Skidding unit for use on a vessel deck

Abstract

Arrangement (100) for use on a support surface (201) of a floating body such as a vessel (200), comprising: - a tool (103), adapted for coupling to an end of an elongated element (300); - a tool storage cradle (102), adapted for holding the tool (103) while being sea-fastened; - a skidding unit (101) displaceable over the support surface (201), the tool storage cradle (102) being comprised in the skidding unit (101), thereby allowing to transport the tool (103) over the support surface (201) from a storage location towards the elongated element (300), while being held in a storage position by the tool storage cradle (102), wherein the skidding unit (101) is adapted to guide the tool (103) while being brought from the storage position in the tool storage cradle (102) to a coupling position, thereby constraining movements of the tool (103) while bringing it into the coupling position.

Description

Field of the Invention

[0001] The present invention generally relates to a solution 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 or piles of jacket foundations. In particular, a solution is presented that ensures safe and damage-free handling of elongated elements and tools at the vessel deck, while allowing for an efficient arrangement and an increased operational efficiency.Background of the Invention

[0002] 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.

[0003] Installing an elongated element such as a pile foundation for an offshore wind turbine typically takes place from the deck of a vessel, which may be in floating condition during installation of the pile. In a typical installation sequence, a monopile lying on the deck of the vessel is first displaced in horizontal condition to a dedicated upending position on the deck. Next, the monopile is upended, i.e. brought into vertical position, by means of a hoisting device such as a crane, wherein the monopile top end is coupled to the crane. For coupling the monopile end to the crane, specific tools have been developed in the prior art, in view of reducing the risk of damaging the monopile while coupling to the crane, in particular when the floating vessel is rocking due to conditions at sea. For example, EP3826952B1 discloses a coupling tool having slidable clamping members, wherein the clamping members may be slit along beams to a position wherein they engage with the inner surface of the monopile. After coupling the tool to the monopile end, the crane may be connected to the coupling tool for upending, thereby allowing coupling to the crane with less chance of damage to the monopile.

[0004] In a next step, the monopile is lowered towards the seabed, while being suspended from the crane, and it may penetrate the underwater bottom under its own weight. Afterwards, the monopile is further driven into the bottom by means of a hammering tool arranged at the upper end of the monopile. For example, a hydraulic impact hammer may be used, which is typically arranged at the top end of the upended monopile after decoupling the pile from the crane. Alternatively, a vibro-hammer may be used, which - unlike a traditional pile driver that uses large weights to strike piles into the earth - uses vibrations to drive the pile. The vibro-hammer may be arranged at the monopile end before upending, and subsequently be connected to the crane, for upending the monopile with the arranged vibro-hammer on top.

[0005] The elongated elements to be installed in these offshore applications are typically large and heavy objects. For example, monopiles can have a length of up to 100 m and more, a diameter of up to 12 m and more, and a weight which can rise up to 2000 tons and more. Installing such massive objects from the deck of a floating vessel goes along with challenges. First, due to waves and weather conditions, the vessel never is in static condition, thereby requiring sea-fastening of everything stored at the deck of the vessel. This does not only apply to the foundation piles, but also to any of the tools or equipment required for the installation operation, e.g. a hammer tool, coupling tool, etc. Moreover, displacing such tool towards the monopile before upending, and arranging it at the monopile end, is challenging due to the continuous movements of the floating vessel, thereby requiring specific measures and procedures to avoid damage to piles or equipment, and to ensure safety of personnel onboard. However, such specific measures and procedures typically are time-intensive, thereby increasing operational time for installing a monopile. This is even more the case due to the limited space available at the deck, wherein the arrangement of piles and tools at the deck may further increase complexity of displacing tools for use during an installation operation. Finally, tools like a hammer or coupling tool typically need to be supplied with hydraulic or electric energy during use, such that energy sources need to be available and supply lines need to be connected, thereby further increasing complexity of the arrangement at the deck and limiting operational efficiency.

[0006] It is an objective of the present invention to disclose a solution for use at a vessel for installing elongated elements such as monopiles, 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 that ensures safe and damage-free handling of elongated elements and tools at the vessel deck, while allowing for an efficient arrangement and an increased operational efficiency.Summary of the Invention

[0007] According to a first aspect of the present invention, the above identified objectives are realized by an arrangement suitable for use on a support surface of a floating body such as a vessel, defined by claim 1, the support surface extending in a horizontal plane and carrying an elongated element in lying condition, and the arrangement comprising: a tool, adapted for coupling to an end of the elongated element; a tool storage cradle, adapted for holding the tool while being sea-fastened; wherein the arrangement comprises a skidding system, wherein: the skidding system comprises a skidding unit displaceable over the support surface, the tool storage cradle being comprised in the skidding unit, thereby allowing to transport the tool over the support surface from a storage location towards the end of the elongated element, while being 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.

[0008] Thus, the invention concerns an arrangement suitable for use on 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. The support surface is adapted to carry an elongated element in lying condition. An elongated element refers to a slender object like a tubular element, pipe or pile. 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. In any case, the lying condition is such that the end of the elongated element can be reached from a horizontal direction, i.e. the elongated element is not in an upright position wherein its upper end would only be reachable from above.

[0009] In the following, the longitudinal direction refers to the direction wherein the elongated element extends when it is in lying condition, while the transverse direction is perpendicular to the longitudinal direction. This implies that the longitudinal direction, defined by the elongated element, 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 element is positioned 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.

[0010] For example, the elongated element is a monopile serving as a foundation structure of an offshore wind turbine. 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.

[0011] The support surface is adapted to carry an elongated element in lying condition, which typically implies that a support structure is provided at the support surface. Such support structure, e.g. comprising one or more fixed or displaceable support cradles, is installed at the deck and allows to support the elongated element while being in lying condition. Typically, apart from the invented arrangement, other types of equipment are installed at the support surface, such as a hoisting device, also referred to as a lifting means or crane, and an upending device adapted to receive the monopile end, and support the monopile during upending towards an upright position.

[0012] The invented arrangement comprises a tool, the tool being adapted for coupling to an end of the elongated element. This means that the tool can be arranged at the pile end, i.e. connected to the pile end, wherein the tool engages with a lateral and / or top wall at the end of the elongated element. For example, the tool engages with the outer and / or inner lateral surface of the tube-shaped wall at the pile end. The end of the elongated element is typically the upper end, i.e. the end of the pile directed upwards after upending. 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 this embodiment, the coupling tool comprises slidable clamping members, wherein the clamping members may be slit along beams of a cross-shaped structure, to a position wherein they engage with the inner surface of the hollow tube-shaped pile end. Moreover, the coupling tool comprises a lifting member provided with lifting eyes, for connection to a crane. 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.

[0013] 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 latter requires an energy supply towards the clamping members, and thus an actuation system on the coupling tool. For example a hydraulic actuation of the clamping members may be provided. E.g., the clamping members may be slidable by means of hydraulic piston cylinders. In another example, clamps are provided at a vibro-hammer tool, which may be actuated for connecting the vibro-hammer tool to the pile end. In other possible embodiments, the coupling system is not comprised in the tool itself, but is provided as separate means or a separate system.

[0014] Coupling of the tool to the elongated element occurs when the elongated element is in lying condition, i.e. before upending the elongated element. In an embodiment, the elongated element is positioned in the upending line when coupling the tool to the end of the elongated element, i.e. the elongated element is carried by some support structure arranged in the upending line. This implies that after coupling the tool and before the start of upending, the elongated element does not need to be displaced anymore in any transverse direction; a displacement in longitudinal direction of the elongated element after coupling the tool and before starting upending may be required though. In other embodiments, it is also possible that the elongated element is not positioned in the upending line yet when coupling the tool, such that the elongated element needs to be transported according to a transverse direction after coupling the tool and before start of upending.

[0015] The arrangement further comprises a tool storage cradle, adapted for holding the tool while being sea-fastened. This implies that the tool 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 tool will not be displaced with respect to the support surface, as long as it is held in the tool storage cradle and the tool storage cradle remains at a fixed position on 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 tool with respect to the support surface may still occur. In other words, while being sea-fastened in the tool storage cradle, the tool follows any movement that the vessel or platform undergoes due to interaction with waves and wind. It is to be noted that the tool storage cradle may be designed according to any possible shape, such that the term cradle refers to any type of holder or docking station for holding the tool, and is not limited to a specific shape of the holder.

[0016] The arrangement further comprises a skidding system, the skidding system comprising a skidding unit. The skidding unit is displaceable over the support surface. Displacing the unit 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. The term skidding unit thus is to be understood as a transport unit in the general sense. In an embodiment, the skidding unit can only be transported according to a predefined trajectory, e.g. defined by a track at the support surface. In other embodiments, however, it is also possible that the unit can freely move over the support surface, e.g. when the skidding unit is provided as a type of car. The tool storage cradle is comprised in the skidding unit, meaning that it makes part of the displaceable unit. For example, the skidding unit comprises a transport cart, and the storage cradle is arranged at the transport cart.

[0017] As such, the tool storage cradle is displaced together with the transport cart, 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. In particular, the tool can be held in the storage cradle at a storage location when the tool is not in use, e.g. during sailing towards an installation location, and may - during an installation operation - be displaced over the support surface towards the end of the lying elongated element, for coupling to the elongated element. During this displacement over the support surface, the tool is held in a storage position by the tool storage cradle, such that it remains sea-fastened. This implies that during storage of the tool as well as during displacement of the tool towards the end of the elongated element, the tool does not substantially move with respect to the skidding unit. In other words, during the displacement of the tool, the tool follows the movement of the skidding unit with respect to the support surface, and follows the movements of the support surface due to the vessel interacting with waves and wind.

[0018] The skidding unit is thus adapted to transport the tool over the support surface, while the tool is 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. The coupling position is the position that allows the tool to be coupled to the pile end, but wherein actual coupling to the pile does not necessarily has taken place yet. For example, in case of a coupling tool with slidable clamping members, the tool is in the coupling position when it has been inserted into the hollow pile end, but the clamping members do not engage yet with the inner surface of the pile; afterwards, by means of a hydraulic coupling system, the clamping members may be slit outwardly for engaging with the inner surface of the pile, thereby coupling the tool to the pile end.

[0019] 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. For example, an element making part of the tool may be shifted in horizontal or vertical direction, pivoted, rotated, lifted, tilted, etc, or any combination thereof. Moving the tool, or a portion thereof, may be done by means of the skidding unit, or by a mechanism on the tool itself, or by another equipment, or by a combination thereof. Moving the tool by means of the skidding unit may e.g. be done by displacing the skidding unit forwards, or shifting the tool upwards by means of an adaptable frame on the skidding unit, or shifting the tool forward by extendable arms mounted on the skidding unit, etc. Moving a portion of the tool by a mechanism on the tool itself may e.g. be the case if a part of the tool is pivoted via an activation mechanism on the tool. Moving the tool by another equipment is e.g. the case when the tool is lifted from the storage cradle by the crane.

[0020] 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.

[0021] The invented arrangement thus 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, during storage, and during every step between storage at the deck and the tool being coupled to the elongated element. This results in a safe operation wherein any risks of damage to the elongated element or equipment are mitigated.

[0022] Moreover, the invented arrangement 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. Indeed, instead of having a sea-fastening storage cradle at a fixed position on the deck, the invented skidding unit allows to transport the storage cradle over the deck. The skidding unit thus transports the tool over the deck in a controlled way, and brings it subsequently into its coupling position. This contributes to an operation that is less time intensive than when an additional step would be required, wherein first the tool needs to be removed from the sea-fastening, and subsequently is placed on a dedicated equipment for coupling to the elongated element.

[0023] Finally, as both the sea-fastening storage function and the guidance function for coupling are integrated in a single unit, the invention allows for a compact arrangement at the deck. This results in a space-saving solution, and further contributes to an increased operational efficiency.

[0024] 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: is shifted in horizontal direction, and / or is shifted in vertical direction, and / or is pivoted, and / or is rotated.

[0025] Shifting in horizontal direction may comprise shifting according to the longitudinal direction and / or according to the transverse direction, thereby changing the longitudinal and / or transverse position with respect to the support surface. Shifting in vertical direction refers to lifting the tool or a portion thereof, implying that the height position with respect to the elongated element is adapted. Pivoting may comprise pivoting about a horizontal axis, e.g. in transverse direction, and / or pivoting about a vertical axis, thereby changing the inclination or orientation of the tool or tool portion with respect to the pile end. Rotating may comprise rotating about a horizontal axis, e.g. in longitudinal direction, thereby changing the angular position or orientation of the tool or tool portion with respect to the pile end.

[0026] 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. Thus, for bringing the tool into the coupling position, the tool is moved as a whole, and / or one or more elements of the tool are moved. Each of these movements contributes to bringing the tool into a position wherein it can be coupled to the pile end. For example, shifting in vertical direction is done for obtaining a height position allowing for coupling with the end of the elongated element, and pivoting or rotating is done for obtaining an orientation allowing for coupling with the end of the elongated element.

[0027] Optionally, the coupling system is comprised in the tool, the coupling system being adapted to engage with the end of the elongated element by operating the coupling system after the tool is brought into the coupling position. For example, the coupling system of the tool comprises one or more elements that may be moved from an uncoupled state to a coupled state, wherein the elements engage with the pile end in the coupled state, and an actuator for moving these elements following an energy supply. The elements may e.g. be provided as clamping members, and the actuator may e.g. be a hydraulic or electric actuator. In an embodiment, the coupling system comprises slidable or movable clamping members, which may be brought in a clamping position by means of an actuator. For example, the clamping members may be slidable or movable by means of hydraulic piston cylinders.

[0028] 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.

[0029] 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.

[0030] Providing the tool with energy, signals or a fluid flow, may be required before upending, e.g. for coupling the tool to the pile end, and / or after upending, e.g. for operating the arranged tool during driving the elongated element into the seabed. For example, a coupling tool may require hydraulic energy under the form of a pressurized fluid for operating the coupling system, e.g. to bring clamping members into a clamping position. In another embodiment, the tool may be a vibro-hammer, wherein energy needs to be supplied to the hammer in view of creating the pile driving vibrations. Energy may supplied to the tool under various forms, e.g. hydraulic energy may be supplied via a pressurized fluid, electric power may be supplied, etc. In others embodiments signals may be supplied to the tool, e.g. control signals or measurement signals. In yet another embodiment, a supply of fresh water may be provided to the tool. In view of supplying energy, signals or a fluid flow to the tool, one or more supply lines are provided on the skidding unit, e.g. provided as cables or hoses.

[0031] In this way, besides the sea-fastening storage function and guiding function for coupling provided on the invented skidding unit, 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.

[0032] Finally, it is to be noted that there is no structural or functional relation between - on the one hand - the energy supply function provided on the skidding unit, and - on the other hand - other features of the arrangement included in claim 1. In particular, the presence of the auxiliary equipment on the skidding unit, e.g. by energy pack(s) and supply lines on the skidding unit, is not linked or related to obtaining sea-fastening by means of the tool storage cradle. Thus, this auxiliary equipment on the skidding unit may as well be used in an arrangement wherein the sea-fastening storge cradle is not provided on the skidding unit, thereby still allowing for the space- and time savings related to having the auxiliary equipment on the skidding unit. The feature of providing auxiliary equipment on the skidding unit adapted for supplying the tool with energy and / or signals and / or a fluid flow, is therefor a further independent aspect of the invention, the feature not being only disclosed in combination with the other features of claim 1.

[0033] Optionally, the skidding unit comprises one or more reels, adapted for winding the one or more supply lines.

[0034] Optionally, the auxiliary equipment comprises one or more power packs adapted for generating or converting energy. In an embodiment, the power pack may be a Hydraulic Power Unit, abbreviated HPU, for producing a pressurized fluid, For example, the HPU may receive electric energy from the vessel, or may have its own diesel generator comprised in the skidding unit. In another embodiment, the power pack is a diesel generator for producing electric power. The one or more supply lines available on the skidding unit, allow to connect the power pack to the tool.

[0035] Optionally, the skidding unit comprises a hydraulic power unit, abbreviated HPU, adapted for producing a pressurized fluid, and a hose connecting the HPU to the tool. The HPU e.g. comprises an electromotor, a hydraulic pump and an oil tank. Additionally, the HPU may comprise a diesel generator for producing electric power, in view of powering the electromotor. In another embodiment, the HPU may be adapted to receive hydraulic power from the vessel, instead of producing a pressurized fluid itself.

[0036] Optionally, the skidding unit is adapted to receive electric power and / or data via a connection with a supply available at the floating body. For example, power packs and hose reels may receive power and data via an umbilical reel or via discrete connection points along skidding rails.

[0037] Optionally, the skidding system is adapted for displacing the skidding unit along a predefined track at the support surface of the floating body.

[0038] Optionally, the arrangement comprises a support structure adapted to carry the elongated element while coupling the tool, wherein the carried elongated element extends in longitudinal direction. This means that a support structure is provided at the support surface, allowing to support the elongated element while being in lying condition during coupling of the tool. For example, the support structure comprises one or more fixed or displaceable support cradles. When carried by the support structure, the central axis of the elongated element defines the longitudinal direction. In other words, the length of the elongated element corresponds to the longitudinal direction.

[0039] Optionally, the support structure comprises at least one pile transport cart, equipped with a support cradle and displaceable over the support surface along the longitudinal direction. This means that during coupling, the elongated element is supported by a support cradle that is displaceable over the deck, in longitudinal direction. This allows the elongated element to be displaced in longitudinal direction, e.g. for shifting it into a upending device, e.g. after coupling the tool to the end of the elongated element.

[0040] Optionally, the skidding system is adapted for displacing the skidding unit along a predefined path in longitudinal direction, for transporting the tool from the storage location towards the end of the elongated element. This implies that the skidding unit is only displaced according to one direction, namely the longitudinal direction, wherein it follows a straight predefined path. Skidding may be such that for positioning the tool centrally in front of the pile end, not any movements in transverse direction are needed. Transporting the skidding unit towards the end of the elongated element, therefore only requires shifting the unit forwards, thereby allowing for a simple arrangement at the deck and quickly moving the skidding unit from the storage location to the coupling location at the deck.

[0041] Optionally, the arrangement comprises an upending device, adapted for upending the lying elongated element towards an upright position. 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.

[0042] Optionally, the skidding system is adapted for displacing the skidding unit over the support surface along the upending line. The upending line is defined by the central axis of the elongated element when being received by the upending device before upending. The upending line thus 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. This implies that the skidding unit is displaced according to a straight predefined path, the latter corresponding to the upending line. In this way, the elongated element may already be positioned in the upending line when coupling the tool, thereby allowing for rapidly starting the upending sequence after coupling the tool to the pile end.

[0043] Optionally, the support structure comprises at least one pile transport cart, equipped with a support cradle and displaceable over the support surface along the longitudinal direction, wherein the pile transport cart is adapted for shifting the elongated element in the upending device, by displacing the transport cart along the upending line while supporting the elongated element. This means that the pile transport cart has a double function, namely supporting the elongated element during coupling of the tool, and displacing the elongated element for shifting it into the upending device.

[0044] Optionally, the skidding system is adapted for further displacing the skidding unit along the upending line, during upending of the elongated element by the upending device. This means that during bringing the elongated element from the lying condition into the upright condition, the skidding unit further moves forward along the upending line. In this way, the skidding unit always remains close to the tool, the latter being arranged on the top end of the pile during upending. This contributes to making hose and cable handling more convenient, wherein hoses and / or cables are connected to the tool for supplying it with energy and / or signals and / or a fluid flow.

[0045] Optionally, the skidding system comprises: the skidding unit, comprising a transport cart, and a track comprising one or more rails, the transport cart being adapted to slide over the one or more rails, and the tool storage cradle being mounted to the transport cart.

[0046] Optionally, the skidding system comprises a rack and pinion drive system, adapted for driving the skidding unit while moving along a trajectory defined by a rack provided at the support surface. The system thus comprises a rack for installation at the deck, and a pinion arranged at the skidding unit, the rack defining the trajectory followed by the skidding unit.

[0047] 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. The adjustable position of the frame may refer to adjusting the height position with respect to the support surface, the longitudinal position on the support surface, the transverse position on the support surface, the angular position, the inclination with respect to the support surface, etc.

[0048] 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. In this way, e.g. the tool can be transported over the support surface while being at a low height position, and subsequently be lifted to allow for coupling with the elongated element.

[0049] 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. The guiding elements are typically movable or adjustable components, that can be moved according to a specific trajectory. As they engage with the tool, they restrict the possible movements of the tool, by imposing or defining a travelling path to be followed by the tool or a portion of the tool. For example, the guiding elements are provided as guiding arms.

[0050] 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.

[0051] 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. For example, during coupling of the tool with the pile end, the tool may be lifted by a crane. During this movement, the pivotable guiding arms may move along with the lifted tool, thereby restricting swinging movements of the tool in longitudinal and / or transverse direction.

[0052] Optionally, one or more parts of the tool are pivotable about a horizontal axis, thereby allowing to obtain, by operating the tool, an orientation suitable for coupling to the end of the elongated element and / or suitable for storing the tool in the tool storage cradle. In an embodiment, the tool is a vibro-hammer, which is stored with the face down in the storage cradle. Before coupling, the hammer, or a portion thereof, is pivoted over 90 degrees to allow for connecting the face of the hammer to the end of the elongated element. In another embodiment, the tool is a coupling tool, comprising a lifting member that is pivotable with respect to the rest of the tool. During storage of the tool and coupling to the elongated element, the lifting member is in a first state. Afterwards, during upending of the elongated element, the lifting member is pivoted over 90 degrees with respect to the rest of the coupling tool. Before placing the coupling tool back into the storage cradle again, the lifting member may again be pivoted over 90 degrees, for bringing it back in the first state.

[0053] Optionally, the tool is a coupling tool, adapted for connecting the end of the elongated element to a hoisting device via the mounted coupling tool. This means that the tool, on the one hand, is adapted to be arranged at the end of the elongated element. For example, the tool may comprise clamping members, that may engage with the inner and / or outer surface of the pile end for coupling with the elongated element. On the other hand, the tool is adapted to be connected to a crane. For example, the tool may comprises a lifting member, e.g. having lifting eyes for connecting to a crane.

[0054] Optionally, the tool is a hammer tool, such as a vibro-hammer, adapted for hammering the elongated element via the mounted hammer tool.

[0055] 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.

[0056] Optionally, the storage location, for storing the skidding unit when not using the tool, is in the bridge structure of the vessel.

[0057] Storage of the skidding unit in the vessel bridge structure ensures that - in an embodiment wherein the elongated elements are stored in longitudinal direction - transverse displacements of the elongated elements, are not obstructed by the skidding unit present on the deck. Transverse displacements may e.g. be done for transporting a pile from a storage line to the upending line. Moreover, avoiding such obstruction is obtained without adding additional space in longitudinal direction of the vessel, thereby contributing to a reduced vessel length. In an alternative embodiment, the storage location may be aft of the bridge structure, such that the skidding unit is stored close to the bridge, but not in the bridge structure.

[0058] According to a third aspect of the present invention, there is provided a method for using a tool at a support surface of a floating body such as a vessel, the method comprising: providing the floating body comprising the support surface, wherein the support surface carries at least one elongated element in lying condition; providing an arrangement according to the first aspect of the invention; storing the skidding unit at a storage location on the support surface, wherein the tool is held by the tool storage cradle, thereby being sea-fastened; transporting the tool from the storage location towards the end of the elongated element, by displacing the skidding unit over the support surface, while the tool is held in a storage position in the tool storage cradle; bringing the tool from the storage position into a coupling position, while being guided by the skidding unit, thereby constraining movements of the tool while bringing it into the coupling position.

[0059] Optionally, the method comprises: after being brought in the coupling position, coupling the tool to the end of the elongated element by operating the coupling mechanism.

[0060] Optionally, the method comprises: after or before coupling the tool to the elongated element, releasing the tool from the tool storage cradle. Thus, coupling of the tool may happen while the tool is still held in the tool storage cradle, or after releasing the tool from the tool storage cradle.Brief Description of the Drawings

[0061] Fig. 1 shows an arrangement according to a first embodiment of the invention. Fig. 2 shows a vessel provided with the arrangement of Fig. 1. Fig. 3 shows the vessel of Fig. 2, wherein monopiles are stored on the vessel deck. Fig. 4 shows a skidding unit, as comprised in the arrangement of Fig. 1. Fig. 5 and Fig. 6 illustrate the use of the arrangement of Fig. 1, for coupling a coupling tool to a monopile lying on the vessel deck. Fig. 7 shows the vessel of Fig. 2, in a condition after coupling the coupling tool and after upending the monopile. Fig. 8 shows a vessel provided with an arrangement according to a second embodiment of the invention. Fig. 9 shows the vessel of Fig. 8, wherein monopiles are stored on the vessel deck. Fig. 10 shows a skidding unit, as comprised in the arrangement of Fig. 8. Fig. 11 to Fig. 13 illustrate the use of the arrangement of Fig. 8, for coupling a vibro-hammer to a monopile lying on the vessel deck. Detailed Description of Embodiment(s)

[0062] Fig. 1 to Fig. 7 illustrate a first possible embodiment of the invention. Fig. 1 shows an arrangement 100 according to the first embodiment. The arrangement 100 is suitable for use on a support surface of a floating body such as a vessel 200, as is illustrated in Fig. 2. In the embodiment of Fig. 2, the vessel 200 is a vessel for installing monopiles, and the support surface 201 makes part of the deck of the vessel 200. Besides the arrangement 100, the vessel 200 has other equipment on board, such as an upending device 203, a hoisting device or crane 202, and a hydraulic impact hammer 204. Fig. 3 shows the vessel 200 wherein four monopiles 301 are stored on the deck of the vessel, and one monopile 300 is positioned in the upending device 203. 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. 3. The upending device 203 is adapted to guide and support the monopile 300 while being pivoted from the lying condition of Fig. 3 towards an upright condition as illustrated in Fig. 7. The length direction of the monopile 300, when it is in the lying condition like in Fig. 3, is defined as the longitudinal direction X. In the shown embodiment, the X-direction corresponds to the longitudinal direction of the vessel 200. The transverse direction is indicated as Y, and the height direction as Z.

[0063] The arrangement 100 comprises a tool 103. In the embodiment of Fig. 1, the tool 103 is a coupling tool 103, adapted to be coupled to an end of the monopile 300 while it is in lying condition on the support surface 201, before upending of the monopile 300. The coupling tool 103 comprises a cross-shaped structure 403, and clamping members 404, wherein the latter engage with the outer lateral surface of the monopile 300 when the coupling tool 103 is coupled to the end of the monopile 300. The coupling tool 103 further comprises a lifting member 406, which is connected to the crane 202 before upending. The cross-shaped structure 403 may pivot with respect to the lifting member 406, around pin 405. In this way, the orientation of the cross-shaped structure and clamping members 404 may change with respect to the lifting member 406, during upending of the monopile by the crane, as is illustrated in Fig. 7. The coupling tool 103 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.

[0064] The arrangement 100 further comprises a skidding system. The skidding system comprises a skidding unit 101, which is shown in more detail in Fig. 4. The skidding unit 101 comprises a transport cart 104 and is displaceable over the support surface 201. For this purpose, the skidding system comprises a track 105, comprising two rails 410, 411, wherein the transport cart 104 may slide over the rails 410, 411. The track 105 defines a predefined path for displacement of the skidding unit 101. In the shown embodiment, this predefined path runs in longitudinal direction, along the upending line 205, thereby allowing to displace the skidding unit 101 according to a straight path, towards the monopile 300 when the latter is positioned in the upending device 203. In the shown embodiment, the skidding unit 101 is driven by means of a rack and pinion drive system, wherein a toothed rack 409 is installed at the support surface 201, and two pinions 413 are arranged at the transport cart 104.

[0065] The skidding unit 101 comprises a tool storage cradle 102, which allows for holding the coupling tool 103 in a sea-fastened way. In particular, the tool storage cradle 102 comprises a frame 401, at the back of the tool 103, and a bar or edge 412, at the front of the tool 103. When the coupling tool 103 is positioned in the tool storage cradle 102, the pin 405 at the back of the coupling tool is placed in a recess 402 of the frame 401, and the front of the cross-shaped structure 403 engages with the edge 412. In this way, the frame 401 allows to hold the coupling tool 103 in a sea-fastened position without requiring additional fasteners. Furthermore, the frame 401 is height-adjustable, as the frame 401 may be slid upwards and downwards with respect to the rest of the tool storage cradle 102, see Fig. 6. In this way, the height position of the coupling tool 103 with respect to the support surface 201 may be changed while being held by the frame 401.

[0066] The tool storage cradle 102 is mounted to the transport cart 104, thereby allowing to transport the coupling tool 103 over the deck while being held by the tool storage cradle 102. Furthermore, auxiliary equipment such as a power pack 408 and a cable reel 407 are mounted to the transport cart 104. The auxiliary equipment is adapted for supplying the coupling tool 103 with energy and / or signals, e.g. when coupling the tool 103 to the monopile end and during upending. In this way, the auxiliary equipment can be transported over the deck together with the coupling tool 103. In particular, the cable reel 407 and power pack 408 allow to provide electrical, hydraulic, or signals to and from the coupling tool 103. Typically, each tool on the deck has its own dedicated power packs, HPU's and hose reels as applicable to the tool function. For the skidding unit 101, one embodiment is that the cable reel 407 is connected to a fixed point on deck and transfers electrical power and signals to and from the vessel and the skidding unit. As the skidding unit 101 moves, the cable reel 407 pays in or out to eliminate loose cable on deck. From the connection point of the cable reel 407 on the skidding unit 101, the power may be passed to the power pack 408, or to a hydraulic power unit.

[0067] The arrangement 100 comprises a support structure, adapted to carry the monopile 300 during coupling of the coupling tool 103, and supporting the monopile at two length positions when it is in lying condition. For this purpose, the support structure comprises two spaced-apart portions 106 and 107, each of them comprising a support cradle 112, 113. In the shown embodiment, both support cradles 112 and 113 are mounted to a transport cart or skid 110, 111, such that support structure portions 106 and 107 are displaceable in longitudinal direction. Longitudinal displacement of the skids 110, 111 may e.g. be applied during the loading process of monopiles, or when inserting a monopile into the upending device 203. With respect to the invented skidding unit 101, with tool storage cradle for holding coupling tool 103, however, movability of the support structure 106, 107 is not essential; during coupling of the tool 103 to the monopile end, the monopile 300 may as well be supported by a static support structure. Finally, Fig. 1 shows that the arrangement 100 comprises skids 108, 109, which are displaceable in transverse direction. Such transverse skids may e.g. be used during the loading process of monopiles, or for bringing a monopile from a storage line towards the upending line. In the context of the to the invented skidding unit 101, with tool storage cradle for holding coupling tool 103, however, the availability of such transverse skids is not required.

[0068] A possible use of the arrangement 100 is further illustrated by Fig. 5 to 7. An initial state is shown in Fig. 3, when the coupling tool 103 is not in use. The monopile 300 is in lying condition, and is placed with one end in the upending device 203. In this state, the monopile 300 is supported by support structure portions 106 and 107. Compared to Fig. 2, pile transport cart 106 has been moved in longitudinal direction, towards upending device 203; for inserting monopile 300 into the upending device, pile transport cart 106 was moved forwards while pile transport cart 107 remained in static condition. The skidding unit 101 is located at a storage location on the deck, wherein the storage location is aft of the bridge structure of the vessel 200. The coupling tool 103 is held by the tool storage cradle 102. In particular, it is held by the frame 401, thereby being sea-fastened. In the state of Fig. 3, the tool 103 is held in its storage position, wherein the frame 401 is at low height, close to the deck.

[0069] Next, the skidding unit 101 is displaced over the deck, in longitudinal direction, towards the end of the lying monopile 300, see Fig. 5. The skidding unit 101 is transported along the upending line 205, for reaching the monopile 300 which is positioned in the upending device 203. During transport of the skidding unit 101, the coupling tool 103 is held by the tool storage cradle 102, wherein the coupling tool 103 still is in the storage position, i.e. the frame 401 is at low height.

[0070] Fig. 6 shows that, once the skidding unit 101 has approached the monopile end, the frame 401 is shifted towards a higher position, thereby increasing the height position of the coupling tool 103. In particular, the coupling tool 103 is brought to a height position corresponding to the height position of the monopile's end. Next, the skidding unit 101 may further be moved forward, for reaching the monopile's end and bringing the coupling tool 103 in the coupling position. The coupling position is the position that allows the tool 103 to be coupled to the pile end, but wherein actual coupling to the pile has not necessarily taken place yet. For example, the tool 103 is in the coupling position when the clamping members 404 have been placed around the outer lateral surface of the monopile 300, but actual coupling, e.g. by means of a hydraulic coupling system, has not taken place yet.

[0071] One the coupling tool 103 has been coupled to the end of the monopile 300, the lifting member 406 of the tool 103 is connected to the crane 202, and upending of the monopile 300 may start. Fig. 7 illustrates the state obtained after upending, i.e. after bringing the monopile 300 in upright position. During upending of the monopile 300, the skidding unit 101 may further move forward, along the upending line, such that the skidding unit 101 remains close to the tool 103, and handling of supply lines towards the tool 103 becomes more convenient.

[0072] Afterwards, the monopile will be lowered into the water, for insertion into the seabed. After some insertion depth has been reached, the coupling tool 103 is decoupled from the monopile 300. Accordingly, the decoupled coupling tool 103 may be brought back to the skidding unit 101 by the crane, and placed in the tool storage cradle 102, in its storage position. The skidding unit may be transported back to the storage location in the bridge, before or after receiving the tool 103.

[0073] The above makes clear that during the whole process of storing, transporting and coupling the tool, all movements of the coupling tool are constrained by the skidding unit 101, thereby avoiding any uncontrolled movements of the tool. This results in a safe coupling operation wherein any risks of damage to the monopile or equipment are mitigated. Furthermore, the skidding unit 101 results in a very compact unit, wherein a sea-fastening storage cradle, guiding elements and auxiliary equipment are combined, thereby allowing for a space-saving solution, and further contributing to an increased operational efficiency.

[0074] Fig. 8 to Fig. 13 illustrate a second possible embodiment of the invention. Fig. 8 shows an arrangement according to the second embodiment, wherein the arrangement is used on a support surface 802 of a vessel 800. The arrangement according to the second embodiment comprises a skidding unit 801 and tool 803 different from the first embodiment of Fig. 1 to 7, but other components of the arrangement like the track 105 and the support structure 106, 107 are the same as in the first embodiment. Also the design of the vessel, and equipment such as the hoisting device 202 and upending device 203 are similar as in the first embodiment. Fig. 9 shows the vessel 800 wherein four monopiles 301 are stored on the deck of the vessel, and one monopile 300 is positioned in the upending device 203, similar to the first embodiment.

[0075] In the second embodiment, the tool 803 is a vibro-hammer, which allows to drive a monopile into the seabed by means of vibrations. The vibro-hammer 803 is arranged at the monopile's end before upending, when the monopile is in lying condition like in Fig. 9. Subsequently, the crane 202 is connected to the vibro-hammer 803, for upending the monopile 300 with the arranged vibro-hammer 803 on top.

[0076] The vibro-hammer 803 and skidding unit 801 are shown in more detail in Fig. 10. The vibro-hammer comprises a main portion 1009, which comprises the actual hammering or vibrating elements, and two lifting members 1006. The main portion further comprises a series of circumferentially positioned clamps 1005, for coupling with the monopile's end. The circumferentially positioned clamps 1005 may either engage with the inner and outer lateral surface of the monopile, for monopiles without a flange, or may engage with the inner and outer longitudinal surface of the flange, for monopiles with a flange. The lifting members 1006 are pivotable with respect to the main portion 1009 of the vibro-hammer 803, around pin 1003, and may be connected to hoisting cables 1100. In this way, the orientation of the main portion 1009 may change with respect to the lifting members 1006, during coupling of the vibro-hammer 803 and upending of the monopile by the crane.

[0077] The skidding unit 801 comprises a tool storage cradle 1000, which allows for holding the hammer tool 803 in a sea-fastened way. In particular, the tool storage cradle 1000 comprises an open box or base 1007 having raised edges, wherein the hammer 803 may be placed in horizontal position, i.e. with the clamps 1005 directed downwards, towards the bottom of the base. When the hammer 803 is positioned in the base 1007, its outer circumference engages with the raided edges of the base 1007, allowing to sea-fasten the hammer 803 without requiring additional fastening means. The skidding unit 801 further comprises guiding elements, provided as pivotable guiding arms 1001 and 1200. A plate 1002 is connected to the end of guiding arm 1001, the plate 1002 having a recess 1008. When the hammer 803 is in the storage position, the pin 1003 of the hammer 803 is placed in the recess 1008.

[0078] The tool storage cradle 1000 is mounted to a transport cart, which may slide over rails 410 and 411. In this way, the vibro-hammer 803 can be transported over the deck while being held by the tool storage cradle 1000. Furthermore, auxiliary equipment is mounted to the same transport cart. The auxiliary equipment is adapted for supplying the vibro-hammer with energy and / or signals, e.g. when coupling the hammer 803 to the monopile end and during hammering. In the shown embodiment, the auxiliary equipment comprises hydraulic power packs 1004, hydraulic and signal hose reels 1010, and a cable reel inside a weathertight container 1011. In this way, the auxiliary equipment can be transported over the deck together with vibro-hammer 803.

[0079] A possible use of the arrangement according to the second embodiment is further illustrated by Fig. 11 to 13. An initial state is shown in Fig. 9, when the vibro-hammer 803 is not in use. The monopile 300 is in lying condition, and is placed with one end in the upending device 203. The skidding unit 801 is located at a storage location on the deck, wherein the storage location is aft of the bridge structure of the vessel 800. The vibro-hammer 803 is held by the tool storage cradle 1000, the vibro-hammer 803 being in its storage position with the clamps 1005 directed downwards. In particular, the vibro-hammer 803 is positioned in the open base 1007, thereby being sea-fastened.

[0080] Next, the skidding unit 801 is displaced over the deck, in longitudinal direction, towards the end of the lying monopile 300, see Fig. 11. The skidding unit 801 is transported along the upending line 205, for reaching the monopile 300 which is positioned in the upending device 203. During transport of the skidding unit 801, the vibro-hammer 803 is held by the tool storage cradle 1000, wherein the vibro-hammer 803 still is in the storage position, i.e. with the main portion 1009 oriented horizontally and the clamps 1005 directed downwards.

[0081] Fig. 11 shows that, once the skidding unit 801 has approached the monopile end, hoisting cables 1100 are connected to the lifting members 1006 of the vibro-hammer 803. Subsequently, as shown in Fig. 12, the vibro-hammer 803 is lifted from the base 1007 by means of the crane 202. While being lifted, the main portion 1009 of the vibro-hammer 803 is pivoted over 90 degrees with respect to the lifting members 1006, such that the orientation of the main portion 1009 is changed from horizontal, with the clamps 1005 downward, to vertical, with the clamps 1005 directed towards the monopile end. Fig. 11 and 12 further show that during lifting and pivoting of the vibro-hammer 803, the guiding arms 1001, 1200 are pivoted, while still engaging with the pin 1003 of the vibro-hammer 803. In this way, movements of the vibro-hammer 803 in longitudinal and transverse direction are restricted, thereby avoiding uncontrolled swings of the vibro-hammer 803 while being lifted.

[0082] Next, as shown in Fig. 13, the skidding unit 801 is further moved forward, for reaching the monopile's end and bringing the vibro-hammer 803 in the coupling position. The coupling position is the position that allows the hammer 803 to be coupled to the pile end, but wherein actual coupling to the pile has not necessarily taken place yet. For example, the hammer 803 is in the coupling position when the clamping members 404 have been placed inside the open end of the monopile 300, but actual coupling, e.g. by means of a hydraulic coupling system, has not taken place yet.

[0083] Once the vibro-hammer 803 has been coupled to the end of the monopile 300, upending of the monopile 300 by means of the crane 202 may start. During upending of the monopile 300, the skidding unit 801 may further move forward, along the upending line, such that the skidding unit 801 remains close to the vibro-hammer 803, and handling of supply lines towards the tool 803 becomes more convenient.

[0084] 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.

Examples

first embodiment

[0062]Fig. 1 to Fig. 7 illustrate a first possible embodiment of the invention. Fig. 1 shows an arrangement 100 according to the The arrangement 100 is suitable for use on a support surface of a floating body such as a vessel 200, as is illustrated in Fig. 2. In the embodiment of Fig. 2, the vessel 200 is a vessel for installing monopiles, and the support surface 201 makes part of the deck of the vessel 200. Besides the arrangement 100, the vessel 200 has other equipment on board, such as an upending device 203, a hoisting device or crane 202, and a hydraulic impact hammer 204. Fig. 3 shows the vessel 200 wherein four monopiles 301 are stored on the deck of the vessel, and one monopile 300 is positioned in the upending device 203. 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. 3. The upending device 203 is adapted to guide and suppo...

second embodiment

[0075]In the second embodiment, the tool 803 is a vibro-hammer, which allows to drive a monopile into the seabed by means of vibrations. The vibro-hammer 803 is arranged at the monopile's end before upending, when the monopile is in lying condition like in Fig. 9. Subsequently, the crane 202 is connected to the vibro-hammer 803, for upending the monopile 300 with the arranged vibro-hammer 803 on top.

[0076]The vibro-hammer 803 and skidding unit 801 are shown in more detail in Fig. 10. The vibro-hammer comprises a main portion 1009, which comprises the actual hammering or vibrating elements, and two lifting members 1006. The main portion further comprises a series of circumferentially positioned clamps 1005, for coupling with the monopile's end. The circumferentially positioned clamps 1005 may either engage with the inner and outer lateral surface of the monopile, for monopiles without a flange, or may engage with the inner and outer longitudinal surface of the flange, for monopiles w...

Field of the Invention

[0001] The present invention generally relates to a solution 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 or piles of jacket foundations. In particular, a solution is presented that ensures safe and damage-free handling of elongated elements and tools at the vessel deck, while allowing for an efficient arrangement and an increased operational efficiency.Background of the Invention

[0002] 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.

[0003] Installing an elongated element such as a pile foundation for an offshore wind turbine typically takes place from the deck of a vessel, which may be in floating condition during installation of the pile. In a typical installation sequence, a monopile lying on the deck of the vessel is first displaced in horizontal condition to a dedicated upending position on the deck. Next, the monopile is upended, i.e. brought into vertical position, by means of a hoisting device such as a crane, wherein the monopile top end is coupled to the crane. For coupling the monopile end to the crane, specific tools have been developed in the prior art, in view of reducing the risk of damaging the monopile while coupling to the crane, in particular when the floating vessel is rocking due to conditions at sea. For example, EP3826952B1 discloses a coupling tool having slidable clamping members, wherein the clamping members may be slit along beams to a position wherein they engage with the inner surface of the monopile. After coupling the tool to the monopile end, the crane may be connected to the coupling tool for upending, thereby allowing coupling to the crane with less chance of damage to the monopile.

[0004] In a next step, the monopile is lowered towards the seabed, while being suspended from the crane, and it may penetrate the underwater bottom under its own weight. Afterwards, the monopile is further driven into the bottom by means of a hammering tool arranged at the upper end of the monopile. For example, a hydraulic impact hammer may be used, which is typically arranged at the top end of the upended monopile after decoupling the pile from the crane. Alternatively, a vibro-hammer may be used, which - unlike a traditional pile driver that uses large weights to strike piles into the earth - uses vibrations to drive the pile. The vibro-hammer may be arranged at the monopile end before upending, and subsequently be connected to the crane, for upending the monopile with the arranged vibro-hammer on top.

[0005] The elongated elements to be installed in these offshore applications are typically large and heavy objects. For example, monopiles can have a length of up to 100 m and more, a diameter of up to 12 m and more, and a weight which can rise up to 2000 tons and more. Installing such massive objects from the deck of a floating vessel goes along with challenges. First, due to waves and weather conditions, the vessel never is in static condition, thereby requiring sea-fastening of everything stored at the deck of the vessel. This does not only apply to the foundation piles, but also to any of the tools or equipment required for the installation operation, e.g. a hammer tool, coupling tool, etc. Moreover, displacing such tool towards the monopile before upending, and arranging it at the monopile end, is challenging due to the continuous movements of the floating vessel, thereby requiring specific measures and procedures to avoid damage to piles or equipment, and to ensure safety of personnel onboard. However, such specific measures and procedures typically are time-intensive, thereby increasing operational time for installing a monopile. This is even more the case due to the limited space available at the deck, wherein the arrangement of piles and tools at the deck may further increase complexity of displacing tools for use during an installation operation. Finally, tools like a hammer or coupling tool typically need to be supplied with hydraulic or electric energy during use, such that energy sources need to be available and supply lines need to be connected, thereby further increasing complexity of the arrangement at the deck and limiting operational efficiency.

[0006] It is an objective of the present invention to disclose a solution for use at a vessel for installing elongated elements such as monopiles, 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 that ensures safe and damage-free handling of elongated elements and tools at the vessel deck, while allowing for an efficient arrangement and an increased operational efficiency.Summary of the Invention

[0007] According to a first aspect of the present invention, the above identified objectives are realized by an arrangement suitable for use on a support surface of a floating body such as a vessel, defined by claim 1, the support surface extending in a horizontal plane and carrying an elongated element in lying condition, and the arrangement comprising: a tool, adapted for coupling to an end of the elongated element; a tool storage cradle, adapted for holding the tool while being sea-fastened; wherein the arrangement comprises a skidding system, wherein: the skidding system comprises a skidding unit displaceable over the support surface, the tool storage cradle being comprised in the skidding unit, thereby allowing to transport the tool over the support surface from a storage location towards the end of the elongated element, while being 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.

[0008] Thus, the invention concerns an arrangement suitable for use on 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. The support surface is adapted to carry an elongated element in lying condition. An elongated element refers to a slender object like a tubular element, pipe or pile. 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. In any case, the lying condition is such that the end of the elongated element can be reached from a horizontal direction, i.e. the elongated element is not in an upright position wherein its upper end would only be reachable from above.

[0009] In the following, the longitudinal direction refers to the direction wherein the elongated element extends when it is in lying condition, while the transverse direction is perpendicular to the longitudinal direction. This implies that the longitudinal direction, defined by the elongated element, 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 element is positioned 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.

[0010] For example, the elongated element is a monopile serving as a foundation structure of an offshore wind turbine. 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.

[0011] The support surface is adapted to carry an elongated element in lying condition, which typically implies that a support structure is provided at the support surface. Such support structure, e.g. comprising one or more fixed or displaceable support cradles, is installed at the deck and allows to support the elongated element while being in lying condition. Typically, apart from the invented arrangement, other types of equipment are installed at the support surface, such as a hoisting device, also referred to as a lifting means or crane, and an upending device adapted to receive the monopile end, and support the monopile during upending towards an upright position.

[0012] The invented arrangement comprises a tool, the tool being adapted for coupling to an end of the elongated element. This means that the tool can be arranged at the pile end, i.e. connected to the pile end, wherein the tool engages with a lateral and / or top wall at the end of the elongated element. For example, the tool engages with the outer and / or inner lateral surface of the tube-shaped wall at the pile end. The end of the elongated element is typically the upper end, i.e. the end of the pile directed upwards after upending. 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 this embodiment, the coupling tool comprises slidable clamping members, wherein the clamping members may be slit along beams of a cross-shaped structure, to a position wherein they engage with the inner surface of the hollow tube-shaped pile end. Moreover, the coupling tool comprises a lifting member provided with lifting eyes, for connection to a crane. 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.

[0013] 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 latter requires an energy supply towards the clamping members, and thus an actuation system on the coupling tool. For example a hydraulic actuation of the clamping members may be provided. E.g., the clamping members may be slidable by means of hydraulic piston cylinders. In another example, clamps are provided at a vibro-hammer tool, which may be actuated for connecting the vibro-hammer tool to the pile end. In other possible embodiments, the coupling system is not comprised in the tool itself, but is provided as separate means or a separate system.

[0014] Coupling of the tool to the elongated element occurs when the elongated element is in lying condition, i.e. before upending the elongated element. In an embodiment, the elongated element is positioned in the upending line when coupling the tool to the end of the elongated element, i.e. the elongated element is carried by some support structure arranged in the upending line. This implies that after coupling the tool and before the start of upending, the elongated element does not need to be displaced anymore in any transverse direction; a displacement in longitudinal direction of the elongated element after coupling the tool and before starting upending may be required though. In other embodiments, it is also possible that the elongated element is not positioned in the upending line yet when coupling the tool, such that the elongated element needs to be transported according to a transverse direction after coupling the tool and before start of upending.

[0015] The arrangement further comprises a tool storage cradle, adapted for holding the tool while being sea-fastened. This implies that the tool 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 tool will not be displaced with respect to the support surface, as long as it is held in the tool storage cradle and the tool storage cradle remains at a fixed position on 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 tool with respect to the support surface may still occur. In other words, while being sea-fastened in the tool storage cradle, the tool follows any movement that the vessel or platform undergoes due to interaction with waves and wind. It is to be noted that the tool storage cradle may be designed according to any possible shape, such that the term cradle refers to any type of holder or docking station for holding the tool, and is not limited to a specific shape of the holder.

[0016] The arrangement further comprises a skidding system, the skidding system comprising a skidding unit. The skidding unit is displaceable over the support surface. Displacing the unit 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. The term skidding unit thus is to be understood as a transport unit in the general sense. In an embodiment, the skidding unit can only be transported according to a predefined trajectory, e.g. defined by a track at the support surface. In other embodiments, however, it is also possible that the unit can freely move over the support surface, e.g. when the skidding unit is provided as a type of car. The tool storage cradle is comprised in the skidding unit, meaning that it makes part of the displaceable unit. For example, the skidding unit comprises a transport cart, and the storage cradle is arranged at the transport cart.

[0017] As such, the tool storage cradle is displaced together with the transport cart, 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. In particular, the tool can be held in the storage cradle at a storage location when the tool is not in use, e.g. during sailing towards an installation location, and may - during an installation operation - be displaced over the support surface towards the end of the lying elongated element, for coupling to the elongated element. During this displacement over the support surface, the tool is held in a storage position by the tool storage cradle, such that it remains sea-fastened. This implies that during storage of the tool as well as during displacement of the tool towards the end of the elongated element, the tool does not substantially move with respect to the skidding unit. In other words, during the displacement of the tool, the tool follows the movement of the skidding unit with respect to the support surface, and follows the movements of the support surface due to the vessel interacting with waves and wind.

[0018] The skidding unit is thus adapted to transport the tool over the support surface, while the tool is 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. The coupling position is the position that allows the tool to be coupled to the pile end, but wherein actual coupling to the pile does not necessarily has taken place yet. For example, in case of a coupling tool with slidable clamping members, the tool is in the coupling position when it has been inserted into the hollow pile end, but the clamping members do not engage yet with the inner surface of the pile; afterwards, by means of a hydraulic coupling system, the clamping members may be slit outwardly for engaging with the inner surface of the pile, thereby coupling the tool to the pile end.

[0019] 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. For example, an element making part of the tool may be shifted in horizontal or vertical direction, pivoted, rotated, lifted, tilted, etc, or any combination thereof. Moving the tool, or a portion thereof, may be done by means of the skidding unit, or by a mechanism on the tool itself, or by another equipment, or by a combination thereof. Moving the tool by means of the skidding unit may e.g. be done by displacing the skidding unit forwards, or shifting the tool upwards by means of an adaptable frame on the skidding unit, or shifting the tool forward by extendable arms mounted on the skidding unit, etc. Moving a portion of the tool by a mechanism on the tool itself may e.g. be the case if a part of the tool is pivoted via an activation mechanism on the tool. Moving the tool by another equipment is e.g. the case when the tool is lifted from the storage cradle by the crane.

[0020] 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.

[0021] The invented arrangement thus 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, during storage, and during every step between storage at the deck and the tool being coupled to the elongated element. This results in a safe operation wherein any risks of damage to the elongated element or equipment are mitigated.

[0022] Moreover, the invented arrangement 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. Indeed, instead of having a sea-fastening storage cradle at a fixed position on the deck, the invented skidding unit allows to transport the storage cradle over the deck. The skidding unit thus transports the tool over the deck in a controlled way, and brings it subsequently into its coupling position. This contributes to an operation that is less time intensive than when an additional step would be required, wherein first the tool needs to be removed from the sea-fastening, and subsequently is placed on a dedicated equipment for coupling to the elongated element.

[0023] Finally, as both the sea-fastening storage function and the guidance function for coupling are integrated in a single unit, the invention allows for a compact arrangement at the deck. This results in a space-saving solution, and further contributes to an increased operational efficiency.

[0024] 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: is shifted in horizontal direction, and / or is shifted in vertical direction, and / or is pivoted, and / or is rotated.

[0025] Shifting in horizontal direction may comprise shifting according to the longitudinal direction and / or according to the transverse direction, thereby changing the longitudinal and / or transverse position with respect to the support surface. Shifting in vertical direction refers to lifting the tool or a portion thereof, implying that the height position with respect to the elongated element is adapted. Pivoting may comprise pivoting about a horizontal axis, e.g. in transverse direction, and / or pivoting about a vertical axis, thereby changing the inclination or orientation of the tool or tool portion with respect to the pile end. Rotating may comprise rotating about a horizontal axis, e.g. in longitudinal direction, thereby changing the angular position or orientation of the tool or tool portion with respect to the pile end.

[0026] 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. Thus, for bringing the tool into the coupling position, the tool is moved as a whole, and / or one or more elements of the tool are moved. Each of these movements contributes to bringing the tool into a position wherein it can be coupled to the pile end. For example, shifting in vertical direction is done for obtaining a height position allowing for coupling with the end of the elongated element, and pivoting or rotating is done for obtaining an orientation allowing for coupling with the end of the elongated element.

[0027] Optionally, the coupling system is comprised in the tool, the coupling system being adapted to engage with the end of the elongated element by operating the coupling system after the tool is brought into the coupling position. For example, the coupling system of the tool comprises one or more elements that may be moved from an uncoupled state to a coupled state, wherein the elements engage with the pile end in the coupled state, and an actuator for moving these elements following an energy supply. The elements may e.g. be provided as clamping members, and the actuator may e.g. be a hydraulic or electric actuator. In an embodiment, the coupling system comprises slidable or movable clamping members, which may be brought in a clamping position by means of an actuator. For example, the clamping members may be slidable or movable by means of hydraulic piston cylinders.

[0028] 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.

[0029] 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.

[0030] Providing the tool with energy, signals or a fluid flow, may be required before upending, e.g. for coupling the tool to the pile end, and / or after upending, e.g. for operating the arranged tool during driving the elongated element into the seabed. For example, a coupling tool may require hydraulic energy under the form of a pressurized fluid for operating the coupling system, e.g. to bring clamping members into a clamping position. In another embodiment, the tool may be a vibro-hammer, wherein energy needs to be supplied to the hammer in view of creating the pile driving vibrations. Energy may supplied to the tool under various forms, e.g. hydraulic energy may be supplied via a pressurized fluid, electric power may be supplied, etc. In others embodiments signals may be supplied to the tool, e.g. control signals or measurement signals. In yet another embodiment, a supply of fresh water may be provided to the tool. In view of supplying energy, signals or a fluid flow to the tool, one or more supply lines are provided on the skidding unit, e.g. provided as cables or hoses.

[0031] In this way, besides the sea-fastening storage function and guiding function for coupling provided on the invented skidding unit, 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.

[0032] Finally, it is to be noted that there is no structural or functional relation between - on the one hand - the energy supply function provided on the skidding unit, and - on the other hand - other features of the arrangement included in claim 1. In particular, the presence of the auxiliary equipment on the skidding unit, e.g. by energy pack(s) and supply lines on the skidding unit, is not linked or related to obtaining sea-fastening by means of the tool storage cradle. Thus, this auxiliary equipment on the skidding unit may as well be used in an arrangement wherein the sea-fastening storge cradle is not provided on the skidding unit, thereby still allowing for the space- and time savings related to having the auxiliary equipment on the skidding unit. The feature of providing auxiliary equipment on the skidding unit adapted for supplying the tool with energy and / or signals and / or a fluid flow, is therefor a further independent aspect of the invention, the feature not being only disclosed in combination with the other features of claim 1.

[0033] Optionally, the skidding unit comprises one or more reels, adapted for winding the one or more supply lines.

[0034] Optionally, the auxiliary equipment comprises one or more power packs adapted for generating or converting energy. In an embodiment, the power pack may be a Hydraulic Power Unit, abbreviated HPU, for producing a pressurized fluid, For example, the HPU may receive electric energy from the vessel, or may have its own diesel generator comprised in the skidding unit. In another embodiment, the power pack is a diesel generator for producing electric power. The one or more supply lines available on the skidding unit, allow to connect the power pack to the tool.

[0035] Optionally, the skidding unit comprises a hydraulic power unit, abbreviated HPU, adapted for producing a pressurized fluid, and a hose connecting the HPU to the tool. The HPU e.g. comprises an electromotor, a hydraulic pump and an oil tank. Additionally, the HPU may comprise a diesel generator for producing electric power, in view of powering the electromotor. In another embodiment, the HPU may be adapted to receive hydraulic power from the vessel, instead of producing a pressurized fluid itself.

[0036] Optionally, the skidding unit is adapted to receive electric power and / or data via a connection with a supply available at the floating body. For example, power packs and hose reels may receive power and data via an umbilical reel or via discrete connection points along skidding rails.

[0037] Optionally, the skidding system is adapted for displacing the skidding unit along a predefined track at the support surface of the floating body.

[0038] Optionally, the arrangement comprises a support structure adapted to carry the elongated element while coupling the tool, wherein the carried elongated element extends in longitudinal direction. This means that a support structure is provided at the support surface, allowing to support the elongated element while being in lying condition during coupling of the tool. For example, the support structure comprises one or more fixed or displaceable support cradles. When carried by the support structure, the central axis of the elongated element defines the longitudinal direction. In other words, the length of the elongated element corresponds to the longitudinal direction.

[0039] Optionally, the support structure comprises at least one pile transport cart, equipped with a support cradle and displaceable over the support surface along the longitudinal direction. This means that during coupling, the elongated element is supported by a support cradle that is displaceable over the deck, in longitudinal direction. This allows the elongated element to be displaced in longitudinal direction, e.g. for shifting it into a upending device, e.g. after coupling the tool to the end of the elongated element.

[0040] Optionally, the skidding system is adapted for displacing the skidding unit along a predefined path in longitudinal direction, for transporting the tool from the storage location towards the end of the elongated element. This implies that the skidding unit is only displaced according to one direction, namely the longitudinal direction, wherein it follows a straight predefined path. Skidding may be such that for positioning the tool centrally in front of the pile end, not any movements in transverse direction are needed. Transporting the skidding unit towards the end of the elongated element, therefore only requires shifting the unit forwards, thereby allowing for a simple arrangement at the deck and quickly moving the skidding unit from the storage location to the coupling location at the deck.

[0041] Optionally, the arrangement comprises an upending device, adapted for upending the lying elongated element towards an upright position. 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.

[0042] Optionally, the skidding system is adapted for displacing the skidding unit over the support surface along the upending line. The upending line is defined by the central axis of the elongated element when being received by the upending device before upending. The upending line thus 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. This implies that the skidding unit is displaced according to a straight predefined path, the latter corresponding to the upending line. In this way, the elongated element may already be positioned in the upending line when coupling the tool, thereby allowing for rapidly starting the upending sequence after coupling the tool to the pile end.

[0043] Optionally, the support structure comprises at least one pile transport cart, equipped with a support cradle and displaceable over the support surface along the longitudinal direction, wherein the pile transport cart is adapted for shifting the elongated element in the upending device, by displacing the transport cart along the upending line while supporting the elongated element. This means that the pile transport cart has a double function, namely supporting the elongated element during coupling of the tool, and displacing the elongated element for shifting it into the upending device.

[0044] Optionally, the skidding system is adapted for further displacing the skidding unit along the upending line, during upending of the elongated element by the upending device. This means that during bringing the elongated element from the lying condition into the upright condition, the skidding unit further moves forward along the upending line. In this way, the skidding unit always remains close to the tool, the latter being arranged on the top end of the pile during upending. This contributes to making hose and cable handling more convenient, wherein hoses and / or cables are connected to the tool for supplying it with energy and / or signals and / or a fluid flow.

[0045] Optionally, the skidding system comprises: the skidding unit, comprising a transport cart, and a track comprising one or more rails, the transport cart being adapted to slide over the one or more rails, and the tool storage cradle being mounted to the transport cart.

[0046] Optionally, the skidding system comprises a rack and pinion drive system, adapted for driving the skidding unit while moving along a trajectory defined by a rack provided at the support surface. The system thus comprises a rack for installation at the deck, and a pinion arranged at the skidding unit, the rack defining the trajectory followed by the skidding unit.

[0047] 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. The adjustable position of the frame may refer to adjusting the height position with respect to the support surface, the longitudinal position on the support surface, the transverse position on the support surface, the angular position, the inclination with respect to the support surface, etc.

[0048] 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. In this way, e.g. the tool can be transported over the support surface while being at a low height position, and subsequently be lifted to allow for coupling with the elongated element.

[0049] 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. The guiding elements are typically movable or adjustable components, that can be moved according to a specific trajectory. As they engage with the tool, they restrict the possible movements of the tool, by imposing or defining a travelling path to be followed by the tool or a portion of the tool. For example, the guiding elements are provided as guiding arms.

[0050] 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.

[0051] 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. For example, during coupling of the tool with the pile end, the tool may be lifted by a crane. During this movement, the pivotable guiding arms may move along with the lifted tool, thereby restricting swinging movements of the tool in longitudinal and / or transverse direction.

[0052] Optionally, one or more parts of the tool are pivotable about a horizontal axis, thereby allowing to obtain, by operating the tool, an orientation suitable for coupling to the end of the elongated element and / or suitable for storing the tool in the tool storage cradle. In an embodiment, the tool is a vibro-hammer, which is stored with the face down in the storage cradle. Before coupling, the hammer, or a portion thereof, is pivoted over 90 degrees to allow for connecting the face of the hammer to the end of the elongated element. In another embodiment, the tool is a coupling tool, comprising a lifting member that is pivotable with respect to the rest of the tool. During storage of the tool and coupling to the elongated element, the lifting member is in a first state. Afterwards, during upending of the elongated element, the lifting member is pivoted over 90 degrees with respect to the rest of the coupling tool. Before placing the coupling tool back into the storage cradle again, the lifting member may again be pivoted over 90 degrees, for bringing it back in the first state.

[0053] Optionally, the tool is a coupling tool, adapted for connecting the end of the elongated element to a hoisting device via the mounted coupling tool. This means that the tool, on the one hand, is adapted to be arranged at the end of the elongated element. For example, the tool may comprise clamping members, that may engage with the inner and / or outer surface of the pile end for coupling with the elongated element. On the other hand, the tool is adapted to be connected to a crane. For example, the tool may comprises a lifting member, e.g. having lifting eyes for connecting to a crane.

[0054] Optionally, the tool is a hammer tool, such as a vibro-hammer, adapted for hammering the elongated element via the mounted hammer tool.

[0055] 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.

[0056] Optionally, the storage location, for storing the skidding unit when not using the tool, is in the bridge structure of the vessel.

[0057] Storage of the skidding unit in the vessel bridge structure ensures that - in an embodiment wherein the elongated elements are stored in longitudinal direction - transverse displacements of the elongated elements, are not obstructed by the skidding unit present on the deck. Transverse displacements may e.g. be done for transporting a pile from a storage line to the upending line. Moreover, avoiding such obstruction is obtained without adding additional space in longitudinal direction of the vessel, thereby contributing to a reduced vessel length. In an alternative embodiment, the storage location may be aft of the bridge structure, such that the skidding unit is stored close to the bridge, but not in the bridge structure.

[0058] According to a third aspect of the present invention, there is provided a method for using a tool at a support surface of a floating body such as a vessel, the method comprising: providing the floating body comprising the support surface, wherein the support surface carries at least one elongated element in lying condition; providing an arrangement according to the first aspect of the invention; storing the skidding unit at a storage location on the support surface, wherein the tool is held by the tool storage cradle, thereby being sea-fastened; transporting the tool from the storage location towards the end of the elongated element, by displacing the skidding unit over the support surface, while the tool is held in a storage position in the tool storage cradle; bringing the tool from the storage position into a coupling position, while being guided by the skidding unit, thereby constraining movements of the tool while bringing it into the coupling position.

[0059] Optionally, the method comprises: after being brought in the coupling position, coupling the tool to the end of the elongated element by operating the coupling mechanism.

[0060] Optionally, the method comprises: after or before coupling the tool to the elongated element, releasing the tool from the tool storage cradle. Thus, coupling of the tool may happen while the tool is still held in the tool storage cradle, or after releasing the tool from the tool storage cradle.Brief Description of the Drawings

[0061] Fig. 1 shows an arrangement according to a first embodiment of the invention. Fig. 2 shows a vessel provided with the arrangement of Fig. 1. Fig. 3 shows the vessel of Fig. 2, wherein monopiles are stored on the vessel deck. Fig. 4 shows a skidding unit, as comprised in the arrangement of Fig. 1. Fig. 5 and Fig. 6 illustrate the use of the arrangement of Fig. 1, for coupling a coupling tool to a monopile lying on the vessel deck. Fig. 7 shows the vessel of Fig. 2, in a condition after coupling the coupling tool and after upending the monopile. Fig. 8 shows a vessel provided with an arrangement according to a second embodiment of the invention. Fig. 9 shows the vessel of Fig. 8, wherein monopiles are stored on the vessel deck. Fig. 10 shows a skidding unit, as comprised in the arrangement of Fig. 8. Fig. 11 to Fig. 13 illustrate the use of the arrangement of Fig. 8, for coupling a vibro-hammer to a monopile lying on the vessel deck. Detailed Description of Embodiment(s)

[0062] Fig. 1 to Fig. 7 illustrate a first possible embodiment of the invention. Fig. 1 shows an arrangement 100 according to the first embodiment. The arrangement 100 is suitable for use on a support surface of a floating body such as a vessel 200, as is illustrated in Fig. 2. In the embodiment of Fig. 2, the vessel 200 is a vessel for installing monopiles, and the support surface 201 makes part of the deck of the vessel 200. Besides the arrangement 100, the vessel 200 has other equipment on board, such as an upending device 203, a hoisting device or crane 202, and a hydraulic impact hammer 204. Fig. 3 shows the vessel 200 wherein four monopiles 301 are stored on the deck of the vessel, and one monopile 300 is positioned in the upending device 203. 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. 3. The upending device 203 is adapted to guide and support the monopile 300 while being pivoted from the lying condition of Fig. 3 towards an upright condition as illustrated in Fig. 7. The length direction of the monopile 300, when it is in the lying condition like in Fig. 3, is defined as the longitudinal direction X. In the shown embodiment, the X-direction corresponds to the longitudinal direction of the vessel 200. The transverse direction is indicated as Y, and the height direction as Z.

[0063] The arrangement 100 comprises a tool 103. In the embodiment of Fig. 1, the tool 103 is a coupling tool 103, adapted to be coupled to an end of the monopile 300 while it is in lying condition on the support surface 201, before upending of the monopile 300. The coupling tool 103 comprises a cross-shaped structure 403, and clamping members 404, wherein the latter engage with the outer lateral surface of the monopile 300 when the coupling tool 103 is coupled to the end of the monopile 300. The coupling tool 103 further comprises a lifting member 406, which is connected to the crane 202 before upending. The cross-shaped structure 403 may pivot with respect to the lifting member 406, around pin 405. In this way, the orientation of the cross-shaped structure and clamping members 404 may change with respect to the lifting member 406, during upending of the monopile by the crane, as is illustrated in Fig. 7. The coupling tool 103 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.

[0064] The arrangement 100 further comprises a skidding system. The skidding system comprises a skidding unit 101, which is shown in more detail in Fig. 4. The skidding unit 101 comprises a transport cart 104 and is displaceable over the support surface 201. For this purpose, the skidding system comprises a track 105, comprising two rails 410, 411, wherein the transport cart 104 may slide over the rails 410, 411. The track 105 defines a predefined path for displacement of the skidding unit 101. In the shown embodiment, this predefined path runs in longitudinal direction, along the upending line 205, thereby allowing to displace the skidding unit 101 according to a straight path, towards the monopile 300 when the latter is positioned in the upending device 203. In the shown embodiment, the skidding unit 101 is driven by means of a rack and pinion drive system, wherein a toothed rack 409 is installed at the support surface 201, and two pinions 413 are arranged at the transport cart 104.

[0065] The skidding unit 101 comprises a tool storage cradle 102, which allows for holding the coupling tool 103 in a sea-fastened way. In particular, the tool storage cradle 102 comprises a frame 401, at the back of the tool 103, and a bar or edge 412, at the front of the tool 103. When the coupling tool 103 is positioned in the tool storage cradle 102, the pin 405 at the back of the coupling tool is placed in a recess 402 of the frame 401, and the front of the cross-shaped structure 403 engages with the edge 412. In this way, the frame 401 allows to hold the coupling tool 103 in a sea-fastened position without requiring additional fasteners. Furthermore, the frame 401 is height-adjustable, as the frame 401 may be slid upwards and downwards with respect to the rest of the tool storage cradle 102, see Fig. 6. In this way, the height position of the coupling tool 103 with respect to the support surface 201 may be changed while being held by the frame 401.

[0066] The tool storage cradle 102 is mounted to the transport cart 104, thereby allowing to transport the coupling tool 103 over the deck while being held by the tool storage cradle 102. Furthermore, auxiliary equipment such as a power pack 408 and a cable reel 407 are mounted to the transport cart 104. The auxiliary equipment is adapted for supplying the coupling tool 103 with energy and / or signals, e.g. when coupling the tool 103 to the monopile end and during upending. In this way, the auxiliary equipment can be transported over the deck together with the coupling tool 103. In particular, the cable reel 407 and power pack 408 allow to provide electrical, hydraulic, or signals to and from the coupling tool 103. Typically, each tool on the deck has its own dedicated power packs, HPU's and hose reels as applicable to the tool function. For the skidding unit 101, one embodiment is that the cable reel 407 is connected to a fixed point on deck and transfers electrical power and signals to and from the vessel and the skidding unit. As the skidding unit 101 moves, the cable reel 407 pays in or out to eliminate loose cable on deck. From the connection point of the cable reel 407 on the skidding unit 101, the power may be passed to the power pack 408, or to a hydraulic power unit.

[0067] The arrangement 100 comprises a support structure, adapted to carry the monopile 300 during coupling of the coupling tool 103, and supporting the monopile at two length positions when it is in lying condition. For this purpose, the support structure comprises two spaced-apart portions 106 and 107, each of them comprising a support cradle 112, 113. In the shown embodiment, both support cradles 112 and 113 are mounted to a transport cart or skid 110, 111, such that support structure portions 106 and 107 are displaceable in longitudinal direction. Longitudinal displacement of the skids 110, 111 may e.g. be applied during the loading process of monopiles, or when inserting a monopile into the upending device 203. With respect to the invented skidding unit 101, with tool storage cradle for holding coupling tool 103, however, movability of the support structure 106, 107 is not essential; during coupling of the tool 103 to the monopile end, the monopile 300 may as well be supported by a static support structure. Finally, Fig. 1 shows that the arrangement 100 comprises skids 108, 109, which are displaceable in transverse direction. Such transverse skids may e.g. be used during the loading process of monopiles, or for bringing a monopile from a storage line towards the upending line. In the context of the to the invented skidding unit 101, with tool storage cradle for holding coupling tool 103, however, the availability of such transverse skids is not required.

[0068] A possible use of the arrangement 100 is further illustrated by Fig. 5 to 7. An initial state is shown in Fig. 3, when the coupling tool 103 is not in use. The monopile 300 is in lying condition, and is placed with one end in the upending device 203. In this state, the monopile 300 is supported by support structure portions 106 and 107. Compared to Fig. 2, pile transport cart 106 has been moved in longitudinal direction, towards upending device 203; for inserting monopile 300 into the upending device, pile transport cart 106 was moved forwards while pile transport cart 107 remained in static condition. The skidding unit 101 is located at a storage location on the deck, wherein the storage location is aft of the bridge structure of the vessel 200. The coupling tool 103 is held by the tool storage cradle 102. In particular, it is held by the frame 401, thereby being sea-fastened. In the state of Fig. 3, the tool 103 is held in its storage position, wherein the frame 401 is at low height, close to the deck.

[0069] Next, the skidding unit 101 is displaced over the deck, in longitudinal direction, towards the end of the lying monopile 300, see Fig. 5. The skidding unit 101 is transported along the upending line 205, for reaching the monopile 300 which is positioned in the upending device 203. During transport of the skidding unit 101, the coupling tool 103 is held by the tool storage cradle 102, wherein the coupling tool 103 still is in the storage position, i.e. the frame 401 is at low height.

[0070] Fig. 6 shows that, once the skidding unit 101 has approached the monopile end, the frame 401 is shifted towards a higher position, thereby increasing the height position of the coupling tool 103. In particular, the coupling tool 103 is brought to a height position corresponding to the height position of the monopile's end. Next, the skidding unit 101 may further be moved forward, for reaching the monopile's end and bringing the coupling tool 103 in the coupling position. The coupling position is the position that allows the tool 103 to be coupled to the pile end, but wherein actual coupling to the pile has not necessarily taken place yet. For example, the tool 103 is in the coupling position when the clamping members 404 have been placed around the outer lateral surface of the monopile 300, but actual coupling, e.g. by means of a hydraulic coupling system, has not taken place yet.

[0071] One the coupling tool 103 has been coupled to the end of the monopile 300, the lifting member 406 of the tool 103 is connected to the crane 202, and upending of the monopile 300 may start. Fig. 7 illustrates the state obtained after upending, i.e. after bringing the monopile 300 in upright position. During upending of the monopile 300, the skidding unit 101 may further move forward, along the upending line, such that the skidding unit 101 remains close to the tool 103, and handling of supply lines towards the tool 103 becomes more convenient.

[0072] Afterwards, the monopile will be lowered into the water, for insertion into the seabed. After some insertion depth has been reached, the coupling tool 103 is decoupled from the monopile 300. Accordingly, the decoupled coupling tool 103 may be brought back to the skidding unit 101 by the crane, and placed in the tool storage cradle 102, in its storage position. The skidding unit may be transported back to the storage location in the bridge, before or after receiving the tool 103.

[0073] The above makes clear that during the whole process of storing, transporting and coupling the tool, all movements of the coupling tool are constrained by the skidding unit 101, thereby avoiding any uncontrolled movements of the tool. This results in a safe coupling operation wherein any risks of damage to the monopile or equipment are mitigated. Furthermore, the skidding unit 101 results in a very compact unit, wherein a sea-fastening storage cradle, guiding elements and auxiliary equipment are combined, thereby allowing for a space-saving solution, and further contributing to an increased operational efficiency.

[0074] Fig. 8 to Fig. 13 illustrate a second possible embodiment of the invention. Fig. 8 shows an arrangement according to the second embodiment, wherein the arrangement is used on a support surface 802 of a vessel 800. The arrangement according to the second embodiment comprises a skidding unit 801 and tool 803 different from the first embodiment of Fig. 1 to 7, but other components of the arrangement like the track 105 and the support structure 106, 107 are the same as in the first embodiment. Also the design of the vessel, and equipment such as the hoisting device 202 and upending device 203 are similar as in the first embodiment. Fig. 9 shows the vessel 800 wherein four monopiles 301 are stored on the deck of the vessel, and one monopile 300 is positioned in the upending device 203, similar to the first embodiment.

[0075] In the second embodiment, the tool 803 is a vibro-hammer, which allows to drive a monopile into the seabed by means of vibrations. The vibro-hammer 803 is arranged at the monopile's end before upending, when the monopile is in lying condition like in Fig. 9. Subsequently, the crane 202 is connected to the vibro-hammer 803, for upending the monopile 300 with the arranged vibro-hammer 803 on top.

[0076] The vibro-hammer 803 and skidding unit 801 are shown in more detail in Fig. 10. The vibro-hammer comprises a main portion 1009, which comprises the actual hammering or vibrating elements, and two lifting members 1006. The main portion further comprises a series of circumferentially positioned clamps 1005, for coupling with the monopile's end. The circumferentially positioned clamps 1005 may either engage with the inner and outer lateral surface of the monopile, for monopiles without a flange, or may engage with the inner and outer longitudinal surface of the flange, for monopiles with a flange. The lifting members 1006 are pivotable with respect to the main portion 1009 of the vibro-hammer 803, around pin 1003, and may be connected to hoisting cables 1100. In this way, the orientation of the main portion 1009 may change with respect to the lifting members 1006, during coupling of the vibro-hammer 803 and upending of the monopile by the crane.

[0077] The skidding unit 801 comprises a tool storage cradle 1000, which allows for holding the hammer tool 803 in a sea-fastened way. In particular, the tool storage cradle 1000 comprises an open box or base 1007 having raised edges, wherein the hammer 803 may be placed in horizontal position, i.e. with the clamps 1005 directed downwards, towards the bottom of the base. When the hammer 803 is positioned in the base 1007, its outer circumference engages with the raided edges of the base 1007, allowing to sea-fasten the hammer 803 without requiring additional fastening means. The skidding unit 801 further comprises guiding elements, provided as pivotable guiding arms 1001 and 1200. A plate 1002 is connected to the end of guiding arm 1001, the plate 1002 having a recess 1008. When the hammer 803 is in the storage position, the pin 1003 of the hammer 803 is placed in the recess 1008.

[0078] The tool storage cradle 1000 is mounted to a transport cart, which may slide over rails 410 and 411. In this way, the vibro-hammer 803 can be transported over the deck while being held by the tool storage cradle 1000. Furthermore, auxiliary equipment is mounted to the same transport cart. The auxiliary equipment is adapted for supplying the vibro-hammer with energy and / or signals, e.g. when coupling the hammer 803 to the monopile end and during hammering. In the shown embodiment, the auxiliary equipment comprises hydraulic power packs 1004, hydraulic and signal hose reels 1010, and a cable reel inside a weathertight container 1011. In this way, the auxiliary equipment can be transported over the deck together with vibro-hammer 803.

[0079] A possible use of the arrangement according to the second embodiment is further illustrated by Fig. 11 to 13. An initial state is shown in Fig. 9, when the vibro-hammer 803 is not in use. The monopile 300 is in lying condition, and is placed with one end in the upending device 203. The skidding unit 801 is located at a storage location on the deck, wherein the storage location is aft of the bridge structure of the vessel 800. The vibro-hammer 803 is held by the tool storage cradle 1000, the vibro-hammer 803 being in its storage position with the clamps 1005 directed downwards. In particular, the vibro-hammer 803 is positioned in the open base 1007, thereby being sea-fastened.

[0080] Next, the skidding unit 801 is displaced over the deck, in longitudinal direction, towards the end of the lying monopile 300, see Fig. 11. The skidding unit 801 is transported along the upending line 205, for reaching the monopile 300 which is positioned in the upending device 203. During transport of the skidding unit 801, the vibro-hammer 803 is held by the tool storage cradle 1000, wherein the vibro-hammer 803 still is in the storage position, i.e. with the main portion 1009 oriented horizontally and the clamps 1005 directed downwards.

[0081] Fig. 11 shows that, once the skidding unit 801 has approached the monopile end, hoisting cables 1100 are connected to the lifting members 1006 of the vibro-hammer 803. Subsequently, as shown in Fig. 12, the vibro-hammer 803 is lifted from the base 1007 by means of the crane 202. While being lifted, the main portion 1009 of the vibro-hammer 803 is pivoted over 90 degrees with respect to the lifting members 1006, such that the orientation of the main portion 1009 is changed from horizontal, with the clamps 1005 downward, to vertical, with the clamps 1005 directed towards the monopile end. Fig. 11 and 12 further show that during lifting and pivoting of the vibro-hammer 803, the guiding arms 1001, 1200 are pivoted, while still engaging with the pin 1003 of the vibro-hammer 803. In this way, movements of the vibro-hammer 803 in longitudinal and transverse direction are restricted, thereby avoiding uncontrolled swings of the vibro-hammer 803 while being lifted.

[0082] Next, as shown in Fig. 13, the skidding unit 801 is further moved forward, for reaching the monopile's end and bringing the vibro-hammer 803 in the coupling position. The coupling position is the position that allows the hammer 803 to be coupled to the pile end, but wherein actual coupling to the pile has not necessarily taken place yet. For example, the hammer 803 is in the coupling position when the clamping members 404 have been placed inside the open end of the monopile 300, but actual coupling, e.g. by means of a hydraulic coupling system, has not taken place yet.

[0083] Once the vibro-hammer 803 has been coupled to the end of the monopile 300, upending of the monopile 300 by means of the crane 202 may start. During upending of the monopile 300, the skidding unit 801 may further move forward, along the upending line, such that the skidding unit 801 remains close to the vibro-hammer 803, and handling of supply lines towards the tool 803 becomes more convenient.

[0084] 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.

Examples

first embodiment

[0062]Fig. 1 to Fig. 7 illustrate a first possible embodiment of the invention. Fig. 1 shows an arrangement 100 according to the The arrangement 100 is suitable for use on a support surface of a floating body such as a vessel 200, as is illustrated in Fig. 2. In the embodiment of Fig. 2, the vessel 200 is a vessel for installing monopiles, and the support surface 201 makes part of the deck of the vessel 200. Besides the arrangement 100, the vessel 200 has other equipment on board, such as an upending device 203, a hoisting device or crane 202, and a hydraulic impact hammer 204. Fig. 3 shows the vessel 200 wherein four monopiles 301 are stored on the deck of the vessel, and one monopile 300 is positioned in the upending device 203. 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. 3. The upending device 203 is adapted to guide and suppo...

second embodiment

[0075]In the second embodiment, the tool 803 is a vibro-hammer, which allows to drive a monopile into the seabed by means of vibrations. The vibro-hammer 803 is arranged at the monopile's end before upending, when the monopile is in lying condition like in Fig. 9. Subsequently, the crane 202 is connected to the vibro-hammer 803, for upending the monopile 300 with the arranged vibro-hammer 803 on top.

[0076]The vibro-hammer 803 and skidding unit 801 are shown in more detail in Fig. 10. The vibro-hammer comprises a main portion 1009, which comprises the actual hammering or vibrating elements, and two lifting members 1006. The main portion further comprises a series of circumferentially positioned clamps 1005, for coupling with the monopile's end. The circumferentially positioned clamps 1005 may either engage with the inner and outer lateral surface of the monopile, for monopiles without a flange, or may engage with the inner and outer longitudinal surface of the flange, for monopiles w...

Claims

1. An arrangement (100) suitable for use on a support surface (201) of a floating body such as a vessel (200), the support surface (201) extending in a horizontal plane and carrying an elongated element (300) in lying condition, the arrangement (100) comprising: - a tool (103), adapted for coupling to an end of the elongated element (300); - a tool storage cradle (102), adapted for holding the tool (103) while being sea-fastened; wherein the arrangement (100) comprises a skidding system, wherein: - the skidding system comprises a skidding unit (101) displaceable over the support surface (201), the tool storage cradle (102) being comprised in the skidding unit (101), thereby allowing to transport the tool (103) over the support surface (201) from a storage location towards the end of the elongated element (300), while being held in a storage position by the tool storage cradle (102); - the skidding unit (101) is adapted to guide the tool (103) while being brought from the storage position in the tool storage cradle (102), to a coupling position wherein the tool (103) can be coupled to the end of the elongated element (300) by means of a coupling system, thereby constraining movements of the tool (103) while bringing it into the coupling position.

2. An arrangement (100) according to claim 1, wherein bringing the tool (103) from the storage position into the coupling position comprises moving the tool (103) and / or one or more portions thereof, wherein said moving comprises: - shifting in horizontal direction, for approaching the end of the elongated element (300), and / or - shifting in vertical direction, for changing the height position with respect to the elongated element (300), and / or - pivoting and / or rotating, for changing the orientation with respect to the elongated element (300).

3. An arrangement (100) according to any of the preceding claims, wherein the tool storage cradle (102) is adapted for holding the tool (103) in position due to the tool (103) engaging with one or more edges (412) and / or recesses (402) of the tool storage cradle (102), thereby allowing for sea-fastening of the tool (103) without additional fastening means.

4. An arrangement (100) according to any of the preceding claims, wherein the skidding unit (101) comprises auxiliary equipment (408, 407) 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.

5. An arrangement (100) according to claim 4, wherein the auxiliary equipment comprises one or more power packs (408) adapted for generating or converting energy.

6. An arrangement (100) according to any of the preceding claims, wherein the skidding system is adapted for displacing the skidding unit (101) along a predefined track at the support surface (201) of the floating body.

7. An arrangement (100) according to any of the preceding claims, wherein - the arrangement (100) comprises a support structure (106, 107) adapted to carry the elongated element (300) while coupling the tool (103), wherein the carried elongated element (103) extends in longitudinal direction, and - the skidding system is adapted for displacing the skidding unit (101) along a predefined path in longitudinal direction, for transporting the tool (103) from the storage location towards the end of the elongated element (300).

8. An arrangement (100) according to any of the preceding claims, wherein the arrangement (100) comprises an upending device (203), adapted for upending the lying elongated element (300) towards an upright position, wherein an upending line (205) is defined by the central axis of the elongated element (300) when being received by the upending device (203) before upending, and wherein the skidding system is adapted for displacing the skidding unit (101) over the support surface (201) along the upending line.

9. An arrangement (100) according to claim 8, wherein the skidding system is adapted for further displacing the skidding unit (101) along the upending line (205), during upending of the elongated element (300) by the upending device (203).

10. An arrangement (100) according to any of the preceding claims, wherein the skidding system comprises: ∘ the skidding unit (101), comprising a transport cart (104), and ∘ a track (105) comprising one or more rails (410, 411), the transport cart (104) being adapted to slide over the one or more rails (410, 411), and the tool storage cradle (102) being mounted to the transport cart (104).

11. An arrangement (100) according any of the preceding claims, wherein the skidding unit (101) comprises a frame (401) of which the position is adjustable, thereby allowing to change the position of the tool (103) with respect to the support surface (201) while being held in the frame (401).

12. An arrangement according to any of the preceding claims, wherein the skidding unit (801) comprises one or more guiding elements (1001, 1200), adapted to engage with the tool (803) while being moved, thereby restricting uncontrolled movements of the tool (803) while bringing the tool (803) into the coupling position.

13. An arrangement according to any of the preceding claims, wherein the tool is a coupling tool (103), adapted for connecting the end of the elongated element (300) to a hoisting device (202) via the mounted coupling tool (103), or wherein the tool is a hammer tool (803), such as a vibro-hammer, adapted for hammering the elongated element (300) via the mounted hammer tool (803).

14. A vessel (200) for installing an elongated element (300), the vessel comprising an arrangement (100) according to any of the preceding claims, wherein the support surface (201) is comprised in the deck of the vessel (200), and wherein the storage location, for storing the skidding unit (101) when not using the tool (103), is in the bridge structure of the vessel (200).

15. Method for using a tool (103) at a support surface (201) of a floating body such as a vessel (200), the method comprising: - providing the floating body (200) comprising the support surface (201), wherein the support surface (201) carries at least one elongated element (300) in lying condition; - providing an arrangement (100) according to any of the claims 1 to 14; - storing the skidding unit (101) at a storage location on the support surface (201), wherein the tool (103) is held by the tool storage cradle (102), thereby being sea-fastened; - transporting the tool (103) from the storage location towards the end of the elongated element (300), by displacing the skidding unit (101) over the support surface (201), while the tool (103) is held in a storage position in the tool storage cradle (102); - bringing the tool (103) from the storage position into a coupling position, while being guided by the skidding unit (101).

Images