A displacement system for a submersible electrical system such as a tidal turbine system, the displacement system comprising a base for the turbine or related electrical components, a vessel having a buoyant body and at least three rigid legs each displaceable relative to the body between a raised and a lowered position, and in which the base is adapted to be secured to and displaceable by the three legs in order to allow the base to be deployed or retrieved from the seabed using the legs, which legs can also be utilised to raise the body of the vessel out of the water to provide a stable work platform above the deployment site.

Described is a tool and apparatus for positioning a blade for a wind turbine the wind turbine including a tower and a rotatable hub on the tower. The tool is mounted on a side of the tower so that the blade is supported on the tower in an initial configuration. The tool includes a first part arranged to be angularly movable relative to a second part for tilting the blade with respect to the tower to position the blade in a position that can allow the blade to be connected to the hub.

A safety door assembly for a hoist window of a structure includes a sliding door arranged to reveal or conceal the hoist window; and a barrier assembly which is closed to inhibit access to an area in front of the hoist window or opened to permit access to the area in front of the hoist window; and wherein the barrier assembly is adapted to prevent the sliding door from revealing the hoist window when the barrier assembly is open; and the sliding door is adapted to prevent opening of the closed barrier assembly when the sliding door reveals the hoist window.

A method for performing maintenance on an outer surface of at least one wind turbine part, such as a tower (2), a nacelle (3) or a wind turbine blade (5), of an offshore wind turbine (1) is disclosed. An access system (10) is transported to a site of the offshore wind turbine (1), and the access system (10) is transferred to a transition platform (6) at a lower part of the offshore wind turbine (1), while operating the offshore wind turbine (1) in accordance with a normal operating mode. Normal operation of the offshore wind turbine (1) is then stopped, and maintenance is performed on an outer surface of at least one wind turbine part (2, 3, 5) of the offshore wind turbine (1), using the access system (10). When the maintenance has been completed, normal operation of the offshore wind turbine (1) is restarted in accordance with a normal operating mode. Normal operation of the offshore wind turbine (1) is only stopped while the actual maintenance takes place. Thereby the loss in power production is minimised.

A wind turbine generator nacelle (14) comprises a nacelle frame (44) having a first forward hub end and a second aft end. Dedicated transport fittings (46) are positioned at each of the ends of the nacelle frame (44). The fittings (46) are adapted to be engaged by transport frames (86) on first and second transport trailers (80) for supporting the nacelle frame (44) for transport by the trailers (80). A service platform (20) is mounted to the transport fittings (46) on the aft end of the nacelle frame (44) such that the service platform (20) is cantilevered off of the aft end of the nacelle frame (44).

The invention relates to a wind driven power plant comprising a nacelle having a nacelle cover and a helicopter hoisting platform, the nacelle further comprising a hatch extension and a hatch cover, the hatch extension being arranged between the nacelle cover and the hatch cover, wherein the hatch extension has a channel-like shape, wherein the hatch cover is mounted on top of the hatch extension, and wherein a the hatch extension provides a distance between the hatch cover and the nacelle cover.

A method for lifting/lowering a long object in a wind power generating apparatus which includes a rotatably disposed rotor head, the rotor head having an openable and closable opening which causes an interior space of the rotor head and an exterior of the rotor head to communicate with each other, the interior space being disposed with a long jig for hanging the long object, the method includes a horizontal movement step of moving the long object in a horizontal attitude along a horizontal direction to be close to the opening or to be away from the opening in the interior space, an attitude change step of changing an attitude of the long object between the horizontal attitude and a vertical attitude vertically above the opening in the interior space, and a lifting/lowering step of lifting/lowering the long object in the vertical attitude while hanging the long object from the jig.

A method of erecting a wind turbine on a wind turbine site, the wind turbine comprising a turbine tower and a nacelle. The method comprises the following steps: providing a plurality of tower sections being arrangeable upon each other in a vertical orientation in a tower structure to form the turbine tower; providing at least one damper unit configured to dampen oscillations of the turbine tower; attaching a damper unit to one of the plurality of the tower sections on an outside thereof, and subsequently arranging the tower section in the tower structure, and arranging the nacelle on top of the tower structure while the damper unit is attached to a tower section in the tower structure.

An offshore wind turbine blade and tower maintenance devices and systems, more particularly, to the system for service tools positioning relative to the offshore wind turbine blade and tower. An arrangement for lowering and raising service tools used for offshore wind turbine blade and tower maintenance, having: a truss system, a rigging and a rigging pulling in and letting out means. The truss system, includes booms, pivotally attached to a supporting means, which are adapted to be leaned against or releasably fixed to a wind turbine tower or wind turbine tower mooring elements; wherein the rigging and a rigging pulling in and letting out means are operably connected with the truss system, so to allow lowering and raising service tools used for offshore wind turbine blade and tower maintenance.

An assembly and method are provided for preventing exposure of personnel to an opening defined by a surface of a wind turbine. Accordingly, a hatch assembly is arranged adjacent to the opening. The hatch assembly includes a frame structure and a support structure. The frame structure includes a plurality of frame members arranged together to at least partially surrounded opening the plurality of frame members further define a passageway for receiving the support surface. The support surface is slidable between a first position and a second position. The support surface occludes the opening defined by the surface of the wind turbine when the support surface is in the first position and occludes the passageway defined by the plurality frame members when in the second position so as to prevent exposure of personnel to the opening.