If this works, that would be cool. However, these defense contractors are incentivized to make it seem like something is working so that they beat other contrac

If this works, that would be cool. However, these defense contractors are incentivized to make it seem like something is working so that they beat other contractors to follow-on funding. That doesn't necessarily mean that they are close to making it production-ready for a Navy boat. SQUID is tough technology. It takes liquid nitrogen or liquid helium to get them cold enough to superconduct. A tank of liquid nitrogen is easy enough to take on a boat, though. The devices are so sensitive that you can rotate a cheap one 90 degrees and easily measure the earth's magnetic field. Advanced ones are used to measure brain wave activity. My concern is that SQUID devices are so sensitive that they cannot be stabilized enough on a boat in the ocean to prevent noise (from Earth, boats, gyroscopes, liquid nitrogen pumps, etc) that would make it able to consistently detect the Debye effect.