Aggressive-class minesweeper

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.

USS Constant (MSO-427) in 1988
Class overview
NameAggressive class
Operators
SubclassesOnversaagd class
In commission1953–Present
Completed53
Active1
Retired52
Preserved2
General characteristics
TypeMinesweeper
Displacement853 tons (full load)
Length172 ft (52 m)
Beam35 ft (11 m)
Draft10 ft (3 m)
Propulsion
  • 4 × aluminum block Waukesha diesels, 2,400 bhp (1,800 kW)
  • 2 × shafts
  • 2 × controllable pitch propellers
Speed14 knots (26 km/h; 16 mph)
Complement7 officers, 70 enlisted
Sensors and
processing systems
AN/SQQ-14 mine hunting sonar
Armament

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 Yung Yang-class minesweepers. They were still in active service in 2012. USS Implicit 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 Link
Aggressive[1] 422 Luders Marine Construction Co. of Stamford, Connecticut 1953–1971 Sold for scrap 1980
Avenge 423 Luders Marine Construction Co. of Stamford, Connecticut 1954-1970 Destroyed by fire, sold for scrapping 1969
Bold[2]424Norfolk Naval Shipyard1953-1971Sold for scrap 1981
Bulwark[3] 425 Norfolk Naval Shipyard 1953-1971 Sold for scrap 1980
Conflict[4] 426Fulton Shipyard, Antioch, California 1954-1973 Sold for scrap 1973
Constant427Fulton Shipyard, Antioch, California1954-1992Sold for scrap 2001Naval Vessel Register
428 - 431 were US Dash-class minesweepers
Dynamic432Colberg Boat Works, Stockton, California1953-1971Sold or loaned to Spain as Guadalete M41, 1971.Naval Vessel Register
Engage433Colberg Boat Works, Stockton, California1953-1991Scrapped 2002Naval Vessel Register
Embattle434Colberg Boat Works, Stockton, California1954-1972Sold to be scrapped 1976, privately held until scrapped by USACE in 1993.Naval Vessel Register
Endurance435J. M. Martinac Shipbuilding Corp., Tacoma, Washington1954-1972Sold for scrap 1973Naval Vessel Register
Energy436J. M. Martinac Shipbuilding Corp., Tacoma, Washington1954-1972Loaned to Philippines 1972
Sold for scrap 1977
Naval Vessel Register
Enhance437Martinolich Shipbuilding Co., San Diego, California1955-1970
1971-1991
Sold for scrap 2000Naval Vessel Register
Esteem438Martinolich Shipbuilding Co., San Diego, California1955-1970
1971-1991
Sold for scrap 2000Naval Vessel Register
Excel439Higgins Corp., New Orleans, Louisiana1955-1992Sold for scrap 2000Naval Vessel Register
Exploit440Higgins Corp., New Orleans, Louisiana1954-1993Sold for scrap 2002Naval Vessel Register
Exultant441Higgins Corp., New Orleans, Louisiana1954-1993Sold for scrap 2002Naval Vessel Register
Fearless442Higgins Corp., New Orleans, Louisiana1954-1990Sold for scrap 1992Naval Vessel Register
Fidelity443Higgins Corp., New Orleans, Louisiana1955-1989Sold for scrap 1990Naval Vessel Register
Firm444J. M. Martinac Shipbuilding Corp., Tacoma, Washington1954-1972Loaned to Philippines 1972
Scrapped 1977
Naval Vessel Register
Force445J. M. Martinac Shipbuilding Corp., Tacoma, Washington1955-1973Sunk after a fireNaval Vessel Register
Fortify446Seattle Shipbuilding and Drydocking Co., Seattle, Washington1954-1992Scrapped 2002Naval Vessel Register
Guide447Seattle Shipbuilding and Drydocking Co., Seattle, Washington1955-1972Sold for scrap 1973Naval Vessel Register
Illusive448Martinolich Shipbuilding Co., San Diego, California1953-1990Sold for scrap 1993Naval Vessel Register
Impervious449Martinolich Shipbuilding Co., San Diego, California1954-1991Scrapped 2002Naval Vessel Register
450 - 454 built at Bellingham Shipyards Co., Bellingham, Washington for France, not necessarily Aggressive-class ships.
Implicit455Wilmington Boat Works Inc., Wilmington, California1954-1994Sold to Taiwan 1994Naval Vessel Register
Inflict456Wilmington Boat Works Inc., Wilmington, California1954-1990Sold for scrap 1992Naval Vessel Register
Loyalty457Wilmington Boat Works Inc., Wilmington, California1954-1972Sold for scrap 1973Naval Vessel Register
Lucid458Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1976
Currently being restored by the Stockton Historical Maritime Museum as a museum ship
Naval Vessel Register
Nimble459Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1981Naval Vessel Register
Notable 460 Higgins Corp., New Orleans, Louisiana 1955-1970 Sold for scrap 1971 Naval Vessel Register
Observer 461 Higgins Corp., New Orleans, Louisiana 1955-1972 Sold for scrap 1979 Naval Vessel Register
Pinnacle462Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1978Naval Vessel Register
Pivot463Wilmington Boat Works Inc., Wilmington, California1954-1971Initially loaned then sold to Spain as Guadalmedina M42, 1974. Decommissioned by Spain 2001.Naval Vessel Register
Pluck464Wilmington Boat Works Inc., Wilmington, California1954-1990Sold for scrap 1992Naval Vessel Register
Prestige465Wilmington Boat Works Inc., Wilmington, California1954-1958Grounded and sunk, 1958 in the Naruto Strait
Prime466Wilmington Boat Works Inc., Wilmington, California1954-1970Sold for scrap 1976Naval Vessel Register
Reaper467Wilmington Boat Works Inc., Wilmington, California1954-1972Sold for scrap 1976Naval Vessel Register
Rival468Luders Marine Construction Co. of Stamford, Connecticut1954-1970Sold for scrap 1971Naval Vessel Register
Sagacity469Luders Marine Construction Co. of Stamford, Connecticut1955-1970Grounded at Charleston Harbor then sold for scrap 1970.
Salute470Luders Marine Construction Co. of Stamford, Connecticut1955-1970Sold for scrap 1971Naval Vessel Register
Skill471Luders Marine Construction Co. of Stamford, Connecticut1950-1970Sold for scrap 1979, scrapped 1983.Naval Vessel Register
Valor472Burger Boat Company, Manitowoc, Wisconsin1954-1970Sold for scrap 1971Naval Vessel Register
Vigor473Burger Boat Company, Manitowoc, Wisconsin1954-1972Sold to Spain as Guadiana M44, 1972. Scrapped by Spain after 1999.Naval Vessel Register
Vital474Burger Boat Company, Manitowoc, Wisconsin1955-1972Sold for scrap 1979Naval Vessel Register
475 - 487 built for France, Portugal, Spain, Belgium and the Netherlands, not necessarily Aggressive-class ships.
Conquest 488 J. M. Martinac Shipbuilding Corp., Tacoma, Washington 1955-1970
1971-1994
Sold to Taiwan 1994 and decommissioned in 2020. Naval Vessel Register
Gallant 489J. M. Martinac Shipbuilding Corp., Tacoma, Washington 1955-1994 Sold to Taiwan 1994 and decommissioned in 2013. Naval Vessel Register
Leader 490 J. M. Martinac Shipbuilding Corp., Tacoma, Washington 1955-1970
1971-1991/92
Sold for scrap 1994 Naval Vessel Register
Persistent 491J. M. Martinac Shipbuilding Corp., Tacoma, Washington 1956-1971 Initially loaned in 1971 then sold to Spain as Guadalquivir M43 Naval Vessel Register
Pledge[5] 492 J. M. Martinac Shipbuilding Corp., Tacoma, Washington 1956-1994 Sold to Taiwan 1994 and decommissioned 2021. Naval Vessel Register
Stalwart493Broward Marine Inc, Fort Lauderdale, Florida1956-1966Caught fire pier side at San Juan, Puerto Rico, sunk 1966. Later raised and sunk as an artificial reef.
Sturdy494Broward Marine Inc, Fort Lauderdale, Florida1957-1971Sold for scrap 1978Naval Vessel Register
Swerve495Broward Marine Inc, Fort Lauderdale, Florida1957-1971Sold for scrap 1978Naval Vessel Register
Venture [6] 496 Broward Marine Inc, Fort Lauderdale, Florida 1958-1971 Sold for scrap 1978
MSO-497 497 Cancelled, never built

See also

References

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