Avenger-class mine countermeasures ship

Class overview
The USS Avenger (MCM-1) underway in Hawaiian waters in July 2004.
Builders:	Peterson Shipbuilders Marinette Marine
Preceded by:	Ability-class minesweeper
Succeeded by:	Littoral combat ship
In commission:	1987
Completed:	14
Active:	11
Lost:	1
Retired:	2
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 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
Speed:	14 knots (26 km/h; 16 mph)
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 for the United States Navy from 1987 to 1994, designed to clear mines from vital waterways. The ships have the hull designator MCM.

History

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 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

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.^[1] 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.^[1]

Design

Hull

Shock trial of USS Avenger

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, 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

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 1,070 metres (3,510 ft) cable and under control of the vessel.

The ATK/Raytheon ROV is a similar system, but has a 1,500 metres (4,900 ft) tether cable, 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^[1] 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

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 (447.4 kW) (combined 1.79 MW) sustained power, 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 294 kW. Precision maneuvering capability is provided by a 257 kW Omnithruster hydrojet (powered by Solar (Caterpillar Inc) Magnetic Marine Gas Turbine Generator).

Isotta Fraschini Engine: http://magazines.marinelink.com/Magazines/MaritimeReporter/198407/content/diesel-power-review-203686

Isotta Fraschini Engine: http://www.trucktrend.com/cool-trucks/1206dp-avenger-class-navy-mine-hunters/

Ships

Ship	Hull No.	Commissioned	Decommissioned	Builder	Home Port	NVR Page
Avenger	MCM-1	12 September 1987	30 September 2014	Peterson Shipbuilders		MCM01
Defender	MCM-2	30 September 1989	1 October 2014	Marinette Marine		MCM02
Sentry	MCM-3	2 September 1989		Peterson Shipbuilders	Manama, Bahrain	MCM03
Champion	MCM-4	8 February 1991		Marinette Marine	San Diego, California	MCM04
Guardian	MCM-5	16 December 1989	15 February 2013^[2]	Peterson Shipbuilders		MCM05
Devastator	MCM-6	6 October 1990		Peterson Shipbuilders	Manama, Bahrain	MCM06
Patriot	MCM-7	18 October 1991		Marinette Marine	Sasebo, Japan	MCM07
Scout	MCM-8	15 December 1990		Peterson Shipbuilders	San Diego,California	MCM08
Pioneer	MCM-9	7 December 1992		Peterson Shipbuilders	Sasebo, Japan	MCM09
Warrior	MCM-10	7 April 1993		Peterson Shipbuilders	Sasebo, Japan	MCM10
Gladiator	MCM-11	18 September 1993		Peterson Shipbuilders	Manama, Bahrain	MCM11
Ardent	MCM-12	18 February 1994		Peterson Shipbuilders	San Diego, California	MCM12
Dextrous	MCM-13	9 July 1994		Peterson Shipbuilders	Manama, Bahrain	MCM13
Chief	MCM-14	5 November 1994		Peterson Shipbuilders	Sasebo, Japan	MCM14

Gallery

USS Sentry and USS Kingfisher
USS Guardian
USS Gladiator in the Persian Gulf

References

Notes

1 2 3 Tringham, Kate (16 March 2012). "US to double the number of minesweepers in the Persian Gulf". Jane's Navy International. Jane's Information Group.
↑ Guardian grounded on Tubbataha Reef on the night of 17 January 2013. Removing the ship intact off the reef proved impossible so it was cut into three pieces, effectively ending her career.

Sources

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

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Avenger-class mine countermeasures ship

Avenger Defender Sentry Champion Guardian Devastator Patriot Scout Pioneer Warrior Gladiator Ardent Dextrous Chief

List of mine countermeasure ships of the United States Navy

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