The U.S. Navy has punished the captain and three of his crew for the January 17 grounding of a 1,300 ton Avenger class minesweeper on a reef off the Philippines (in the Sulu Sea). By the end of January it was determined that the ship was stuck and would have to be taken apart and removed. This was completed by early April. A U.S. Navy investigation determined that the grounding was the result of sloppiness by some of the crew and avoidable. It’s common knowledge in this area that you have to be very careful navigating the shallow seas west of the Philippines.
The Philippines is surrounded by shallow waters that are full of reefs and shoals that are just below the surface. Larger ships must move carefully through these waters and groundings like this one are common. A Chinese warship recently went aground in a similar manner.
The unfortunate American minesweeper is one of 14 in the U.S. Navy. The Avengers are 72.3 meter (224 foot) long ships that draw only 4.8 meters (15 feet) of water, enabling them to operate close to shore. The crews are supposed to be trained in navigating such shallow areas. The Avengers are armed with two .50 cal. (12.7mm) machine guns, two 7.62mm machine guns, two 40mm automatic grenade launchers, and have a crew of 84. Four Avengers are in the Persian Gulf, operating out of Bahrain. Another four (now three) are based in Sasebo, Japan. The other six are based at San Diego, California.
The U.S. Navy needs these minesweepers because replacements (minesweeping helicopters and minesweeping versions of the new LCS ship) have been delayed by technical problems. Thus the loss of one Avenger will be felt if there is a war with Iran or North Korea.
The U.S. recently upgraded the sonars on its Avenger class ships. The new AN/SQQ-32(V)4 mine hunting sonar improves the ability of the sonar to spot mines on sea bottoms cluttered with other stuff (natural or manmade). In many parts of the world shallow coastal waters are used as a dumping ground for junk that won’t float ashore. This has been found to help hide bottom mines. The Avengers have also received new engines. The four original diesel engines in each Avenger have never been very reliable. With their new engines the Avengers can still move at up to 27 kilometers an hour. Normally, however, the Avengers move much more slowly (3-4 kilometers an hour) when searching for mines. The Avengers also recieved improved hydraulics and new mine destruction systems.
The upgrade is part of an attempt to deal with delays in the new LCS class ships, or at least the ones equipped for mine hunting. So for the last decade the navy has been hustling to refurbish its existing Avengers. The 3,000 ton LCS ships are designed for minesweeping (and a lot of other jobs) but the 1,400 ton Avengers specialize in minesweeping. Built mostly of wood and very little iron, the fourteen Avengers entered the fleet between 1987 and 1994, and all are still in service. The upgrades will enable the surviving Avengers to remain in service at least until 2016 and probably until the end of the decade.
The navy also had a dozen smaller Osprey class coastal mine hunters (900 tons displacement, crew of 51), but these were all given away to foreign navies and are to be replaced by the LCS and new minesweeping helicopters.