Geometrics G-881 caesium vapour magnetometerMarine magnetometers detect variations in the Earth's magnetic field. These variations may be caused by the presence of ferrous material such as iron on or under the seabed, geological features or the daily variations in the Earth's magnetic field that are caused by the sun. Marine magnetic surveying is now a standard technique for mapping ferrous material on the seabed.

Marine Magnetics ExplorerAs the survey vessels create a magnetic disturbance themselves, the magnetometer is usually towed behind it.

During the 2005 fieldwork, a Geometrics G-881 caesium vapour magnetometer was used for the 2km x 2km area survey while a Marine Magnetics Explorer was used on the three deep wreck sites.

In the post processing the magnetometer data was imported into a Geographical Information Systems (GIS) and overlaid on the results of the sidescan sonar interpretation to compare the results of the two surveys.