System for transporting an offshore structure, the system comprising: a transport apparatus, in particular a vessel or a vehicle, which is configured to receive an offshore structure and to form a slip joint with a slip joint section of a received offshore structure, wherein the system is configured to enter a releasable state, from a fixing state, wherein, in the releasable state, the slip joint formed by the transport apparatus and the offshore structure is smaller than that force in the fixing state.

The invention allows setting up floating platforms comprising an elongated central body (1) from the lower portion of which legs (2) come out intended to fix the platform to anchoring elements arranged in the sea bed (5). The vessel comprises: a) a longitudinal through groove (4) up to the vessel bottom, and leaving part of the vessel bow (5) open; and b) a plurality of slots (6, 7) placed at the bottom of the vessel, wherein the groove (4) and the slots (6, 7) are configured both in dimension and in shape in such a way that they fit in at least some of the legs (2), so that the legs (2) can be inserted, at least partially, in the slots (6, 7) to attach the platform to the vessel.

A method for installation of a transition piece on a monopile foundation of an offshore wind turbine along a common axis extending in a longitudinal direction is performed from a floating installation vessel. Buffer elements are arranged around an inner circumference of the transition piece and/or the monopile structure. The transition piece is lifted and lowered onto the monopile structure by use of a crane, and landed onto the monopile structure through the use of the buffer elements. A number of hydraulic cylinder jacks for circumferential alignment of bolt holes are provided in the transition piece and monopile, and alignment tools are used for alignment of the flanges provided on each of the transition piece and the monopile. The transition piece is lifted and the buffer elements are removed after which the transition piece is lowered onto the monopile, and bolts are tensioned fix the transition piece to the monopile.

The invention allows setting up floating platforms comprising an elongated central body (1) from the lower portion of which legs (2) come out intended to fix the platform to anchoring elements arranged in the sea bed (5). The vessel comprises: a) a longitudinal through groove (4) up to the vessel bottom, and leaving part of the vessel bow (5) open; and b) a plurality of slots (6, 7) placed at the bottom of the vessel, wherein the groove (4) and the slots (6, 7) are configured both in dimension and in shape in such a way that they fit in at least some of the legs (2), so that the legs (2) can be inserted, at least partially, in the slots (6, 7) to attach the platform to the vessel.

Systems for assembling a wind turbine without the assistance of cranes. According to some implementations a system is provided that includes lifting systems having lifting platforms arranged peripherally around the tower. The lifting platforms cooperate with different connection tools that can be supported on an auxiliary column and thus lift or lower the tower modules.

An apparatus (1) for transportation, installation and retrieval of marine structures (10) is disclosed and illustrated. It comprises at least two suitably connected vessels (1,2) with adjustable buoyancy, each having a first end (5) and a second end (8). The apparatus is equipped with lifting mechanism for lifting a marine structure on and from it. The vessels (1,2) are connected to each other at each said first end (5) at an angle (4) and are free at each said second end (8), thus forming a V-shape. The invention also embraces the methodology for transportation, installation and retrieval of marine structures, using the apparatus (1).

An adjustable platform for installing a wind turbine generator comprises an adjustable platform shell, the adjustable platform shell is installed on a hull, pile legs are connected vertically in the adjustable platform shell in a sliding way, a plurality of adjusting jacks are arranged on the pile legs, an electric plug-in component is arranged in the adjustable platform shell and used for fitting with the adjusting jacks. The fitting of electric plug-in component with the adjusting jacks of the pile legs replaces the bolted connection between the installation platform and the pile legs, and the electric power is used to replace the manual operation, solving the technical problems in the prior art that bolted connection is required between the installation platform and the pile legs, bolts are required to be removed manually before the pile legs sink, and the labor cost is greatly consumed.

A deployed L-shaped rack structure interengaged with a self-elevating vessel is used for supporting a feeder transport vessel, such as an ocean or sea barge, to eliminate relative motion or movement between the vessels. Some of the proposed rack structures are movable between a stowed position and a deployed position. The method of use for the movable rack structures includes the self-elevating vessel arriving at a predetermined location, elevating the hull of the self-elevating to a suitable height above the sea surface at a desired still water line (SWL) to create an air gap, and then deploying the rack structure. A feeder transport vessel, with its cargo and/or components, can then be floated over the deployed rack structure. The self-elevating vessel then uses its jacking system including a plurality of legs supported on the seabed to raise the feeder transport vessel and its cargo and/or components to a desired height above the SWL. From this position relative motion between the self-elevating vessel and transport vessel is eliminated so that the self-elevating vessel lifting device, such as a crane, can be more safely used to install energy components, such as wind turbine components. A bottom supported tower/column section could also be assembled and installed in seabed using the self-elevating vessel and rack structure along with the lifting device. A fixed rack structure system and its method can also be advantageously used with a self-elevating vessel. The systems and methods could be used in reversing the method or steps for deinstallation of the energy components installed in the sea.