Avenger-class mine countermeasures ship

Avenger-class mine countermeasures ships are a class of 14 ships[1] constructed for the United States Navy from 1987 to 1994, designed to clear mines from vital waterways. The ships have the hull designator MCM.

The USS Avenger (MCM-1) underway in Hawaiian waters in July 2004
Class overview
Builders
Preceded byAbility-class minesweeper
Succeeded byLittoral combat ship
In commission1987
Completed14
Active8
Lost1
Retired5
General characteristics
TypeMine countermeasures ship
Displacement1,312 tons
Length224 ft (68 m)
Beam39 ft (12 m)
Draft15 ft (4.6 m)
Propulsion
  • 4 × Waukesha Diesel engines (first two ships) or 4 × Isotta-Fraschini Diesel engines (600 hp (450 kW) ea.)
  • 2 × 200 hp (150 kW) electric propulsion motors
  • 2 × shafts with controllable pitch propellers
  • 1 × 350 hp (260 kW) Omnithruster waterjet bow thruster
Speed14 knots (26 km/h; 16 mph)
Complement8 officers, 76 enlisted
Armament
  • Mine neutralization system,
  • 4 × .50 caliber machine guns

The Avenger-class ships are being replaced by the Freedom and Independence-class littoral combat ships, as well as other MCM platforms, which use various unmanned air, surface, and undersea vehicles to detect and destroy naval mines at a standoff distance.[2]

History

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Background

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In the early 1980s, the U.S. Navy began development of a new mine countermeasures (MCM) force, which included two new classes of ships and minesweeping helicopters. The vital importance of a state-of-the-art mine countermeasures force was strongly underscored in the Persian Gulf during the eight years of the Iran–Iraq War, and in Operations Desert Shield and Desert Storm in 1990 and 1991 when Avenger and Guardian conducted MCM operations.

Avenger-class ships are designed as mine hunter-killers capable of finding, classifying, and destroying moored and bottom mines. The last three MCM ships were purchased in 1990, bringing the total to 14 fully deployable, oceangoing Avenger-class ships. These ships use sonar and video systems, cable cutters and a mine-detonating device that can be released and detonated by remote control. They are also capable of conventional sweeping measures.

Operations

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As of 2012, eight Avengers were forward-based: four at Sasebo, Japan with standing crews, and four at Manama, Bahrain, with ten ships' companies on rotational deployments.[3] In March 2012, the USN announced plans to deploy another four MCMs to Bahrain to counter potential Iranian threats to mine the Strait of Hormuz reflecting increasing tensions between the United States and Iran over the latter's nuclear program.[3]

Design

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Hull

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Shock trial of USS Avenger hull

The hulls of the Avenger-class ships are constructed of wood with an external coating of fiberglass. The wood used is oak, Douglas fir and Nootka Cypress because of their flexibility, strength and low weight. This construction allows the hull to withstand a nearby blast from a mine, and also gives the ship a low magnetic signature.

Mine countermeasures systems

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The ships use AN/SLQ-48 remotely operated mine disposal system supplied by Alliant Techsystems (ATK) and the EX116 Mod 0 remotely operated vehicle (ROV) mine neutralization system supplied by ATK and Raytheon. The AN/SLQ-48 detects, locates, classifies, and neutralizes moored mines and mines resting on the seabed. The vehicle uses high-frequency, high-resolution sonar, low light level television (LLLTV), cable cutters, and explosive charges to detect and dispose of mines, while remaining tethered to the vessel by a 3,510-foot (1,070 m) cable and under control of the vessel.

The ATK/Raytheon ROV is a similar system, but has a 4,900-foot (1,500 m) tether cable, and also carries cable cutters for dealing with tethered or moored mines, and explosive charges to detonate the mines.

Sensor systems

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The ships employ the AN/SQQ-32 advanced minehunting and classification sonar from Raytheon[3] and Thales Underwater Systems (formerly Thomson Marconi Sonar). The system has two sonars fitted in a small submersible pod towed under the ship. When not deployed the submersible is housed in a trunk below the deck of the ship. The sonars are a Raytheon search and detection sonar and a Thales high-resolution, high-frequency, _target-classification sonar. The deployment and retrieval system for the submersible was designed by the Charles Stark Draper Laboratory in Massachusetts.

The Avenger class employ the AN/SPS-55 surface-search and navigation radar supplied by Cardion, Inc. of New York. The ships have been equipped with CMC Electronics LN66 or Raytheon AN/SPS-66 navigation radars, but are slated to be upgraded with the AN/SPS-73.

Propulsion

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The Avenger-class ships are equipped with four Waukesha-Pearce diesel engines (MCM 1 and 2) or Isotta-Fraschini ID 36SS6V diesel engines (remainder), which are designed to have very low magnetic and acoustic signatures. Each engine develops 600 horsepower (450 kW), with a combined power of 2,400 horsepower (1.8 MW), providing a cruising speed of 14 knots (26 km/h; 16 mph) with controllable pitch propellers. For stationkeeping the ship uses two Hansome electric motors rated at 394 horsepower (294 kW). Precision maneuvering capability is provided by a 345 horsepower (257 kW) Omnithruster hydrojet (powered by Solar (Caterpillar Inc) Magnetic Marine Gas Turbine Generator).[4][5]

Ships

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Ship Hull no. Commissioned Decommissioned Builder Home port NVR Page
Avenger MCM-1 12 September 1987 30 September 2014 Peterson Shipbuilders   This article includes information collected from the Naval Vessel Register, which, as a U.S. government publication, is in the public domain.
Defender MCM-2 30 September 1989 1 October 2014 Marinette Marine
Sentry MCM-3 2 September 1989 Proposed 2025[6] Peterson Shipbuilders Manama, Bahrain
Champion MCM-4 8 February 1991 25 August 2020[7] Marinette Marine San Diego, California
Guardian MCM-5 16 December 1989 15 February 2013 (Scrapped)[8] Peterson Shipbuilders
Devastator MCM-6 6 October 1990 Proposed 2025[6] Peterson Shipbuilders Manama, Bahrain
Patriot MCM-7 18 October 1991 Proposed 2027[6] Marinette Marine Sasebo, Japan
Scout MCM-8 15 December 1990 26 August 2020[9] Peterson Shipbuilders San Diego, California
Pioneer MCM-9 7 December 1992 Proposed 2027[6] Peterson Shipbuilders Sasebo, Japan
Warrior MCM-10 7 April 1993 Proposed 2027[6] Peterson Shipbuilders Sasebo, Japan
Gladiator MCM-11 18 September 1993 Proposed 2025[6] Peterson Shipbuilders Manama, Bahrain
Ardent MCM-12 18 February 1994 27 August 2020[10] Peterson Shipbuilders San Diego, California
Dextrous MCM-13 9 July 1994 Proposed 2025[6] Peterson Shipbuilders Manama, Bahrain
Chief MCM-14 5 November 1994 Proposed 2027[6] Peterson Shipbuilders Sasebo, Japan
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A fictional Avenger Class MCM is the vessel at the center of the 2023 film The Caine Mutiny Court-Martial. While no scenes appear on board the ship, it is shown in a photo posted in the courtroom, and much of the dialog involves the typical missions and capabilities of Avenger Class MCMs.

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See also

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References

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Notes

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  1. ^ "Mine Countermeasures Ships (MCM)". www.surfpac.navy.mil.
  2. ^ OPNAV N95: Expeditionary Sea Bases Ideal Ships to Operate Mine Countermeasure Mission Packages. USNI News. 28 August 2020.
  3. ^ a b c Tringham, Kate (16 March 2012). "US to double the number of minesweepers in the Persian Gulf". Jane's Navy International. Jane's Information Group.
  4. ^ "DIESEL POWER REVIEW – Magazines". magazines.marinelink.com.
  5. ^ "Avenger Class Navy Mine Hunters – Diesel Power Magazine". 1 June 2012.
  6. ^ a b c d e f g h "Report to Congress on the Annual Long-Range Plan for Construction of Naval Vessels" (PDF). media.defense.gov. 20 April 2022. Retrieved 7 October 2022.
  7. ^ "USS Champion Decommissions After 30 Years of Service". Lt. j.g. Russell J. Natherson, USS Champion Public Affairs. 18 August 2020.
  8. ^ Guardian grounded on Tubbataha Reef on the night of 17 January 2013. Removing the ship intact off the reef proved impossible, so it was chainsawed into four pieces lifted off by crane, scrapping her. [1]
  9. ^ "USS Scout Decommissions". USS Scout Public Affairs. 19 August 2020.
  10. ^ "CHAMPION, SCOUT, ARDENT Decommission After Distinguished Service" (Press release). United States Navy. 20 August 2020.

Sources

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