A magnetic signature minesweeping device (10) comprising a water driven turbine power generator (12) and a superconducting material magnet (14), wherein the turbine power generator is arranged, in use, to supply a driving current for the superconducting material magnet (14) when the minesweeping device is towed through the water. In a further embodiment a control unit (24) is arranged, in use, to control the magnetic output of the superconducting magnet (14) and the power output of the turbine power generator (12). Further more a method of minesweeping using the device (10), and an array of the devices (10) is disclosed.