A crane with a pivotal boom. The crane has a first and a second main hoisting system, which main hoisting system are configured for independent operation. Each system comprises a hoisting cable, an upper sheave block, a hoisting block assembly suspended from the upper sheave block by the hoisting cable in a multiple fall configuration, and a hoisting winch. The upper sheave blocks of the first and second main hoisting systems are each independently pivotable about a common pivot axis relative to the boom. Each hoisting block assembly comprises a hoisting block body, multiple fixed sheaves that are fixed on the hoisting block body, and multiple disconnectable sheave members, each disconnectable sheave member comprising a frame and at least one sheave rotatably supported by the frame.

In order to provide an improved and cost-efficient method for performing an exchange of up-tower main components on an off-shore wind turbine a method is disclosed in during which a non-permanent service platform is temporarily coupled to a wind turbine tower lower section. In addition, a wind turbine structure and a system including such a structure are described, the wind turbine structure and the respective system being designed to allow performing the described method.

In order to provide an improved and cost-efficient method for performing an exchange of up-tower main components on an off-shore wind turbine a method is disclosed in during which a non-permanent service platform is temporarily coupled to a wind turbine tower lower section. In addition, a wind turbine structure and a system including such a structure are described, the wind turbine structure and the respective system being designed to allow performing the described method.

A crane vessel for hoisting of an offshore wind turbine or a component thereof, includes a hull having a deck. A crane configured for hoisting of an offshore wind turbine or a component thereof includes a vertical crane structure having a crane structure base fixed to the hull, the crane structure extending from the hull over a height thereof to a top along a vertical axis of the crane structure, a boom, and a slew bearing allowing to revolve the boom, about a slew axis. A main hoisting system includes at least one main hoisting winch, an associated main hoisting cable and a load connector, the main hoisting cable extending from the main hoisting winch to a main hoist cable guide on the boom and then to the load connector. The crane further includes a dynamic behaviour adjustment system that is configured to adjust the dynamic behaviour of the vessel by moving and/or arranging an adjustment mass that is distinct from the offshore wind turbine or component thereof into or in at least one dynamic behaviour adjustment position along the height of the vertical crane structure.

A marine knuckle boom crane includes a pedestal and a crane housing rotational relative to the pedestal. A knuckle boom assembly is attached to the crane housing and includes a main boom and a spreader type jib. A hoisting system includes a first departure sheave and a second departure sheave on the jib, and a third departure sheave mounted to the main boom or to the crane housing. One or more winches drive a first, second, and third cable which are each connected to an object suspension device and each pass via the first, second, and third departure sheave, respectively, to the respective winch. The first, the second, and the third cable together define an inverted pyramid which diverges upwards from the object suspension device when handling the object.

A marine knuckle boom crane includes a pedestal and a crane housing rotational relative to the pedestal. A knuckle boom assembly is attached to the crane housing and includes a main boom and a spreader type jib. A hoisting system includes a first departure sheave and a second departure sheave on the jib, and a third departure sheave mounted to the main boom or to the crane housing. One or more winches drive a first, second, and third cable which are each connected to an object suspension device and each pass via the first, second, and third departure sheave, respectively, to the respective winch. The first, the second, and the third cable together define an inverted pyramid which diverges upwards from the object suspension device when handling the object.

A jack-up crane vessel or semi-submersible crane vessel is provided including a hull with a deck, and a crane on the hull for hoisting a load outside the deck. The crane includes a slewing crane base with a first suspension, an elongated boom that is rotatable around a horizontal rotation axis with respect to the first suspension, at least two pendants between the boom and the first suspension that mutually converge toward the distal boom section, a boom spacer between the boom and the first suspension, and a boom luffing installation for driving the rotation of the boom around the horizontal rotation axis between a lowered transport position and a raised operational position. In the direction of the vertical rotation axis the first suspension extends at least in the lowered transport position of the boom above the boom heel of the boom.

Disclosed is a system for the storage and traction of a cable, in particular a synthetic cable fitted to an offshore crane. The storage/traction system includes a frame that carries in particular a storage device including a support carrying a storage reel through an assembly defining an axis of rotation. Between the storage reel and the support, the assembly includes of a single slewing ring including two rings that are free to rotate with respect to each other: —a fixed ring that is fastened to the support; and —a moving ring that is, on the one hand, fastened to the storage reel and, on the other hand, rotated by a motorization.

Disclosed is a system for the storage and traction of a cable, in particular a synthetic cable fitted to an offshore crane. The storage/traction system includes a frame that carries in particular a storage device including a support carrying a storage reel through an assembly defining an axis of rotation. Between the storage reel and the support, the assembly includes of a single slewing ring including two rings that are free to rotate with respect to each other: —a fixed ring that is fastened to the support; and —a moving ring that is, on the one hand, fastened to the storage reel and, on the other hand, rotated by a motorization.

A system for controlling a motion compensated pile guide for a floating vessel comprises a pile guide for guiding a monopile in its longitudinal direction during driving the monopile into a seabed, an actuator for moving the pile guide in horizontal direction with respect to a vessel to which the pile guide is mounted, a control unit for controlling the actuator, which control unit is configured for compensating motion of the vessel to which the pile guide is mounted so as to maintain the horizontal position of the pile guide during driving a monopile into a seabed, a first sensor for determining an inclination angle of a monopile with respect to the vertical during driving the monopile into a seabed, and a second sensor for determining magnitude and direction of an actual force of a monopile onto the pile guide during driving the monopile into a seabed. The control unit is configured to determine a desired force of the pile guide onto the monopile for minimizing the inclination angle when determined by the first sensor, and to control the actuator for moving the pile guide opposite to the direction of the actual force when the desired force is larger than the actual force and in the same direction as the actual force when the actual force is larger than the desired force.