All Navy submarines based in the Pacific will stop periodically in Hawaii for "magnetic silencing" with the completion of a new $88.3 million facility at Pearl Harbor and the closing of similar stations in San Diego and Bangor, Wash., officials said.
The Navy has 19 submarines home-ported at Pearl Harbor, 13 in Bangor, Wash., six in San Diego and three on Guam.
Submarines need to be demagnetized periodically because they accumulate magnetism that makes them easier to detect.
The Pearl Harbor-based Los Angeles-class submarine USS Olympia became on Dec. 15 the first vessel to undergo the demagnetization, or "deperming," at the new Beckoning Point facility here.
Aaron Leong, the project’s lead supervisor, said in a Navy news story that the facility’s completion represents the culmination of 11 years of work.
"With the certification of this facility and the USS Olympia, we now are prepared to continue operations for all types of submarines," Leong said.
A magnetic silencing facility in San Diego closed a few years ago, and the silencing facility in Bangor, Wash., will be decommissioned early next year, the U.S. Pacific Fleet submarine force said.
All the Pacific-based subs will need to sail to Hawaii for the periodic "drive-in" treatment, which takes about a day.
During normal ship operations, ships and submarines develop a magnetic signature, which can be detected by mines, ships or aircraft. Crossing the earth’s magnetic fields can accumulate magnetism, as can hull stress, including that incurred from deep diving.
Removing the magnetism requires surrounding a submarine with electrical cables and using high current to reset its magnetic signature. The cables at the Pearl Harbor facility are built into the structure above, below and on the sides of the submarine.
The Pentagon decided in 2006 to shift 60 percent of the Navy’s attack submarines to the Pacific, the new economic and military center of gravity for the world. Until then there had been about an even split between the Atlantic and Pacific.
In January 2009 contractor Watts-Healy Tibbitts began dredging operations for the new pier location and approach area at Beckoning Point so the new facility would be able to accommodate newer and larger Virginia-class submarines, the Navy said.
One hundred seventy-three piles fabricated on Guam with a nonmagnetic, coral-based concrete aggregate were shipped to Hawaii and installed over a nine-month period, the Navy said.
An access pier and a set of 700-foot-long parallel piers also were built.
In October 2010 workers installed 18 trusses that straddle the parallel piers and hold high-voltage cables.
Three Virginia-class submarines — the Hawaii, Texas and North Carolina — are based at Pearl Harbor, and more will be assigned to Hawaii in the future.