Conflicting, but interesting Submarine Information
Open source [pdf] documents now reveal that an AIP submarine, HMS Gotland, utilizes onboard degaussing technology that is 95% effective. Moreover, the technology is being used routinely not only for submarines but for surface combatants at least since the Gotland's installation, perhaps earlier.
The Seawolf and Virginia class boats have a similar on-board system; as a result, you can't use standard CRT TV screens.
The Navy said it has completed construction of an $84.8 million drive-in submarine magnetic silencing facility at Pearl Harbor. ... Removing the magnetism requires wrapping a submarine with electrical cables and using high current to reset its magnetic signature. The Navy said submarines are depermed about once a year. Three new Virginia-class submarines are based at Pearl Harbor, and more will be assigned to Hawaii in the future.