Find Spot MPM2125 - Degaussing coil detectors, Portsmouth Harbour

Four 1950s degaussing units recovered from the Solent during dredging as part of the Queen Elizabeth Class Capital Dredge Project in 2017. The units would have formed part of a degaussing range used to protect shipping from magnetic sea mines. They may have been abandoned by the Navy once they had become obsolete. The units consisted of four identical wheel-like objects with a diameter of 1206mm and width of 290mm. Each 'wheel' had a central brass unit with a sealed lead container surrounded by bitumen. The lead container was capped inside by a metal plate. Inside the central unit was a copper coil connected to wires leading outside. See Queen Elizabeth Class Capital Dredge Project report for detailed object description.

The units were found within the same area as a concrete sinker and scaffolding frame. The sinker was cone shaped with an eye and shackle at the top and had a diameter of c.1200mm. It would have been used to anchor something to the seabed, possibly a buoy or mooring, or it may have been connected to the degaussing units. The scaffolding frame had probably been discarded.

UID: BWL7_0014 in Queen Elizabeth Class Capital Dredge Project report.

Wessex Archaeology, 2018, Queen Elizabeth Class Capital Dredge Project Her Majesty's Naval Base, Portsmouth: Archaeological Assessment Report (Unpublished document). SPM646.