Ship Deperming by Seabed Superconducting Coil:

From an Outrageous Idea to Challenges toward Realization

Abstract

Naval ship deperming is a magnetic treatment that decreases the magnetization of a ship. The deperming aims to reduce the risk posed by weapons in seawater equipped with magnetic detonators against ships. Ships are usually built from high-tensile steel and possess magnetism induced by the Earthʼs magnetic field and residual magnetization due to the steelʼs ferromagnetism. This paper discusses the possibility of using seabed coils made with high-temperature superconducting wires, which have been increasingly commercialized in recent years, to reduce the permanent magnetization of ships. Starting from the concept, the value of the magnetic field generated by the coil was determined based on the magnetic properties of high-tensile steel, and the required current for the coil was calculated. We investigated the superconducting materials that make this up, conducted repeated design calculations on the basic characteristics during cabling and cooling, and examined the feasibility of manufacturing coils for seabed installation.