A system for holding a pile and being mounted on a vessel includes a support assembly and a pile holder. The support assembly provides compensation for wave-induced motion of the vessel to maintain a predetermined X-Y location of the pile holder. The pile holder has a center axis and is mounted on the support assembly so as to be tiltable about a substantially horizontal tilt axis relative to the support assembly. The pile holder has at least one ring which includes a ring structure and multiple pile engaging devices connected to the ring structure of the ring, distributed about the circumference of the ring. The substantially horizontal tilt axis of the system is located, with the pile extending substantially vertically through the at least one ring, further forward from the location at which the support assembly is mounted to the vessel than the center axis of the pile holder.

A system for holding a pile and being mounted on a vessel includes a support assembly and a pile holder. The support assembly provides compensation for wave-induced motion of the vessel to maintain a predetermined X-Y location of the pile holder. The pile holder has a center axis and is mounted on the support assembly so as to be tiltable about a substantially horizontal tilt axis relative to the support assembly. The pile holder has at least one ring which includes a ring structure and multiple pile engaging devices connected to the ring structure of the ring, distributed about the circumference of the ring. The substantially horizontal tilt axis of the system is located, with the pile extending substantially vertically through the at least one ring, further forward from the location at which the support assembly is mounted to the vessel than the center axis of the pile holder.

An assembly for producing offshore electricity comprising: a wind turbine, and a monopile extending along an axis for fully supporting the wind turbine, the monopile comprising a lower end for penetrating in a seabed, the lower end comprising an outer tube and defining an interior volume.

The lower end comprises: an inner tube extending in the interior volume and defining a lower opening, the inner tube and the outer tube defining an annular volume, a closure plate welded on the inner tube and closing the lower opening, and wing plates extending in the annular volume and welded on the inner tube and on the outer tube, the wing plates defining a plurality of compartments extending along the axis and defining lower entries adapted for allowing part of the seabed to enter the compartments.

An apparatus for, and method of, reducing a pendulum motion of a piece of subsea equipment during a landing operation includes a frame assembly arranged for connection to the piece of subsea equipment; a sheet of arrestor material disposed within a perimeter of the frame assembly, and a drive mechanism arranged to move the sheet of arrestor material between a first position and a second position, each position providing a different amount of surface area than the other to create a different drag force on the equipment.

An apparatus for, and method of, reducing a pendulum motion of a piece of subsea equipment during a landing operation includes a frame assembly arranged for connection to the piece of subsea equipment; a sheet of arrestor material disposed within a perimeter of the frame assembly, and a drive mechanism arranged to move the sheet of arrestor material between a first position and a second position, each position providing a different amount of surface area than the other to create a different drag force on the equipment.

An underwater pile foundation comprises a pump in fluid communication with an internal chamber of the pile to pump water out of or into the chamber. This reduces or increases the pressure of water in the chamber relative to ambient pressure of water outside the chamber during installation or removal of the pile. While that pumping phase is ongoing, and potentially before or after that pumping phase, a pressure variator in fluid communication with the chamber imparts oscillations in the pressure of the water in the chamber. The resulting pressure waves in water within the chamber reduce resistance to movement of the pile relative to soil in which the pile is embedded.

A tubular foundation element, in particular a pile e.g. a jacket pile, to be installed in a ground formation has at least one open end, typically both ends open, allowing a pile driver with an anvil to be inserted into the tubular foundation element. The tubular foundation element comprises a support at the inside thereof, which support is adapted to transmit energy from the anvil directly to the tubular foundation element, during installation of the tubular foundation element.

A subsea foundation comprises at least one mudmat having a top panel and a skirt depending from the top panel to be embedded into seabed soil. At least one auxiliary plate is supported by the mudmat, the plate being deployable downwardly like a guillotine blade from a raised, retracted position in which the plate is held above a lower edge of the skirt into a lowered, deployed position in which the plate extends beneath the lower edge of the skirt to be embedded further into the seabed soil. The foundation may be used to restrict movement of an elongate subsea element, such as a pipeline, relative to the seabed.

In an assembly of an offshore support structure for a wind turbine, tubular members are interconnected in grouted connections where a first tubular member has fastened to it a shell-unit comprising a cavity into which an end-part of a second tubular member is inserted and fixed by grouting. The cavity is closed by a rigid entrance-flange that is fastened to the walls of the shell-unit. The design converts forces acting on the second tubular member to compression forces acting on the grout in the cavity.

A vessel comprises an upending hinge having a frame mounted to at least one of a deck and a hull and a bearing member having a bearing surface between legs for bearing a monopile. The bearing member has bearing member pivots having a common axis of rotation. The bearing member has a monopile receiving position, which is a rotational position with respect to the common axis of rotation in which the bottom of the bearing member is located below the common axis of rotation and the bearing surface is facing upwardly. The bearing member also has a monopile upending position, which is a rotational position with respect to the common axis of rotation of in which the bearing surface is located outside and facing away from a circumferential wall at the location of the upending hinge. The frame is provided with a lifting mechanism for lowering the bearing member pivots.