A method for connecting an offshore structure (2) to a subsea pile (1) includes inserting a connecting portion (14) of the structure inside the subsea pile. The connecting portion (14) comprises a plurality of outwardly moveable clamping members (5). Moving each of the plurality of clamping members (5) into gripping contact with an inside surface of the subsea pile provides a mechanical connection. The method may also include a grouting step to make the connection permanent.

Described and disclosed is a foundation structure of an offshore structure, in particular of a wind turbine, with a floating foundation, including at least one floating body for floating on the surface of the sea, at least one anchor for anchoring the at least one floating body the seafloor and at least one holding element for holding the at least one floating body to the at least one anchor. At least one transmission cable extends from the at least one anchor along the at least one holding element to the at least one floating body and/or back. To enable a reliable monitoring of the anchoring of the offshore structure, provision is made for the transmission cable to be guided in sections through at least one protection element provided between the holding element and the at least one anchor and/or the at least one floating body.

In particular, a foundation for an offshore structure is disclosed. The foundation includes: a tower having an anchoring section which is anchorable in the seabed and a connection section arranged at the opposite end of the tower. An electricity generation device arrangable above the water surface is connectable with the connection section of the tower. A natural frequency of the offshore structure is below an excitation from a single revolution number 1P of at least one exciting component. Further disclosed is an offshore structure.

A vessel and a method for installation of a pile adapted to support an offshore wind turbine are described. The method includes a) suspending the pile from a hoisting cable in a substantially vertical orientation; b) providing a lower end of the pile in a pile holding system limiting horizontal motion of a pile portion held by the pile holding system; and c) lowering the pile with the pile being held by the pile holding system. The lowering includes at least lowering the pile through a splash zone of a body of water, and during step c), two tugger lines are directly or indirectly connected to the pile at a location between the pile holding system and the hoisting cable, said tugger lines being operated to damp motion of the pile in two respective horizontal directions.

A method includes mounting a first jacket connector block (400) to an apparatus. The first jacket connector block includes a first frame (415), a plurality of first conductor tubes (405) connected to the first frame, a first plurality of releasable connectors (420) coupled to first ends of the first conductor tubes, and a second plurality of releasable connectors (420) coupled to second ends of the first conductor tubes and engaging the apparatus.

A method of installing foundation elements, in particular (mono)piles having a diameter of five meters or more, in an underwater ground formation includes lowering a leader from a surface vessel with at least the tip of the leader into the water, and lowering a foundation element and/or a noise mitigation screen along the leader.

An off-shore wind turbine system is assembled using a platform or jack-up vessel, and a first base anchored to the seafloor at a bade assembly off-shore location. A buoyant tower is attached to the first base. A crane provided on the platform or jack-up vessel is used to lift blades and blades, which are then coupled to a turbine held in a nacelle provided at the top of the buoyant tower. The buoyant tower, the nacelle, and the blades are detached from the first base. The buoyant tower, the nacelle, and the blades are towed to a wind farm and connected to a second base provided in the wind farm. The buoyant tower, the nacelle, and the blades are further stabilized using mooring lines spanning between the buoyant towers and other bases provided in the wind farm. The first base and/or the second base include anti-rotation features.

An offshore wind energy system comprising a foundation having a first hollow structural element with a longitudinally extending, circumferential first wall. A cable bushing penetrates through the first wall and is arranged in the first wall. At least one cable guide arrangement extends in a radial direction and is arranged at an outer shell surface of the first wall of the first hollow structural element. The cable guide arrangement is configured to guide a submarine cable exiting the cable bushing from the cable bushing to a submarine bottom surface.

A wind turbine foundation structure comprising a hollow structural element with a circumferential wall extending in the longitudinal direction. A first cable feed-through breaking through the wall is arranged in the wall. A transition piece with an overlap region projects into the hollow structural element and a transition region projects out of the hollow structural element at the end face. A circumferential wall extends in the longitudinal direction. A second cable feed-through which breaks through the wall is arranged in the overlap region in the wall. The first and the second cable feed-through bear against one another in an at least partially overlapping manner in the assembled state of the hollow structural element and the transition piece.

The present invention relates to a hydraulic down-the-hole hammer. The hammer comprises an elongate shaft and a piston having a central bore therethrough, the piston slidably mounted for reciprocal movement on the shaft and arranged to impact a percussion bit. Forward and rear drive chambers for the piston are disposed between the piston and the shaft and the forward chamber is separated from the rear chamber by an annular shoulder formed internally of the piston bore. The hammer also comprises a control valve to control reciprocation of the piston, wherein the control valve is arranged within the central bore of the piston. The hammer may be a disposable water hammer in which the piston is an outermost component of the hammer.