The offshore jack-up has a hull and a plurality of moveable legs engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises securing the vessel with respect to the hull of the offshore jack-up when the hull is positioned out of the water and the legs engage the seafloor. A lifting mechanism mounted on the offshore jack-up engages with a cargo carrying platform positioned on the vessel. The platform is lifted with the lifting mechanism between a first position on the vessel and a second position clear of the vessel.

A method and an installation facility for assembling a plurality of floating wind turbines (12). The method comprising establishing an installation facility by arranging an installation vessel (1), having a crane (4), at a sheltered place, mooring a barge (2) next to said vessel (1). Further transporting a plurality of turbine blades (6), a plurality of tower sections (8) and a plurality of nacelles (10) to said installation facility, lifting of these parts onto said installation facility. Further towing a first floating wind turbine foundation (11 a) to said installation facility, erecting a tower (8a) on said first foundation (11 a) by assembling a set of said tower sections (8), installing a nacelle (10) on top of said tower (8a), installing a set of turbine blades (6) onto said nacelle (10) to make a completed wind turbine (12a), and finally towing said first wind turbine (12a) away.

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.

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.

Tower erection systems and methods utilizing a load-sharing support member (LS support member) are disclosed. The LS support member can have a first end coupled to a crane tower and a second end configured to repeatably couple to the upper-most tower section of a partially assembled tower stack during assembly. During lifting, a portion of the vertical load is transferred to the partially assembled tower stack.

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.

A method of assembling a structure, such as a wind turbine, is disclosed. The method comprises a step of providing a lifting arrangement comprising a gantry disposed over and/or directly above a rail, and lifting means coupled to the gantry. The method further comprises stacking portions of the structure by: conveyably disposing a first portion of the structure relative to the rail; lifting a second portion of the structure using the lifting means; disposing the first portion underneath the second portion by conveying the first portion along the rail; and lowering the second portion onto the first portion. Also disclosed is a corresponding system for assembling a structure, such as a wind turbine, and corresponding clamping and/or gripping system.

The disclosure relates to a crane (200) for erecting a tower including a plurality of tower segments (171, 72, 173, 174, 175), the crane (200) comprising: a telescopic mast (210), and a jib (230) rotatably mounted with respect to the telescopic mast (210) and comprising lifting equipment (240). The telescopic mast (210) comprises a lower mast segment (211) having one or more lower clamp assemblies (202, 204) for selectively gripping portions of the tower and a roller assembly (300) for rolling along the tower, and comprising one or more further mast segments (212, 213, 214, 215, 216) having an upper clamp assembly (206) for selectively gripping portions of the tower, the further mast segments (212, 213, 214, 215, 216) being slidable with respect to the lower mast segment (211). The disclosure also relates to methods for climbing a tower with a crane (200) and methods for mounting a wind turbine tower.

A hoisting arrangement for hoisting an offshore wind turbine blade, comprising a gripper attachment 150 arranged to be connected to the wind turbine blade, comprising a set of cable attachment points 191, 192,193 arranged as a first polygon, a vessel attachment module 194 arranged to be connected to a vessel, comprising a plurality of cable guide elements 190 arranged as a second polygon, a plurality of cables 141, 142, 143, 144 spanned between the cable attachment points and the cable guide elements, and a control system for controlling a position and/or orientation of the gripper attachment within a work space by controlling a spanned length of at least two cables of the plurality of cables between the cable attachment points and the cable guide elements.

A lift system mountable in a nacelle of a wind turbine has a boom having a proximal end mountable in the nacelle and a distal end extending over a hub of a rotor of the wind turbine when the lift system is mounted in the nacelle. The lift system has a frame structure for mounting the proximal end of the boom in the nacelle, a winch mounted to the boom, a fastener situated below the boom and operatively connected to the winch by at least one cable, and a trolley movably mounted to the boom to permit translation of the trolley longitudinally along the boom thereby permitting longitudinal movement of the fastener with respect to the boom.