NAVY FACT FILE MINE COUNTERMEASURES SHIPS MISSION: Clear vital waterways, such as choke points, harbors and channels, of bottom and moored mines. COMMENTARY: In the early 1980s, the U.S. Navy embarked on a program to replace its aging minesweeper fleet with a new mine countermeasures (MCM) force. This force development includes two new classes of ships, minesweeping helicopters, a craft of opportunity program (COOP) and several major combatant systems including a mine neutralization system, new generation variable depth sonar and a precise navigation system. The force would be built using current technology with systems being specifically built to meet U.S. Navy mission requirements. 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. AVENGER CLASS (MCM 1) COMMENTARY: The Avenger class represents a revolutionary concept in mine warfare. These ships are designed as mine hunter/killers capable of performing reconnaissance, classification and neutralization of moored and bottom mines. The last three MCM ships are scheduled to be purchased in 1990. A total of 14 fully deployable, ocean going Avenger class ships are planned, eight of which are presently under contract with Peterson Shipbuilders and Marinette Marine, of Marinette, Wisconsin. These ships operate the remotely piloted, tethered Mine Neutralization System (MNS). This vehicle combines sonar and video capability with cable cutters and a mine detonating device (a releasable, remotely controlled explosive). Using the MNS an operator aboard the MCM can maneuver within visual range of a suspected mine. Visual identification using closed-circuit television on the MNS can be made of the object. If the object is determined to be a bottom mine, a detonating charge can be placed near for subsequent destruction. If the object proves to be a moored mine, the cable can be cut allowing the mine to float to the surface for subsequent destruction. The Avenger class is also capable of conventional sweeping measures. The ships are of fiberglass sheathed, wooden hull construction. They are the first large mine countermeasures ships built in the United States in nearly 25 years. CHARACTERISTICS Displacement: 1,312 tons (full load) Length: 224 feet Beam: 39 feet Max Speed: 13.5 knots Power Plant: 4 - Aluminum block Diesels, 2 shafts, 2,280-2,600 bhp Aircraft: None Armament: Mine Neutralization System Complement: 74: 6 officer, 68 enlisted Builders: Peterson Shipbuilders, Sturgeon Bay, WI: MCM 1, MCM 3, 5, 6, 8, 9, 10, 11; Marinette Marine, Marinette, WI: MCM 2, 4, 7 AVENGER CLASS SHIPS USS Avenger (MCM 1); Charleston, S.C.* Defender (MCM 2) Sentry (MCM 3) Champion (MCM 4) Guardian (MCM 5) Devastator (MCM 6) Patriot (MCM 7) Scout (MCM 8) Pioneer (MCM 9) Warrior (MCM 10) Gladiator (MCM 11) (MCM 12) (MCM 13) (MCM 14) OSPREY CLASS (MHC 51) COMMENTARY: The Osprey (MHC 51) class ships are designed as mine hunter-killers capable of performing reconnaissance, classification and neutralization of moored and bottom mines in U.S. harbors and coastal waterways. The MHC-51 has a maximum five day endurance and depends on shore based facilities for resupply. MHC-51 is designed with modularized, interchangeable mine countermeasures equipment which permits the ship to perform one mission at a time. Mission conversion time is very short and can be accomplished during normal returns to port for resupply. The design is based on the glass-reinforced plastic hull design of the Italian "Lerici" class mine countermeasures ships. The Osprey class is being constructed by Intermarine USA, Savannah, Georgia (a division of Intermarine of LaSpezia, Italy). A total of 17 ships are planned with delivery of the last ship scheduled for calender year 1998. Osprey (MHC 51) and MHC-52 have been awarded to Intermarine USA. Selection of a second source builder is expected to occur in the summer of 1989. A total of 17 Osprey class MHC's are planned. CHARACTERISTICS Displacement: 840 tons (full load) Length: 188 feet Beam: 36 feet Max Speed: 15 knots Power Plant: 2 - Aluminum block Diesels; 2 Voith-Scheider (cycloidal) propulsion system Aircraft: None Armament: 2 - .50 cal machine guns; Mine Neutralization System and other mine countermeasures systems Complement: 45: 4 officer, 41 enlisted Builders: Intermarine USA, Savannah, Ga. OSPREY CLASS SHIPS Osprey (MHC 51) (MHC 52) (MHC 53)(MHC 54) (MHC 55) (MHC 56) ACME CLASS (MSO 508) COMMENTARY: Approximately the same size as, though with improved capabilities over, the Agile and Aggressive classes, these Naval Reserve Force ships perform function of Mine Division flagships. CHARACTERISTICS Displacement: 818 tons (full load) Length: 173 feet Beam: 36 feet Max Speed: 14 knots Power Plant: 4 - Aluminum block Diesels; 2 shafts, 2,800 bhp Aircraft: None Armament: 2 - .50 cal twin machine guns Complement: NRF: 57: 5 officer, 52 enlisted plus 25 reserves Builders: Frank L. Sample, Jr., Boothbay Harbor, Maine ACME CLASS SHIPS USS Adroit (MSO 509); Little Creek, Va. USS Affray (MSO 511); Charleston, S.C. AGGRESSIVE CLASS (MSO 422) COMMENTARY: These ocean going minesweepers were designed to counter North Korean mining during the Korean War. They are capable of sweeping for moored and bottom contact, magnetic and acoustic mines. Two remain on active service with the remaining 18 ships assigned to the Naval Reserve Force. During the 1987-88 Persian Gulf escort missions, active and reserve MSO's were dispatched to the Gulf. Both ships and crews performed extremely well in very demanding conditions, clearing hundreds of mines from the international waterway. CHARACTERISTICS Displacement: 853 tons (full load) Length: 172 feet Beam: 35 feet Max Speed: 15 knots Power Plant: 4 - Aluminum block Diesels; 2 shafts, 2,400 bhp Aircraft: None Armament: 2 - .50 cal twin machine guns Complement: Active: 77: 7 officer, 70 enlisted; NRF: 57: 5 officer, 52 enlisted plus 25 reserve AGGRESSIVE CLASS SHIPS USS Constant (MSO 427); San Diego, Calif. USS Engage (MSO 433); Mayport, Fla. USS Enhance (MSO 437); Tacoma, Wash. USS Esteem (MSO 438); Seattle, Wash. USS Excel MSO 439); San Francisco, Calif. USS Exploit (MSO 440); Newport, R.I. USS Exultant (MSO 441); Charleston, S.C. USS Fearless (MSO 442); Charleston, S.C. USS Fortify (MSO 446); Little Creek, Va. USS Illusive (MSO 448); Mayport, Fla.* USS Impervious (MSO 449); Mayport, Fla. USS Implicit (MSO 455); Tacoma, Wash. USS Inflict (MSO 456); Little Creek, Va. USS Pluck (MSO 464); San Diego, Calif. USS Conquest (MSO 488); Seattle, Wash. USS Gallant (MSO 489); San Francisco, Calif. USS Leader (MSO 490); Charleston, S.C.* USS Pledge (MSO 492); Seattle, Wash. * Denotes active ships SOURCE: Department of the Navy (OP-03PA); Washington, D.C. 20350-2000; (202) 694-6049