ARRANGEMENT FOR LOADING MONOPILES ONTO A VESSEL DECK

Description

RELATED APPLICATION

This application claims the benefit of priority from European Patent Application No. 24206041.6 filed on Oct. 11, 2024, the entirety of which is incorporated by reference.

FIELD OF THE INVENTION

The present invention generally relates to an arrangement for use on a vessel deck, the vessel being suitable for installing elongated elements in an underwater bottom, e.g. foundation piles of offshore wind turbines like monopiles. In particular, a solution is presented for loading, storing and displacing elongated elements at the vessel deck, that allows for a time-efficient loading process, while ensuring an efficient space usage and a cost-efficient mechanical design.

BACKGROUND OF THE INVENTION

In various offshore applications, sizeable elongated or tubular elements need to be driven into the seabed, e.g. for installing foundation structures of offshore wind turbines, jetties, radar and other towers, and the like. With respect to offshore wind turbines, foundations come in a number of variants, including monopile foundations and jacket foundations. Monopiles typically comprise a hollow cylindrical structure of steel or concrete. A lower end of the monopile is driven into the underwater bottom, while the upper end is provided with a transition piece forming the connection to a turbine mast arranged on the monopile. In use, a large part of the monopile foundation is thus located under water, and its slender design allows to bridge the height difference with the underwater bottom. Jacket foundations comprise a lattice framework, wherein the legs of the lattice framework are anchored to the seabed with piles, these foundation piles being driven into the underwater bottom.

Installing an elongated element such as a pile foundation for an offshore wind turbine typically takes place from the deck a vessel, which may be a jack-up vessel or a floating vessel. In a typical installation sequence, a monopile lying on the deck of the vessel is brought to an upending position on the deck, and next upended, i.e. brought into vertical position, by means of a hoisting device such as a crane. Subsequently, the monopile is lowered towards the seabed, and is driven into the bottom by means of a hammering tool.

A monopile may be transported over sea towards an installation location by means of a specific transport vessel, or by the installation vessel itself. Multiple monopiles may be loaded from the quay onto the vessel deck, where they are stored in lying condition, e.g. according to the transverse or longitudinal direction of the vessel. Typically, a dedicated support structure is available at the deck, which ensures sea-fastened storage of each of the monopiles. After loading, the monopiles are transported over sea towards various installation locations, where at each location an individual monopile is brought in the upending line and installed in the seabed. Preferably, as many piles as possible are stored on the vessel deck. Given the continued trend of monopiles growing in size, deck space of newly designed installation vessels has to be increased accordingly.

Loading of monopiles from the quayside onto the vessel deck typically is done by means of the crane available at the vessel, i.e. the vessel crane that is also used during the installation operation at sea. In this, use of a given crane type not only puts restrictions on the lifting loads, but also on the reach of the crane. Indeed, the boom of the crane may be rotated over a circular area, and the range in radial direction is restricted by both a minimal and maximal radius. Since the operational range of conventional vessel cranes is restricted, and increasingly larger monopiles need to be stored on the deck, additional challenges arise with respect to loading and arranging monopiles on the deck, and bringing them in reach of the crane during an installation operation. Moreover, the loading process, wherein monopiles have to be unloaded on the deck one after the other, and to be brought to their respective storage lines on the deck, may be a time-intensive operation, thereby posing challenges concerning operational efficiency.

In the prior art, solutions have been proposed for storing monopiles on the vessel deck and bringing them within reach of the crane. For example, EP3650686B1 discloses a support structure for carrying monopiles in lying position on a vessel deck, wherein the support structure is displaceable relative to the deck. In particular, the support structure, wherein one or more monopiles are received, may be translated over the deck, in a direction perpendicular to the length direction of the supported monopiles. In this way, monopiles stored on the deck can be moved within reach of the lifting crane, thereby avoiding that a larger lifting crane needs to be used. However, as the supporting structure is displaced as a whole, particular requirements apply concerning the mechanical design, in particular with respect to moving parts, certainly if increasingly large monopiles would need to be supported and displaced. Moreover, the obtained flexibility in reaching various deck areas is still limited in this solution, and obtaining a time-efficient loading process remains challenging.

It is an objective of the present invention to disclose an arrangement for use at the deck of a vessel, that resolves one or more of the above-described shortcomings of the prior art solutions. More particularly, it is an objective to present a solution for loading, storing and displacing elongated elements such as monopiles at the vessel deck, that allows for a time-efficient loading process, while ensuring an efficient space usage and a cost-efficient mechanical design.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, the above identified objectives are realized by an arrangement for loading an elongated element onto a support surface of a floating body such as a vessel, defined by claim 1, the arrangement comprising:

• • a hoisting device;
  • a storage system comprising one or more storage structures, each storage structure adapted for holding an individual elongated element in lying condition while being sea-fastened, wherein the length direction of a held elongated element corresponds to the longitudinal direction of the arrangement;
    wherein:
  • the arrangement comprises a longitudinal and a transverse skidding system, operable independently,
    • the longitudinal and transverse skidding system each comprising one or more transport carts displaceable over the support surface according to a path in longitudinal respectively transverse direction, and
    • any of the transport carts being equipped with a support cradle, the one or more support cradles of both the longitudinal and transverse skidding system being adapted to carry an elongated element extending in longitudinal direction;
  • the arrangement is adapted for
    • receiving an elongated element loaded with the hoisting device by the longitudinal skidding system;
    • transporting an elongated element in longitudinal direction by means of the longitudinal skidding system;
    • transferring an elongated element between the longitudinal skidding system and the transverse skidding system;
    • transporting an elongated element in transverse direction by means of the transverse skidding system;
    • transferring an elongated element between the transverse skidding system and any of the respective storage structures of the storage system.

Thus, the invention concerns an arrangement for loading an elongated element onto a support surface of a floating body, wherein the floating body e.g. is a vessel, ship, or boat, a floating platform, etc. The floating body comprises a support surface, for example the deck of a vessel or platform, or a portion of such deck. The support surface defines a horizontal plane, independent of any movement of the support surface during use in floating condition. An elongated element refers to a slender object like a tubular element, pipe or pile. For example, the elongated element is a monopile serving as a foundation structure of an offshore wind turbine, or a leg connected to the lattice framework of a jacket foundation. Typically, the support surface makes part of a vessel or platform suitable for installing the elongated element in an underwater bottom, e.g. for installing a monopile in the seabed. Although the invention will be elucidated with reference to offshore wind turbines, in particular to installation of monopiles, it is equally applicable to the installation of other types of elongated elements, e.g. foundation structures or components of jetties, radar towers, other towers, and the like.

The arrangement comprises a storage system. The storage system is adapted to store one or more elongated elements on the support surface, e.g. during sailing of the vessel towards an installation location. The storage system comprises one or more storage structures, wherein each storage structure is adapted for holding an individual elongated element in lying condition. A lying condition of the elongated element refers to a condition wherein the central axis of the elongated element is substantially parallel to the horizontal plane defined by the support surface, although a certain inclination of the central axis with respect to the horizontal plane may apply. For example, a storage structure comprises two spatially separated storage cradles, to support the lying elongated element at two different positions along its length when being carried by the storage structure. The length direction of a lying elongated element, while being held in the storage structure, is defined as the longitudinal direction of the arrangement. The direction perpendicular to the longitudinal direction is defined as the transverse direction. The longitudinal direction, defined by the storage structure, may correspond to the longitudinal direction of the vessel, i.e. from bow to stern, or may correspond to the transverse direction of the vessel, i.e. from side to side, dependent on how the elongated elements are stored on the deck in a particular embodiment. Whenever a direction of the elongated element or of a vessel's component or part is mentioned, being substantially in a particular direction refers to a deviation of at most 20%, more preferably at most 10%, still more preferably at most 5%, and most preferably at most 0.5% with respect to the indicated direction.

Typically, multiple storage structures are positioned next to one another, such that multiple elongated elements may be stored side by side, with their central axes mutually parallel. In this case, the direction wherein any of these central axes extends is defined as the longitudinal direction of the arrangement, the latter corresponding to either the longitudinal or transverse direction of the vessel. In this, every individual storage structure defines a storage line, according to the longitudinal direction of the arrangement and corresponding to the central axis of an elongated element when held in the storage structure. Accordingly, a storage zone may be identified at the support surface wherein the parallel storage lines are found, each of the storage lines at a different transverse position with respect to the arrangement, and the storage zone extending in a longitudinal range corresponding to the length of the stored elongated elements.

When an elongated element is held by a storage structure, it is sea-fastened, meaning that the elongated element is stored at the support surface in such a way that, under the conditions prevailing at sea wherein the floating body continuously moves due to interaction with waves and wind, the elongated element will not be displaced with respect to the support surface. In this context, not being displaced is to be understood as: not being substantially shifted, tilted or lifted with respect to the support surface; minor movements of the elongated element with respect to the support surface may still occur. In other words, while being sea-fastened in the storage structure, the elongated element follows any movement that the vessel or platform undergoes due to interaction with waves and wind.

The arrangement further comprises a hoisting device. A hoisting device, also referred to as a lifting means or crane, typically comprises a crane arm or boom provided with hoisting cables, the crane arm being mounted onto a crane base, wherein the crane arm may be rotated with respect to the base, and the free end of the arm may be moved up and down. Typically, the boom of the crane may be rotated over a circular area, wherein the range in radial direction is restricted by a minimal and a maximal radius. The hoisting device is installed at the support surface and typically serves different purposes on the vessel, for which specific equipment may be attached to the hoisting cables. In particular, the hoisting device allows to load elongated elements onto the support surface, wherein loading may e.g. happen from a quayside or a barge. Furthermore, the hoisting device typically allows for upending a monopile from the lying condition to an upright position, wherein during upending one end of the monopile is coupled to the hoisting device. The hoisting device may further allow for lowering the upended elongated element towards the underwater bottom, the elongated element being suspended from the hoisting device. Moreover, the hoisting device may be equipped for other purposes, e.g. for taking up an elongated element from the deck in horizontal position, for taking up and placing a hammering tool, etc.

The arrangement further comprises a longitudinal skidding system. The longitudinal skidding system comprises one or more transport carts, wherein each of the one or more transport carts is equipped with a support cradle. The one or more support cradles of the longitudinal skidding system are adapted to carry an elongated element, while the latter is in lying condition and its central axis extends in longitudinal direction. This implies that the central axis of an elongated element carried by the one or more support cradles of the longitudinal skidding system, is parallel to the central axis of another elongated element stored in one of the storage structures. The one or more transport carts of the longitudinal skidding system are displaceable over the support surface according to a path in longitudinal direction. Displacement of a transport cart over the support surface is not restricted to skidding in the strict sense, but may happen in any possible way, e.g. by means of sliding over a track, by riding on wheels, by use of a chain, etc. Typically, the longitudinal transport cart(s) may only be transported according to a predefined trajectory in longitudinal direction, e.g. defined by a track at the support surface. In other embodiments, however, it is also possible that no such track is available, and the transport cart is e.g. provided as a type of car that may freely move over the support surface. In such an embodiment, however, the control of the longitudinal skidding system will typically be such that the longitudinal transport cart(s) may only move according to the longitudinal direction.

The longitudinal skidding system may comprise multiple transport carts, each of them equipped with a support cradle. In this, the multiple transport carts may be adapted to move simultaneously in longitudinal direction, and/or may may be adapted to move in longitudinal direction individually, i.e. independently from one another. In another embodiment, the longitudinal skidding system may comprise a single transport cart equipped with a support cradle, wherein the latter has sufficient length to support the carried elongated element. In any case, the longitudinal skidding system is adapted to carry a lying elongated element extending in longitudinal direction, and to displace the elongated element in longitudinal direction while being carried by the one or more support cradles.

The arrangement further comprises a transverse skidding system. The transverse skidding system comprises one or more transport carts, wherein each of the one or more transport carts is equipped with a support cradle. The one or more support cradles of the transverse skidding system are adapted to carry an elongated element, while the latter is in lying condition and its central axis extends in longitudinal direction. This implies that the central axis of an elongated element carried by the one or more support cradles of the transverse skidding system, is parallel to the central axis of another elongated element stored in one of the storage structures, or of another elongated element carried by the longitudinal skidding system. The one or more transport carts of the transverse skidding system are displaceable over the support surface according to a path in transverse direction. Displacement of a transport cart over the support surface is not restricted to skidding in the strict sense, but may happen in any possible way, e.g. by means of sliding over a track, by riding on wheels, by use of a chain, etc. Typically, the transverse transport cart(s) may only be transported according to a predefined trajectory in transverse direction, e.g. defined by a track at the support surface. In other embodiments, however, it is also possible that no such track is available, and the transport cart is e.g. provided as a type of car that may freely move over the support surface. In such an embodiment, however, the control of the transverse skidding system will typically be such that the transverse transport cart(s) may only move according to the transverse direction.

The transverse skidding system may comprise multiple transport carts, each of them equipped with a support cradle. In this, the multiple transport carts may be adapted to move simultaneously in transverse direction, and/or may may be adapted to move in transverse direction individually, i.e. independently from one another. In another embodiment, the transverse skidding system may comprise a single transport cart equipped with a support cradle, wherein the latter has sufficient length to support the carried elongated element. In any case, the transverse skidding system is adapted to carry a lying elongated element extending in longitudinal direction, and to displace the elongated element in transverse direction while being carried by the one or more support cradles.

Due to the presence of both skidding systems, the arrangement is adapted for transporting an elongated element in longitudinal direction, by means of the longitudinal skidding system, and for transporting an elongated element in transverse direction, by means of the transverse skidding system. Moreover, the arrangement is adapted for transferring an elongated element between the longitudinal skidding system and the transverse skidding system. This implies that an elongated element carried by the support cradle(s) of the longitudinal skidding system, may be moved towards a position wherein it is carried by the support cradle(s) of the transverse skidding system, and vice versa. Such transfer may be made possible due to the design of the skidding systems themselves, or may be implemented via use of additional equipment onboard.

Moreover, the arrangement is adapted for receiving an elongated element loaded with the hoisting device by the longitudinal skidding system. This implies that an elongated element, initially found e.g. on the quayside or a barge, may be taken up by the hoisting device, and brought into a position wherein it is carried by the support cradle(s) of the longitudinal skidding system. In this, the loaded elongated element may be received directly by the longitudinal system, i.e. unloading happens directly onto the support cradle(s) of the longitudinal skidding system. In another embodiment, the loaded elongated element may be received by the longitudinal system in an indirect way, e.g. when unloading first happens onto the support cradle(s) of the transverse skidding system or onto another support structure, and afterwards the elongated element is transferred to the longitudinal skidding system.

In any case, once the elongated element is positioned onto the longitudinal support cradle(s), it can be displaced in longitudinal direction, by moving the corresponding transport cart(s) in longitudinal direction, thereby reaching the longitudinal position corresponding with the storage area on the deck. Subsequently, the elongated element may be transferred to the transverse skidding system, and may be displaced in transverse direction, by moving the corresponding transport cart(s) in transverse direction, thereby reaching the appropriate storage line where a storage structure is found. Finally, the arrangement is adapted for transferring an elongated element between the transverse skidding system and any of the respective storage structures of the storage system. This implies that an elongated element carried by the support cradle(s) of the transverse skidding system, may be moved towards a position wherein it is carried by one of the storage structures, and vice versa. Such transfer may be made possible due to the design of the skidding system itself, or may be implemented via use of additional equipment onboard.

The longitudinal and transverse skidding system are operable independently, implying that the transport cart(s) of the longitudinal skidding system can be displaced in longitudinal direction while displacing the transport cart(s) of the transverse skidding system in transverse direction. The longitudinal skid(s) thus can be moved at the same time as the transverse skid(s), such that a displacement by the longitudinal skidding system is independent from a displacement by the transverse skidding system. In particular, this implies that the arrangement is such that the two skidding systems each have their own set of skids, wherein the transport cart(s) of the longitudinal system and the transverse system is/are different and not physically coupled or linked. In various embodiments, however, it may be possible that for use of the arrangement during a loading sequence or other operation, a specific control is implemented, such that e.g. a movement of the one system is only executed when the other system is in a specific state or has ended a specific movement.

Having an arrangement with a longitudinal and a transverse skidding system, brings the advantage that virtually any position at the deck can be reached, without limitations imposed by the operational range of the crane, or the mutual distance between crane and storage system. Indeed, the longitudinal skidding system allows a loaded elongated element to first be brought to a longitudinal position corresponding to the longitudinal position of the storage area on the deck, and subsequently, the transverse skidding system may be used to transport the elongated element to a selected storage line. This allows for an increased flexibility in the arrangement of devices and structures at the deck, thereby contributing to an optimized use of deck space for storing monopiles. Moreover, a convenient type of crane may still suffice, even if monopiles of large size need to be stored.

Furthermore, in the invented solution, the transport function, for displacing an elongated element over the deck, and the storage function, for storing an elongated element onto the deck, are provided by independent systems, namely by the moving skidding systems and the static storage system respectively. Accordingly, moving parts are only present in the skidding systems, thereby leading to a lower complexity and cost than prior art solutions wherein the storage structure is moved with respect to the deck. This contributes to a cost-efficient solution with an increased robustness and durability, and less stringent maintenance requirements. Moreover, as the invented arrangement allows to first bring the elongated element to the longitudinal position of the storage area at the deck, and next transport it in transverse direction to the selected storage line, a single track in longitudinal direction suffices, without requiring a longitudinal track for each individual storage line. This further contributes to a compact and cost-efficient design.

Moreover, as the longitudinal and transverse skidding systems are operable independently, sequences become possible wherein certain steps are performed in parallel. In particular, displacing the first set of skids in longitudinal direction may be done simultaneously with displacing the second set of skids in transverse direction, thus allowing for an overlap in longitudinal and transverse displacements during a loading or installation sequence. For example, the longitudinal skid(s) may be placed back into the receiving position, for receiving a newly loaded monopile, while transverse transport of a previously loaded monopile to a storage line has not ended yet or the transverse skids have not returned yet to the longitudinal track. Such parallel execution of steps results in time savings compared to prior art solutions wherein all actions need to be performed sequentially, thereby contributing to an increased time-efficiency of the loading and installation process.

Finally, the arrangement may be used during the loading process, for bringing the loaded monopiles to their respective storage lines, as well as during an installation operation, for bringing a monopile from a storage line towards the upending line. Throughout the loading and installation process, the crane is only required for the actual unloading and for upending; every other action or displacement at the deck may be performed without any intervention from the crane. Accordingly, all actions at the deck are performed in a fully controlled way, by means of skids, while avoiding swing motions due to crane intervention. This contributes to an increased safety and decreased damage risks, and to an increased efficiency of the loading and installation operation.

Optionally, the arrangement comprises an upending device, adapted for upending an elongated element positioned in lying condition at the support surface towards an upright position, the central axis of the lying elongated element received in the upending device defining an upending line at the support surface. Typically, an upending device is connected to the hull and/or the deck of the vessel or platform, and is adapted to pivot the elongated element from a horizontal position towards an upright position, while supporting the elongated element by engaging with the lateral surface of the elongated element. For example, the upending device may comprise a cage-like structure, adapted for receiving the first end of the elongated element, and support the elongated element during upending. An example of an upending device is described in EP3517479. The upending line corresponds to a straight line in the direction of the central axis of the elongated element, when the elongated element is received by the upending device before upending.

Optionally, the longitudinal path followed by the one or more longitudinal transport carts corresponds to the upending line, thereby allowing to shift an elongated element carried by the longitudinal skidding system in the upending device. This implies that the longitudinal skids are displaceable in longitudinal direction, along the upending line. In this way, the longitudinal skidding system has a double function, wherein it cannot only be used during the loading process, for displacing a loaded elongated element towards the longitudinal position of the storage area at the deck, but also for bringing an elongated element into the upending device. Indeed, during an installation operation at sea, an elongated element may be first be displaced from the storage structure towards the upending line, by means of the transverse skidding system, and next the longitudinal skidding system may be used for shifting the elongated element into the upending device, before upending by the crane. Bringing the elongated element into the upending device may comprise various steps, wherein e.g. first two longitudinal skids are moved simultaneously for displacing the elongated element towards the upending device, and next only one of the skids is used for further shifting the elongated element into the upending device. During the latter step, the elongated element may be supported by the upending device itself and/or by the non-moving longitudinal skid. Due to the longitudinal skidding system having this double function, a design is obtained with a reduced number of components, leading to savings in cost and space, and an increased robustness with less stringent maintenance requirements. Moreover, also for bringing an elongated element in upending position, no crane intervention is required, thereby resulting in an increased safety, reduced damage risks, and an increased flexibility in arranging the various devices onto the deck.

Optionally, the arrangement comprises a bumper device positioned at the support surface, the bumper device comprising a bumper element, for example a bumper arm, adapted to be arranged between

• • an elongated element carried by a first storage structure, the first storage structure being positioned next to longitudinal path of the longitudinal skidding system without any other storage structure therebetween, and
  • an elongated element received by the longitudinal skidding system,
    thereby protecting an elongated element carried by the first storage structure from contact with an elongated element loaded onto the longitudinal skidding system.

When taking up an elongated element by the hoisting device, and unloading it onto the longitudinal skidding system, the loaded elongated element may be subject to swinging motions in the air. This entails the risk that the swinging elongated element would clash with an elongated element already stored at the deck, in particular with an elongated element stored in a storage line being the first storage line next to the track of the longitudinal skidding system. By providing a bumper device, forming a bumper between the longitudinal skidding system and the first storage line, the stored elongated element is protected, thereby avoiding damage to the elongated elements and allowing to safely load monopiles with a crane in offshore conditions.

Optionally, the bumper device is foldable, such that in folded condition the bumper device is retracted, thereby allowing passing of an elongated element over the folded bumper device when being transported by the transverse skidding system. Thus, when not being in use for protecting a stored elongated element, the bumper device may be folded down. In this way, the presence of the bumper device does not impede or hinder the transverse displacement to any position at the deck.

Optionally, the bumper device is foldable, such that in folded condition the bumper device is retracted, thereby allowing unhindered displacement of the one or more longitudinal transport carts. Thus, when not being in use for protecting a stored elongated element, the bumper device may be folded down. In this way, the presence of the bumper device does not impede or hinder the displacements of the longitudinal skid(s).

Optionally, the bumper arm is pivotable with respect to the rest of the bumper device. In this way, the position of the bumper arm may be adjusted, e.g. to avoid that it would hinder displacement of the longitudinal skid(s), or to adjust according to the diameter of the elongated element carried by the first storage structure.

Optionally, each of the support cradles of the transverse skidding system is adjustable in height, thereby allowing

• • to move any of the transverse transport carts, with empty support cradle and the support cradle in lowered condition, underneath an elongated element carried by the longitudinal skidding system, and
  • to lift the elongated element from the longitudinal skidding system by raising the support cradles of the transverse skidding system.
    The support cradles of the transverse skidding system may be brought at a height position which is higher than the height position of the support cradles of the longitudinal skidding system. In this way, the transverse skid(s) allow to transfer an elongated element from the longitudinal skid(s) to the transverse skid(s). A transfer may thus be performed by means of the skidding systems themselves, without requiring any additional equipment.

Optionally, each of the support cradles of the transverse skidding system is adjustable in height, thereby allowing

• • to move any of the transverse transport carts, with empty support cradle and the support cradle in lowered condition, underneath an elongated element carried by one of the storage structures, and
  • to lift the elongated element from the storage structure by raising the support cradles of the transverse skidding system.
    The support cradles of the transverse skidding system may be brought at a height position which is higher than the height position of the storage cradles of the storage structure. In this way, the transverse skid(s) allow to transfer an elongated element from a storage structure to the transverse skid(s). A transfer may thus be performed by means of the skidding systems themselves, without requiring any additional equipment.

Optionally, the height of each of the support cradles of the transverse skidding system is adjustable by changing the height position of the support cradle as a whole. Additionally or alternatively, the shape of each of the support cradles of the transverse skidding system is adjustable. For example, the support cradle may brought into a first position wherein the support cradle is raised and its shape conforms to the curved shape of a carried elongated element, and into a second position wherein the support cradle is lowered and its shape is more flat than in the first position.

Optionally, any of the support cradles of the longitudinal and/or transverse skidding system comprises multiple saddles, of which the position or orientation is individually adjustable with respect to the transport cart. By adjusting the position or orientation of the saddles, the support cradle may e.g. be adjusted according to the diameter of the carried elongated element, or the shape of the support cradle may be changed between a curved and a more flat shape.

Optionally, the height and/or shape of each of the support cradles of the longitudinal and/or transverse skidding system is adjustable by means of one or more linear actuators.

Optionally, each of the longitudinal and transverse skidding system comprises at least two transport carts, any of the carts being equipped with a support cradle, thereby allowing to support an elongated element at two separate length positions during longitudinal respectively transverse transport.

Optionally, any of the transport carts comprised in the longitudinal respectively transverse skidding system is displaceable by shifting in longitudinal respectively transverse direction, without allowing movement in transverse respectively longitudinal direction.

Optionally, each of the longitudinal and transverse skidding system comprises a track adapted to guide the one or more transport carts, the track comprising one or more rails extending in longitudinal respectively transverse direction, and any of the transport carts adapted to slide over the one or more rails. The rails of the track thus define the trajectory that can be followed by the transport carts. In an embodiment, the rails may be plates with low-friction surfaces, thereby offering support and guidance for the transport cart(s).

Optionally, the one or more longitudinal rails are continuous rails, and the one or more transverse rails are interrupted, thereby allowing crossing with the longitudinal rails, or the one or more transverse rails are continuous rails, and the one or more longitudinal rails are interrupted, thereby allowing crossing with the transverse rails.

Optionally, at the position of crossing of the longitudinal and transverse rails, clearance is present between an end of the interrupted rail and the continuous rail, thereby allowing a transport cart to travel over the continuous rails without engaging with the ends of the interrupted rails.

Optionally, any of the transport carts sliding over the interrupted rails comprises at least one sliding block, of which the size measured according to the rail direction is larger than any of the gaps present between subsequent portions of an interrupted rail. This allows the sliding block to gross the gaps in the rails, thereby ensuring unhindered sliding of a transport cart.

Optionally, the rails of the longitudinal and transverse skidding system all have the same height.

Optionally, the one or more transport carts of the longitudinal skidding system are driven by a rack and pinion drive system, the rack and pinion drive system comprising a toothed rack mounted to the support surface and extending in longitudinal direction, and at least one pinion mounted to any of the transport carts, and/or the one or more transport carts of the transverse skidding system are driven by a rack and pinion drive system, the rack and pinion drive system comprising a toothed rack mounted to the support surface and extending in transverse direction, and at least one pinion mounted to any of the transport carts.

Optionally, the one or more transport carts of the transverse skidding system are driven by a push-pull system, the push-pull system comprising a perforated track mounted to the support surface and extending in transverse direction, and a hydraulic push-pull cylinder mounted to any of the transport carts, and/or the one or more transport carts of the longitudinal skidding system are driven by a push-pull system, the push-pull system comprising a perforated track mounted to the support surface and extending in longitudinal direction, and a hydraulic push-pull cylinder mounted to any of the transport carts.

Optionally, the one or more transport carts of the longitudinal skidding system are driven by a rack and pinion drive system, and the one or more transport carts of the transverse skidding system are driven by a push-pull system, or the one or more transport carts of the transverse skidding system are driven by a rack and pinion drive system, and the one or more transport carts of the longitudinal skidding system are driven by a push-pull system. In both embodiments, the rack and pion drive system comprising a toothed rack mounted to the support surface, and the push-pull system comprising a perforated track mounted to the support surface, wherein the toothed rack is continuous and the perforated track is interrupted, thereby allowing crossing with the toothed rack. Because of the crossing of the tracks of the longitudinal and transverse skidding system, only one of the two respective drive systems may use a rack and pinion system. The other drive system therefore uses a push-pull system, which allows for crossing. In yet another embodiment, the one or more transport carts of both the longitudinal and transverse skidding system are driven by a push-pull system. In this case, the rails of both the longitudinal and transverse skidding system may be continuous, such that no interrupted rails are present at the support surface.

Optionally, any of the transport carts of the longitudinal and transverse skidding system is equipped with a Hydraulic Power Unit, abbreviated HPU.

Optionally, any of the transport carts of the longitudinal and transverse skidding system receives power via an electric cable connected to the transport cart. When the arrangement is used at a vessel deck, the transport carts are thus connected to vessel power using an electric cable.

Optionally, the electric cable connected to a transverse transport cart is positioned in a cable chain or drag chain, of which one end is fixed to the support surface of the floating body and the other end is fixed to the transport cart. In this way, when displacing the transverse skid, the cable chain follows the skid, thereby crossing the longitudinal track. The cable chain or drag chain may be connected next to the crossing point of transverse and longitudinal rails, such that when the transverse skids are positioned at one side of the longitudinal track, the longitudinal skids can pass without being hindered by the cable chains of the transverse skids. Such a setup thus allows the two skid directions to pass each other without conflict.

Optionally, any of the longitudinal transport carts is equipped with a reel, adapted for rolling and unrolling the electric cable, and any of the electric cables connected to a longitudinal transport cart is positioned in a cable trench provided at the support surface of the floating body. In this way, the cable trench allows the transverse skids to be displaced without being hindered by the electric cables of the longitudinal skids.

Optionally, one end of the electric cable is connected to the longitudinal transport cart, and the other end is connected to power provided at a point of the support surface, or the other end is connected to another longitudinal transport cart.

Optionally, any of the one or more storage structures comprises at least two storage cradles spaced apart from each other, adapted to support an elongated element at two separate positions according to its length.

Optionally, the storage system comprises multiple storage structures, positioned at both sides of the longitudinal path.

Optionally, the arrangement further comprises:

• • a tool, adapted for coupling to an end of an elongated element;
  • a tool storage cradle, adapted for holding the tool while being sea-fastened;
  • a tool skidding system comprising a skidding unit, wherein:
    • the skidding unit is displaceable over the support surface along the longitudinal path defined by the longitudinal skidding system, towards an elongated element being in lying condition and being supported by at least one of the support cradles of the longitudinal skidding system;
    • the tool storage cradle is comprised in the skidding unit, thereby allowing to transport the tool over the support surface according to the longitudinal direction, from a storage location towards the end of the elongated element, while the tool is held in a storage position by the tool storage cradle;
    • the skidding unit is adapted to guide the tool while being brought from the storage position in the tool storage cradle, to a coupling position wherein the tool can be coupled to the end of the elongated element by means of a coupling system, thereby constraining movements of the tool while bringing it into the coupling position.

This implies that besides the longitudinal and transverse skidding system, for displacing an elongated element over the support surface, another additional skidding system is comprised in the arrangement, namely a tool skidding system. The tool skidding system allows to transport a tool towards the end of an elongated element, for coupling with the end of the elongated element, while the elongated element is supported by at least one of the support cradles of the longitudinal skidding system. For this purpose, the tool skidding system comprises a tool storage cradle, wherein the tool can be held, mounted to a transport cart. The transport cart is displaceable over the support surface in longitudinal direction, along the longitudinal path defined by the longitudinal skidding system.

For example, the longitudinal skidding system may comprise one or more rails, wherein the same set of rails is also used by the tool skidding system. In such an embodiment, both the transport cart of the tool skidding system and the one or more transport carts of the longitudinal skidding system are adapted to slide over the same set of rails, the latter extending in longitudinal direction. Also parts of the drive system comprised the longitudinal skidding system may be used in common by the tool skidding system. For example, a toothed rack extending in longitudinal direction may be provided at the support surface, the toothed rack making part of the rack and pinion drive system of the longitudinal skidding system and making part of the rack and pinion drive system of the tool skidding system. Use of such components in common by both skidding systems contributes to a compact and cost-efficient design. In an embodiment, both the transport carts of the tool skidding system and of the longitudinal skidding system are displaceable along the upending line. This allows for an efficient sequence during an installation operation, wherein the longitudinal skids may be used for longitudinally displacing the elongated element, and for shifting the elongated element into the upending device, and the tool may be displaced along the same longitudinal track for coupling to the end of the elongated element, before upending.

The tool is adapted for coupling to an end of the elongated element, wherein the tool engages with a lateral and/or top wall at the end of the elongated element. The tool is for example a coupling tool adapted to be arranged at the upper end of the elongated element and adapted to be connected to a hoisting device like a crane. After coupling the coupling tool to the pile end, and connecting the crane to the coupling tool, the pile may be upended by means of the crane. An embodiment of a coupling tool is e.g. disclosed in EP3826952B1. In another embodiment, the tool may be a vibro-hammer or other type of hammer tool that needs to be coupled to the pile end before upending. Coupling of the tool to the elongated element is done by means of a coupling system. The coupling system may be comprised in the tool itself. For example, in the coupling tool of EP3826952B1, the coupling system comprises slidable clamping members, which may be brought in a clamping position.

The tool storage cradle is adapted for holding the tool while being sea-fastened. The tool storage cradle is comprised in the skidding unit, thereby allowing to transport the storage cradle over the support surface. The tool, being sea-fastened in the storage cradle, thus can be transported over the support surface, while being held in a storage position by the tool storage cradle. Furthermore, the skidding unit is also adapted to guide the tool while the tool is brought from the storage position in the tool storage cradle, to a coupling position. Thus, after having been displaced over the deck towards the pile end, the tool is brought into a coupling position, thereby being guided by the skidding unit. The coupling position is a position wherein the tool can be coupled to the end of the elongated element by means of the coupling system. Bringing the tool from the storage position into the coupling position comprises moving the tool and/or one or more portions of the tool. In this, the term position may refer to the location of the tool on the support surface, i.e. its longitudinal or transverse position, as well as to the state of the tool, e.g. its height position, angular position, orientation, inclination, etc. Moving the tool from the storage position to the coupling position thus may comprise shifting the tool in horizontal or vertical direction, pivoting the tool about an axis, rotating the tool, lifting the tool, tilting the tool, etc, or any combination thereof. It is also possible that bringing the tool into the coupling position, comprises one or more steps wherein only a portion of the tool is moved instead of moving the tool as a whole.

While the tool is brought from the storage position in the tool storage cradle to the coupling position, it is guided by the skidding unit. This means that during the movements needed to couple the tool to the pile end, these movements are constrained due to the skidding unit engaging with the tool, thereby avoiding any uncontrolled movements of the tool. In this, constraining movements of the tool refers to movements of the tool as a whole as well as to movements of portions of the tool. In an embodiment, guidance may be provided by means of a frame on the skidding unit, wherein the tool is held in the frame and the position of the frame is adaptable. E.g. the frame's height position is adaptable, thereby allowing to change the height position of the tool in a controlled way. In other examples, the frame may be shiftable, tiltable, rotatable, pivotable, etc. In another embodiment, guidance may be provided due to guiding elements available on the skidding unit, wherein the guiding elements engage with the tool or portion thereof while being moved. For example, guiding arms may be provided that allow to guide the tool while it is lifted by the crane or while a portion of the tool rotates via a mechanism on the tool itself. In yet another embodiment, the tool is guided due to being held in the storage cradle; while the skidding unit is displaced, e.g. shifted forward, the tool merely follows the skidding unit's movement, such that it is moved in a controlled way. Also a combination of the various embodiments for providing guidance by the skidding unit is possible.

The tool skidding system allows to integrate in a single unit the functions of storing the tool in a sea-fastened way, displacing the tool, and guiding the tool while being coupled to the pile end. In this way, any uncontrolled movements of the tool are avoided, resulting in a safe operation wherein any risks of damage to the elongated element or equipment are mitigated. Moreover, the tool skidding system allows for a time-efficient operation, as the tool does not need to be removed from the sea-fastening for bringing it towards the pile end. Finally, as both the sea-fastening storage function and the guidance function for coupling are integrated in a single unit, the tool skidding system allows for a compact arrangement at the deck.

Optionally, bringing the tool from the storage position into the coupling position comprises moving the tool and/or one or more portions thereof, wherein said moving comprises:

• • shifting in horizontal direction, for approaching the end of the elongated element, and/or
  • shifting in vertical direction, for changing the height position with respect to the elongated element, and/or
  • pivoting and/or rotating, for changing the orientation with respect to the elongated element.

Optionally, the tool storage cradle is adapted for holding the tool in position due to the tool engaging with one or more edges and/or recesses of the tool storage cradle, thereby allowing for sea-fastening of the tool without additional fastening means. The tool storage cradle may e.g. comprise as a stand or holder that carries the tool, or an open box or base wherein the tool is placed. The design of the tool storage cradle is such that edges and/or recesses are provided engaging with the tool when held by the tool storage cradle. The cradle thus functions as a docking station for the tool, allowing to sea-fasten the tool but without requiring additional fastening means. In this way, the tool remains in position, in an easy releasable way.

Optionally, the skidding unit comprises auxiliary equipment adapted for supplying the tool with energy and/or signals and/or a fluid flow, the auxiliary equipment comprising one or more supply lines provided as cables or hoses. This implies that auxiliary equipment is available on the skidding unit, wherein this auxiliary equipment serves to provide the tool with energy, signals or a fluid flow, in view of actuating or operating the tool. The auxiliary equipment is comprised in the skidding unit, meaning that it is displaced together with the rest of the skidding unit. For example, the auxiliary equipment is installed on a transport cart comprised in the skidding unit. In this way, an additional energy supply function is integrated in the same skidding unit. This allows for additional space savings on the deck and additional time savings, as all energy packs and hoses remain close to the tool during coupling, upending and pile installation, thereby making hose handling more compact and easier.

Optionally, the skidding unit comprises a frame of which the position is adjustable, thereby allowing to change the position of the tool with respect to the support surface while being held in the frame. Optionally, the skidding unit comprises a height-adjustable frame, thereby allowing to change the height position of the tool with respect to the support surface while being held in the frame.

Optionally, the skidding unit comprises one or more guiding elements, adapted to engage with the tool while being moved, thereby restricting uncontrolled movements of the tool while bringing the tool into the coupling position. Optionally, the one or more guiding elements are adapted to engage with the tool while being moved, thereby preventing uncontrolled swinging of the tool in transverse and/or longitudinal direction while bringing the tool into the coupling position. Optionally, the one or more guiding elements are provided as pivotable guiding arms, and adapted to avoid uncontrolled swings of the tool while being lifted by a hoisting device.

According to a second aspect of the present invention, there is provided a vessel for installing an elongated element, the vessel comprising an arrangement according to the first aspect of the invention, wherein the support surface is comprised in the deck of the vessel.

Optionally, the support surface extends according to a length direction of the vessel, from forward to aft of the vessel, and the arrangement is installed such that the longitudinal direction corresponds to the length direction of the vessel.

According to a third aspect of the present invention, there is provided a method for loading an elongated element onto a support surface of a floating body such as a vessel, the method comprising:

• • providing an arrangement according to the first aspect of the invention; and subsequently executing the steps of:
  • loading an elongated element with the hoisting device;
  • receiving the loaded elongated element by the one or more support cradles of the longitudinal skidding system;
  • transporting the elongated element carried by the longitudinal skidding system, by displacing the one or more longitudinal transport carts along the longitudinal path;
  • transferring the elongated element carried by the longitudinal skidding system to the one or more support cradles of the transverse skidding system;
  • transporting the elongated element carried by the transverse skidding system, by displacing the one or more transverse transport carts along the transverse path,
  • transferring the elongated element carried by the transverse skidding system to one of the storage structures.

Optionally, before transferring the elongated element from the longitudinal to the transverse skidding system:

• • the one or more transport carts of the transverse skidding system are displaced towards the longitudinal path, and are positioning underneath the elongated element carried by the longitudinal skidding system, and subsequently
  • the one or more support cradles of the transverse skidding system are raised, thereby lifting the elongated element from the longitudinal skidding system.

Optionally, before transferring the elongated element from the transverse skidding system to the storage structure:

• • the one or more support cradles of the transverse skidding system are lowered, thereby landing the elongated element onto the storage structure.

Optionally the upending device comprising a cage structure adapted for receiving the end of an elongated element, and the cage structure of the upending device is opened before receiving the loaded elongated element by the longitudinal skidding system, the elongated element being partly positioned in the opened cage when unloaded onto the longitudinal skidding system.

Optionally, the method comprises subsequently executing the steps of:

• • transferring an elongated element carried by the storage structure to the one or more support cradles of the transverse skidding system;
  • transporting the elongated element carried by the transverse skidding system, by displacing the one or more transverse transport carts along the transverse path,
  • transferring the elongated element carried by the transverse skidding system to the one or more support cradles of the longitudinal skidding system.

Optionally, after transferring the elongated element from the transverse to the longitudinal skidding system, the elongated element carried by the longitudinal skidding system is shifted in the upending device, by displacing at least one of the longitudinal transport carts along the longitudinal path.

Optionally, after transferring the elongated element from the transverse to the longitudinal skidding system, the elongated element carried by the longitudinal skidding system is shifted in the upending device, by

• • simultaneously displacing the first and second transport cart along the longitudinal path, towards the upending device,
  • and subsequently displacing the first transport cart along the longitudinal path, towards the upending device, while the second transport cart is not displaced and while the elongated element is rolling over rollers comprised in the upending device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 and FIG. 2 show an arrangement according to an embodiment of the invention.

FIG. 3 shows a vessel provided with the arrangement of FIGS. 1 and 2.

FIG. 4 and FIG. 5 give a more detailed view of the longitudinal skidding system, comprised in the arrangement of FIG. 1.

FIG. 6 to FIG. 11 give a more detailed view of the transverse skidding system, comprised in the arrangement of FIG. 1.

FIG. 12 illustrates the combination of a longitudinal and transverse skidding system, comprised in the arrangement of FIG. 1.

FIG. 13 gives a more detailed view of the bumper device comprised in the arrangement of FIG. 1.

FIG. 14 gives a more detailed view of the tool skidding system comprised in the arrangement of FIG. 1.

FIG. 15 to FIG. 24 illustrate the use of the vessel of FIG. 3, during a loading and upending process.

DETAILED DESCRIPTION OF EMBODIMENT(S)

FIG. 1 and FIG. 2 illustrate an arrangement 100 according to an embodiment of the invention. The arrangement 100 is suitable for use on a support surface of a floating body such as a vessel 300, as is shown in FIG. 3. In the embodiment of FIG. 3, the vessel 300 is a vessel for installing monopiles, and the support surface 301 makes part of the deck of the vessel 300.

FIG. 1 shows that the arrangement 100 comprises a longitudinal skidding system and a transverse skidding system. The longitudinal skidding system comprises a track 105 extending in longitudinal direction X, and two skids 101, 102, the latter being displaceable over the longitudinal track 105. The transverse skidding system comprises two tracks 106, 110 extending in transverse direction X, and two skids 103, 104, the latter being displaceable over the respective transverse track 106, 110. In the shown embodiment, the arrangement further comprises a bumper device 107, and a tool skidding system comprising a skidding unit 108 and tool 109.

FIG. 2 shows that the arrangement 100 comprises a storage system. The storage system comprises four storage structures 201, 202, 203, 204, according to four respective storage lines 205, 206, 207, 208. Every storage structure 201, 202, 203, 204 comprises two spaced-apart storage cradles 209, 210, provided with saddles, and is adapted to carry a monopile in lying condition, while being sea-fastened. Four monopiles may thus be stored next to each other by the storage system, with their central axes in parallel, wherein the length direction these lying monopiles defines the longitudinal direction X of the arrangement 100.

FIG. 3 shows that for the shown embodiment of the vessel 300, the longitudinal direction of the arrangement 100 corresponds to the longitudinal direction of the vessel 300, from bow to stern. The longitudinal direction X and transverse direction Y define a horizontal plane, and the Z-direction or height direction is perpendicular to the horizontal XY-plane.

FIG. 3 further shows that the arrangement 100 comprises a hoisting device or crane 302. The crane 302 is adapted for loading a monopile onto the deck of the vessel 300, and for upending a monopile to an upright position when the crane 302 is connected to an end of the monopile. The arrangement further comprises an upending device 303. In the shown embodiment, the upending device comprises an openable and closable cage-like structure, which, after closing, forms a closed ring structure surrounding the monopile, as is shown in FIG. 22. The upending device 303 is adapted to guide and support a monopile while being pivoted from the lying condition towards an upright condition, before lowering the pile towards the seabed. When a monopile is positioned in lying condition in the upending device 303, its central axis defines a upending line 304 at the deck, as is schematically indicated in FIG. 3.

The longitudinal track 105 allows the skids 101, 102 to be displaced in longitudinal direction X over the deck, along the upending line 304. The skidding unit 108 of the tool skidding system is displaceable in longitudinal direction X using the same track 105 as the longitudinal skidding system. The two transverse skids 103, 104 are displaceable over the deck in transverse direction, from side to side of vessel 300, using the two respective tracks 106 and 110.

The storage structures 201-204 define a storage area at the deck, extending over a longitudinal range at the deck, and comprising the four storage lines 205-208 at different transverse positions. Two storage lines 205, 206 are found at one side of the upending line 304, and two storage lines 207, 208 are found at the other side of the upending line 304. Apart from storing four monopiles in the storage structures 201-204 during sailing, an additional fifth monopile may be stored at the position of the upending line 304.

FIG. 4 and FIG. 5 give a more detailed view of the longitudinal skidding system. The first longitudinal skid 101 comprises a transport cart 401 and a support cradle 403, and the second longitudinal skid 102 comprises a transport cart 402 and a support cradle 404. The support cradle 404 comprises four saddles 501-504, together conforming to the curved shape of a monopile. The transport carts 401, 402 are adapted to slide over two rails 407, 408 extending in longitudinal direction. The transport carts 401, 402 are driven by a rack-and-pinion drive system. For this purpose, a toothed rack 409 extending in longitudinal direction is provided at the deck, and the transport carts are equipped with pinions 500. The longitudinal skids 101, 102 receive power via an electric cable 410, and are equipped with an HPU 406 and cable reel 405. The electric cable 410 is positioned in a cable trench, such that it does not hinder displacement of the transverse skids 103, 104. The aft skid 101 is connected directly to vessel power, while the forwards skid 102 is connected to the aft skid 101.

FIG. 6 to FIG. 11 give a more detailed view of the transverse skidding system. The transverse skidding system comprises two skids 103, 104 and two tracks 106, 110. The design of both transverse skids and both transverse tracks is similar, and is discussed underneath with respect to the first transverse skid 103. FIG. 6 shows that the skid 103 comprises a transport cart 601 and a support cradle 611, wherein the support cradle 611 comprises four saddles 607-610. The support cradle 611 has an adjustable height, as is illustrated in FIG. 6 to 8. For this purpose, the two saddles 607, 608 are mounted to a first structure 702, provided with a first hydraulic piston 700, and the two saddles 609, 610 are mounted to a second structure 703, provided with a second hydraulic piston 701. FIG. 7 shows that the pistons 700, 701 allows to raise the structures 702, 703, thereby increasing the height of the support cradle 611 without altering its shape. Moreover, FIG. 8 shows that both the first and second structure 702, 703 can be tilted with respect to cart 601, thereby changing the shape of the support cradle 611. In particular, the relatively flat shape of the cradle 611 in FIGS. 6 and 7 is changed towards a more curved shape, wherein the four saddles 607-610 together conform to the curved shape of the monopile.

The transport cart 601 is adapted to slide over two rails 602, 604 extending in transverse direction. The transport cart 601 is driven by a push-pull system. For this purpose, a perforated track 603 extending in transverse direction is provided at the deck. A hydraulic push-pull cylinder 900 and pin 901 are mounted to the cart 601 the pin 901 fitting in the apertures 902 of the perforated track 603, as is shown in FIG. 9. An HPU 606 is mounted to the transport cart 601, and the skid 103 receives power via an electric cable connected to the cart 601. The electric cable is positioned in a drag chain 605. FIG. 10 shows that one end 1001 of the drag chain 605 is connected to the transport cart 601, and the other end 1000 is connected to the deck, at a position where the transverse track 106 crosses with the longitudinal track 105. When the transverse skids 103, 104 are displaced in transverse direction, towards the other side of the vessel like is shown in FIG. 11, the drag chain 605 follows the skids accordingly. On the other hand, when the transverse skids 103, 104 are positioned at one side of the upending line, namely at the side of the connection point 1000 of the drag chains 605, like is shown in FIG. 10, then the longitudinal skids 101, 102 are not hindered by the electric cables or drag chains 605 of the transverse skids 103, 104.

FIGS. 10, 11 and 12 show that the rails 407, 408 and toothed rack 409 of the longitudinal skidding system are uninterrupted. Conversely, the rails 602, 604 and perforated track 603 of the transverse skidding system are interrupted, see gaps 1002, thereby allowing for crossing with the longitudinal track. In view of crossing the gaps 1002 in the transverse tracks 106, 110, the transverse skids 103, 104 are driven by a push-pull system, as described above, and not with a rack-and-pinion drive system like the longitudinal skids 101, 102. In an alternative embodiment, both the transverse and longitudinal skids could be driven by a push-pull system. Moreover, the transport cart 601 comprises a sliding block 600, of which the size is larger than the size of the gaps 1002, thereby allowing the sliding block to cross a gap. Also remark that some clearance 1200 is present between an end of the interrupted rails 602, 604 and the continuous rails 407, 408, thereby allowing the transport cart of the longitudinal skid 101 to travel over the continuous rails 407, 408 without engaging with the ends of the interrupted rails 602, 604.

FIG. 13 gives a more detailed view of the bumper device 107. FIG. 13(a) illustrates the state wherein the bumper device 107 is in use, i.e. in unfolded condition, and FIG. 13(b) illustrates the state wherein the bumper device 107 is not in use, i.e. in folded or retracted condition. The bumper device 107 comprises a bumper arm 1300, mounted to a frame 1301. The bumper device 107 may be folded down as a whole, by pivoting around axis 1303, using hydraulic piston 1302, thereby reaching the folded condition of FIG. 13(b). In this retracted condition, a monopile being displaced in transverse direction may pass over the folded bumper device 107, and the longitudinal skids 101, 102 can be displaced without any hinder. Furthermore, the bumper arm 1300 is pivotable with respect to the frame 1301, via pin 1304.

FIG. 14 gives a more detailed view of the tool skidding system, for storing, displacing and guiding a tool 109. In the shown embodiment, the tool 109 is a coupling tool, adapted to be coupled to an end of a monopile while it is in lying condition on the support surface 301, before upending of the monopile. The coupling tool 109 comprises a cross-shaped structure 1403, and clamping members 1404, wherein the latter may engage with the outer lateral surface of a monopile. The coupling tool 109 further comprises a lifting member 1406, which may be connected to the crane 302 before upending. The cross-shaped structure 1403 may pivot with respect to the lifting member 1406, around pin 1405. In this way, the orientation of the cross-shaped structure and clamping members 1404 may change with respect to the lifting member 1406, during upending of the monopile by the crane. The coupling tool 109 allows for damage-free coupling of the crane to the monopile end before upending. Other embodiments of a coupling tool are possible; another embodiment of a coupling tool is e.g. disclosed in EP3826952B1, wherein slidable clamping members engage with the inner lateral surface of the monopile. In yet other embodiments, the tool may have another functionality, e.g. the tool may be a vibro-hammer being coupled to the monopile end before upending.

The tool 109 is placed in a tool storage cradle 1409, which allows for holding the coupling tool 109 in a sea-fastened way. In particular, the tool storage cradle 1409 comprises a frame 1401, at the back of the tool 109, and a bar or edge 1411, at the front of the tool 109. When the coupling tool 109 is positioned in the tool storage cradle 1409, the pin 1405 at the back of the coupling tool is placed in a recess 1402 of the frame 1401, and the front of the cross-shaped structure 1403 engages with the edge 1411. In this way, the frame 1401 allows to hold the coupling tool 109 in a sea-fastened position without requiring additional fasteners. Furthermore, the frame 1401 is height-adjustable, as the frame 1401 may be slid upwards and downwards with respect to the rest of the tool storage cradle 1409, see FIG. 23. In this way, the height position of the coupling tool 109 with respect to the support surface 301 may be changed while being held by the frame 1401.

The tool storage cradle 1409 is comprised in a skidding unit 108. The skidding unit 108 comprises a transport cart 1410 and is displaceable over the support surface 301. For this purpose, the tool skidding system comprises a track 105, comprising two rails 407, 408, wherein the transport cart 1410 may slide over the rails 407, 408. In the shown embodiment, the rails 407, 408 are the same rails as used by the longitudinal skidding system, thereby defining a path in longitudinal direction, along the upending line 304. The skidding unit is thus displaceable over the deck, using the same track 106 as the longitudinal skids 101, 102. The skidding unit 108 is driven by means of a rack and pinion drive system, wherein two pinions 1412 are arranged at the transport cart 1410, and the toothed rack 409 comprised in the driving system of the longitudinal skidding system is also used by the driving system of the tool skidding system.

The tool storage cradle 1409 is mounted to the transport cart 1410, thereby allowing to transport the coupling tool 109 over the deck while being held by the tool storage cradle 1410. Furthermore, auxiliary equipment such as a power pack 1408 and a cable reel 1407 are mounted to the transport cart 1410. The auxiliary equipment is adapted for supplying the coupling tool 109 with energy and/or signals, e.g. when coupling the tool 109 to the monopile end and during upending. In this way, the auxiliary equipment can be transported over the deck together with the coupling tool 109. The power pack and hose reel may receive power and data via an umbilical reel or via discrete connection points along the skidding rails.

FIG. 15 to 24 illustrate the use of the arrangement 100 and vessel 300 during a loading and upending process. In FIG. 15, a number of monopiles 1501 is provided at the quayside 1502. A monopile 1500 is taken up by the hoisting device 302 of the vessel 300, thereby using a hoisting tool 1503 comprising a spreader bar and slings. The monopile 1500 is unloaded onto the skids 101, 102 of the longitudinal skidding system, wherein the respective support cradles 403, 404 support the monopile 1500 at two spaced-apart positions along its length. While receiving the monopile 1500, the longitudinal skids 101, 102 are in a receiving position at the deck, wherein the aft skid 102 is placed close to the upending device 303. During unloading of monopile 1500, the cage structure of the upending device 303 is opened, thereby leaving room for the bottom end of the unloaded monopile 1500.

FIG. 16 shows that the monopile 1500 is transported over the deck in longitudinal direction, by displacing the longitudinal skids 101, 102 towards the bow of the vessel 300, away from the upending device 303. The two longitudinal skids 101, 102 are displaced simultaneously, thereby maintaining their mutual distance. In this way, monopile 1500 is brought into a longitudinal position at the deck corresponding to the longitudinal position of the storage area at the deck. Remark that while displacing the longitudinal skids, the transverse skids 103, 104 are positioned at one side of the upending line 304, such that their drag chains 605 do not hinder the longitudinal skidding.

FIG. 17 shows that, while monopile 1500 is still carried by the longitudinal skids 101, 102, the transverse skids 103, 104 are moved in transverse direction, towards the upending line 304. The transverse skids 103, 104 are displaced until being positioned underneath the monopile 1500, at the upending line. For this purpose, the support cradle 611 of both transverse skids 103, 104 is in the lowered, flat condition of FIG. 6.

Next, as is shown in FIG. 18, the support cradles 611 of the transverse skids 103, 104 are raised, thereby obtaining the raised, more curved condition of FIG. 8. In particular, as the support cradles 611 of the transverse skids are raised to a height higher than the support cradles 403, 404 of the longitudinal skids 101, 102, the monopile 1500 is transferred to the transverse skids 103, 104, i.e. it is now carried by the support cradles 611 of the transverse skidding system.

FIG. 19 shows that subsequently the transverse skids 103, 104 are moved in transverse direction, towards a selected storage line 208, while carrying the monopile 1500. When reaching the storage line 208, the monopile 1500 is transferred to storage structure 204, as is shown in FIG. 20. For this purpose, the support cradles 611 of the transverse skids 103, 104 are brought in their lowered, flat condition of FIG. 6, wherein their height is lower than the height of the storage cradles 209, 210 of storage structure 204. Remark that while the transverse skidding and unloading onto the storage structure is taking place, the longitudinal skids 101, 102 can be brought back into their receiving position, closer to the upending device, for receiving a next monopile 1600 from the crane.

FIG. 20 shows that monopile 1500 is now carried by storage structure 204, in a sea-fastened way. In the same way, three other monopiles 1600, 2000 and 2001 are loaded and brought to their respective storage lines 207, 206, 205. Remark that during the transverse displacement of monopiles 2000 and 2001, for reaching storage lines 207 and 206, the bumper device 107 is folded down, thus being brought in the retracted condition of FIG. 13(b). In this way, the monopile 2000, 2001 can move over the retracted bumper device 107.

In the state shown in FIG. 20, a fifth monopile 2002 may be loaded onto the deck. For this purpose, the bumper device 107 is brought into the unfolded condition of FIG. 13(a). In this way, the bumper arm 1300 protects monopile 2001 that is stored in the first storage structure 201 next to the upending line 304, thereby preventing damage caused by swinging movements of monopile 2002 when loaded by the crane.

FIG. 21 shows that subsequently monopile 2002 is landed onto the longitudinal skids 101, 102, wherein the latter are placed in the receiving position, close to the upending device 303. After closing the doors of the upending device 303, as is shown in FIG. 22, the vessel 300 may sail towards a first installation location, having five monopiles on board. In this, the upending line 304 actually serves as a fifth storage line.

When arrived at an installation location, an upending operation may start, for upending monopile 2002. For this purpose, coupling tool 109 is coupled to the top end of monopile 2002, when the latter is in lying condition and carried by the longitudinal skids 101, 102. FIG. 23 shows that the skidding unit 108 is displaced over the deck, from a storage location in the bridge of the vessel 300, towards the end of the lying monopile 2002. In this, the transport cart 1410 of the skidding unit 108 slides over the rails 407, 408 of the longitudinal skidding system. During this displacement, the coupling tool 109 is held by the tool storage cradle 1409, the tool 109 being in a storage position, namely with the frame 1401 at low height as shown in FIG. 14. When having approached the monopile end, the frame 1401 is raised, as is shown in FIG. 23, such that the coupling tool 109 is brought at the height of the monopile 2002. Next, the skidding unit 108 may further be moved forward, for coupling the tool 109 with the monopile end. The coupling tool 109 is thus brought into a coupling position by the skidding unit 108, wherein the tool 109 is guided by the skidding unit 108 and any uncontrolled movements are avoided. In this way, damage to the monopile or equipment is prevented, and an efficient coupling process is obtained. Moreover, together with the coupling tool 109, also the auxiliary equipment 1407, 1408 is brought to the monopile end by means of the skidding unit 108, thereby contributing to a space-saving arrangement and further increasing operational efficiency.

After coupling the tool 109 to the end of monopile 2002, by means of the clamping members 1404, the lifting member 1406 of tool 109 is connected to the crane 302. Next, the monopile 2002 is upended by the crane 302, thereby reaching an upright position as shown in FIG. 24. Afterwards, the monopile 2002 may be lowered into the water, and driven into the bottom by means of a hammering tool. Before placing the hammering tool, the monopile is disconnected from the crane, and the coupling tool is placed back in the tool storage cradle of the skidding unit 108. The skidding unit 108 may be transported back to its storage location in the bridge of the vessel 300.

Next, the vessel 300 may sail to a following installation location, where monopile 1600 will be installed. In view of upending monopile 1600, it is first transported in transverse direction towards the upending line 304 by means of the transverse skids 103, 104. At the upending line, the longitudinal skids 101, 102 are in the position corresponding to the longitudinal position of the storage area, further away from the upending device 303, i.e. the position as shown in FIG. 16. When the transverse skids 103, 104 have reached the upending line, the monopile 1600 is transferred to the longitudinal skids 101, 102, by lowering the support cradles of the transverse skids 103, 104.

While being carried by the longitudinal skids 101, 102, the monopile 1600 is transported in longitudinal direction towards the upending device 303. For this purpose, the skids 101, 102 are displaced simultaneously, thereby reaching the position like shown in FIG. 15. Afterwards, the monopile 1600 is further shifted into the upending device 303. For this purpose, the support cradle of the aft skid 102 is lowered, such that the monopile 1600 is only supported by the forward skid 101 and rollers in the upending device 303. Next, the forward skid 101 is further displaced towards the upending device 303, thereby pushing the monopile 600 into the cage of the upending device, against the bottom beam of the upending device. Afterwards, the coupling tool 109 is coupled to the monopile 1600 and the monopile may be upended, in the same way as described for the previous monopile.

Although the present invention has been illustrated by reference to specific embodiments, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied with various changes and modifications without departing from the scope thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. In other words, it is contemplated to cover any and all modifications, variations or equivalents that fall within the scope of the basic underlying principles and whose essential attributes are claimed in this patent application. It will furthermore be understood by the reader of this patent application that the words “comprising” or “comprise” do not exclude other elements or steps, that the words “a” or “an” do not exclude a plurality, and that a single element, such as a computer system, a processor, or another integrated unit may fulfil the functions of several means recited in the claims. Any reference signs in the claims shall not be construed as limiting the respective claims concerned. The terms “first”, “second”, third”, “a”, “b”, “c”, and the like, when used in the description or in the claims are introduced to distinguish between similar elements or steps and are not necessarily describing a sequential or chronological order. Similarly, the terms “top”, “bottom”, “over”, “under”, and the like are introduced for descriptive purposes and not necessarily to denote relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and embodiments of the invention are capable of operating according to the present invention in other sequences, or in orientations different from the one(s) described or illustrated above.