April 22, 2009 Naval mine strikes are cited as the root cause of almost 4/5ths of U.S. Navy ship casualties occurring since 1950, so any device that either detects mines or cloaks the ship to avoid detonation will aid in the reduction of these alarming statistics. This new technology developed by the Office of Naval Research (ONR) consists of a high temperature superconducting (HTS) degaussing coil which acts to form a cloaking device which eliminates the magnetic signature of the ship. This interferes with undersea mines' ability to detect and detonate when a large magnetic field – like the one created by a ship – comes within close proximity.

According to a report by Peter Vietti from the ONR, naval mine strikes are the root cause of 77 percent of U.S. Navy ship casualties since 1950, and as operations increase in the coastal areas (or littorals) of the world's oceans, so too does the threat from naval mines.

There are many systems out there to avoid ship casualties and as the mine technology advances, so must the avoidance capabilities of military vessels at sea. Recently the Northrop Grumman Airborne Laser Mine Detection System (ALMDS) was given the go ahead by the U.S. Navy, with 25 units to be manufactured over the next 5 years. This system is mounted in an H-60 helicopter that flies ahead of the fleet to determine if mines lie in the ships' path. The new HTS cloaking device is designed act in concert with this technology when either a helicopter is not available or when a ship must pass through a mine field.

Benefits of HTS cloaking

In the first-ever measurement of an HTS degaussing loop installed on a naval combatant, the prototype HTS system was fitted to the USS Higgins in mid-2008. The degaussing coil uses superconducting ceramic materials instead of traditional copper cables to neutralize the magnetic signature of the ship.

Cooled by a cryogenic compressor to nearly minus 400 degrees Fahrenheit, the coils can be operated at current densities that are a factor of 100 to 200 times higher than that of room temperature conductors. The super conductivity of this new degaussing system means less energy is required, yet it enables greater degaussing performance, says the ONR. Additionally, there is significant weight savings – up to 80 percent in some cases which gives the ship designer the ability to lower the weight and size of the degaussing system, meaning potential fuel savings or options to add different payloads.

Partners on the HTS degaussing system include American Superconductor, Nexans GmbH, PHPK Industries, Cryomagnetics, Cryomech, Navy Small Business Innovation Research investments under Office of Naval Research and the Naval Sea Systems Command.

David Greig