Abstract: An apparatus and method for recovering equipment from within a body of water. The apparatus comprises a frame supporting a mesh and an engagement element. The engagement element is shaped to co-engage with the mesh and is attached to the equipment to be recovered prior to its deployment. Following deployment of the equipment, its recovery can be effected by lowering the mesh supported by the frame onto the equipment to cause the engagement element and the mesh to co-engage. The frame and mesh may then be lifted to the surface of the water bringing the equipment with them. Recovery may include searching for the equipment by monitoring a load associated with the frame and the mesh as it is lowered and raised at different locations, whereby an appropriate increase in load is taken to indicate that the equipment has become attached to the mesh.

Abstract: A detector for underwater electromagnetic surveying is described. The detector comprises first, second, third and fourth electrodes which are arranged to define first, second and third electric dipole antennae extending between pairs of the electrodes. Each dipole antennae extends between a pair of the electrodes and the fourth electrode is common to all three dipole antennae. Thus the first electrode is separated from the fourth electrode along a first direction to provide the first dipole antenna, the second electrode is separated from the fourth electrode along a second direction to provide the second dipole antenna, and the third electrode is separated from the fourth electrode along a third direction to provide the third dipole antenna. The electrodes are arranged so that the first, second and third directions are inclined at an angle of between 20 and 70 degrees to a surface on which the detector rests when in normal use.

Abstract: A detector for underwater electromagnetic surveying is described. The detector comprises first, second, third and fourth electrodes which are arranged to define first, second and third electric dipole antennae extending between pairs of the electrodes. Each dipole antennae extends between a pair of the electrodes and the fourth electrode is common to all three dipole antennae. Thus the first electrode is separated from the fourth electrode along a first direction to provide the first dipole antenna, the second electrode is separated from the fourth electrode along a second direction to provide the second dipole antenna, and the third electrode is separated from the fourth electrode along a third direction to provide the third dipole antenna. The electrodes are arranged so that the first, second and third directions are inclined at an angle of between 20 and 70 degrees to a surface on which the detector rests when in normal use.