A system and method for mating equipment offshore to a spar buoy secured to a foundation without the use of a crane barge. The system comprises a floating vessel having a pair of forks defining a slot. A gimbal table, defining an opening, is positioned within the slot and connected to the vessel and a locking collar is mounted to the gimbal table. A mating member is attached to the spar buoy. The vessel is maneuvered to bring the spar buoy within the gimbal table opening. With the spar buoy positioned within the gimbal table opening, the locking collar is arranged and designed to releasably attach to the mating member of the spar buoy and restrict relative vertical motion between the spar buoy and the vessel while the gimbal table allows the floating vessel to roll and pitch without driving these motions into the spar buoy.

A method for installation of a pile adapted to support an offshore wind turbine in which the piles are transported horizontally, positioned in a pile holder, rotated to a vertical orientation while being held by the pile holder, and subsequently lowered into the water while being held by the pile holder. The installation vessel is in a floating condition, and the pile holder is compensated for wave-induced motion of the vessel to maintain a predetermined X-Y location independent of the wave-induced motion of the vessel. A pile holding system, a pile holder, and a vessel comprising a pile holding system are also disclosed.

A method for retrofitting a wind turbine foundation is provided. The foundation comprises a first substantially elongated pile (31) in the ground. The method further comprises: arranging a lower end of an elongated channel (41) of a second substantially elongated pile (40) around the first pile (31), wherein the elongated channel (41) extends substantially along a longitudinal direction of the second pile (40), wherein the channel (41) is configured to receive at least a portion of the first pile. The method further comprises lowering the second pile (40) such that the elongated channel (41) surrounds at least a portion of the first pile (31). Finally, the second pile (40) is driven into the ground (35).

In embodiments, motion may be arrested and/or dampened using a motion arresting and dampening device comprising a lifting spreader bar, one or more bar mounted winches, deployment wire, a restorative inflation device, restraining wires and winches, hoses and controller, mechanical connection release system circuitry. Multiple restraints from winches mounted strategically on a vessel crane's boom may be applied to the spreader bar to restrain the bar during the lifting operation. The forces induced into the lifted object by the movement of the crane as it deploys the object into installation position are attenuated by the physical restrain of the adjustable wires. These adjustable wires may also be used to provide rotation of the object during final alignment of the object during installation.

Provided is a foundation building system for an offshore wind turbine, whereby a monopile is configured to be placed on the seabed, having an upper portion with a first attachment interface for attaching a foundation platform unit, at least one internal, second attachment interface in an interior cavity of the monopile for attaching at least one electrical platform unit, and a third attachment interface for attaching a tower of the offshore wind turbine atop the at least one electrical platform unit, wherein the upper portion is to be placed at least partly above sea level, the foundation platform unit providing at least one foundation platform extending around the tower when installed, and the at least one electrical platform unit comprising at least one platform for electrical equipment for guiding and/or connecting of an connection cable for connecting the offshore wind turbine.

An offshore wind turbine installation vessel includes a crane provided with a computerized crane control system. The computerized crane control system is linked to the slew drive, the luffing drive, and the hoisting winch of the crane, and is programmed to perform a foundation pile installation routine providing a coordinated pattern of slew motion of the superstructure and of luffing motion of the boom structure, as well as operation of the hoisting winch so that the load connector of the crane moves from a foundation pile pick up position thereof, where the load connector is connected to the top end of a horizontally oriented foundation pile stored on a storage deck, to a foundation pile overhoarding position thereof, wherein the foundation pile is in vertical suspended from the load connector, outside of the hull.

Seal arrangement for a joint of two joint elements, in particular realized as a monopile and a transition piece, of an offshore structure, preferably an offshore wind energy installation, in particular a substructure thereof, in which, for the purpose of producing a stable joint, an upper joint element and a lower joint element are inserted into each other in a clamping manner by means of at least one seal unit, comprising one of the joint elements and the at least one seal unit fixed to the joint element, in such a manner that the seal unit, in a joining position, is arranged between an inner joint surface of one joint element and an outer joint surface of the other joint element, at least one seal unit having at least one elastic sealing element, which extends in the circumferential direction around the entire circumference and the thickness (D) of which is greater than the thickness (D) of an adjoining seal unit region and method for producing a seal arrangement.

The invention relates to a boat landing structure suitable for being used in a marine construction, wherein said marine construction comprises, essentially, a concrete shaft intended for being installed anchored at a depth level with respect to the water level, and wherein said boat landing structure comprises two substantially vertical and parallel ribs, integrated in the shaft of the marine construction and projecting out from same, wherein said ribs are made partially or entirely of concrete. Likewise, the space comprised between said ribs houses an access ladder suitable for being used by personnel accessing the marine construction from an operation boat. The invention also relates to a marine construction and a segment comprising the mentioned boat landing structure.

An offshore structure has an upending device for upending an elongate suppo structure from a substantially horizontal loading position on a deck of the offshore structure to a substantially vertical launch position outboard of the offshore structure. The upending device has a pivot axis situated near a side of the offshore structure for pivoting the upending device between the loading position and the launch position. A first end of the upending device has a connector member for pivotally connecting to the elongate support structure. The connector member in the launch position is in a position outboard from the side of the offshore structure. A second end of the upending device is attached to a pulling device that is located on the deck of the offshore structure. The upending device is within reach of one or more hoisting means for the elongate support structure.

A pull-in head assembly (8) for releasably connecting a pulling arrangement (112) to an elongate flexible structure (4, 6). The pull-in head assembly (8) comprises a body (30) which defines a pulling axis X of the pull-in head assembly (8) and a retaining member (32) arranged around the pulling axis X. The retaining member (32) is configured to secure the pull-in head assembly (8) to an elongate flexible structure (4, 6) such that, in use, a pulling force exerted on the pull-in head assembly (8) along the pulling axis X is transferred to the elongate flexible structure (4, 6). The retaining member (32) is configured to release the pull-in head assembly (8) from the elongate flexible structure (4, 6) when the pulling force exceeds a predetermined threshold such that the pull-in head assembly (8) can be separated from the elongate flexible structure (4, 6).