I was in the Navy, they are called Degaussing stations
Degaussing is the process of decreasing or eliminating a remnant magnetic field. It is named after the gauss, a unit of magnetism, which in turn was named after Carl Friedrich Gauss. Due to magnetic hysteresis, it is generally not possible to reduce a magnetic field completely to zero, so degaussing typically induces a very small "known" field referred to as bias. Degaussing was originally applied to reduce ships' magnetic signatures during World War II. Degaussing is also used to reduce magnetic fields in cathode ray tube monitors and to destroy data held on magnetic storage.
https://en.m.wikipedia.org/wiki/Degaussing
Lambert's Point Deperming Station is a United States Navy deperming facility located in the Elizabeth Riverjust off Lambert's Point, Norfolk, Virginia, United States. It was built in the mid-1940s and services the U.S. Atlantic Fleet.
USS Ronald Reagan (CVN 76)prepares for deperming at Naval Station Norfolk Lambert's Point Deperming Station
The station, which is administered by Naval Station Norfolk,[1] consists of two parallel pile-supported piers, roughly 1140 ft. (345 m.) in length, which form a slip that can accommodate all Navy and Coast Guard ships up to and including the largest warships afloat, the Nimitz class aircraft carriers. There is a second pier for smaller vessels and support craft. The station has administrative offices and a medical clinic on site. When viewed from the air, the pier configuration resembles the number 41.