So if you made the ship from aluminium, that should work too? Seems easier than using glass reinforced plastic but I guess it's expensive.,(reply>), @Phil Himsworth I see, cool!,(reply>), Almost; aluminium isn't magnetic like steel is, but as it is electrically conductive it can still suffer from electrical eddy currents when moving through the earth's magnetic field, and those eddy currents generate their own magnetic field, which can still be detected by mines.