A water current power generating system comprising: a support structure located on the bed of a body of water and including an export connector of the support structure for the export of electrical power from the system; a power generating apparatus including a rotor assembly, an electrical power generating unit rotatable by the rotor assembly and operable to output electrical power, and an electrical output for export of electrical power from the power generating apparatus, the power generating apparatus including an engagement portion which is releasably attached to the support structure; a clamp mechanism for releasably attaching the power generating apparatus to the support portion, the clamp having a first position in which the power generating apparatus is fixed with respect to the support structure, a second position in which the power generating apparatus is rotatable about a substantially vertical axis with respect to the support structure, and a third position in which the power generating apparatus is removable from the support structure; a cable management system (32, 34) arranged to connect the electrical power generating unit of the power generating apparatus to the export connector of the support structure, the cable management system (32, 34) comprising: an internal connector located on the engagement portion of the power generating apparatus and electrically connected with the power generating unit of the power generating apparatus; a first support plate attached to, and extending at least partially around, an outer surface the engagement portion of the power generating apparatus for rotation therewith; a second support plate mounted radially outwards of the first support plate for rotation about the axis with respect to the power generating apparatus; a power connector mounted on the second support plate, and movable between a first position in which the power connector is disconnected from the export connector of the support structure and a second position in which the power connector is electrically connected with the export connector of the support structure; and a flexible electrical cable which extends from the internal connector to the power connector thereby connecting electrically those connectors, and which is supported by the first and second support plates (36, 38). a support structure located on the bed of a body of water and including an export connector of the support structure for the export of electrical power from the system; a power generating apparatus including a rotor assembly, an electrical power generating unit rotatable by the rotor assembly and operable to output electrical power, and an electrical output for export of electrical power from the power generating apparatus, the power generating apparatus including an engagement portion which is releasably attached to the support structure; a clamp mechanism for releasably attaching the power generating apparatus to the support portion, the clamp having a first position in which the power generating apparatus is fixed with respect to the support structure, a second position in which the power generating apparatus is rotatable about a substantially vertical axis with respect to the support structure, and a third position in which the power generating apparatus is removable from the support structure; a cable management system (32, 34) arranged to connect the electrical power generating unit of the power generating apparatus to the export connector of the support structure, the cable management system (32, 34) comprising: an internal connector located on the engagement portion of the power generating apparatus and electrically connected with the power generating unit of the power generating apparatus; a first support plate attached to, and extending at least partially around, an outer surface the engagement portion of the power generating apparatus for rotation therewith; a second support plate mounted radially outwards of the first support plate for rotation about the axis with respect to the power generating apparatus; a power connector mounted on the second support plate, and movable between a first position in which the power connector is disconnected from the export connector of the support structure and a second position in which the power connector is electrically connected with the export connector of the support structure; and a flexible electrical cable which extends from the internal connector to the power connector thereby connecting electrically those connectors, and which is supported by the first and second support plates (36, 38). an internal connector located on the engagement portion of the power generating apparatus and electrically connected with the power generating unit of the power generating apparatus; a first support plate attached to, and extending at least partially around, an outer surface the engagement portion of the power generating apparatus for rotation therewith; a second support plate mounted radially outwards of the first support plate for rotation about the axis with respect to the power generating apparatus; a power connector mounted on the second support plate, and movable between a first position in which the power connector is disconnected from the export connector of the support structure and a second position in which the power connector is electrically connected with the export connector of the support structure; and a flexible electrical cable which extends from the internal connector to the power connector thereby connecting electrically those connectors, and which is supported by the first and second support plates (36, 38).