Itrec B.V.

A crane housing for a leg encircling crane to be mounted onto a slew bearing includes an annular base component, two support components, and a frontal component, each having bulkheads. The support components are connected to the annular base component at respective lateral sides of a front segment thereof. The frontal component is connected to the front segment of the annular base component, between the two support components such as to interconnect these. The two support components and the frontal component together form a front torsion box, which provides torsional rigidity. The load of the boom, as applied on the support components, subjects the base component via the torsion box to a torsion that is distributed over the front segment of the base component.

A vessel for use in installation of a wind turbine on a floating foundation is provided, where both the vessel and the floating foundation are in floating condition and subject to sea-state induced motions. The vessel includes a floating hull; a crane including a hoisting system to suspend the wind turbine; a mast alignment system provided to engage on the wind turbine mast of the suspended wind turbine, and bring and maintain the wind turbine mast in alignment with the mounting axis of the floating foundation in order to compensate for sea-state induced motions; and a restraining system arranged to restrain the floating foundation only in a horizontal plane relative to the floating hull of the vessel and to allow for both sea-state induced heave motion and sea-state induced tilt motions in one or more vertical planes of the mast mounting structure relative to the hull of the vessel.

An offshore wind turbine foundation monopile in a seabed, the monopile having a foot end, a top end, and a longitudinal axis, by revolving the monopile about the longitudinal axis, such that the monopile makes multiple revolutions while being driven into the seabed.

A dual hoist crane is provided with a heave compensation system that can be used for both the main and for the auxiliary hoisting assembly. The heave compensation system includes a first set of sheaves for guiding the main hoisting cable and a second set of sheaves for guiding the auxiliary hoisting cable. The heave compensation system is configured to individually lock the first set of sheaves and the second set of sheaves to a heave compensation cylinder, for respectively providing the main hoisting assembly and the auxiliary hoisting assembly with heave compensation.

A riser section includes two filament-reinforced tubulars and a coupling sleeve for connecting the two filament-reinforced tubulars. The coupling sleeve includes a screw thread at opposite ends for cooperating with a screw thread provided on sections of the filament-reinforced tubulars. The riser section includes two torque locks, wherein the torque locks are each mounted on one of the filament-reinforced tubulars, and are on opposite ends of the coupling sleeve. The torque locks are provided with coupling teeth extending in an axial direction. The coupling sleeve is at opposite ends provided with coupling teeth extending in the axial direction. When the tubulars are screwed into the coupling sleeve and the torque locks have been mounted to secure the rotational movement of the tubulars relative to the coupling sleeve, the coupling teeth of each of the torque locks engages the coupling teeth of the coupling sleeve such that they block rotation of the torque lock relative to the coupling sleeve and allow for movement of the torque lock relative to the coupling sleeve in the axial direction, and thus allow for elongation of the sections of the tubulars including the screw thread. The pitch of the screw thread of the tubulars increases in a direction away from the end of the tubular, and the pitch of the screw threads of the coupling sleeve increases in a direction towards the end of the coupling sleeve.

A pile driving method for driving a hollow tubular pile having a vertical centreline, a top end and an open foot end vertically into the soil, e.g. into the seabed, e.g. a large diameter pile having an outer diameter at the open foot end of at least 5 meters, e.g. a monopile of an offshore wind turbine, wherein use is made of a pile driving system, wherein the system includes at least one hammer device and a torsional vibration drive.

In the installation of a rotor blade in horizontal orientation to the hub of a horizontal axis offshore wind turbine, use is made of a blade motion synchronization and positioning device, which comprises a wind turbine coupler, a blade coupler, a motion arm between the wind turbine coupler and the blade coupler, and a controllable motion arm actuator assembly. The method includes bringing and maintaining the blade coupler in a motion compensated receiving position, wherein the arm is operated to compensate for sea state and/or wind induced tower top motion. In receiving position, the coupler is coupled to the blade that is suspended from a crane. The actuator assembly is then operated to gradually bring, and then maintain, the coupled blade in a horizontal motion that is synchronized with tower top motion, and to displace the coupled blade root into a pre-mounting position. Then a mounting motion is performed wherein the blade root is moved into a mounting position and the blade root is fastened to mounting structure by fasteners.

A mobile land rig is adapted to perform drilling and/or wellbore related activities. The mobile land rig includes a drilling tower, a loader and a top drive system including a pivotal top drive unit. The top drive system is provided with an actuator assembly adapted to cause the pivot motion of the top drive unit.

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.

In an installation of a wind turbine on a floating foundation in floating condition and subject to sea-state induced motions, e.g. at the site of an offshore windfarm, use is made of a vessel with a crane arranged on the hull and provided with a hoisting system adapted to support the weight of the wind turbine and suspend the wind turbine from the crane. A heave compensation device compensates for sea-state induced heave motion of the wind turbine mast relative to the mast mounting structure of the floating foundation. Use is made of a mast alignment system configured to engage on the suspended wind turbine, e.g. on the mast of the suspended wind turbine, and to bring and maintain the mast of the wind turbine in alignment with the mounting axis of the floating foundation in order to compensate for sea-state induced motions, at least including tilt motions in one or more vertical planes, of the wind turbine mast relative to the mounting axis of the floating foundation.