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
Name: Aggressive class
Operators:
In commission: 1953–Present
Completed: 53
Preserved: 2
General characteristics
Type: Minesweeper
Displacement: 853 tons (full load)
Length: 172 ft (52 m)
Beam: 35 ft (11 m)
Draft: 10 ft (3 m)
Propulsion:
  • 4 × aluminum block Waukesha diesels, 2,400 bhp (1,800 kW)
  • 2 × shafts
  • 2 × controllable pitch propellers
Speed: 14 knots (26 km/h; 16 mph)
Complement: 7 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.

General development of minesweeping

Minesweepers have been in operation since World War I and originally involved a simple metal detector, which sailors used to locate naval mines. This practice was dangerous not only from the risk of missing and detonating a mine, but also because the enemy would be making the task harder for the sweepers by keeping them under constant, heavy fire. Minesweepers were greatly admired by their peers because of their bravery.

Aggressive-class minesweepers used AN/SQQ-14 mine hunting sonar to locate moored or bottom mines. They used electromagnetic cables to set off mines or other cables to cut their mooring lines, and various magnetic and acoustical devices to set off mines. Toward the end of their use, the class also employed remote submersibles like Super Sea Rover to locate and classify mines.

Today, active minesweepers or minehunters are frequently used. The Royal Navy of the United Kingdom uses small submarines that are controlled by wireless operators on board the several minesweeping frigates that it possesses. Sweden produced a robotic Self-propelled Acoustic/Magnetic Minesweeper (SAM), which proved its worth during Operation Desert Storm, when it was successfully used for minesweeping by the US Navy. SAMs are currently in service with the Swedish Navy, the Japanese Navy, the Royal Navy and the US Navy, though not necessarily aboard Aggressive-class minesweepers.

Units

Ship Name Hull no. Builder Commission–
Decommission
Fate Link
Aggressive422Luders Marine Construction Co. of Stamford, Connecticut1953–1971Sold for scrap 1980NVR
Avenge423Luders Marine Construction Co. of Stamford, Connecticut1954-1970Destroyed by fire, sold for scrapping 1969
Bold424Norfolk Naval Shipyard1953-1971Sold for scrap 1981NVR
Bulwark425Norfolk Naval Shipyard1953-1971Sold for scrap 1980NVR
Conflict426Fulton Shipyard, Antioch, California1954-1973Sold for scrap 1973NVR
Constant427Fulton Shipyard, Antioch, California1954-1992Sold for scrap 2001NVR
428 - 431 were US Dash-class minesweepers
Dynamic432Colberg Boat Works, Stockton, California1953-1971Sold or loaned to Spain as Guadalete M41, 1971.NVR
Engage433Colberg Boat Works, Stockton, California1953-1991Scrapped 2002NVR
Embattle434Colberg Boat Works, Stockton, California1954-1972Sold to be scrapped 1976, privately held until scrapped by USACE in 1993.NVR
Endurance435J. M. Martinac Shipbuilding Corp., Tacoma, Washington1954-1972Sold for scrap 1973NVR
Energy436J. M. Martinac Shipbuilding Corp., Tacoma, Washington1954-1972Loaned to Philippines 1972
Sold for scrap 1977
NVR
Enhance437Martinolich Shipbuilding Co., San Diego, California1955-1970
1971-1991
Sold for scrap 2000NVR
Esteem438Martinolich Shipbuilding Co., San Diego, California1955-1970
1971-1991
Sold for scrap 2000NVR
Excel439Higgins Corp., New Orleans, Louisiana1955-1992Sold for scrap 2000NVR
Exploit440Higgins Corp., New Orleans, Louisiana1954-1993Sold for scrap 2002NVR
Exultant441Higgins Corp., New Orleans, Louisiana1954-1993Sold for scrap 2002NVR
Fearless442Higgins Corp., New Orleans, Louisiana1954-1990Sold for scrap 1992NVR
Fidelity443Higgins Corp., New Orleans, Louisiana1955-1989Sold for scrap 1990NVR
Firm444J. M. Martinac Shipbuilding Corp., Tacoma, Washington1954-1972Loaned to Philippines 1972
Scrapped 1977
NVR
Force445J. M. Martinac Shipbuilding Corp., Tacoma, Washington1955-1973Sunk after a fireNVR
Fortify446Seattle Shipbuilding and Drydocking Co., Seattle, Washington1954-1992Scrapped 2002NVR
Guide447Seattle Shipbuilding and Drydocking Co., Seattle, Washington1955-1972Sold for scrap 1973NVR
Illusive448Martinolich Shipbuilding Co., San Diego, California1953-1990Sold for scrap 1993NVR
Impervious449Martinolich Shipbuilding Co., San Diego, California1954-1991Scrapped 2002NVR
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 1994NVR
Inflict456Wilmington Boat Works Inc., Wilmington, California1954-1990Sold for scrap 1992NVR
Loyalty457Wilmington Boat Works Inc., Wilmington, California1954-1972Sold for scrap 1973NVR
Lucid458Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1976
Currently being restored by the Stockton Historical Maritime Museum as a museum ship
NVR
Nimble459Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1981NVR
Notable460Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1971NVR
Observer461Higgins Corp., New Orleans, Louisiana1955-1972Sold for scrap 1979NVR
Pinnacle462Higgins Corp., New Orleans, Louisiana1955-1970Sold for scrap 1978NVR
Pivot463Wilmington Boat Works Inc., Wilmington, California1954-1971Initially loaned then sold to Spain as Guadalmedina M42, 1974NVR
Pluck464Wilmington Boat Works Inc., Wilmington, California1954-1990Sold for scrap 1992NVR
Prestige465Wilmington Boat Works Inc., Wilmington, California1954-1958Grounded and sunk, 1958 in the Naruto Strait
Prime466Wilmington Boat Works Inc., Wilmington, California1954-1970Sold for scrap 1976NVR
Reaper467Wilmington Boat Works Inc., Wilmington, California1954-1972Sold for scrap 1976NVR
Rival468Luders Marine Construction Co. of Stamford, Connecticut1954-1970Sold for scrap 1971NVR
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 1971NVR
Skill471Luders Marine Construction Co. of Stamford, Connecticut1950-1970Sold for scrap 1979, scrapped 1983.NVR
Valor472Burger Boat Company, Manitowoc, Wisconsin1954-1970Sold for scrap 1971NVR
Vigor473Burger Boat Company, Manitowoc, Wisconsin1954-1972Sold to Spain as Guadiana M44, 1972. Scrapped by Spain after 1999.NVR
Vital474Burger Boat Company, Manitowoc, Wisconsin1955-1972Sold for scrap 1979NVR
475 - 487 built for France, Portugal, Spain, Belgium and the Netherlands, not necessarily Aggressive-class ships.
Conquest488J. M. Martinac Shipbuilding Corp., Tacoma, Washington1955-1970
1971-1994
Sold to Taiwan 1994NVR
Gallant489J. M. Martinac Shipbuilding Corp., Tacoma, Washington1955-1994Sold to Taiwan 1994NVR
Leader490J. M. Martinac Shipbuilding Corp., Tacoma, Washington1955-1970
1971-1991/92
Sold for scrap 1994NVR
Persistent491J. M. Martinac Shipbuilding Corp., Tacoma, Washington1956-1971Initially loaned in 1971 then sold to Spain as Guadalquivir M43NVR
Pledge492J. M. Martinac Shipbuilding Corp., Tacoma, Washington1956-1994Sold to Taiwan 1994NVR
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 1978NVR
Swerve495Broward Marine Inc, Fort Lauderdale, Florida1957-1971Sold for scrap 1978NVR
Venture496Broward Marine Inc, Fort Lauderdale, Florida1958-1971Sold for scrap 1978NVR
MSO-497497Cancelled, never built

See also

References

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