Avenger class mine countermeasures ship

USS Avenger (MCM-1) in Hawaiian waters
Class overview
Builders:	Peterson Shipbuilders, Marinette Marine
Preceded by:	Ability-class minesweepers
Succeeded by:	Littoral combat ship
In commission:	1987
Completed:	14
Active:	14
General characteristics
Type:	Mine Countermeasures ship
Displacement:	1,312 tons
Length:	224 ft (68 m)
Beam:	39 ft (12 m)
Draft:	15 ft (4.6 m)
Propulsion:	4 × Waukesha Motors Co. 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 2 × 350 hp (260 kW) bow thrusters
Speed:	14 knots (25.76 km/h)
Complement:	8 officers, 76 enlisted
Armament:	Mine neutralization system, 2 × .50 caliber machine guns

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

Background

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 the Avenger and Guardian ships 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.

Hull design

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

Mine countermeasures systems

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 1070 m cable and under control of the vessel.

The ATK/Raytheon ROV is a similar system but has a slightly longer tether cable (1500 m) and also carries cable cutters for dealing with tethered or moored mines, and explosive charges to detonate the mines.

Sensor systems

The ships employ the AN/SQQ-32 advanced minehunting and classification sonar from Raytheon and Thales Underwater Systems (formerly Thomson Marconi Sonar). The system has two sonars fitted in a small submersible pod towed behind 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

The Avenger-class ships are equipped with four Waukesha Motors Co. 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 (447.4 kW) (combined 1.79 MW) sustained power, providing a cruising speed of 14 knots (26 km/h) with controllable pitch propellers. For stationkeeping the ship uses two Hansome electric motors rated at 294 kW. Precision maneuvering capability is provided by a 257 kW Omnithruster hydrojet.

Ships

Ship	Hull No.	Commissioned	Builder	Home Port	NVR Page
Avenger	MCM-1	1987	Peterson Shipbuilders	Sasebo, Japan	MCM01
Defender	MCM-2	1989	Marinette Marine	Sasebo, Japan	MCM02
Sentry	MCM-3	1989	Peterson Shipbuilders	San Diego, California	MCM03
Champion	MCM-4	1991	Marinette Marine	San Diego, California	MCM04
Guardian	MCM-5	1989	Peterson Shipbuilders	Sasebo, Japan	MCM05
Devastator	MCM-6	1990	Peterson Shipbuilders	San Diego, California	MCM06
Patriot	MCM-7	1991	Marinette Marine	Sasebo, Japan	MCM07
Scout	MCM-8	1990	Peterson Shipbuilders	Manama, Bahrain	MCM08
Pioneer	MCM-9	1992	Peterson Shipbuilders	San Diego, California	MCM09
Warrior	MCM-10	1993	Peterson Shipbuilders	San Diego, California	MCM10
Gladiator	MCM-11	1993	Peterson Shipbuilders	Manama, Bahrain	MCM11
Ardent	MCM-12	1994	Peterson Shipbuilders	Manama, Bahrain	MCM12
Dextrous	MCM-13	1994	Peterson Shipbuilders	Manama, Bahrain	MCM13
Chief	MCM-14	1994	Peterson Shipbuilders	San Diego, California	MCM14

See also

• List of mine warfare vessels of the United States Navy

References

• United States Navy Fact File: Mine Countermeasures Ships - MCM
• Globalsecurity.org MCM-1 Avenger Mine Countermeasures Ships
• Globalsecurity.org MCM-1 Avenger Mine Countermeasures Ships
• Naval-Technology.com: Avenger Class Mine Countermeasures Vessel, USA
• Federation of American Scientists: MCM-1 Avenger Mine Countermeasures Ships
• This article includes information collected from the Naval Vessel Register, which, as a U.S. government publication, is in the public domain. The entry can be found here.

External links

• Globalsecurity.org: Plans and schematics of the Avenger class
• Globalsecurity.org: Photo gallery

Photographs

• 

  Shock trial of USS Avenger

• 

  USS Sentry and USS Kingfisher

• 

  USS Guardian

• 

  USS Gladiator in the Persian Gulf