The invention relates to an offshore installation, comprising an underwater foundation structure, a construction placed onto the foundation structure, a docking device for a boat, and a device for cathodic corrosion protection for the underwater foundation structure, said device having at least two anodes (2), which are arranged at a distance from each other and are each fastened to a beam (4) or a support of the foundation structure, the extension arms or the supports being connected directly to the foundation structure below the waterline.

A method includes providing a lower platform block (300) including a first frame (315), a plurality of docking tubes (305) connected to the first frame, and a plurality of first conductor tubes (310) connected to the first frame. At least a first jacket connector block (400) including a second frame (415) and a plurality of second conductor tubes (405) connected to the second frame is releasably coupled to the lower platform block to align the second conductor tubes with the first conductor tubes. A platform deck block (500) including a third frame (515) defining a deck and a plurality of third conductor tubes (505) connected to the third frame is releasably coupled to the first jacket connector to align the third conductor tubes with the first conductor tubes.

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).

A transportation device for an offshore platform, including a vessel and a floating structure which are fixedly connected. The floating structure is placed on a sea surface and is configured to assist the vessel to sail. The floating structure is provided with an adjustment mechanism which is configured to adjust the floating structure to rise and fall relative to the sea surface. A rail is arranged on the vessel and is in sliding connection with the topside module, so that the topside module slides onto the vessel from land. During the transportation of the topside module, the buoyancy of the floating structure is adjusted through the adjustment mechanism, so that the floating structure provides sufficient anti-rolling moments beside the vessel, thereby reducing the vibration of the topside module caused by the winds and waves during the sailing and reducing the potential damage to the topside module.

Various embodiments relate to a method and a harbour plant for mooring a floating body. The harbour plant includes a piled base structure provided with two upwards through sea level projecting sidewalls terminated above sea level and a laterally arranged bottom structure interconnecting the sidewalls, where a top surface of the bottom structure is arranged at a depth allowing the floating body to be floated in between the sidewalls, and where the floating body is arranged to be rigidly, but releasably supported by at least parts of the sidewalls. The method includes bringing the floating body into a position between the sidewalls and fixing rigidly the floating body to the vertical sidewalls of the base structure and still exposing the floating body more or less fully to buoyancy by allowing a water-filled gap at least between bottom of the floating body and a corresponding upper surface of the base structure.

An offshore structure having a foundation structure, wherein the foundation structure has at least a first and a second profile, the first profile is designed as a pile and the second profile is designed as a pile sleeve, the second profile encloses the first profile over a penetration length, wherein an interspace is formed between the first and the second profile, the interspace has a casting compound filling over the total penetration length, shear elements are provided on the first and/or the second profile, the shear elements extend into the interspace and effect an axial load dissipation into the casting compound filling, the shear elements are provided only over a first partial length of the penetration length, the first partial length is between 65 and 90% of the total penetration length and a second partial length is free of shear elements, wherein the second partial length forms the upper length of the penetration length in the installed position.

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.

An assembly includes first and second tubular members of a wind turbine support structure. The second member has a fork-shaped cross section with a main body between two substantially parallel walls that each comprise at least one through hole, the first member is between the two walls of the second member, and the through holes of the first and second member define a channel. A connector insertable in the channel is consecutively radially expandable. An actuator is configured to move the connector in an axial direction in said channel. The connector, when expanded, pushes the first member in a radial direction relative to said channel against the second member to define a clamping contact and thereby a pre-tensioned connection in said radial direction between a face of the first member and a face of the main body of the second member. A method of assembling the assembly.

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).