Los Angeles-Class Submarine USS Olympia Completes Magnetic Silencing Treatment

Los Angeles-class submarine USS Olympia (SSN 717) finished undergoing deperming at the new drive-in submarine magnetic silencing facility (MSF) at Joint Base Pearl Harbor-Hickam’s Beckoning Point, Dec. 15.

Olympia is the first submarine to complete this treatment at the facility.

“After a culmination of 11 years of work by numerous Department of the Navy civilian contractors and Navy personnel, the completion and success of this treatment marks a milestone for future evolutions of this type,” said Aaron Leong, MSF Pearl Harbor project lead supervisor. “With the certification of this facility and the USS Olympia, we now are prepared to continue operations for all types of submarines.”

Due to magnetic fields that are constantly being encountered during normal ship operations, ships and submarines build up a magnetic signature. The earth’s natural magnetic fields between the North and South poles are being crossed routinely while the vessels are underway.

The traversing of these natural fields and vessels lying dormant for extended periods of time during scheduled maintenance results in changes to a vessel’s magnetic signature. Correcting those changes requires a thorough treatment process to minimize the level of permanent magnetism.

Deperming is performed at the submarine MSF by temporarily surrounding a submarine with coils and supplying current to those coils to create high magnetic fields. By cycling the coil field, the permanent magnetization of the submarine is manipulated.

The magnitude of the coil-induced magnetic field starts high and then is decreased with each cycle. When the process is completed, the magnitude of the permanent magnetization is equal to the ambient field. The MSF can control the ambient field to desired magnitudes.

A closed-wrap MSF requires the submarine to be manually wrapped with heavy copper cables whereas the cables at a drive-in MSF are built into the facility; suspended above, below and on the sides of the submarine. The Pearl Harbor MSF, managed by Commander Navy Region Hawaii and operated by personnel from the Naval Undersea Warfare Center Detachment Pacific is capable of deperming all classes of U.S. submarines including Virginia-class submarines.

“Our main concern was the safety of the crew and the integrity of the components inside the submarine,” said Cmdr. Michael Boone, USS Olympia commanding officer.
“The treatment process was a complete success, and I am proud of everybody who helped out in making Olympia capable of anything required by her to complete future mission tasking.”

Olympia is the United States Navy’s 104th nuclear powered submarine and the 95th of the attack submarine fleet. She is the 29th of the Los Angeles nuclear powered fast attack submarine class to be delivered to the Navy.

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Naval Today Staff , December 20, 2011