Heave compensator for an offshore crane, offshore crane, vessel and hoisting method

Abstract

An offshore crane and a heave compensator (10) suspended in line from a lower block and a method for hoisting an object. The heave compensator comprises a frame (11a, 11b) suspended in line from a lower block, a vertical passive heave compensation system and a vertical active heave compensation system. The passive heave compensation system comprises a vertical passive cylinder (20) with a downwardly extending piston rod (21), a media separator (25) and a plurality of pressurized gas tanks (26a-t). The active heave compensation system comprises a vertical column (31) connected to the downwardly extending piston rod and extending vertically in parallel with the passive cylinder, wherein the vertical column is vertically guided by the frame, and wherein a vertical rack (33) is mounted to the vertical column and one or more pinions (34) and associated one or more electric motors (35) are supported by the frame.

Description

Technical Field

[0001] This invention relates to offshore cranes with heave compensators. Background Technology

[0002] In the field of offshore wind turbine installation, one approach envisions using vessels to transport wind turbines or components thereof between onshore and offshore locations, and to install them offshore. Thus, for example, a vessel is loaded with monopiles, typically stored horizontally on the deck at the onshore location, and then the vessel sails to the offshore wind farm. At the offshore wind farm, the vessel's crane is used to erect and install the monopiles, for example, by further utilizing monopile grippers to precisely position them. In another example, the foundation has already been installed, and the vessel is loaded with the wind turbine's mast, nacelle, and blades. The vessel sails to the wind farm, and then a crane is used to install the mast onto the foundation, followed by the nacelle, and then the blades. Alternative installation processes are also known.

[0003] Another approach in the installation of offshore wind turbines envisions positioning a dedicated installation vessel at an offshore location, equipped with a crane configured for maneuvering the wind turbine and / or its components. A supply vessel is then used to shuttle between the onshore and offshore locations to supply wind turbine components. For example, a jack-up or semi-submersible installation vessel is positioned offshore. A supply vessel, such as a self-propelled or towed barge, is then used to supply, for example, monopiles or other foundations.

[0004] A drawback of the "feeding vessel method" is the need to unload wind turbine components from the feeding vessel. In this context, the feeding vessel is typically floating and therefore subject to wave-induced heave. On the other hand, cranes mounted on installation vessels do not experience heave on jack-up vessels, or very little on semi-submersible vessels or vessels with different responses. In this method, the combination of relative motion and the large weight of the object to be lifted can be problematic. For example, unloading a horizontally oriented monopile from the feeding vessel can be difficult, given its enormous weight and size, such as a length exceeding 80 meters, a diameter exceeding 8 meters, a height of 12 to 13 meters, and a weight exceeding 2000 tons.

[0005] Proposals have been made to provide heave compensation carriers for delivery vessels, which are configured to support wind turbine components to be unloaded by a crane. The carrier is supported on the hull of the delivery vessel by a heave compensation support system. Examples of these proposals are presented in WO2022 / 238152 and WO2020 / 011679. Summary of the Invention

[0006] This invention aims to provide a solution in which a crane installed on a ship is equipped with a heave compensator. This crane can be used in place of a heave compensator on the ship, or in addition to a heave compensator on the ship. For example, the carrier carrying the object can rotate, and the crane's heave compensator is configured to compensate for all types of heave.

[0007] The first aspect of the invention provides an offshore crane according to claims 1 and 11, a vessel according to claim 9, a heave compensator according to claim 10, and a method according to claim 12.

[0008] The offshore crane of this invention is suitable for use on ships for maneuvering objects, such as wind turbine components, and for use on installation ships for unloading objects, such as wind turbine components, from delivery ships, such as barges. Typically, objects such as monopiles or rotor blades are horizontally supported on the delivery ship. The objects can also be monopiles used to form foundations for, for example, substations, drilling platforms, or even as foundations for viaducts or the like.

[0009] For example, the delivery vessel is moved to the range of the offshore crane of the present invention, such as the offshore crane mounted on the installation vessel, which is already present at the offshore location where the wind turbine is to be installed.

[0010] For example, key design factors for monopiles necessitate a base diameter of 8 to 11 meters, a length of up to 120 meters, and a wall thickness of up to 150 millimeters. These key design factors include turbines with capacities up to 15 megawatts and rotor diameters up to 230 meters, resistance to extreme wind loads, particularly those caused by hurricanes or typhoons, and the ability to operate underwater at depths up to 65 meters and under wave loads in the Atlantic and Pacific Oceans. The final weight of such monopiles can reach up to 2,500 tons, or 2,500,000 kilograms.

[0011] The crane includes a hoisting cable extending between a hoisting winch and a lower block suspended from the hoisting cable. Alternatively, in some embodiments, an upper block is disposed between the winch and the lower block, for example, at the distal end of the crane boom or jib.

[0012] The heave compensator includes a vertical passive heave compensation system and an active heave compensation system, preferably a vertical rack and pinion active heave compensation system.

[0013] The vertical passive heave compensation system includes a vertical passive cylinder having a cylinder body, a piston, and a vertically downward-extending piston rod that defines a lower rod-side chamber and an upper piston-side chamber of the passive cylinder. The cylinder body can have dimensions of approximately 1 meter in diameter and 4.5 meters in length. The piston rod can have a diameter of approximately 50 centimeters. Advantageously, the cylinder body is supported by a frame. Advantageously, the vertical passive cylinder is equipped with a cover, preferably a hydraulic cover, and particularly end dampers.

[0014] The vertical passive heave compensation system includes one or more media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the rod side chamber of the passive cylinder.

[0015] In this implementation, multiple media separators are arranged in parallel. This is particularly advantageous when the rod-side chamber of the driven cylinder has a large volume, thus requiring a large amount of hydraulic fluid from one or more media separators.

[0016] In an alternative implementation, multiple media separators are provided, each of which is associated with a group of pressurized gas tanks having the same pressure.

[0017] The vertical passive heave compensation system also includes multiple pressurized gas tanks, each of which can be selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve.

[0018] It is conceivable that a passive heave compensation system has multiple pressurized gas tanks, where the gas pressure in each tank can be adjusted according to the type of lifting operation. For example, in one operation, all gas tanks can have the same pressure, while for another operation, the pressure in the gas tanks is adjusted to create different groups of tanks, each group consisting of gas tanks with the same pressure.

[0019] Advantageously, the stiffness of the passive heave compensation system increases during lifting and / or decreases during descent. For low stiffness, a set of low-pressure tanks are connected to a media separator supplying the rod-side chamber of the passive cylinder, while for high stiffness, a set of high-pressure tanks are connected to a media separator supplying the rod-side chamber of the passive cylinder.

[0020] In an alternative embodiment according to claim 11, the passive heave compensation system has a vertically downward-extending piston rod supported by a frame. Additionally, the vertical column of the active heave compensation system is connected to the cylinder body. In this embodiment, the hydraulic side chamber of the media separator is connected to the piston side chamber at the upper part of the passive cylinder.

[0021] The heave compensator of the present invention also includes an active heave compensation system, which is implemented as a vertical rack and pinion active heave compensation system. Alternative active heave compensation systems are known, such as winch and cable-based active heave compensation systems. Active heave compensation systems are used, for example, to improve the accuracy of the heave compensator. In particular, hydraulic systems are less accurate due to the compression of oil. Therefore, rack and pinion-based systems are inherently more accurate. Active heave compensation systems are used, for example, during the connection of an object to the heave compensator, or, for example, a lifting device suspended from the heave compensator.

[0022] The vertical active heel-slip compensation system is a rack and pinion system comprising a vertical column extending vertically parallel to the driven cylinder, wherein the vertical column is vertically guided by a frame, and wherein a vertical rack is mounted to the vertical column. Advantageously, the vertical column is connected to a downwardly extending piston rod. Alternatively, the vertical column is connected to the cylinder body.

[0023] The active heave compensation system also includes one or more pinions and one or more associated electric motors. The pinions and one or more electric motors are all supported by a frame. Preferably, each pinion has an associated electric motor. When the electric motors and pinions are operating, the rack is allowed to move vertically relative to the frame. This provides active heave compensation through the frame supporting the driven cylinder and the rack connected to the piston rod.

[0024] This type of electric active heave compensation is advantageous because energy storage and return are more efficient compared to hydraulic systems, and / or because electrical control is more precise and / or faster. Additionally, energy can be recovered, or in other words, the motor can be used as a generator. In this way, batteries can be charged, or supercapacitors can be advantageously applied.

[0025] Advantageously, a clutch is provided between the electric motor and the pinion, allowing the pinion to be disconnected from its drive, thus enabling them to operate freely. Furthermore, the clutch provides improved control over the pinion.

[0026] Advantageously, the frame also supports one or more column guides to guide the vertically extending columns relative to the frame. The advantage of the guides is particularly evident when considering the length of the vertical column, which can be 8 to 12 meters long and is connected only to a downwardly extending piston rod and engaged by a piston. Thus, a set of upper and lower guides provides additional support for the vertical column.

[0027] In the implementation method, the frame of the heave compensator includes:

[0028] - A top frame that supports the cylinder body of the passive cylinder, as well as one or more pinions and one or more associated electric motors, and preferably also supports the upper column guide.

[0029] - A landing frame, which is mounted to the cylinder body of the passive cylinder, and preferably also includes a lower column guide.

[0030] The active heave compensation system also includes a battery for powering one or more electric motors. Advantageously, in one embodiment, a supercapacitor is provided to receive power from and supply power to the electric motors when they are used as generators.

[0031] In one embodiment, a lifting device is provided, configured for lifting wind turbine components, such as monopiles, blades, or nacelles, which can be connected to a heave compensator to suspend from the heave compensator / can be suspended from the heave compensator or connected to the heave compensator to suspend from the heave compensator / suspend from the heave compensator, see, for example, WO2021156508.

[0032] In this implementation, sensors and a control system are provided, thereby using the sensor information to control the active heave compensation system. The active heave compensation system is advantageously used to increase the accuracy of the passive heave compensation system.

[0033] An active heave compensation system may also include: a position sensor for determining the distance between an object and the heave compensator; and a control system that uses information from the position sensor to control the active heave compensation system. For example, the distance sensor may be mounted on a crane or a ship.

[0034] Sensors, such as position or distance sensors (optical, radar, laser, mechanical, etc.), measure the distance to the deck. Advantageously, a motion reference unit (MRU) is used. An MRU is a high-tech device capable of measuring motion in all six degrees of freedom—roll, pitch, yaw, sway, roll, and heave. This high-tech device is an important component for monitoring the motion of ships, helicopter decks, offshore gangways, cranks and winches, sonar, etc. The sensor is preferably mounted on the heave compensator, but other locations are also conceivable.

[0035] The heave compensator of a first aspect of the present invention includes a frame. In an embodiment, the heave compensator is configured such that:

[0036] - The passive cylinder is vertically oriented in the central position.

[0037] - On either side are two opposing rows of vertically oriented pressurized gas cylinders, for example, each row includes one or more pressurized gas cylinders with the same pressure; and

[0038] - One or more vertically oriented media separators are located on one side of the passive cylinder between the gas tanks, and

[0039] - In this system, the vertical column, rack, and pinion of the active heave compensation system are positioned between the gas tanks on the side of the passive cylinder opposite to one or more media separators.

[0040] - In this system, the battery of the active heave compensation system is located adjacent to one or more vertically oriented media separators.

[0041] Alternatively, the heave compensator is configured as follows:

[0042] - The passive cylinder is vertically oriented in the central position.

[0043] - There are two vertical columns on both sides, and the rack and pinion of the active heave compensation system are symmetrically arranged between each row of gas tanks on the opposite side of the passive cylinder.

[0044] For example, the passive cylinder may still have two opposing rows of vertically oriented pressurized gas tanks on either side, such as each row comprising one or more pressurized gas tanks with the same pressure. Alternatively, it is conceivable to have only one row of gas tanks. One or more vertically oriented media separators and the battery for the active heave compensation system may be located adjacent to, for example, the vertically oriented pressurized gas tanks or adjacent to a vertical column.

[0045] In this implementation, different groups of pressurized gas tanks are provided, each group comprising one or more pressurized gas tanks with the same pressure. It is conceivable that there is a group of high-pressure tanks, a group of medium-pressure tanks, and a group of low-pressure tanks, wherein each group of pressure tanks can be selectively connected to the media separator. Multiple groups of pressurized gas tanks provide a passive heave compensation system with different stiffness characteristics.

[0046] The heave compensator of the present invention is suspended in a straight line from the lower block member, for example, via a connector.

[0047] In one embodiment, the lower block is provided with a connector, and the heave compensator includes a connector guide funnel. Advantageously, for example, an operable mechanism is provided above the funnel, configured to engage the connector of the lower block with a vertical engagement movement during connection, and to releasably lock the lower block to the heave compensator so that the heave compensator is suspended from the lower block, and the operable mechanism is configured to unlock the lower block from the heave compensator and disengage the heave compensator from the connector during disconnection.

[0048] In an alternative embodiment, the heave compensator is provided with a connector, and the lower block includes a connector guide funnel and an operable mechanism located above the funnel. The operable mechanism is configured to engage the connector of the heave compensator with a vertical engagement movement during connection and to releasably lock the heave compensator to the lower block so that the heave compensator is suspended from the lower block. The operable mechanism is also configured to unlock the heave compensator from the lower block and disengage the lower block from the connector during disconnection.

[0049] The present invention also relates to an installation vessel, for example for installing objects, such as wind turbine components, the installation vessel including the offshore crane described above.

[0050] The present invention also relates to a method for lifting an object, wherein an installation vessel comprising a crane as described above is used. Preferably, the lifting method comprises the following steps:

[0051] a) Providing the object to a delivery vessel that is susceptible to heave and sag;

[0052] b) Position the offshore crane's heave compensator near the object;

[0053] c) Connect the object to the heave compensator;

[0054] d) Operate the passive heave compensation system;

[0055] e) Lift the object.

[0056] In this implementation, during step b), the heave compensator is used to bring the hook / spreader to a fixed distance above the load. The pressure in the passive cylinder is relatively low, while the active heave compensation is provided via a rack and pinion.

[0057] In this implementation, prior to step c), the method further includes the following steps:

[0058] - Connect the spreader to the heave compensator to suspend from the heave compensator;

[0059] - Install a position sensor to determine the distance between the object and the lifting device;

[0060] - The active heave compensation system is operated using information from position sensors to maintain a stable distance between the spreader and the object, thereby facilitating the connection between the object and the spreader.

[0061] This is a possible application of active heave compensation systems.

[0062] In embodiments where different groups of pressurized gas tanks are arranged, each group comprises one or more pressurized gas tanks with the same pressure. During step d), one group of tanks is first connected to the media separator, followed by another group of tanks. For example, a group of low-pressure tanks is connected first, followed by a group of high-pressure tanks. Alternatively, a group of low-pressure tanks is connected first, followed by a group of medium-pressure tanks, and finally a group of high-pressure tanks. Advantageously, the pressure is increased to approximately 90% of the load.

[0063] In the rapid lift function, the object moves at approximately 0.5 m / s. 2 The speed is rapidly increased, which requires an additional traction force of approximately 100 tons. This is achieved through a combination of rack and pinion drive and an additional high-pressure gas cylinder, which is activated to actuate the passive lifting cylinder.

[0064] In one embodiment, prior to step d), the method includes setting a position sensor to determine the distance between the object and the lifting device; and during step d), using information from the position sensor to operate an active heave compensation system as a braking mechanism for upward movement of the piston rod of the driven cylinder, particularly when the high-pressure tank is connected to the gas side chamber of the media separator to enable rapid lifting. This is an alternative possible use of the active heave compensation system. In this embodiment, both uses of the active heave compensation system are applied during lifting.

[0065] A second aspect of the invention relates to an offshore crane for use on a ship for manipulating objects, such as wind turbine components, wherein the crane includes a hoisting cable extending between a hoisting winch and a lower block, wherein a heave compensator is mounted to the lower block, and wherein the object can be suspended from the heave compensator, which includes a frame.

[0066] The heave compensator also includes a vertical heave compensation system, which has the following characteristics:

[0067] - One or more vertical cylinders, each of the one or more vertical cylinders having a cylinder body supported by a frame, a piston and a piston rod extending vertically upward, the piston defining an upper rod-side chamber and a lower piston-side chamber of the cylinder;

[0068] - One or more media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the piston side chamber of the cylinder;

[0069] - Multiple pressurized gas tanks, each of which can be selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve;

[0070] The heave compensator also includes a vertical load connector, which has a lifting tool, such as a lifting hook, at its lower end. One or more piston rods are connected to the vertical load connector, such that the vertical load connector is configured to move vertically relative to the frame when one or more piston rods extend or retract.

[0071] A heave compensator can function like a passive heave compensator. Instead of being suspended from the lower block by cables, the heave compensator is mounted to the lower block. Because the heave compensator is integrated with the frame, there is no double-swinging motion that increases load stability. Furthermore, by combining the heave compensator with the lower block, the overall length between the crane boom tip and the load can be reduced, which also increases the load's stability relative to the crane.

[0072] In one embodiment, the heave compensator further includes an active heave compensation system comprising: a vertical rack mounted to a vertical load connector, one or more pinions supported by a frame and one or more associated electric motors, and a battery configured to power one or more electric motors. The rack and pinions can be operated to provide active heave compensation, thereby providing both active and passive heave compensation.

[0073] In an alternative implementation, the active heave compensation system includes:

[0074] - A vertical column, which is connected to an upwardly extending piston rod and extends vertically parallel to the cylinder, wherein the vertical column is vertically guided by a frame, and wherein a vertical rack is mounted to the vertical column;

[0075] - One or more small gears supported by a frame and one or more associated electric motors;

[0076] - A battery that powers one or more electric motors.

[0077] In an alternative implementation, the active heave compensation system includes one or more pump units configured to extend and retract an upwardly extending piston rod. Preferably, the crane and / or heave compensator includes one or more sensors that measure the position and movement of the load relative to the lower block, wherein the measurement data is transmitted to a control system configured to operate the pump units.

[0078] In one embodiment, the frame includes a vertical guide structure extending vertically along most of the length of the frame, wherein the vertical guide structure is configured to guide the vertical load connector as the vertical load connector moves vertically relative to the frame.

[0079] In one implementation, an umbilical element is connected to a heave compensator to provide power to an active heave compensation system, wherein the umbilical element extends from the crane to the vertical active heave compensation system.

[0080] In this implementation, all components of the heave compensation system are at least partially housed within the frame.

[0081] In this implementation, the lifting tool is pivotally connected to the vertical load connector.

[0082] In this implementation, the heave compensation system includes two vertical heave cylinders, two media separators, and two pressurized gas tanks, wherein the two pressurized gas tanks are under the same pressure.

[0083] In one embodiment, one or more piston rods are connected to a connecting frame, and a vertical load connector is connected to the connecting frame, wherein the connecting frame and therefore the vertical load connector also move vertically when the piston rods extend or retract.

[0084] In one embodiment, the frame, vertical cylinder, media separator, and pressurization tank define a central receiving opening configured to receive the vertical load connector. The heave compensator has a retracted position and an extended position, wherein—in the retracted position—the vertical load connector is substantially inside the frame and positioned along the vertical cylinder and pressurization tank.

[0085] In one implementation, the frame can be connected to the lower block via a pin connector that allows for quick connection and disconnection.

[0086] In implementation, the heave compensator is configured for underwater use; for example, the compensator can be submerged to a water depth of up to 300m.

[0087] A third aspect of the invention relates to an offshore crane for use on a vessel for manipulating objects, such as pile hammers. The crane includes a hoisting cable extending between a hoisting winch and a lower block. A main hoisting tool, preferably an interchangeable tool, such as a crane hook, is connected to the lower block. The crane also includes an auxiliary hoisting tool, such as a damping tool or a heave compensation tool. An object can be suspended from either the main hoisting tool or the auxiliary hoisting tool. The auxiliary hoisting tool includes:

[0088] - One or more vertical cylinders, each of the vertical cylinders including a piston and a piston rod extending vertically downward, each piston of the respective cylinder defining a lower rod-side chamber and an upper piston-side chamber of the cylinder.

[0089] - A lower lifting frame, wherein the lower lifting frame is suspended only from the lower end of one or more piston rods, wherein the lower lifting frame is configured to support an object, for example, an object can be suspended from the lower lifting frame.

[0090] The crane comprises both a main lifting tool and an auxiliary lifting tool, from which objects can be selectively suspended. Depending on the current lifting operation, either the main or auxiliary lifting tool will be required, as both tools are simultaneously connected to the lower block, allowing for rapid tool switching and thus reducing operation time.

[0091] In one embodiment, the auxiliary lifting tool is implemented as a damping tool, wherein one or more vertical cylinders of the damping tool are filled with compressible liquid or gas and / or include an overpressure relief valve. When an object moves vertically, for example, suddenly relative to the lower block, the fluid or gas is compressed and / or discharged, resulting in a damping effect. For example, hydraulic fluid may exit the chamber via a pressure relief valve, such as via a throttle valve.

[0092] This type of damping tool is particularly useful during piling, where the pile hammer is suspended from the lower lifting frame. One problem that can sometimes occur during piling is what is known as pile-run. This creates huge instantaneous forces throughout the crane. By using a damping tool, these forces are introduced into the crane relatively more gradually.

[0093] In one implementation, the lower lifting frame is annular, for example rectangular, and includes a central opening.

[0094] In this implementation, the lower lifting frame is sized such that the main lifting tool, in its top-to-bottom projection, is located within the central opening of the lower lifting frame. This allows the main lifting tool to be used to lift objects while the lower lifting frame is still in place.

[0095] In one embodiment, the auxiliary lifting tool includes four cylinders, all of which are connected to the lower block and each of the four cylinders is connected at its lower end to the lower lifting frame.

[0096] In one embodiment, the lower lifting frame has a rectangular shape, wherein four cylinders are arranged at or near the corresponding corners of the rectangular lower lifting frame.

[0097] In one embodiment, one or more cylinders are connected to the lower block via a multi-axis connector.

[0098] In this implementation, the auxiliary lifting tool is a heave compensation tool, which includes:

[0099] - One or more media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the rod side chamber of the cylinder;

[0100] - One or more pressurized gas tanks, one or more pressurized gas tanks are installed to the lower block, each tank being selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve.

[0101] In this embodiment, the heave compensation device is an active heave compensation device, which is equipped with one or more pump devices configured to extend and retract the piston rods of one or more vertical cylinders, thereby operating the pump devices to lower or raise the lower lifting frame relative to the lower block. Preferably, the crane and / or heave compensator includes one or more sensors that measure the position and movement of the load relative to the lower block, wherein the measurement data is transmitted to a control system configured to operate the pump devices.

[0102] In one embodiment, the lower frame has an active position and an elevated parking position, wherein—in the active position—the lower lifting frame is located vertically below the main lifting tool and configured to lift the object. In the parking position, the lower lifting frame is located in an elevated position above at least a portion of the main lifting tool, such that the main lifting tool can be used to lift the object without interference from the lower lifting frame. An actuator may be present to move the lower frame between the active position and the elevated parking position and / or vice versa. In one embodiment, a cylinder is configured to controllably move the lower frame between the active position and the elevated parking position and / or vice versa.

[0103] In one embodiment, the crane is configured to provide active heave compensation to the lower block, for example, wherein a hoisting winch is wound to raise, lower, or lift the lower block, and wherein a control system provides active heave compensation to the lower block.

[0104] A third aspect of the invention also relates to a method for installing a monopile in the seabed, wherein an offshore crane is used. The method includes the following steps:

[0105] - Connect the monopile to the main lifting tool;

[0106] - Lift the monopile into an upright position onto the seabed;

[0107] - Disconnect the main lifting tool from the monop;

[0108] - Connect the pile hammer to the lower lifting frame of the damping tool;

[0109] - A single pile is driven into the seabed using a pile hammer supported by a damping tool.

[0110] A fourth aspect of the invention relates to an offshore crane for use on a vessel for manipulating objects, such as wind turbine components. The crane includes a hoisting cable extending between a hoisting winch and a lower block assembly, and also includes a heave compensator.

[0111] The heave compensator includes a heave cylinder assembly horizontally arranged inside, for example, a lower block-shaped component. The heave cylinder assembly includes one or more heave cylinders, each having a cylinder body, a piston, and a piston rod.

[0112] The lifting cylinder assembly is connected to a first tilting bracket and a second tilting bracket, wherein the first tilting bracket and the second tilting bracket can each be tilted and installed to the lower block assembly.

[0113] The first connecting rod and the second connecting rod each have a support end that is respectively connected to the first tilting bracket and the second tilting bracket, and each of the first connecting rod and the second connecting rod is connected at its frame end to a connecting frame located below the lower block assembly.

[0114] The connecting frame is configured to be connected to or attached to a load connector, from which the load can be suspended, for example, via a hanger.

[0115] The first and second tilting brackets are pivotally connected to the lower block assembly about a tilting bracket pivot axis, such that when one or more horizontal lifting cylinders extend or retract, the tilting brackets pivot about the tilting bracket pivot axis, thereby moving the connecting rod up and down, and thus the connecting frame, and therefore the load connector and the load, move in a substantially vertical direction.

[0116] The heave cylinder assembly is configured to move the load connector and load in a substantially vertical direction, thereby providing heave compensation. Typically, a heave compensator includes a vertically oriented cylinder. By using a horizontally oriented cylinder, the overall height of the heave compensator is significantly reduced, which offers several advantages. The distance between the load and the tip of the crane boom can be reduced, thus decreasing the swing length, which in turn reduces the swaying motion of the load relative to the crane, resulting in a more stable load. Furthermore, the reduced length of the heave compensator compared to one with a vertically oriented cylinder allows for a reduction in the required crane height or an increase in the crane's lifting height.

[0117] In one embodiment, one or more lifting cylinders each include a rod-side chamber and a piston-side chamber defined by a piston.

[0118] The horizontal heave assembly also includes:

[0119] - One or more media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the piston side chamber of the cylinder.

[0120] - Multiple pressurized gas tanks, each of which can be selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve.

[0121] In one embodiment, the heave cylinder assembly includes a synchronization system configured to synchronize the rotation of the first tilting bracket and the second tilting bracket. If the rotation of the first tilting bracket and the second tilting bracket is not synchronized, the connecting frame may become tilted.

[0122] In one embodiment, the horizontal lifting cylinder assembly includes a single horizontal lifting cylinder, wherein the cylinder body is pivotally connected to one of a first tilting bracket or a second tilting bracket, and wherein a piston rod is connected to the other of the first tilting bracket or the second tilting bracket. When the piston rod extends, it pushes against the first or second tilting bracket, while the cylinder body also pushes against the other tilting bracket, causing the first and second tilting brackets to rotate about corresponding first and second tilting axes. In this embodiment, the single horizontal lifting cylinder is movably supported by a lower block member.

[0123] In an alternative embodiment, the horizontal lifting cylinder assembly includes a first horizontal lifting cylinder and a second horizontal lifting cylinder, wherein the cylinder bodies of both the first and second horizontal lifting cylinders are connected to the lower block assembly, and wherein the piston rods of the first and second horizontal lifting cylinders are pivotally connected to a first tilting bracket and a second tilting bracket, respectively. Preferably, the synchronization system is configured to synchronize the extension and retraction of the piston rods of the first and second cylinders.

[0124] In one implementation, the synchronization system is configured to operate the first and second horizontal lifting cylinders based on position control, such that the first and second horizontal cylinders extend and retract by the same distance and simultaneously extend and retract by the same distance.

[0125] In this implementation, the synchronization system includes:

[0126] - The first pipeline, which connects to the piston side chamber of the first cylinder,

[0127] - A second pipeline, which connects to the piston side chamber of the second cylinder.

[0128] - A rotary distributor having a first pump assembly and a second pump assembly located on a common rotation axis, the first pump assembly being connected to a first pipeline and the second pump assembly being connected to a second pipeline.

[0129] For example, the first and second pipelines extend between the cylinder and the media separator.

[0130] In one embodiment, one or more pressurized gas tanks are connected to the lower block in a horizontal orientation; for example, one or more pressurized gas tanks, preferably two, are arranged on each side of the lower block. By orienting the pressurized gas tanks horizontally, the height of the heave compensator is reduced.

[0131] In one embodiment, the lower block assembly includes two parallel lower block panels spaced apart to define a space between them. The lower block panels are connected to each other by lower block connecting members, such as a lower plate and an upper plate. A horizontal lifting cylinder and an inclined support are arranged in the space between the lower block panels. Preferably, one or more pressurized gas cylinders are arranged on the outer side of the lower block panels.

[0132] In one implementation, the connection frame includes a load connector structure, such as the load connector structure described in WO2020 / 055249. The load connector structure allows for quick and easy connection between the connection frame and a load connector, such as a lifting hook.

[0133] In one embodiment, the first connecting rod and the second connecting rod comprise one or more rods, preferably two rods.

[0134] In one embodiment, the crane also includes a lifting device configured, for example, for lifting wind turbine components such as monopiles, blades, or nacelles, which can be connected to or attached to a load connector to suspend from the heave compensator.

[0135] In one embodiment, a sensor and a control system are provided, wherein the sensor is configured to measure the position and / or movement of the load and the lower block, and wherein the control system is configured to operate a heave compensator based on information provided by the sensor to maintain a stable distance between the load and the lower block.

[0136] A fourth aspect of the invention also relates to a method for lifting an object, wherein a heave compensator as described herein is used. Attached Figure Description

[0137] The invention is further illustrated by reference to the accompanying drawings, in which:

[0138] Figure 1This is a front view of a compensator with a lifting device and a monopile;

[0139] Figure 2 yes Figure 1 Detailed cross-sectional view of the heave compensator;

[0140] Figure 3 This is a schematic diagram of the heave compensator of the present invention;

[0141] Figure 4 It is in a stationary position on the deck. Figure 1 Front view of the heave compensator;

[0142] Figure 5 yes Figure 1 A bottom view of the heave compensator;

[0143] Figure 6 yes Figure 1 A cross-sectional view of the central part of the heave compensator.

[0144] Figures 7a to 7b The front and side views of the heave compensator are shown.

[0145] Figure 8 An isometric view of the heave compensator is shown.

[0146] Figures 9a to 9c Different positions of the heave compensator with a horizontally oriented cylinder are shown. Detailed Implementation

[0147] exist Figure 1 The heave compensator 10 is shown. How the heave compensator 10 is suspended in a straight line from the offshore crane and the lower block of the offshore crane's hoisting system is not shown. Providing a hoisting system for a crane is common knowledge; the crane includes a hoisting cable extending between a hoisting winch and the lower block.

[0148] The heave compensator 10 is provided with frames 11a and 11b and can be suspended linearly from a lower block (not shown). In the illustrated embodiment, the heave compensator 10 can be suspended when the connector, located on the lower block (not shown), is locked to a connector guide funnel 12, which is located at the heave compensator 10 and here at the top frame 11a. This system is commonly referred to as a quick connector system, such as that disclosed in WO2020 / 055249. Advantageously, for example, an operable mechanism is provided above the funnel 12, configured to engage the connector on the lower block with a vertical engagement movement during connection and to releasably lock the lower block to the heave compensator so as to suspend the heave compensator from the lower block, and the operable mechanism is configured to unlock the lower block from the heave compensator and disengage the heave compensator and connector during disconnection.

[0149] The diameter of the top portion of the funnel-shaped piece can be as high as 2 meters, for example.

[0150] exist Figure 2 Other details of the quick connector interface 12' are visible. Furthermore, the top frame 11a with the connector guide funnel 12 and the lifting frame 11b supporting the heave compensator are shown in more detail.

[0151] Alternatively, one could envision an alternative system in which the heave compensator is equipped with a connector and the lower block is equipped with a connector funnel-shaped component.

[0152] Any alternative connection system that allows the heave compensator 10 to be suspended from the lower block of the crane's hoisting system can be envisioned.

[0153] exist Figure 1 In this configuration, object 1, here part of a monopile, is suspended from settlement compensator 10, here via a lifting device 2. The lifting device is connected to the lower end 21a of the piston rod 21 of the vertical passive settlement compensation system of settlement compensator 10. The lifting device 2 includes: a first set of cables 2a to be connected to the lower end 21a of the piston rod 21; a lifting device frame 2b; and a second set of cables 2c for connecting the object, here monopile 1, to the lifting device frame. Figure 1 The image indicates two positions of the piston rod: the connected monopile 1 is shown as being in the lower position of the piston rod, while the portion of the lifting device 2 connected to the lower end 21a of the piston rod is also shown as being in the upper position of the piston rod.

[0154] exist Figure 2The heave compensator 10 is shown in more detail below. The heave compensator 10 includes a vertical passive heave compensation system having a vertical passive cylinder 20 having a cylinder body 22 supported by a frame, here a lifting frame 11b and a top frame 11a.

[0155] The vertical passive heave compensation system also includes Figure 3 The piston 23 and the piston rod 21 extending vertically downwards are visible in the image. Figure 3 As shown, the piston defines the lower rod-side chamber 23a and the upper piston-side chamber 23b of the passive cylinder.

[0156] Considering the capacity of the heave compensator, the cylinder body shown has a diameter of over 1 meter and a length of approximately 4.5 meters. The piston rod has a diameter of approximately 50 cm. The stroke length of the piston rod is sufficient to allow it to function as a heave compensation system for lifting heavy loads in conditions susceptible to heave. The piston is capable of vertical translation at speeds up to 1 m / sec, and more advantageously up to 0.75 m / sec.

[0157] The vertical passive heave compensation system also includes one or more media separators 25, in Figure 3 As shown in detail, one or more media separators 25 each have a hydraulic side chamber 25a and a gas side chamber 25b, the hydraulic side chamber being connected to the rod side chamber 23a of the driven cylinder. The volume of the hydraulic side chamber of the media separator is, for example, approximately 2500 liters. Figure 6 As can be seen in the top view, two media separators 25 are provided in this embodiment. The hydraulic pressure generated in the media separators is advantageously variable and can be, for example, about 330 bar.

[0158] The connection between the hydraulic side chamber 25a of the media separator 25 and the rod side chamber 23a of the driven cylinder allows for the transfer of hydraulic fluid, advantageously at a flow rate of up to 30,000 liters per minute.

[0159] The pressure in the media separator 25 is generated by a plurality of pressurized gas tanks 26a to 26t, which include, for example, nitrogen and N2, each tank being selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve. Figure 1 and Figure 4 Of these gas cylinders, only five are visible. Figure 6 In the middle, all gas tanks 26a to 26t are visible. Figure 3 The diagram schematically shows two gas cylinders 26a and 26b and associated gas cylinder valves 26a' and 26b'. (As shown in...) Figure 6As can be seen in the top view, 20 gas tanks 26a to 26t are provided in this embodiment. For example, the volume of each gas tank is between 1000 liters and 1500 liters.

[0160] The heave compensator also includes a vertical active heave compensation system having a vertical column 31 connected to a downwardly extending piston rod 21 and extending vertically parallel to the driven cylinder 20. The vertical column 31 is vertically guided by the frame, specifically by an upper column guide 32a supported by the top frame 11a and a lower column guide 21b supported by the lifting frame 11b.

[0161] A vertical rack 33 is mounted to a vertical column 31. The vertical active heave compensation system also includes one or more pinions 34 supported by a frame, specifically a top frame 11a, and associated with one or more electric motors 35. A battery 36 is provided to supply power to one or more electric motors. It is conceivable that a supercapacitor may also be provided.

[0162] In the illustrated embodiment, four pinions are equipped with associated motors, each with an exemplary capacity of 100 kW. The battery can have a capacity of up to 500 kWh.

[0163] like Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, utility unit 38 is advantageously positioned at landing frame 11b to provide connections for battery charging and gas pressurization. Here, a power unit 39, in this case a 40-foot deck container for the HPU (Hydraulic Power Unit), is located on the deck and can be connected to utility unit 38.

[0164] exist Figure 4 In the diagram, the heave compensator 10 is shown in a parked position, for example, for charging the battery. The funnel-shaped member 12 is prepared to receive the connector of the lower block member for linear suspension from the lower block member. The lower end 21a of the downwardly extending piston rod is adapted to connect to, for example... Figure 1 The lifting equipment visible in the image is placed on the deck.

[0165] like Figure 4 The total height of the heave compensator shown can exceed 10 meters, for example, up to 13 meters. The dimensions of the landing frame 11a are, for example, 6×6 meters, or 6.5×6.5 meters.

[0166] Figures 7a to 7b An alternative heave compensator according to a second aspect of the invention is shown. The compensator is shown in its fully extended state.

[0167] The lower block 100 is suspended from a lifting cable 101, which passes through one or more pulleys on the lower block. A heave compensator 102 is mounted to the lower block 100. The heave compensator 102 is configured to support the object and provide at least passive heave compensation.

[0168] The heave compensator 102 includes a frame 103. The lower block 100 is fixed to the frame, for example, such that the frame 103 cannot move relative to the lower block 100.

[0169] The heave compensator 102 also includes a vertical passive heave compensation system.

[0170] The vertical passive heave compensation system includes two vertical cylinders 104. Each cylinder has a cylinder body 104a supported by a frame 103, a piston, and a piston rod 104b extending vertically downward. The piston defines the lower rod-side chamber and the upper piston-side chamber of the passive cylinder.

[0171] The vertical heave compensation system also includes one or more media separators (not shown), such as two media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the piston side chamber of the passive cylinder.

[0172] The vertical passive heave compensation system also includes one or more pressurized gas tanks 105, such as two pressurized gas tanks 105, each of which is connected to the gas side chamber of the media separator via a corresponding gas tank valve.

[0173] The vertical load connector 106 is connected to the two piston rods via the transverse connecting frame 107. The lifting hook 108 is pivotally connected to the lower end of the vertical load connector.

[0174] The vertical load connector 106 is configured to move vertically relative to the frame 102 when the two piston rods 104b extend or retract.

[0175] Frame 103 includes a vertical guide structure 109 that extends vertically along most of the length of frame 103. The vertical guide structure 109 guides the vertical load connector 106 as the vertical load connector moves vertically relative to frame 103.

[0176] All components of the heave compensation system 103 are at least partially housed inside the frame 102.

[0177] The frame 102, vertical cylinder 104, media separator and pressurization tank 105 define a central receiving opening configured to receive a vertical load connector 106.

[0178] The heave compensator has a retracted position and an extended position. The extended position is... Figures 7a to 7b As shown, in the retracted position, the vertical load connector is mostly located inside the frame and positioned along the vertical cylinder and pressurized tank.

[0179] The frame 102 can be connected to the lower block 100 via a pin connector that allows for quick connection and disconnection.

[0180] Figure 8 An example of the third aspect is shown, wherein the lower block 200 is suspended by a lifting cable 201 extending between the lifting winch and the lower block 200.

[0181] The crane hook 202 is connected to the lower block 200 and is configured to support the load 203 when desired.

[0182] In the illustrated embodiment, the crane is equipped with an auxiliary lifting tool, which is implemented as a damping tool. The damping tool has four vertical cylinders 210 connected to a lower block 200. Each vertical cylinder includes a piston 210a and a vertically downward extending piston rod 210b. Each piston 210a of the respective cylinder defines a lower rod-side chamber and an upper piston-side chamber of the cylinder.

[0183] In one embodiment, one or more vertical cylinders of the damping tool are filled with compressible liquid or gas and / or include an overpressure relief valve.

[0184] In an alternative embodiment (not shown), the auxiliary lifting tool is a heave compensation tool, wherein the heave compensator includes:

[0185] - One or more media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the rod side chamber of cylinder 210a;

[0186] - One or more pressurized gas tanks are installed to the lower block 200, each tank being selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve.

[0187] The lower lifting frame 211 is suspended only from the lower ends of the four piston rods 210b.

[0188] The lower lifting frame 211 is annular, shown here as rectangular, and defines a central opening, wherein four vertical cylinders 210 are arranged at the corresponding corners of the rectangular lifting frame 211. In a top-down projection, the crane hook 203 is located within the central opening of the lower lifting frame 211.

[0189] Damping tool cables 212 extend from each corner of the rectangular lower lifting frame 211 toward the central connection point of the pile hammer 203. Alternatively, damping tool cables extend toward different connection points of the lifting device or load.

[0190] In an embodiment not shown, each of the four vertical cylinders 210 is connected to the lower block 200 via a multi-axis connector, thereby allowing, for example, cylinder rotation.

[0191] Figure 8 The lower frame 211 in the active position is shown, wherein the lower lifting frame 211 is located vertically below the crane hook 202 and configured to lift the object 203. In the parking position, the lower lifting frame 211 is located vertically above the hook 202, such that the crane hook can be used to lift the object without interference from the lower lifting frame.

[0192] A third aspect of the invention also relates to a method for installing a monopile in the seabed, wherein an offshore crane is used. The method includes the following steps:

[0193] - For example, connecting a monopile to a crane hook 202 via a monopile lifting tool;

[0194] - Lift the monopile into an upright position onto the seabed;

[0195] - Disconnect the crane hook 202 and any possible monopile hoist from the monopile;

[0196] - Connect the pile hammer 203 to the lower lifting frame 211 of the damping tool;

[0197] - A single pile is driven into the seabed using a pile hammer 203 supported by a damping tool.

[0198] Figures 9a to 9c A heave compensator 300 including a heave cylinder assembly 301 is shown, which is horizontally arranged inside a lower block assembly 302 (dashed line). The lower block assembly 302 is connected to a hoisting cable 303 extending between the hoisting winch and the lower block assembly.

[0199] The lifting cylinder assembly 301 includes a plurality of, specifically two, horizontally oriented lifting cylinders 304. Each lifting cylinder includes a cylinder body 304a, a piston 304b, and a piston rod 304c. The cylinder bodies 304a of both the first and second lifting cylinders 304 are connected to the lower block assembly 302. The piston rods 304c of the first and second lifting cylinders 304 are pivotally connected to a first tilting bracket 305a and a second tilting bracket 305b, respectively.

[0200] The first connecting rod 306a and the second connecting rod 306b each have a support end that is respectively connected to the first inclined bracket 305a and the second inclined bracket 305b. The first connecting rod 306a and the second connecting rod 306b are each connected to the connecting frame 307 at their respective frame ends.

[0201] The connecting frame 307 is connected to the load connector 308 from which the load can be suspended, the load connector 308 being shown here as a lifting hook 308.

[0202] Both the first tilting bracket 305a and the second tilting bracket 305b are pivotally connected to the lower block assembly 302 at their opposite ends about tilting bracket pivot axes 309a and 309b, such that when the first lifting cylinder 304 and the second lifting cylinder 304 extend or retract, the tilting brackets 305a and 305b pivot about the tilting bracket pivot axes 309a and 309b, thereby causing the connecting rods 306a and 306b to move up and down, and causing the connecting frame 307, and thus the load connector and the load, to move in a substantially vertical direction.

[0203] Figure 9a The heave compensator is shown at its lowest position on the connecting frame 307, where the piston rod 304c is not extended.

[0204] Figure 9b The heave compensator is shown at its highest position on the connecting frame 307, where the piston rod 304c has extended, causing the first tilting bracket 305a and the second tilting bracket 305b to rotate about the tilting bracket pivot axes 309a and 309b. This causes the connection points between the tilting brackets 305a and 305b and the connecting rods 306a and 306 to pivot upwards, causing the connecting frame to move upwards as well.

[0205] In an embodiment not shown, each of the two lifting cylinders 304 includes a lower rod-side chamber and an upper piston-side chamber defined by a piston.

[0206] The horizontal heave assembly also includes:

[0207] - One or more media separators, each having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the rod side chamber of the driven cylinder.

[0208] - Multiple pressurized gas tanks, each of which can be selectively connected to the gas side chamber of the media separator via a corresponding gas tank valve.

[0209] In one embodiment, the horizontal tilting cylinder assembly includes a synchronization system configured to synchronize the rotation of the first tilting bracket and the second tilting bracket. If the rotation of the first tilting bracket and the second tilting bracket is not synchronized, the connecting frame 307 may tilt.

[0210] In one implementation, the synchronization system is configured to operate the first and second lifting cylinders based on position control, such that the first and second horizontal cylinders extend and retract by the same distance and simultaneously extend and retract by the same distance.

[0211] The lower block assembly 302 includes two parallel lower block panels 310, which are spaced apart to define a space between them. The lower block panels are connected to each other via lower block connecting members, such as a lower plate and an upper plate. Figure 9a , Figure 9b As shown, the horizontal lifting cylinder 304 and the inclined supports 305a and 305b are arranged in the space between the lower block panel.

[0212] Four pressurized gas cylinders 310 are connected to the lower block in a horizontal orientation.

[0213] Two pressurized gas tanks 310 are arranged on each side of the lower block assembly 302.

[0214] In one embodiment, the connection frame 307 is configured to include a load connector guide structure, such as a funnel-shaped element, see WO2020 / 055249. The load connector guide structure allows for quick and easy connection between the connection frame and a load connector, such as a lifting hook.

[0215] In an embodiment not shown, the crane also includes a lifting device configured to lift wind turbine components, such as monopiles, blades, or nacelles, which can be connected to or attached to load connector 308 to suspend from the heave compensator.

[0216] In one embodiment, a sensor and a control system are provided, wherein the sensor is configured to measure the position and / or movement of the load and the lower block, and wherein the control system is configured to operate a heave compensator based on information provided by the sensor to maintain a stable distance between the load and the lower block.

Claims

1. An offshore crane for use on a vessel for manipulating objects (1), such as wind turbine components, the crane comprising a hoisting cable extending between a hoisting winch and a lower block, wherein, A heave compensator (10) is suspended in a straight line from the lower block, and the object can be suspended from the heave compensator, for example, by means of a lifting device. The heave compensator includes a frame. The heave compensator also includes a vertical passive heave compensation system, which has the following features: - A vertical passive cylinder (20) having a cylinder body (22) supported by the frame (11a, 11b), a piston (23) and a piston rod (21) extending vertically downward, the piston defining the lower rod-side chamber (23a) and the upper piston-side chamber (23b) of the passive cylinder. - One or more media separators (25), each of the media separators (25) having a hydraulic side chamber (25a) and a gas side chamber (25b), the hydraulic side chamber being connected to the rod side chamber (23a) of the passive cylinder. - Multiple pressurized gas tanks (26a to 26t), each of which can be selectively connected to the gas side chamber (25b) of the media separator (25) via a corresponding gas tank valve (26a', 26b'). The heave compensator also includes a vertical active heave compensation system, which has the following features: - A vertical column (31) is connected to the downwardly extending piston rod and extends vertically parallel to the driven cylinder (20), wherein the vertical column is vertically guided by the frame, and wherein a vertical rack is mounted to the vertical column. - One or more pinions (34) supported by the frame and one or more associated electric motors (35). - A battery (36) that powers one or more electric motors (35).

2. The offshore crane according to claim 1, wherein, The heave compensator is configured such that: - The passive cylinder (20) is vertically oriented in the central position. - On either side are two opposing rows of vertically oriented pressurized gas cylinders, for example, each row includes one or more pressurized gas cylinders with the same pressure; and - One or more vertically oriented media separators are located on one side of the passive cylinder between the rows of gas tanks, and - Wherein, the vertical column, the rack, and the pinion of the active heave compensation system are arranged between the rows of gas tanks on the side of the passive cylinder opposite to one or more of the media separators, and - Wherein, the battery of the active heave compensation system is arranged adjacent to one or more vertically oriented media separators.

3. The offshore crane according to one or more of the preceding claims, wherein, There are different groups of pressurized gas tanks, each group consisting of one or more pressurized gas tanks with the same pressure.

4. The offshore crane according to one or more of the preceding claims, wherein, The frame of the heave compensator includes: - A top frame (11a) suspended in a straight line from the lower block, the top frame supporting the cylinder body of the passive cylinder and one or more pinions and associated one or more electric motors, and preferably also supporting an upper column guide (32a). - A landing frame (11b) is mounted to the cylinder body of the passive cylinder and preferably also includes a lower column guide (32b).

5. The offshore crane according to one or more of the preceding claims, wherein the lower block is provided with a connector, and the heave compensator includes a connector guide funnel (12).

6. The offshore crane according to one or more of the preceding claims, wherein, A supercapacitor is provided to receive power from the electric motor and to supply power to the electric motor when the electric motor is used as a generator.

7. The offshore crane according to one or more of the preceding claims further includes a spreader configured for lifting wind turbine components such as monopiles, blades, or nacelles, or for lifting cargo containers, the spreader being connectable to or connected to the heave compensator for suspension from the heave compensator.

8. The offshore crane according to one or more of the preceding claims, wherein, The system is equipped with sensors and a control system, which uses information from the sensors to control the active heave compensation system. For example, the sensors are position sensors used to determine the distance between the object and the spreader, and the information from the position sensors is used to operate the active heave compensation system to maintain a stable distance between the spreader and the object, thereby facilitating the connection between the object and the spreader.

9. A vessel, for example for mounting objects, such as wind turbine components, the vessel comprising an offshore crane according to one or more of claims 1 to 8.

10. A heave compensator configured to be linearly suspended from a lower block of an offshore crane, the offshore crane including a hoisting cable extending between a hoisting winch and the lower block, wherein, An object can be suspended from the heave compensator, for example by a lifting device; the heave compensator includes a frame; The heave compensator includes a vertical passive heave compensation system, which has the following features: - A vertical passive cylinder having a cylinder body supported by the frame, a piston, and a piston rod extending vertically downward, the piston defining a lower rod-side chamber and an upper piston-side chamber of the passive cylinder; - One or more media separators, each of the media separators having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the rod side chamber of the passive cylinder; - Multiple pressurized gas tanks, each of which can be selectively connected to the gas-side chamber of the media separator via a corresponding gas tank valve; The heave compensator also includes a vertical active heave compensation system, which has the following features: - A vertical column, connected to the downwardly extending piston rod and extending vertically parallel to the driven cylinder, wherein the vertical column is vertically guided by the frame, and wherein a vertical rack is mounted to the vertical column. - One or more pinions supported by the frame and one or more associated electric motors. - A battery that powers one or more electric motors.

11. An offshore crane for use on a vessel for manipulating objects, such as wind turbine components, the crane comprising a hoisting cable extending between a hoisting winch and a lower block, wherein, A heave compensator is suspended in a straight line from the lower block, and the object can be suspended from the heave compensator, for example by a lifting device; the heave compensator includes a frame; The heave compensator includes a vertical passive heave compensation system, which has the following features: - A vertical passive cylinder having a cylinder body, a piston, and a vertically downward extending piston rod supported by the frame, the piston defining a lower rod-side chamber and an upper piston-side chamber of the passive cylinder; - One or more media separators, each of the media separators having a hydraulic side chamber and a gas side chamber, the hydraulic side chamber being connected to the piston side chamber of the upper part of the passive cylinder; - Multiple pressurized gas tanks, each of which can be selectively connected to the gas-side chamber of the media separator via a corresponding gas tank valve; The heave compensator also includes a vertical active heave compensation system, which has the following features: - A vertical column, the vertical column being connected to the cylinder body and extending vertically parallel to the passive cylinder, wherein the vertical column is vertically guided by the frame, and wherein a vertical rack is mounted to the vertical column; - One or more pinions supported by the frame and one or more associated electric motors; - A battery that powers one or more electric motors.

12. A method for lifting an object, such as a wind turbine component, wherein, Using the vessel according to claim 9, the method includes the following steps: a) Providing the object to a vessel susceptible to heave and sag; b) Optionally connect the heave compensator to the crane and provide the heave compensator of the offshore crane to the vicinity of the object; c) Connect the object to the heave compensator; d) Operate the passive heave compensation system and optionally operate the active heave compensation system to lift the object.

13. The lifting method according to claim 12, wherein, Prior to step c), the method further includes the following steps: - Connect the spreader to the heave compensator to suspend it from the heave compensator; - Install a position sensor to determine the distance between the object and the lifting device; - The active heave compensation system is operated using information from the position sensor to maintain a stable distance between the spreader and the object, thereby facilitating the connection between the object and the spreader.

14. The lifting method according to claim 12 or 13, wherein, The system is equipped with different groups of pressurized gas tanks, each group comprising one or more pressurized gas tanks having the same pressure, and wherein, during step d), one group of tanks is first connected to the media separator, and then another group of tanks is connected to the media separator.

15. The lifting method according to any one or more of claims 11 to 14, wherein, Prior to step d), the method includes setting a position sensor to determine the distance between the object and the lifting device; And during step d), the active heave compensation system, which serves as a braking mechanism, is operated using information from the position sensor for the upward movement of the piston rod of the passive cylinder, particularly when the high-pressure tank is connected to the gas side chamber of the medium separator to enable rapid lifting.

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