Vessel Register URL|id=MSO491}}]
	492		1956-1994 1994-	1994 to Taiwan Yung Teh (MSO-1309)	[{{Naval Vessel Register URL|id=MSO492}}]
	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	[{{Naval Vessel Register URL|id=MSO494}}]
	495		1957-1971	Sold for scrap 1978	[{{Naval Vessel Register URL|id=MSO495}}]
	496	Broward Marine Inc, Fort Lauderdale, Florida	1958-1971	Sold for scrap 1978	[{{Naval Vessel Register URL|id=MSO496}}]
MSO-497	497	Cancelled
Lågen	498	Bellingham Shipyards Co., Bellingham, Washington	1955-1966 1966-1996	Built for Norway; transferred to Belgium in 1966 as Dufour (M 903), scrapped 2007	http://www.navsource.org/archives/11/02498.htm
Namsen	499	Bellingham Shipyards Co., Bellingham, Washington	1955-1966 1966-1993	Built for Norway; transferred to Belgium in 1966 as De Brouwer (M 904), scrapped 2007	http://www.navsource.org/archives/11/02499.htm
Berlaimont	500	Bellingham Shipyards Co., Bellingham, Washington	1956-1986	Built for France, scrapped 1986	http://www.navsource.org/archives/11/02500.htm
Origny	501	Bellingham Shipyards Co., Bellingham, Washington	1956-1983	Built for France, converted to oceanographic research ship in 1962, reclassified A640 in 1974, struck 1985	http://www.navsource.org/archives/11/02501.htm
Autun	502	Bellingham Shipyards Co., Bellingham, Washington	1956-1985	Built for France, scrapped 1985	http://www.navsource.org/archives/11/02502.htm
Artevelde	503	Tacoma Boatbuilding Company, Tacoma, Washington	1956-1985	Built for Belgium, scrapped 1985	http://www.navsource.org/archives/11/02503.htm
Breydel	504	Tacoma Boatbuilding Company, Tacoma, Washington	1956-1993	Built for Belgium, scrapped 2006	http://www.navsource.org/archives/11/02504.htm
Baccarat	505	Tacoma Boatbuilding Company, Tacoma, Washington	1956-1993	Built for France, struck 1993	http://www.navsource.org/archives/11/02505.htm
	506		1956-1997	Built for Italy, struck 1997	http://www.navsource.org/archives/11/02506.htm
	506		1956-1996	Built for Italy, struck 1996	http://www.navsource.org/archives/11/02507.htm
Narvik	512	Peterson Builders, Sturgeon Bay, Wisconsin	1956-1988	Built for France, reclassified A769 in 1976, struck 1989	http://www.navsource.org/archives/11/02512.htm
Ouistreham	513	Peterson Builders, Sturgeon Bay, Wisconsin	1956-1994	Built for France, struck 1994	http://www.navsource.org/archives/11/02513.htm
Colmar	514	Peterson Builders, Sturgeon Bay, Wisconsin	1956-1976	Built for France, scrapped 1985	http://www.navsource.org/archives/11/02514.htm
Georges Truffaut	515	Tampa Marine Co., Tampa, Florida	1956-2000	Built for Belgium, scrapped 2007	http://www.navsource.org/archives/11/02515.htm
F. Bovesse	516	Tampa Marine Co., Tampa, Florida	1956-1993	Built for Belgium, scrapped 2004	http://www.navsource.org/archives/11/02516.htm
Sgombro	517	Tampa Marine Co., Tampa, Florida	1957-2000	Built for Italy, reclassified P5432 in 1990, decommissioned 2000	http://www.navsource.org/archives/11/02517.htm
Squalo	518	Tampa Marine Co., Tampa, Florida	1957-2000	Built for Italy, reclassified P5433 in 1990, decommissioned 2000	http://www.navsource.org/archives/11/02518.htm

External links

• FAS - MSO-422 class
• GlobalSecurity - MSO-422 class

Notes and References

1. http://www.navsource.org/archives/11/02idx.htm navsource.org minesweeper class
2. Paul H. Silverstone: US Warships since 1945. Allan Ltd., Shepperton, Surrey (UK) 1986, p. 127.
3. Stefan Terzibaschitsch: Seemacht USA. Bechtermünz Verlag, Augsburg (Germany) 1997, p. 609.
4. Terzibaschitsch, p. 609; http://www.allwoodships.com/MilitaryShips/MineWarfare/AM-421,Agile-Aggressive.htm