Vessels and pile holding systems for pile installation

Abstract

A vessel for pile installation, wherein the stern of the vessel comprises a recess flanked laterally by two lateral hull portions. A pile holding system comprises a pile holding tool to hold the pile in an upright orientation and an X-Y motion support assembly for the pile holding tool. The X-Y motion support assembly comprises a load bearing body supporting the pile holding tool above the recess and an X-Y motion mechanism operative between the hull and the load bearing body. Each of the lateral hull portions is provided with a respective lateral mount and the X-Y motion support assembly is supported on the lateral mounts.

Description

[0001] P36872PC00

[0002] VESSELS AND PILE HOLDING SYSTEMS FOR PILE INSTALLATION

[0003] The present invention relates to the field of vessels for installation of a pile, in particular a monopile as a foundation for an offshore wind turbine in the installation thereof. The invention furthermore relates to the field of pile holding systems for holding a pile, e.g. a monopile, during installation and possibly also for upending such pile prior to lowering of the pile to the seabed.

[0004] Generally, vessels employed in this field can be categorized into jack-up type vessels and floating type vessels. As commonly known, the jack-up type vessels have jack-up legs and associated jack-up mechanisms to lift the hull out of the water. In embodiments, the crane of such a vessel is a so-called around-the-leg crane. The other category has a non-jack-up type floating hull, so lacking jack-up legs and a related jack-up mechanism. It is envisaged that this pile installation vessel is used in floating condition, so subject to wave motion, etc. during pile installation.

[0005] An advantage of not using a jack-up vessel is that the time for jacking up and down can be dispensed with. Also the seabed close to the foundation site may not be suitable for supporting a jack-up vessel. Furthermore, a jack-up vessel is complex and costly.

[0006] A vessel particularly designed for pile installation is the vessel disclosed in EP4373734. The hull is provided with a recess extending at the longitudinal center line of the vessel from the stern and towards a bow of the vessel. Two hull portions are flanking the recess. During installation of a pile at the designated position, it is envisaged that the vessel is oriented such that the bow is substantially facing incoming waves head-on. This reduces the possibility of waves moving into the recess - the recess thus providing a shelter from waves to the benefit of the installation of a pile. Piles are to be stored horizontally and extending in the longitudinal direction of the vessel on a pile storage deck. Between the pile storage deck and the recess, a pile holding system is arranged which is configured for upending a pile in the center line of the vessel and the holding the upright pile while it is being lowered towards the seabed and installed into the seabed. The crane of the vessel is positioned at a lateral side of the vessel and is used for hoisting of the upper end of the pile while its lower end is being held by the pile holding system for upending of the pile and then for lowering the upright pile to the seabed. A further development of the vessel in is shown in the Youtube-video with the title ULSTEIN U-STERN of 23 April 2023 at https: / / www.youtube.com / watch?v=YlpLSRrLpaO.

[0007] A pile holding system having an integrated pile holding and upending tool with an X-Y motion support assembly is known in the art e.g. from WO2022079112. In this example, a subframe is supported on a first pair of rails which are mounted to the deck of the vessel. This subframe is provided with a second pair of rails perpendicular to the first pair. A support frame for the base structure moves on second rails. Associated actuators provide for controlled X-Y motion. Here the pile holding system comprises:

[0008] - a pile holding tool configured to hold the pile in an upright orientation at a pile installation location whilst restraining the pile in radial directions, the pile holding tool comprising:

[0009] - a base structure including a ring comprises a ring base and one or more movable jaws, e.g. two semi-circular jaws, each jaw being movable between a closed position, wherein the ring forms a closed annulus, and an opened position,

[0010] - a plurality of pile engaging devices supported by the ring and distributed in an annular array about a center axis, which pile engaging devices are configured to engage on a circumferential zone of the pile. For example each pile engaging device is provided with one or more pile guiding rollers.

[0011] The known pile holding system furthermore comprises:

[0012] - an X-Y motion support assembly for the pile holding tool, the X-Y motion support assembly providing controllable motion of the pile holding tool in the longitudinal and transverse directions (X,Y), wherein the X-Y motion support assembly comprises:

[0013] - a load bearing body supporting the pile holding tool above the recess,

[0014] - an X-Y motion mechanism operative between the hull and the load bearing body, wherein the X-Y motion mechanism comprises controllable X-Y motion actuators for moving the load bearing body, and therewith a pile held thereby in an upright orientation, relative to the hull, e.g. to compensate for vessel motion.

[0015] Another pile installation vessel with a recess at the stern is disclosed in EP4330180. The pile holding system is arranged on one of the lateral hull portions and a crane is arranged on the other lateral hull portion. Here the pile is upended by hoisting an upper end thereof while the lower end moves on a cart on a longitudinal track from a position near the bow towards the recess. The upended pile is received by the pile holding system once in vertical position. In this case the pile holding system is configured only for holding the pile during lowering, and not used in the upending process. A challenge is formed by the size and weight of the monopiles to be transported. For reasons of efficiency the offshore wind turbines have an ever increasing capacity and size. The Haliade-X 12 MW has been installed and a 14 MW turbine is under development. Most wind farms will require monopile foundations with diameters ranging between 9 - 13 metres from 2025 onwards. The presently largest monopiles are 110 m in length, but 120 m long and longer monopiles are already announced. This requires vessels which are able to transport these to the offshore installation site, in particular horizontally, e.g. as in EP4373734 and EP4330180.

[0016] In a first aspect thereof, the present invention aims to provide an alternative pile holding system for a vessel having a recess at the stern. The first aspect further aims to optimize the monopile storage capacity of such a vessel, in particular in view of the length of monopiles to be stored thereon, and / or to optimize loading of monopiles on the vessel loading.

[0017] According to a first aspect thereof the present invention proposes a vessel according to the claim 1.

[0018] The present invention proposes that each of the lateral hull portions is provided with a respective lateral mount, e.g. on a deck portion of the lateral hull portion, wherein the X-Y motion support assembly is supported on the lateral mounts.

[0019] The weight of the pile holding tool, any load thereon resulting from the weight of the pile, and possible other forces, like wave-induced forces, is / are now absorbed by / distributed over the lateral hull portions via the lateral mounts. In the prior art vessels these loads are less effectively transmitted to the hull, requiring increased local strengthening of the hull.

[0020] In particular, the inventive pile holding system is basically arranged on the lateral hull portions, bridging over the recess. In the prior art vessel of EP4373734 and the mentioned YouTube video, the pile holding system is arranged between the forward edge of the recess and the pile storage deck. The inventive approach allows for the pile storage deck to start closer to the recess, so allows for a longer storage deck than in the prior art (onboard of the same vessel. Therefore, longer monopiles can be transported with the vessel. For example, the pile storage deck has a rear end at or proximity of the forward edge of the recess, as there is no X-Y motion support assembly along the forward edge as in the prior art.

[0021] It follows that the first aspect of the invention provides for a pile holding system with X-Y motion capability, that can be mounted on the vessel so as to be supported effectively on the lateral hull portions, so with a favorable load profile, and at the same time allows to deoccupy deck space forwards of the recess, which can be used to lengthen the pile storage deck.

[0022] The mounting of the pile holding system on the two hull portions flanking the recess makes that deck space remains clear forward of the recess. This is in particular advantageous in view of the mentioned increasing length of monopiles to be stored horizontally in the longitudinal direction on the vessel. Preferably, one monopile can be accommodated on or near the longitudinal centerline of the vessel, generally in line with the pile holding system. This enhances stability of the vessel, e.g. during upending of the monopile.

[0023] In an embodiment, the X-Y motion mechanism comprises:

[0024] - longitudinal motion tracks, e.g. embodied as rails, supported by the lateral mounts, each longitudinal motion track extending in the longitudinal direction (X) of the hull of the vessel, and

[0025] - transverse motion tracks, e.g. embodied as one or more rails, supported on the longitudinal motion tracks such as to be movable in longitudinal direction (X), each transverse motion track extending in the transverse direction (Y) of the vessel, wherein the load bearing body is supported on the transverse motion tracks, e.g. wherein the transverse motion tracks are a pair of rearward transverse motion tracks, each on a respective one of the hull portions, and a pair of forward transverse motion tracks, each being supported each on a respective one of the hull portions on a respective one of the longitudinal motion tracks.

[0026] In embodiments, the X-Y motion mechanism further comprises a subframe which is movably supported on the longitudinal motion tracks so as to be movable in the longitudinal direction relative to the lateral hull portions, and wherein the transverse motion tracks are provided on the load bearing body and supported by the subframe so that the load bearing body is movable in transverse direction relative to the subframe. In embodiments, the subframe is a U-shaped subframe in a top view, wherein legs of the subframe extend longitudinally, each leg along a respective one of the lateral hull portions, and wherein a transverse portion of the subframe extends between the legs and parallel to the forward edge of the recess, and wherein the longitudinal motion tracks extend underneath the legs, and wherein each of a pair of rearward transverse motion tracks extends above and transverse to a respective leg. In embodiments, the load bearing body has a U-shaped main body part in a top view, wherein legs of the main body part extend longitudinally, each leg along a respective one of the lateral hull portions, wherein a transverse portion of the main body part extends between the legs and parallel to the forward edge of the recess , and wherein each leg of the main body part is provided with a lateral support portion thereon for the base structure.

[0027] For example, the lateral mounts extend longitudinally at or near the inward edge of the respective lateral hull portion.

[0028] In embodiments, the vessel further comprises a pile storage deck extending forward of the recess, e.g. for storing multiple piles side by side in longitudinal direction of the hull. For example, support cradles are arranged on the pile storage deck for supporting piles with their length in the longitudinal direction of the vessel. As discussed, preferably, the storage deck has a rear end at or in close proximity of the forward edge of the recess.

[0029] In embodiments, the pile holding system is an integrated pile holding and upending system also configured for supporting the pile during upending thereof, wherein the base structure is pivotally mounted to the load bearing body about an upend pivot axis extending in the transverse direction allowing to, with a lower section of the pile being supported by the base structure, upend the pile from a horizontal orientation to an upright orientation, wherein, preferably, the base structure is provided with a pile foot end support which is configured to engage with the foot end of a pile in order to limit longitudinal movement of the pile during upending of the pile and to be disengaged from the foot end of the pile allowing lowering of the pile to the seabed, e.g. the pile foot end support being secured to and extending downward from the ring base of the base structure.

[0030] In practical embodiments, a pile support for supporting the pile is mounted to the deck of the vessel near the forward edge of the recess, which pile support is configured for longitudinally guiding a pile when being moved in longitudinal direction in order to engage the lower section thereof with the base structure.

[0031] In view of stability of the pile, in particular during upending, it is preferred that the base structure of the pile holding tool further comprises an additional pile restraining structure comprising: one or more spacer arms, each extending upward from the ring base of the ring, along the center axis to a free end of the spacer arm, and one or more restraining members mounted to each spacer arm, e.g. at or near the free end of the spacer arm, one or more clamping actuators operative between the spacer arm and the restraining member and configured to move the one or more restraining members into an operative position thereof in order to clamp the pile in a circumferential zone remote from the circumferential zone engaged by the pile engaging devices of the ring, and into a clearance position free from the pile, e.g. to the one or more restraining members being in operative position during upending of the pile and in clearance position during lowering of the pile the upright orientation.

[0032] Preferably, the spacer arms are located at opposed lateral sides of the base structure. This design is preferred over the additional upper ring of the base structure as in WO2022079112, e.g. in view of weight and in view of the proposed pile support which is mounted to the deck of the vessel near the forward edge of the recess. Preferably, with the base structure horizontal, this pile support is located, when seen in top view, between the spacer arms.

[0033] In a practical embodiment, the restraining members are spaced at least 5 meters, e.g. 5 - 15 meters, e.g. around 8 meters, from the pile engaging devices of the base structure. This provides for a stable interaction between the pile and the base structure, in particular during upending.

[0034] For example, there are two diametrically opposed arms at respective lateral sides of the ring base of the base structure, each arm being provided with one or more restraining members.

[0035] In a practical embodiment, the crane of the vessel is mounted at a lateral edge of the hull of the vessel and forward of the recess. The crane is located, preferably, as far lateral as possible to leave as much deck space for the accommodation of piles as possible.

[0036] For example, the crane has a crane base fixed to the hull and a slewable superstructure thereon with a luffable boom. A main hoisting system of the crane comprises at least one main hoisting winch, an associated main hoisting cable and a load connector, e.g. a hook, the main hoisting cable extending from the main hoisting winch to a main hoist cable guide on the boom and then to the load connector.

[0037] In an embodiment, the vessel further comprises a control unit operatively connected to the X- Y motion actuators, e.g. controlled on the basis of desired GPS-coordinates for the pile location and / or pile inclination and / or feedback from a DP-system of the vessel, etc.

[0038] Generally, the purpose is to maintain the X-Y location of the pile as well as its verticality during lowering, e.g. also during driving of the pile into the seabed. The X-Y motion compensation is in particular envisaged for a vessel to be used for pile installation in floating condition, e.g. a monohull vessel. This may also include a jack-up vessel in floating condition - i.e. with its legs still retracted.

[0039] In practical embodiments, the X-Y motion mechanism is envisaged to be able to make a stroke of at least 4 meters in each direction, e.g. around 6 meters in both the X- and Y direction. The X-Y movability of the mechanism is therefore envisaged to correspond thereto - in particular providing tracks, e.g. rails, having the mentioned lengths.

[0040] In embodiments, the lateral mounts extend longitudinally at or near inward edges of the recess of the hull. This allows for a relatively short distance between the lateral mounts and is beneficial in view of the width to be spanned by the load bearing body which holds the base structure. This is beneficial in view of the loading of both the vessel mountings and the bending loads on the load bearing body and on the base structure itself.

[0041] In embodiments, the longitudinal motion tracks extend over the majority of the length of the lateral hull portions.

[0042] A mounting of the base structure, e.g. the pivotal base structure, at both lateral sides thereof on the load bearing body via a pivot member, e.g. a trunnion, is in particular advantageous in case the pivot member is located in vertical direction above a lateral mount, e.g. when the base structure is in a centre position thereof. Compared to the prior art vessel in the ULSTEIN U-STERN video, the base structure pivot axis is at a significant distance aft of the forward edge of the recess and the X-Y motion support assembly is located forward of the same forward edge, this results in a more favorable vessel loading in particular at said forward edge. In embodiments, the pivot axis of the base structure extends through or slightly offset forward of the base structure center axis to facilitate a controlled upending of the monopile in the last stage thereof near vertical as the center of gravity thereof thereby remains forward of the pivot axis in this stage.

[0043] In case a pile storage deck is provided forward of the recess, in embodiments it is provided that in the horizontal orientation of the pile holding tool, the center axis thereof extends in longitudinal direction along the pile storage deck, and a pile longitudinally stored on the deck portion is moveable from into the base structure for being held by translating or shifting the pile along the longitudinally directed center axis. For example, a pile support for supporting the pile along the vessel longitudinal axis is mounted to the deck of the vessel at or near the forward edge of the recess and serves for longitudinally guiding the pile along the axis when it is being moved into the base structure.

[0044] The first aspect of the invention furthermore relates to a pile holding system according to claim 14, for example for retrofitting existing vessels with the recess and having the specifications described. The embodiments, optional features and possible effects and advantages discussed in relation to the vessel according to the first aspect of the invention similarly apply.

[0045] The invention furthermore relates to a combined facility of the pile holding system according to claim 14 without upending capability with the base structure fixed non-pivotal to the load bearing body and a distinct, dedicated pile upending system for upending of the pile. The options and advantages discussed in relation to the vessel according to the invention similarly apply.

[0046] In a second aspect thereof, the invention provides a vessel for pile installation, e.g. for installation of a pile adapted to support an offshore wind turbine, e.g. a monopile, wherein the vessel has a hull with a bow and a stern, a crane mounted on the hull and configured for hoisting of the pile, and an integrated pile holding and upending system, wherein the hull of the vessel has a longitudinal direction and a transverse direction,

[0047] The stern of the vessel comprises a recess extending forward in the longitudinal direction to a forward edge of the recess, the recess being flanked laterally by two lateral hull portions,

[0048] The integrated pile holding and upending system comprises:

[0049] - a pile holding tool configured to hold the pile in an upright orientation at a pile installation location whilst restraining the pile in radial directions, the pile holding tool comprising:

[0050] - a base structure including a ring comprises a ring base and one or more movable jaws, e.g. two semi-circular jaws, each jaw being movable between a closed position, wherein the ring forms a closed annulus, and an opened position,

[0051] - a plurality of pile engaging devices supported by the ring and distributed in an annular array about a center axis, which pile engaging devices are configured to engage on a circumferential zone of the pile, e.g. each pile engaging device being provided with one or more pile guiding rollers

[0052] - a support assembly for the pile holding tool, which comprises:

[0053] - a load bearing body supporting the pile holding tool above the recess, wherein the base structure is pivotally mounted to the load bearing body about an upend pivot axis extending in the transverse direction allowing to, with a lower section of the pile being supported by the base structure, upend the pile from a horizontal orientation to an upright orientation, wherein, preferably, the base structure is provided with a pile foot end support which is configured to engage with the foot end of a pile in order to limit longitudinal movement of the pile during upending of the pile and to be disengaged from the foot end of the pile allowing lowering of the pile to the seabed, e.g. the pile foot end support being secured to and extending downward from the ring base of the base structure, wherein each of the lateral hull portions is provided with a respective lateral mount, e.g. on a deck portion of the lateral hull portion, wherein the support assembly is supported on the lateral mounts.

[0054] The second aspect encompasses embodiments wherein the X-Y motion mechanism is absent, e.g. when the vessel is a jack-up vessel.

[0055] In embodiments, the pivot axis extends rearward of the forward edge of the recess, and therefore, across the recess and the lateral hull portions as well. For example, it extends through, or slightly offset rearward, of the base structure center axis in the vertical orientation of the base structure (and the pile). This configuration, with this location of the pivot axis and the lateral support on the hull portions, makes for a favorable mechanical loading of the hull of the vessel, including during upending. Preferably, the pivot axis extends within a longitudinal range of the lateral mounts.

[0056] The second aspect furthermore relates to an integrated pile holding and upending system configured to be mounted on a vessel for pile installation as discussed above. For example, the system may be useful for retrofitting an existing vessel with a recess, having the specification as described herein.

[0057] It will be appreciated that details discussed in the claimset, and / or in embodiments, as well as optional features and possible effects and advantages discussed in relation to the vessel according to the first aspect also may apply to the second aspect.

[0058] For example, the second aspect of the invention may readily be combined with practically all embodiments mentioned in relation to the first aspect, e.g. the feature according to the first aspect that the X-Y motion mechanism is provided. In particular, the X-Y motion mechanism may provide a synergistic effect in improving the mechanical load profile of the vessel. The embodiment with the X-Y motion compensation may - with the pivot axis longitudinally located across the recess - even further improve the mechanical load profile and furthermore improve the positioning and handling of the pile during upending in addition to the lowering phase. A pile storage deck in line with the recess combines the favorable load profile with an optimization of the deck space, where for the purpose of upending, the embodiment enabling a longitudinal displaceability of the piles into the tool in a horizontal orientation makes for a particularly efficient process. The discussed configurations of the X-Y motion mechanism, and in particular the discussed embodiment with the U-shaped subframe, would enable a passing of the monopile from the seaside into the system which is useful at the end of the upending stage. An embodiment wherein the discussed restraining structure of the tool would be implemented is considered particularly useful during upending of the pile, therein restraining the pile such that its extension thereof along the base structure center axis is maintained. A longitudinal location of the crane benefiting the angular range of the boom during upending is facilitated by the location of the pivot axis according to the second aspect across the recess as it facilitates the pile to be received and handled relatively far aft. This is even further facilitated by the embodiment with the restraining structure wherein the pivotable connection is provided along the spacer arms thereof, e.g. halfway, as this makes an even further aft receipt of the pile bottom end possible.

[0059] As discussed for the first aspect and pointed out above, also for the second aspect it would be advantageous to have - in the horizontal orientation of the pile holding tool - the center axis thereof extending in longitudinal direction along the pile storage deck, and a pile longitudinally stored on the deck being moveable into the base structure by translating the pile along the longitudinally directed center axis. For example, a pile support for supporting and guiding the pile is provided near the forward edge of the recess.

[0060] The crane of the vessel is also for this aspect, preferably mounted at a lateral edge of the vessel.

[0061] The third aspect of the invention relates to a vessel for pile installation, e.g. for installation of a pile adapted to support an offshore wind turbine, e.g. a monopile, wherein the vessel has a hull with a bow and a stern, a crane mounted on the hull and configured for hoisting of the pile, and an integrated pile holding and upending system, wherein the hull of the vessel has a longitudinal direction and a transverse direction.

[0062] Optionally, the stern of the vessel comprises a recess extending forward in the longitudinal direction to a forward edge of the recess, the recess being flanked laterally by two lateral hull portions, wherein the integrated pile holding and upending system comprises:

[0063] - a pile holding tool configured to hold the pile in an upright orientation at a pile installation location whilst restraining the pile in radial directions, the pile holding tool comprising:

[0064] - a base structure including a ring comprises a ring base and one or more movable jaws, e.g. two semi-circular jaws, each jaw being movable between a closed position, wherein the ring forms a closed annulus, and an opened position,

[0065] - a plurality of pile engaging devices supported by the ring and distributed in an annular array about a center axis, which pile engaging devices are configured to engage on a circumferential zone of the pile, e.g. each pile engaging device being provided with one or more pile guiding rollers

[0066] - a support assembly for the pile holding tool, which comprises:

[0067] - a load bearing body supporting the pile holding tool, e.g. above the recess, wherein the base structure is pivotally mounted to the load bearing body about an upend pivot axis allowing to, with a lower section of the pile being supported by the base structure, upend the pile from a horizontal orientation to an upright orientation, wherein, preferably, the base structure is provided with a pile foot end support which is configured to engage with the foot end of a pile in order to limit longitudinal movement of the pile during upending of the pile and to be disengaged from the foot end of the pile allowing lowering of the pile to the seabed, e.g. the pile foot end support being secured to and extending downward from the ring base of the base structure, wherein the base structure of the pile holding tool further comprises an additional pile restraining structure comprising: one or more spacer arms, each extending upward from the ring base of the along the base structure center axis to a free end of the spacer arm, and one or more restraining members mounted to each spacer arm, e.g. at or near the free end of the spacer arm, one or more clamping actuators operative between the spacer arm and the restraining member and configured to move the one or more restraining members into an operative position thereof in order to clamp the pile in a circumferential zone remote from the circumferential zone engaged by the pile engaging devices of the ring, and into a clearance position free from the pile, e.g. to the one or more restraining members being in operative position during upending of the pile and in clearance position during lowering of the pile the upright orientation. In a practical embodiment, the restraining members are spaced at least 5 meters, e.g. 5 - 15 meters, e.g. around 8 meters, from the pile engaging devices.

[0068] In embodiments, two diametrically opposed arms are provided at respective lateral sides of the ring base of the base structure, each arm being provided with one or more restraining members.

[0069] For example, the stern of the vessel comprises a recess extending forward in the longitudinal direction to a forward edge of the recess, the recess being flanked laterally by two lateral hull portions. For example, each of the lateral hull portions is provided with a respective lateral mount, e.g. on a deck portion of the lateral hull portion, wherein the support assembly is supported on the lateral mounts.

[0070] The restraining members are configured to, in an operative position thereof, clamp the pile in a circumferential zone such as to restrain the pile in radial directions to maintain an extension thereof along the base structure center axis. The one or more restraining members are controllably movable by one or more clamping actuators operative between the spacer arms and the restraining members into the operative position thereof for restraining of the pile, and movable into a clearance position free from the pile. It is envisaged, for example, that the pile is kept restrained while the base structure is pivoted during upending.

[0071] In an example, the one or more spacer arms are embodied as two diametrically opposed arms at respective lateral sides of the tool, the one or more restraining members clamping the pile circumference. In an example, the restraining members are connected to the spacer arms such as to clamp the pile radially in angular positions with respect to the base structure center axis, and thus the center axis of the held pile, spaced from the spacer arms, e.g. arms. In the case of the diametrically opposed arms at respective lateral sides, this makes that the restraining members engage the pile to some extent fore and / or aft of the arms, e.g. one restraining member fore and one aft of each arm. This makes that the radial clamping forces exerted thereby have an aft and / or fore component as well, which may together with the frictional force in this direction e.g. assist in counteracting any tilting of the pile. embodiments, details, and / or optional features and possible effects and advantages discussed in relation to the vessels and systems according to the first and / or second aspect may be combined with the third aspect. The third aspect furthermore relates to an integrated pile holding and upending system as discussed above.

[0072] The skilled person will acknowledge that the third aspect may readily be combined with the first and second aspect of the invention and embodiments thereof to obtain similar or synergistic technical effects and advantages. For example an X-Y movability through the X-Y motion mechanism as according to the first aspect, e.g. motion compensation in the X-Y plane, may be further facilitated by the capability of restraining the pile as it also contributes to the accurate positioning of the pile in the X-Y plane. Furthermore the advantageous positioning of the upend pivot axis aft of the longitudinally inward recess edge, in cases wherein the pile holding system is provided therewith, may further benefit the controllability of the pile positioning and the mechanical load profile of the vessel. In embodiments wherein the pile may be displaced horizontally from the pile storage deck into the pile holding tool in horizontal orientation, the restraining clasps may aid in correcting unintended movements in radial directions, e.g. acting as a cradle for the pile.

[0073] In a fourth aspect thereof the invention relates to a vessel for pile installation, e.g. for installation of a pile adapted to support an offshore wind turbine, e.g. a monopile, wherein the vessel has a deck, a crane mounted on the deck and configured for hoisting of the pile, and a pile holding system, the vessel having a longitudinal direction and a transverse direction. The vessel comprises a, in a longitudinal direction of the vessel inward, recess at a stern of the vessel, the recess being flanked laterally by two lateral hull portions.

[0074] The pile holding system comprises a pile holding tool and a support assembly as discussed herein with reference to any of the first, second, and / or third aspect.

[0075] The pile holding system further comprises a noise mitigation screen (NMS) which is, e.g. releasably, connected to the support assembly at lateral sides of the base structure of the pile holding tool, to be supported by the lateral hull portions via the support assembly. For example, the NMS is connected to the support assembly such as to extend vertically at least partly below the base structure and / or laterally at least partly between the hull portions.

[0076] Alternatively, the NMS is connected to the hull portions at both sides of the base structure of the tool, e.g. furthermore connected to the hull at a forward edge of the recess at the stern of the vessel. As known in the art, the NMS is conventionally connected to the base structure of the pile holding tool to enclose the pile around its circumference underneath the base structure. The NMS generally is openable, like the ring of the base structure, such as to enable lateral insertion and removal of the monopile through the opening.

[0077] The fourth aspect proposes a connection of the NMS to the hull portions or the parts of the system not being the base structure. This eliminates a loading of the load bearing body by the considerable weight of the NMS via the base structure, in addition to the weight of the base structure already loading the load bearing body.

[0078] In an embodiment the base structure is hingeable connected to the load bearing body such as to be pivotable relative to the load bearing body about a substantially horizontal upend pivot axis, extending in the lateral direction, whilst holding the pile, from a horizontal orientation wherein the pile extends substantially parallel to the deck of the vessel to an upright orientation wherein the pile extends substantially vertical. In this embodiment it is particularly advantageous that it is not the base structure which supports the NMS, because this eliminates the required upending thereof along with the pile. The pivotal connection between the base structure and the load bearing body is advantageously not loaded by the weight of the NMS. The connection between the base structure and the NMS moreover does not have to be able to withstand the forces involved with the upending of the NMS. Furthermore, a changing loading of the system and the vessel because of the upending of the NMS during upending is avoided.

[0079] In an embodiment the NMS is U-shaped, having a seaside opening between the legs of the U for receiving the pile therethrough in the longitudinal vessel direction and into the U, e.g. in case of a pivotable base structure, for receiving the pile as it is upended. The NMS may comprise one or more jaws movable, e.g. pivotable around substantially vertical axes, to at least partly close said opening.

[0080] The NMS may in an embodiment extend inwards of and along the edges of the recess, in particular the three edges thereof in case of a U-shape.

[0081] The NMS is preferably connected to the load bearing body to be connected to the support assembly.

[0082] In an embodiment the support assembly further comprises an X-Y motion mechanism as discussed in relation to the first aspect, operative between the lateral mounts and the load bearing body, providing movability and controllable X-Y motion actuators for moving the load bearing body, and therewith the thereon supported pile holding tool and pile held thereby, relative to the hull portions in the longitudinal and transverse directions.

[0083] Preferably, the NMS is connected to the load bearing body to be connected to the support assembly, so that the NMS is movable by means of the actuators relative to the hull portions in the longitudinal and transverse directions along with the load bearing body, or e.g. wherein the NMS is connected to the X-Y motion mechanism to be connected to the support assembly, such that the NMS is movable by means of the actuators relative to the hull portions in the longitudinal and / or transverse directions.

[0084] The X-Y motion mechanism preferably comprises, for providing said movability of the load bearing body, and therewith the thereon supported pile holding tool and pile held thereby, relative to the hull portions in the longitudinal direction and the transverse direction, respectively two longitudinal motion tracks, e.g. embodied as rails, each extending in the longitudinal direction of the vessel on said hull portions, and furthermore one or more transverse motion tracks, e.g. embodied as one or more rails, supported on the longitudinal motion tracks such as to be movable there along relative to the hull portions, and extending in the transverse direction of the vessel. The load bearing body therein being supported on the transverse motion tracks such as to be movable there along relative to the longitudinal motion tracks.

[0085] In an embodiment, the X-Y motion mechanism may comprise a subframe between the longitudinal and transverse motion tracks, so that the transverse motion tracks are supported on the longitudinal motion tracks via the subframe. The longitudinal motion tracks are each provided underneath the subframe, and the transverse motion tracks are provided between the load bearing body and the subframe. The NMS may therein in particular be connected to the subframe to be connected to the support assembly, so that the NMS is movable by means of the actuators relative to the hull portions in the longitudinal direction along with the subframe. For example, this may form an efficient solution for X-movability, for example along with the pile as it is being moved or positioned in this direction, or for facilitating enclosure of the pile in the NMS, e.g. in the last stage of upending when applicable or prior to lowering or thereafter and prior to subsequent piling.

[0086] The subframe may, as discussed in relation to the first aspect, be a U-shaped subframe with the legs of the U extending longitudinally along the hull portions, the free ends of these legs facing the seaside and a transverse part of the subframe between the legs extending along a forward edge of the recess. Therein the longitudinal motion tracks each extend underneath a respective one of the legs of the II, and the transverse motion tracks each extend above said transverse part of the subframe. This embodiment may further facilitate the X-Y movability and insertion of the pile during upending.

[0087] As discussed in relation to the first aspect the longitudinal motion tracks may by means of a respective one of the lateral mounts mounted to a respective one of the hull portions and upwardly facing the subframe, wherein the subframe downwardly engages each track to be movable there along. For example the longitudinal tracks are embodied as rails mounted to the hull portions via the lateral mounts, the subframe having one or more carts at its bottom side to downwardly engage the track. In addition or alternatively the transverse motion tracks are mounted to the bottom side of the load bearing body and downwardly facing the subframe wherein the subframe upwardly engages the track to be movable there along. For example the transverse tracks being embodied as rails mounted to the bottom side of the load bearing body, and the subframe having one or more carts at its top side to upwardly engage the track.

[0088] The vessel may further comprise a control unit operatively connected to the X-Y motion actuators, wherein the X-Y motion actuators are controllable to, and the control unit is programmed to control these such as to move the load bearing body, and therewith the thereon supported pile holding tool and pile held thereby, such as to compensate for sea state induced motions in the X-Y plane. Preferably, the NMS is therein connected to the load bearing body to be connected to the support assembly, so that the NMS is movable by means of the actuators relative to the hull portions in the longitudinal and transverse directions along with the load bearing body to be compensated by sea state induced motions in both directions. Alternatively the NMS is connected to the X-Y motion mechanism to be connected to the support assembly, such that the NMS is movable by means of the actuators relative to the hull portions in the longitudinal and / or transverse directions to be compensated by sea state induced motions in the X- and / or Y-direction.

[0089] The lateral mounts of the support assembly may extend longitudinally at or near inward edges of the lateral hull portions, and / or the longitudinal motion tracks may extend substantially entirely on the lateral hull portions, the transverse motion track(s) extending at least partly at or near a longitudinally inward edge of the recess.

[0090] The fourth aspect of the invention furthermore relates to a pile holding system, e.g. furthermore capable of upending, as discussed in relation to the vessel according to the fourth aspect. The fourth aspect furthermore relates to a facility combining this pile holding system and a dedicated upending system as described herein before.

[0091] Also the fourth aspect may readily be combined with any of the first, second and third aspect and embodiments and optional features discussed in relation thereto to provide particularly advantageous embodiments.

[0092] The invention furthermore relates to methods wherein use is made of a pile holding system, a combined facility of a pile upending system and a pile holding system, e.g. an integrated pile upending and holding system, or a vessel as described in relation to either aspect of the invention.

[0093] The invention, according to either aspect thereof, may be designed to handle a piles of between 8 - 13 meters in diameter and, e.g. 80 - 140m in length. The dimensions of the vessel and the pile holding system are attuned to these pile dimensions.

[0094] In an embodiment, the recess is in particular envisaged to be 20 - 30 meters, e.g. 28 meters, wide.

[0095] The pile storage deck forward of the recess is in embodiments at least 100 meters long, e.g. at least 110 meters, preferably at least 120 meters, most preferably at least 130 meters long, e.g. around 135 - 140 meters long.

[0096] It is noted that where the pile holding system of the invention according to either aspect is not capable of upending, the upending may be achieved in ways and using equipment known in the art, whereafter the pile is inserted in the pile holding tool using the crane, e.g. from above or laterally via an opening, e.g. a closable opening, in the base structure. For example the pile may be upended by two cranes at a side of the vessel as is disclosed in WO2019103611 for a vessel without a recess, by hoisting the upper end of the monopile relative to the lower end. Or the piles may be upended by lifting the upper end while its bottom end moves along a track - e.g. alike in EP4330180. Alternatively the piles may be retained on the deck in upright position instead of horizontally, eliminating upending at the installation site, however this is not preferred for monopiles of the envisaged size.

[0097] The invention also relates to a method for pile installation, e.g. of a monopile, wherein use is made of a vessel and / or system as described herein. The invention will now be discussed in a non-limiting way with reference to the appended drawings. In the drawings: figures 1,2 illustrate a vessel according to the invention prior to upending of a pile, respectively in a side and partial back view, figure 3 illustrates the vessel during upending of a pile, in a back view, figure 4 illustrates the vessel after upending of a pile, prior to lowering, in the same back view, figure 5 illustrates the vessel during lowering of the pile, in the said side view, figure 6 illustrates the vessel in a top view with three relatively large piles being retained thereon, figure 7 illustrates the vessel in a top view with four relatively small piles being retained thereon, figure 8 illustrates for the vessel of figures 1-7 in a side view a monopile prior to longitudinal displacement into the system, figure 9a illustrates in the same side view the monopile being longitudinally displaced into the system, figures 9b-d illustrate in transverse cross-sections the system and a cradle during the longitudinal displacement of the monopile, figure 10a illustrates in the side view the monopile after the displacement being retained in the system and ready for upending, figures 10b-d illustrate in the transverse cross-sections the system and a cradle during the retainment, figure 11 illustrates in a back-side-top perspective view a pile holding and upending system according to the invention, figure 12 illustrates in the same view only a part of the pile holding and upending system, figure 13 illustrates in a front-side-top perspective view the same system whilst holding a pile prior to upending, figures 14,15 illustrate in a back-side-top perspective view the same system whilst holding a pile during and after upending.

[0098] The figures 1-10 illustrate a vessel 1 for pile installation including a pile holding and upending system 4 according to all aspects of the invention. The figures 11-15 illustrate an only slightly different embodiment of a pile holding and upending system 4 according to the invention for use on such vessel. Like parts are indicated by the same reference symbols. The vessel 1 is suitable for installation of a pile 100 adapted to support an offshore wind turbine, in particular a monopile. The vessel 1 has a hull with a deck 2. The hull has a bow and stern. The vessel 1 has a longitudinal direction X and a transverse direction Y.

[0099] The vessel has a crane 3a which is mounted to the hull to extend on the deck 2 and configured for hoisting of the pile 100. Two further, smaller cranes 3b and 3c are mounted to the deck 2 as well.

[0100] The vessel 1 comprises a recess 10 at a stern of the vessel 1 , which extends inward in a longitudinal direction X of the vessel.

[0101] The recess 10 has a forward edge 11 and is flanked laterally by two lateral hull portions 6a, b, seen best in figures 2, 6, 7 and 12. The lateral hull portions 6a, b thus extend laterally from the recess 10 and longitudinally backwards from the forward edge 11. The lateral hull portions 6a, b are buoyant portions of the hull, so they extend to below the waterline in use of the vessel in order to provide buoyancy at the stern.

[0102] Note that in the figures 11-15, only a U-shaped part of the deck 2 with the portions 6a, b is shown, and the rest has been cut off.

[0103] The vessel 1 furthermore comprises an integrated pile holding and upending system 4. The pile holding and upending system 4 comprises a pile holding tool 40. This pile holding tool 40 comprises a base structure 41 for receiving and holding therein the pile 100.

[0104] A pile 100 is shown held in the base structure 41 in figures 1-5, 13-15. In particular a bottom end section 103 of the monopile 100 is being held thereby.

[0105] The base structure 41 includes a ring 41a which comprises a ring base and movable jaws 41b, c, e.g. two semi-circular jaws. Each jaw is movable between a closed position, wherein the ring 41a forms a closed annulus, and an opened position.

[0106] The pile holding tool 40 further comprises a plurality of pile engaging positioning devices 42 supported by the ring 41 of the base structure 41 and distributed in an annular array about a center axis 41c of the base structure 41 . The pile engaging positioning devices 42 can best be identified in figures 2, 9b, 10b, and 11. As indicated in figure 1 , these are configured to engage on a proximate circumferential zone 101 of the pile 100.

[0107] Firstly, for the purpose of lowering of the pile 100, the pile engaging device 42 engage the pile 100 so as to hold the pile 100 in an upright orientation at a pile installation location whilst restraining the pile 100 in radial directions and enabling longitudinal movement of the pile.

[0108] Each pile engaging device 42 is provided with one or more pile guiding rollers. In figures 1-5 and 13-15 the pile 100 is shown being engaged in this way, prior to lowering, wherein in figures 1-5 the pile 100 is downwardly restricted by the foot end support 49, known in the art. In figure 5, the pile 100 is shown being lowered towards the seabed, being laterally restrained by the pile engaging devices 42. The foot support 49 is therein released to extend along the pile instead of across, so that the pile 100 is no longer longitudinally restricted thereby and the lowering is enabled.

[0109] Secondly, the system 4 is furthermore configured for supporting the pile 100 during upending thereof. The base structure 41 is hingeable mounted to the load bearing body 55 such as to be pivotable relative to the load bearing body 55 about a substantially horizontal upend pivot axis 41x, extending in the transverse direction Y of the vessel 1, whilst holding the pile 100, from a horizontal orientation wherein the pile extends substantially parallel to the deck 2 of the vessel 1 to an upright orientation wherein the pile extends substantially vertical. The pile 100 is shown in the horizontal orientation in figures 1 , 2, 10a-d, and 12, and in the upright orientation in figures 4 and 15. As known in the art and shown in figures 2 and 4, the pile 100 is upended by lifting its upper end 103 with its bottom end 104 being retained by the pile holding and upending tool 4. This lifting is done by operating crane 3a, from which the upper end 103 is suspended by means of pile lifting tool 33.

[0110] Upending actuators for controlling the upending movement e.g. for aiding lifting in addition to the crane lifting the upper end 103 of the monopile 100, damping or correcting purposes, are not shown in the figures. As known in the art, for this purpose hydraulic actuators or circlesegment shaped racks with motor driven pinions may for example be applied.

[0111] A pile insertion process is depicted by figures 8, 9a-d and 10a-d. As may be seen from figures 1 and 13 and as demonstrated in figures 8, 9a-d and 10a-d, in the horizontal orientation of the pile holding tool 40, the center axis 41a thereof extends in said longitudinal direction X along said pile storage deck 21, and a pile 100 longitudinally retained on said deck portion 21 is moveable from said deck portion 21 into said base structure 41 for being held thereby by substantially exclusively translating said pile along the longitudinally directed center axis 41a.

[0112] A pile support 7 in the form of a rollerbox for supporting the pile 100 along the vessel longitudinal axis X is mounted to the deck 2 of the vessel at or near the forward edge 11 of the recess 10 is configured for longitudinally guiding the pile 100 along the said axes X,41a when moved from said deck portion 21 and aligned with the axis 41a into said base structure 41.

[0113] Figures 5 and 6 shows piles 100 being retained horizontally on the pile storage deck 21. One of these piles 100 is with its center axis 100c longitudinally in line with the center axis 41c of the base structure 41 of the tool 40 in a horizontal orientation, therein being supported on the laterally movable support cradles 8 and longitudinally movable displacement cradles 9, ready for being inserted in the tool 40.

[0114] For the insertion, demonstrated by the progression from figure 8 to figures 9a-d, the rollerbox 7 is brought to extend to the correct height, and the monopile 100 is lifted slightly by means of the moving cradles 9 to be clear from the cradles 8 and align the monopile axis 100c also vertically in line with the axis 41c of the base structure. The cradles 9 subsequently move towards the base structure 41 to insert the pile 100 into the base structure 41 , as depicted in figures 9a-d. Figure 9b illustrates that at this stage, the pile engaging devices 42 are in a retracted position thereof not engaging the pile 100. Figure 9c illustrates that the storage cradles 8 are neither engaging the pile 100 and figure 9d that this also goes for the restraining members 47a, b of the restraining structure 45 of the tool 40, also being in a retracted position. Figures 10a-d show the horizontal orientation of the pile 100, being inserted into the tool 40 as far as possible such as to with a bottom surface thereof be engaged by the foot support 49 and longitudinally restricted in the direction towards its upper end.

[0115] As shown in figure 10b, the pile engaging devices 42 are in a position engaging and radially restraining the pile 100 at a proximate circumferential zone 101 thereof. In figure 10c it can be verified that the pile 100 has now been lowered onto the storage cradles 9 again, with its center axis 100c extending at a small distance d to the pivot axis 41x and the center axis 41c for the purpose of the earlier discussed reduction of the risk of toppling over. Thereto the pile engaging devices 42 positioned above the pile 100 are extended further than those underneath the pile 100. In figure 10d it is shown that the restraining members 47a, b are now in the operative position thereof engaging the pile 100 to exert a clamping force thereon in the indicated lateral directions.

[0116] As visible in e.g. figure 11 , indicating the pivot axis, and figure 12, indicating the forward edge 11 , the pivot axis 41 x extends aft of the edge 11 of the recess 10. In the vertical orientation, the pivot axis extends slightly aft - at distance d, see fig.10b-d - of the base structure center axis 41c.

[0117] An X-Y motion support assembly 50 of the pile holding and upending system comprises two lateral mounts 51 a, b, via each of which the assembly 50 is at a respective lateral side of the vessel mounted to a respective one of the lateral hull portions 6a, b of the vessel 1 to be supported thereby. See e.g. figures 8-12: the lateral mounts itself are not visible, but their locations underneath rails 57a, b are shown.

[0118] The system further comprises a load bearing body 55 which rests on the lateral mounts 51a, b via a subframe 59 as part of an X-Y motion mechanism of the system. This mechanism provides movability and controllable X-Y motion actuators for moving the load bearing body 55, and therewith the pile holding tool 40 and pile 100 held thereby, relative to the hull portions 6a, b in the longitudinal and transverse directions X,Y.

[0119] The X-Y motion mechanism in this embodiment comprises carts and rails. The configuration of the mechanism is most clearly visible and indicated in figures 8-12.

[0120] Two longitudinal motion tracks are provided as rails 57a, b, each being by means of a respective lateral mount 51a, b mounted to a respective one of the lateral hull portions 6a, b, and extending in the longitudinal direction X of the vessel 1 on said hull portions 6a, b.

[0121] The subframe 59 is a U-shaped subframe in a top view, wherein legs of the subframe extend longitudinally, each leg along a respective one of the lateral hull portions, and wherein a transverse portion of the subframe 59 extends between the legs and parallel to the forward edge 11 of the recess 10.

[0122] The longitudinal motion tracks 57a, b extend underneath the legs of the subframe 59 and carts 56a, b slide over the tracks 57a, b so that the subframe can move in longitudinal direction only relative to the hull. The load bearing body 55 has a U-shaped main body part in a top view, wherein legs of the main body part extend longitudinally, each leg along a respective one of the lateral hull portions, and wherein a transverse portion of the main body part extends between the legs and parallel to the forward edge 11 of the recess 10. Each leg of the main body part is provided with a lateral support portion thereon for the base structure.

[0123] Each of a pair of rearward transverse motion tracks 58a, b is fitted to a leg of the load bearing body and extends above and transverse to a respective leg of the subframe, supported by rearward carts 56a, 56b. One or more forward transverse motion tracks 58c is / are fitted to the transverse portion of the body and are supported on forward carts 56a, b. Therefore, the load bearing body is movable in transverse direction only relative to the subframe 59.

[0124] X-Y motion actuators for the controlled motion of the subframe 59 and of the load bearing body 55 are not shown in the figures, but e.g. rack and pinion drives, or hydraulic cylinders, or winches, may be envisaged for this purpose.

[0125] The vessel 1 further comprises a control unit (not shown), operatively connected to the X-Y motion actuators wherein the X-Y motion actuators are controllable to, and the control unit is programmed to control these such as to, move the load bearing body 55, and therewith the thereon supported pile holding tool 40 and pile 100 held thereby, e.g. such as to compensate for sea state induced motions in the X-Y plane of the vessel, e.g. to correct for any error or inaccuracy of the DP-system of the vessel.

[0126] The lateral mounts 51a, b extend longitudinally at inward edges of the hull portions 6a, b, and the longitudinal motion tracks 57a, b extend substantially entirely on the hull portions 6a, b. There is a small portion of the foremost rails 57a, b which extends forward of the edge 11 to enable an ample motion range in the X-direction. The transverse motion tracks 58a, b extend at least partly at or near the transversely extending longitudinally inward edge 11 of the recess 10.

[0127] The vessel 1 further comprises a pile storage deck 21 extending in the longitudinal direction forward of the vessel recess 10.

[0128] Figures 6 and 7 respectively show this deck portion whilst retaining three large, i.e. with a diameter of 13m and a length of 130m, and four smaller, i.e. with a diameter of 10m and a length of 105m, monopiles, respectively, horizontally in the X-direction. A pile support 7 for supporting the pile 100 along the longitudinal axis X of the vessel is mounted to the deck 2 of the vessel at or near the forward edge 11 of the recess 10, see also figure 12 (schematically) and figures 1 , 8, 9a and 10a.

[0129] From figures 6 and 7, it may be verified that the pile holding and upending system takes up only a minimal amount of deck space, namely along the forward edge 11 of the recess 10 in a fore X-position of the tool 40. This makes that the deck space usable for retaining monopiles 100 is maximized. In particular the longitudinal stretch thereof is crucial since it is the length of the monopiles 100 which is the most determinant factor to the vessel configuration.

[0130] The figures 6 and 7 also show that ten support cradles 8 are provided, a set of five at each of two mutually spaced longitudinal positions and laterally movable across the storage deck, to support at most five piles at adjustable lateral positions. The foremost set of five support cradles can be mounted at tracks at multiple longitudinal positions, adjusted to different pile lengths. In line with the center axis 41c of the base structure 41 in the horizontal orientation as in figures 6 and 7, ready to receive the pile 100 along this axis 41c, a track is provided for displacement cradles 9 longitudinally movable there along to displace the pile over the roller box 7 and into the base structure 41 until engagement with the foot support 49 is reached.

[0131] The base structure 41 of the pile holding tool 40 further comprises a pile restraining structure 45. The restraining structure 45 comprises spacer arms 46a, b extending, seen in the vertical pile orientation, upward along the base structure center axis 41c.

[0132] The pile restraining structure 45 further comprises two pairs of movable restraining members 47a, b. each pair is mounted to the free end of the arms 46a, b. The restraining members 47a, b are configured to, in an operative position thereof, clamp the pile in the distant circumferential zone 102 such as to restrain the pile 100 in corresponding radial directions within the distant circumferential zone 102 - indicated in figure 1.

[0133] The arms are provided at respective lateral sides of the base structure, and the restraining members 47a, b clamp the pile circumference therebetween both laterally and in the X- and vertical direction during upending. The radial clamping directions can be verified in figure 10d: these are separated by 90 degrees with respect to the pile center axis 100c coinciding with the base structure center axis 41c, at a distance of 45 degrees from the X- and Y- directions. By the clamping in these directions, the restraining members 47a, b maintain an extension of the pile 100 along the base structure center axis 41c. With the angular extension, clamping force components in both the vertical, fore and aft, and lateral directions can advantageously be exerted during upending e.g. for corrective actions and prevention of unintended tilting.

[0134] The restraining members 47a, b are controllably movable by respective clamping actuators 48a, b. These actuators are operative between the spacer arms 46a, b and the restraining members 47a, b to bring these into the operative position thereof for restraining of the pile 100. The operative position is shown in figures 3-5, but most clearly in 10d and 13-15. They are movable by the actuators 48a, b into a clearance position free from the pile 100, e.g. to enable lowering of the pile in said upright orientation, but also to facilitate insertion thereof in longitudinal direction of the pile. A clearance position is shown in e.g. figure 9d. Therein the restraining members 47a, b which are in this orientation located underneath the pile, are pivoted inward towards the pile at only a small spacing from its circumference, e.g. for possible corrective actions in the radial directions indicated and, whereas those above the pile 100 are pivoted outwards to 100 face the vertical plane providing unhindered access to the pile from above.

[0135] As visible from figures 1-7, the crane 3a of the vessel 1 is mounted at a lateral edge of the vessel 1 between the pile storage deck 21 and the lateral edge of the vessel 1 .

[0136] The crane has a slewable superstructure and a boom 31 , e.g. an A-frame boom, slewable around a vertical slew axis 32x relative to a crane structure 32 mounted to the vessel, whilst lifting an upper end 102 of a pile 100 suspended from the crane boom 31 via the pile lifting tool 33, to establish upending of the pile from being retained on said retaining deck portion 21 , with a lower end 103 thereof being supported in the base structure 41 pivoting towards the upright orientation as upending progresses.

[0137] In the embodiment of figures 11 and 13-15, a noise mitigation screen 52 is connected to the bottom end of the base structure 41 of the pile holding tool 40, allowing to surround the pile underneath the base structure when lowered to the seabed. This NMS 52 is to be upended along with the monopile to subsequently be lowered for mitigating noise during piling after said lowering. The connection between the NMS 52 and the base structure 41 is such that it can withstand the forces thereon induced by the weight of the NMS. The NMS can in this embodiment closely surround the monopile.

[0138] In a vessel according to the fourth aspect, the NMS is not connected to the base structure 41 so that the upending, and entailing requirements to the base structure connections, are avoided. Instead the NMS is directly suspended from the load bearing structure 55, providing the additional advantage of being movable along with the base structure in the X-Y plane.

Claims

1. -27-C L A I M S1 . Vessel (1) for pile installation, e.g. for installation of a pile (100) adapted to support an offshore wind turbine, e.g. a monopile, wherein the vessel has a hull with a bow and a stern, a crane (3a) mounted on the hull and configured for hoisting of the pile, and a pile holding system (4), wherein the hull of the vessel (1) has a longitudinal direction (X) and a transverse direction (Y), the stern of the vessel (1) comprising a recess (10) extending forward in the longitudinal direction (X) to a forward edge (11) of the recess (10), the recess (10) being flanked laterally by two lateral hull portions (6a, b) wherein the pile holding system (4) comprises:- a pile holding tool (40) configured to hold the pile (100) in an upright orientation at a pile installation location whilst restraining the pile in radial directions, the pile holding tool comprising:- a base structure (41) including a ring (41a) which comprises a ring base and one or more movable jaws, e.g. two semi-circular jaws, each jaw being movable between a closed position, wherein the ring forms a closed annulus, and an opened position,- a plurality of pile engaging devices (42) supported by the ring (41a) and distributed in an annular array about a center axis (41c) of the ring, which pile engaging devices (42) are configured to engage on a circumferential zone (101) of the pile, e.g. each pile engaging device (42) being provided with one or more pile guiding rollers, characterized in that the pile holding system (4) further comprises:- an X-Y motion support assembly (50) for the pile holding tool, the X-Y motion support assembly (50) providing controllable motion of the pile holding tool in the longitudinal and transverse directions (X,Y), wherein the X-Y motion support assembly (50) comprises:- a load bearing body (55) supporting the pile holding tool (40) above the recess (10),- an X-Y motion mechanism operative between the hull and the load bearing body (55), wherein the X-Y motion mechanism comprises controllable X-Y motion actuators for moving the load bearing body (55), and therewith a pile (100) held thereby in an upright orientation, relative to the hull, e.g. to compensate for vessel motion, and in that each of the lateral hull portions (6a, b) is provided with a respective lateral mount (51 a, b), e.g. on a deck portion of the lateral hull portion, wherein the X-Y motion support assembly (50) is supported on the lateral mounts (51a, b).

2. Vessel (1) according to claim 1 , wherein the X-Y motion mechanism comprises:- longitudinal motion tracks (57a, b), e.g. embodied as rails, supported by the lateral mounts (51 a, b), each longitudinal motion track extending in the longitudinal direction (X) of the hull of the vessel (1), and- transverse motion tracks (58a, b,c), e.g. embodied as one or more rails, supported by the longitudinal motion tracks (57a, b) such as to be movable in the longitudinal direction (X), each transverse motion track extending in the transverse direction (Y) of the hull of the vessel (1), wherein the load bearing body (55) is supported on the transverse motion tracks (58a, b,c), e.g. wherein the transverse motion tracks are a pair of rearward transverse motion tracks (58a, b) each on a respective one of the hull portions, and a pair of forward transverse motion tracks (58c) each on a respective one of the hull portions, each of the transverse motion tracks being supported on a respective one of the longitudinal motion tracks (57a, b).

3. Vessel according to claim 2, wherein the X-Y motion mechanism further comprises a subframe (59) which is movably supported on the longitudinal motion tracks (57a, b) so as to be movable in the longitudinal direction (X) relative to the lateral hull portions, and wherein the transverse motion tracks are provided on the load bearing body (55) and supported by the subframe so that the load bearing body (55) is movable in transverse direction (Y) relative to the subframe (59).

4. Vessel according to claim 3, wherein the subframe (59) is a U-shaped subframe in a top view, wherein legs of the subframe extend longitudinally, each leg along a respective one of the lateral hull portions, and wherein a transverse portion of the subframe (59) extends between the legs and parallel to the forward edge (11) of the recess (10), and wherein the longitudinal motion tracks (57a, b) extend underneath the legs, and wherein each of a pair of rearward transverse motion tracks (58a, b) extends above and transverse to a respective one of the legs.

5. Vessel according to any one or more of claims 1 - 4, wherein the load bearing body (55) has a U-shaped main body part in a top view, wherein legs of the main body part extend longitudinally, each leg along a respective one of the lateral hull portions, and wherein a transverse portion of the main body part extends between the legs and parallel to the forwardedge (11) of the recess (10), and wherein each leg of the main body part is provided with a lateral support portion thereon for the base structure.

6. Vessel according to any one or more of claims 1 - 5, wherein the lateral mounts (51a, b) extend longitudinally at or near the inward edge of the respective lateral hull portion (6a, b).

7. Vessel according to any one or more of claims 1 - 6, the vessel (1) further comprising a pile storage deck (21) extending forward of the recess (10), and wherein support cradles (80) are arranged on the pile storage deck (21) for supporting piles (100) with their length in the longitudinal direction (X) of the hull of the vessel.

8. Vessel according to any one or more of claims 1 - 7, wherein the pile holding system (4) is an integrated pile holding and upending system (4) also configured for supporting the pile (100) during upending thereof, wherein the base structure (41) is pivotally mounted to the load bearing body (55) about an upend pivot axis (41x) extending in the transverse direction (Y) allowing to, with a lower section of the pile being supported by the base structure (41), upend the pile from a horizontal orientation to an upright orientation, wherein, preferably, the base structure is provided with a pile foot end support (49) which is configured to engage with a foot end of a pile (100) in order to limit longitudinal movement of the pile during upending of the pile and to be disengaged from the foot end of the pile (100) allowing lowering of the pile to the seabed, e.g. the pile foot end support (49) being secured to and extending downward from the ring base of the base structure.

9. Vessel according to claim 8, wherein a pile support (7) for supporting the pile (100) is mounted to the deck (2) of the vessel near the forward edge of the recess, which pile support is configured for longitudinally guiding a pile (100) when being moved in longitudinal direction in order to engage the lower section thereof with the base structure.

10. Vessel according to any one or more of claims 1 - 9, preferably according to claim 8, wherein the base structure (41) of the pile holding tool (40) further comprises an additional pile restraining structure (45) comprising: one or more spacer arms (46a, b), each extending upward from the ring base of the ring (41a) along the center axis (41c) to a free end of the spacer arm, and one or more restraining members (47a, b) mounted to each spacer arm (46a, b), e.g. at or near the free end of the spacer arm,one or more clamping actuators (48a, b) operative between the spacer arm (46a, b) and the restraining members (47a, b) and configured to move the one or more restraining members into an operative position thereof in order to clamp the pile in a circumferential zone (102) remote from the circumferential zone engaged by the pile engaging devices (42) of the ring (41a), and into a clearance position clear from the pile, e.g. the one or more restraining members being in the operative position during upending of the pile and in clearance position during lowering of the pile in the upright orientation.11 . Vessel according to claim 10, wherein the restraining members (47a, b) are spaced at least 5 meters, e.g. 5 - 15 meters, e.g. around 8 meters, from the pile engaging devices (42).

12. Vessel according to claim 10 or 11 , wherein the one or more spacer arms (46a, b) are embodied as two diametrically opposed arms at respective lateral sides of the ring base of the base structure, each arm being provided with one or more of the restraining members (47a, b).

13. Vessel according to any one or more of claims 1 - 12, wherein the crane (3a) of the vessel (1) is mounted at a lateral edge of the hull of the vessel (1) forward of the recess (10).

14. Pile holding system (4) for use on a vessel (1) for installation of a pile (100), e.g. a pile adapted to support an offshore wind turbine, e.g. a monopile, wherein the vessel has a hull with a bow and a stern, a crane (3a) mounted on the hull and configured for hoisting of the pile, wherein the hull of the vessel (1) has a longitudinal direction (X) and a transverse direction (Y), the stern of the vessel (1) comprising a recess (10) extending forward in the longitudinal direction (X) to a forward edge (11) of the recess (10), the recess (10) being flanked laterally by two lateral hull portions (6a, b), wherein the pile holding system (4) comprises:- a pile holding tool (40) configured to hold the pile (100) in an upright orientation at a pile installation location whilst restraining the pile in radial directions, the pile holding tool comprising:- a base structure (41) including a ring (41a) comprising a ring base and one or more movable jaws, e.g. two semi-circular jaws, each jaw being movable between a closed position, wherein the ring forms a closed annulus, and an opened position,-31-- a plurality of pile engaging devices (42) supported by the ring (41a) and distributed in an annular array about a center axis (41c) of the ring (41a), which pile engaging devices (42) are configured to engage on a circumferential zone (101) of the pile, e.g. each pile engaging device (42) being provided with one or more pile guiding rollers, characterized in that the pile holding system further comprises:- an X-Y motion support assembly (50) for the pile holding tool, the X-Y motion support assembly (50) providing controllable motion of the pile holding tool in the longitudinal and transverse directions (X,Y), wherein the X-Y motion support assembly (50) comprises:- a load bearing body (55) supporting the pile holding tool (40) above the recess (10),- an X-Y motion mechanism operative between the hull and the load bearing body (55), wherein the X-Y motion mechanism comprises controllable X-Y motion actuators for moving the load bearing body (55), and therewith a pile (100) held thereby in an upright orientation, relative to the hull, e.g. to compensate for vessel motion, and in that the pile holding system (4) further comprises lateral mounts (51 a, b) configured to be provided each on a respective lateral hull portion (6a, b), e.g. on a deck portion of the lateral hull portion, wherein the X-Y motion support assembly (50) is configured to be supported on the lateral mounts (51 a, b).

15. Vessel (1) for pile installation, e.g. for installation of a pile (100) adapted to support an offshore wind turbine, e.g. a monopile, wherein the vessel has a hull with a bow and a stern, a crane (3a) mounted on the hull and configured for hoisting of the pile, and an integrated pile holding and upending system (4), wherein the hull of the vessel (1) has a longitudinal direction (X) and a transverse direction (Y), the stern of the vessel (1) comprising a recess (10) extending forward in the longitudinal direction to a forward edge (11) of the recess (10), the recess (10) being flanked laterally by two lateral hull portions (6a, b), wherein the integrated pile holding and upending system (4) comprises:- a pile holding tool (40) configured to hold the pile (100) in an upright orientation at a pile installation location whilst restraining the pile (100) in radial directions, the pile holding tool(4) comprising:- a base structure (41) including a ring (41a) which comprises a ring base and one or more movable jaws, e.g. two semi-circular jaws, each jaw being movable between a closed position, wherein the ring forms a closed annulus, and an opened position,-32-- a plurality of pile engaging devices (42) supported by the ring (41a) and distributed in an annular array about a center axis (41c) of the ring, which pile engaging devices (42) are configured to engage on a circumferential zone (101) of the pile, e.g. each pile engaging device (42) being provided with one or more pile guiding rollers,- a support assembly (50) for the pile holding tool, which comprises:- a load bearing body (55) supporting the pile holding tool (40) above the recess (10), wherein the base structure (41) is pivotally mounted to the load bearing body (55) about an upend pivot axis (41x) extending in the transverse direction (Y) allowing to, with a lower section of the pile being supported by the base structure (41), upend the pile from a horizontal orientation to an upright orientation, wherein, preferably, the base structure is provided with a pile foot end support (49) which is configured to engage with a foot end of a pile in order to limit longitudinal movement of the pile during upending of the pile and to be disengaged from the foot end of the pile (100) allowing lowering of the pile to the seabed, e.g. the pile foot end support (49) being secured to and extending downward from the ring base of the base structure, wherein each of the lateral hull portions (6a, b) is provided with a respective lateral mount (51 a, b), e.g. on a deck portion of the lateral hull portion, wherein the support assembly (50) is supported on the lateral mounts (51 a, b).

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