DK181248B1

DK181248B1 - Roll and pitch compensating platform for a vessel and method for onloading a structure, e.g. a wind turbine structure from a vessel

Info

Publication number: DK181248B1
Application number: DKPA202170580A
Authority: DK
Inventors: Hedegaard Thomas; Just Sørensen Peter
Original assignee: Enabl As
Priority date: 2021-11-23
Filing date: 2021-11-23
Publication date: 2023-05-31
Also published as: DK202170580A1; WO2023093958A1

Abstract

The present disclosure relates to a roll and pitch compensating platform for stabilizing wind turbine elements on a vessel floating on a sea surface. The roll compensating platform comprises a base frame, a carrier frame, a middle frame, multiple actuators and a drive unit. The carrier frame is suspended in a double gimbal suspension formed by the base frame and the middle frame. The multiple actuators are adapted to provide a passive regulation to the carrier frame and to the middle frame respectively to maintain a substantially horizontal position of the carrier frame surface independently of the orientation of the base frame. The present disclosure furthermore relates to a vessel and a roll and pitch compensating system comprising the roll and pitch compensating platform and a method of operation the roll compensating platform.

Description

DK 181248 B1 1

Field of the disclosure

The present disclosure relates to a roll and pitch compensating platform for stabilizing wind turbine elements on a vessel floating on a sea surface. The roll compensating plat- form comprises - abase frame, - a carrier frame with a surface configured for supporting a component, e.g. a wind turbine element, - multiple actuators, and - adriver unit, wherein the actuators in a set of actuators are connected with a driver unit, and wherein each set of actuators is adapted to be operated in - alocked configuration, with each actuator locked in a set position, and - man unlocked configuration with the actuators adapted to provide a balanced po- sition of the connected carrier frame, such that the carrier frame surface is ar- ranged in a substantial horizontal position independently of the orientation of the base frame.

The present disclosure furthermore relates to a vessel and a roll and pitch compensating system comprising the roll and pitch compensating platform and a method of operation the roll compensating platform.

Background of the disclosure

The invention is specifically developed in connection with a marine vessel for trans- porting wind turbine components to offshore windfarms. The wind turbine components (including, but not limited to nacelles, blades and towers) are placed on a marine vessel, e.g. a barge for transporting the components from a logistics harbor/quayside to the offshore site for installation. At the offshore site, the components are lifted from the vessel and onto pre-installed foundations using a large marine crane.

DK 181248 B1 2

Today, the components, when loaded to the vessel deck at quayside, are typically se- cured to the vessel using sea-fastening connections such as bolted or welded connec- tions. This can be labor intensive and time consuming to prepare. Later when the com- ponents are to be removed from the vessel at the offshore site, the sea-fastening con- nections shall be disconnected, which again is labor intensive and time consuming, and can also pose a risk to personnel in vicinity of the component being released.

When using cranes off-shore installed on-site to unload the components from a floating vessel, it is required to release the sea-fastening connections at an instance, to avoid overloading the crane and damaging the vessel or components.

An increased need for quick and safe transfer of components for offshore wind turbines from a marine vessel such as a transport barge to jack-up ship is experienced. Especially there is a need to optimize the costly use of installation vessels, e.g. wind turbine instal- lation vessels (WTIV).

When transferring components from one vessel to another vessel or to a fixed structure it is known to use heave compensation. Heave compensation is used for reducing the influence of waves upon lifting and drilling operations. Both passive heave compensa- tion (PHC) and active heave compensation (AHC) are known in the offshore industry.

Furthermore, from WO2010/114359 a motion compensation device for compensating a carrier frame on a vessel for water motion is known. The disclosed system is an active system where an actuator system controls the carrier frame based on sensed movements of the vessel.

Furthermore, from WO2021/130133 a motion compensation device for compensating a carrier frame on a vessel for water motion as disclosed by way of introduction and as defined in the preamble of claim 1 is known. The disclosed system is operating with a base frame and a carrier frame. The is no disclose of a middle frame arranged between the base frame and the carrier frame.

DK 181248 B1 3

Object of the disclosure

It is an objective of the present disclosure to provide a device and a method for safe offshore transfer of components between a vessel floating on a sea surface and another offshore installation i.e., transfer where at least the vessel is influenced by wave move- ments. It is a further objective to provide a method and a system for safe and quick unloading of wind turbine tower section from a floating vessel to a wind turbine instal- lation vessel (WTIV), e.g. a jack-up ship or the like structure fixed to a seabed by using a crane.

One purpose of the disclosure is to uncouple any roll and pitch motions of the vessel from the components prior to lifting the components off the vessel with the aim of re- ducing risk of collisions between the component to be lifted and other equipment stored on the vessel, and to reduce the lateral load on any lifting device used, e.g. a crane.

Moreover, it is the purpose to provide a method and system to be used with any existing offshore wind turbine installation vessels (WTIV) using lifting devices such as a crane for offshore transfer of components.

Description of the disclosure

One objective of the disclosure is obtained with a roll and pitch compensating platform for stabilizing wind turbine elements on a vessel floating on a sea surface described by way of introduction and as defined in the preamble of claim 1 and being peculiar in that the roll and pitch compensating platform further comprises - amiddle frame, wherein said carrier frame is suspended in the middle frame along a first suspension axis and the middle frame is suspended in the base frame along a second suspension axis, such that the base frame and the middle frame forms a double gimbal suspension for the carrier frame, and wherein said roll and pitch compensating platform is adapted to be arranged on the vessel with the base frame in a fixed position with the carrier frame surface facing away from the base frame, wherein a first set of actuators comprises at least two actuators that connects the carrier frame to the base frame, with one actuator connected to one half of the carrier frame

DK 181248 B1 4 and another actuator connected to another half of the carrier frame, where the two halves of the carrier frame are defined by a division plane arranged perpendicular to the carrier frame along the first suspension axis, and a second set of actuators comprises at least two actuators that connects the middle frame to the base frame with one actuator con- nected to one half of the middle frame and another actuator connected to another half of the middle frame, where the two halves of the middle frame are defined by a division plane arranged perpendicular to the middle frame along the second suspension axis, such that the first set of actuators are arranged to execute a tilt movement of the carrier frame and the second set of actuators are arranged to execute a tilt movement of the middle frame relative to the base frame, wherein each set of actuators is further adapted to be operated in - an unlocked configuration with the actuators further adapted to provide a bal- anced position of the connected middle frame.

The roll and pitch compensating platform comprises a base frame, a middle frame, mul- tiple actuators and a driver unit.

The carrier frame comprises a surface configured for supporting a component, e.g. a wind turbine element.

The carrier frame may be suspended in the middle frame along a first suspension axis and the middle frame may be suspended in the base frame along a second suspension axis, such that the base frame and the middle frame forms a double gimbal suspension for the carrier frame. Hereby a more effective compensation is obtained compared to the compensation obtainable with the system according to WO 2021/130133

The roll and pitch compensating platform may be adapted to be arranged on the vessel with the base frame in a fixed position with the carrier frame surface facing away from the base frame.

A first set of actuators may comprise at least two actuators connecting the carrier frame to the base frame, with one actuator connected to one half of the carrier frame and an- other actuator connected to another half of the carrier frame, where the two halves of

DK 181248 B1 the carrier frame are defined by a division plane arranged perpendicular to the carrier frame along the first suspension axis

A second set of actuators may comprise at least two actuators connecting the middle 5 frame to the base frame with one actuator connected to one half of the middle frame and another actuator connected to another half of the middle frame, where the two halves of the middle frame are defined by a division plane arranged perpendicular to the middle frame along the second suspension axis.

The first set of actuators may be arranged to execute a tilt movement of the carrier frame and the second set of actuators may be arranged to execute a tilt movement of the middle frame relative to the base frame.

The actuators in a set of actuators may be connected to a driver unit. Each set of actua- tors may be adapted to be operated in a locked configuration and an unlocked configu- ration.

In the locked configuration, each actuator is locked in a set position.

In the unlocked configuration, the actuators are adapted to provide a balanced position of the connected carrier frame or middle frame, respectively, such that the carrier frame surface is arranged in a substantial horizontal position independently of the orientation of the base frame. L.e., the RCP may be considered a self-adjusting unit in the unlocked configuration.

The carrier frame is suspended in a double gimbal suspension formed by the base frame and the middle frame.

The multiple actuators are adapted to provide a passive regulation to the carrier frame and to the middle frame respectively to maintain a substantially horizontal position of the carrier frame surface independently of the orientation of the base frame.

The double gimbal suspension of the carrier frame in combination with the connected multiple actuators has the effect that the carrier frame moves independently of the base

DK 181248 B1 6 frame and hence the marine vessel, which will greatly reduce the instability and lateral movements of the components when the vessel is exposed for roll and pitch movements on a sea surface. Due to the uncoupling of the carrier surface from the base frame and hence the roll and pitch of the vessel, the component will be held in vertical stabled position such that the component can be lifted without influence of any roll and pitch angles inflicted on the vessel. The roll and pitch compensated platform (RCP) can there- for reduce the risk of collisions with other equipment on the vessel and reduce the lateral load on the wind turbine installation vessel crane during transfer of the component to be unloaded from the vessel when arranged on the RCP.

The double gimbal suspension may also be known as a cardan suspension or a universal- joint suspension.

One advantage of the RCP is to achieve safe, efficient, and trouble-free unloading of wind turbine tower sections from a vessel (floating feeder barge) to an offshore plat- form, e.g. a wind turbine installation vessel (WTIV) in open sea, e.g. at wave heights of up to 2.5m or even more.

The RCP may be welded to the deck of the vessel. It may be used to support the wind turbine towers during transport between quayside and the offshore installation.

The RCP may be designed to be used with a hook mounted heave compensator, e.g. a passive heave compensator, which can be mounted to the tower lifting yoke.

In further aspects according to the embodiment, the actuators may be linear actuators.

In a further aspect of the embodiment, the roll and pitch compensating platform may comprise multiple locking pins configured for mechanical locking the carrier frame and the middle frame directly or indirectly to the base frame when the roll and pitch com- pensating platform is operated in the locked configuration. This may provide for an additional safety configuration of the RCP during transport and/or loading of compo- nents to the carrier frame.

DK 181248 B1 7

According to a further embodiment of the roll and pitch compensating platform, the driver unit is configured for dampening the movement of the actuator in the actuator set when the actuators transition from the locked configuration to the unlocked configura- tion.

The dampening movement may be beneficial for stabilizing the carrier frame surface into a horizontal position when the RCP transition from the locked to the unlocked con- figuration. In the case, where the carrier frame surface is influenced by roll and pitch angles in the locked position, the dampening effect with ensure that the balanced posi- tion is obtained without abrupt movements originating from the actuators due to a fast regulation. Furthermore, the risk of an uncontrolled regulation cycle should be largely omitted by the dampening effect. In general, the dampening should be designed under consideration of the vessel and the intended load to obtain sufficient regulation of the system to achieve the balanced position of the carrier frame.

According to yet a further embodiment of the roll and pitch compensating platform, the drive unit may be configured to control a time interval of transition from the locked configuration to the unlocked configuration. The time interval may be in the range of 10-120 seconds, preferably 20-90 seconds, more preferably 30-60 seconds.

According to a further embodiment of the roll and pitch compensating platform, the base frame forms part of the marine vessel.

According to a further embodiment of the roll and pitch compensating platform, the base frame, and the carrier frame each comprises two pivot pin bushings and the middle frame comprises four pivot pin bushings. The base frame and the carrier frame may be pin connected to the middle frame via four connection pins arranged partly in the pivot pin bushings of the middle frame and partly in the pivot pin bushings of the base frame or the carrier frame.

According to a further embodiment of the roll and pitch compensating platform, the multiple actuators are hydraulic piston-cylinder units, and the drive unit comprises valves configured for a gradually opening function over time such as a ball valve or a throttle valve.

DK 181248 B1 8

According to yet a further embodiment of the roll and pitch compensating platform, the multiple actuators may be electrical or pneumatic actuators. A comparable unit to a throttle valve should be used in such embodiments, such that the actuators can be driven with a dampening effect built into the drive unit.

One effect of this embodiment may be to achieve a passive regulation of the carrier frame to achieve the balanced position of the carrier frame surface. Furthermore, the dampening effect in the transition from the locked configuration to the unlocked con- figuration of the actuator sets are built in by design when using the throttle effect.

The passive regulation system may rely on very little externally supplied power to op- erate. This may be achieved by use of hydraulic accumulators, with sufficient capacity to allow for an unload operation. The regulation system may thereby also be applied to revert to a safe position, where the carrier frame is adjusted by use of the multiple actu- ators and the stored pressure in the accumulators to a rightened position i.e., the carrier frame may be adjusted to be parallel to the base frame and/or the vessel deck, should the unloading operation be required aborted.

The RCP may be designed to be used with a hook mounted heave compensator, e.g. a passive heave compensator, which can be mounted to the tower lifting yoke before un- coupling of the roll and pitch motions.

According to a further embodiment, the roll and pitch compensating platform may com- prising a clamping system with an adaptor frame configured to be mounted on the com- ponent to be transported on the vessel, and a quick release clamping mechanism mounted on the carrier frame

The quick release clamping mechanism may be operated in a closed position, where the clamping mechanism locks the adaptor frame to the carrier frame.

The quick release clamping mechanism may be operated in an open position, where the adaptor frame is unlocked from the carrier frame, such that the component with the adaptor frame mounted is free to move relative to the carrier frame.

DK 181248 B1 9

The clamping system may be arranged on the carrier frame surface and may be config- ured for clamping a component, e.g. a wind turbine element to the carrier frame surface during transport.

In one aspect, the quick release clamping system may also be configured for quick and easy connection of the load (component to be transported) to the RCP, e.g. having snap fit connection for example in connection with guiding pins.

In another aspect, the quick release clamping mechanism may be designed to be me- chanically released or remote-controlled which enables the crane operator to disconnect the tower from the RCP at the press of a button.

One advantage, due to the quick release clamping mechanism may be that the RCP and hence the unloading may be performed without personal required to be aboard the vessel to operate the release mechanism.

In one aspect, the quick release clamping mechanism may comprise clamps with a clamp lever arranged rotatable on a pivot pin between an open and a closed position and which clamp lever comprises an operation portion at one side of the pivot pin for oper- ating the fastening clamp and a hook portion on the other side of the pin for engagement with the component to be secured. The hook portion may be arranged with an angle in relation to the clamp lever which angle is between 5° and 85°, preferably between 10° and 60° and more preferably between 15° and 25° to cooperate with a correspondingly angled surface associated with the component. The operation portion may be connected to a first clamping actuator, which is arranged for effecting a pivoting of the clamp lever between the closed position and the open position. The clamp lever may comprise an opening for cooperating with a fastening pin arranged on a second clamping actuator which is arranged for effecting a movement of the fastening pin between an engagement position in engagement with the opening in the clamp lever thereby locking the clamp lever against pivoting and a free position where the clamp lever is free to pivot. The first and second clamping actuators may be connected to a drive unit comprising a con- troller for effecting the desired movements of the actuators.

DK 181248 B1 10

Another objective of the disclosure is obtained with a marine vessel for transporting wind turbine elements on a sea surface comprising one or more roll and pitch compen- sating platforms according to one or more of the embodiments disclosed in these spec- ifications.

Yet another objective of the disclosure is obtained with a roll and pitch compensating system for offshore transfer of components from a marine vessel floating on a sea sur- face. The roll and pitch compensating system comprises a heave compensator and the roll and pitch compensated platform according to one or more of the embodiments dis- closed in these specifications.

Yet another objective of the disclosure is obtained through use of a roll and pitch com- pensating system for transferring components from a marine vessel floating on a sea surface to a wind turbine installation vessel (WTIV). The roll and pitch compensated platform being according to one or more of the embodiments disclosed in these speci- fications.

Yet another objective of the disclosure is obtained by a method of operating the roll and pitch compensating platform when loading a component onto a vessel. The roll and pitch compensated platform being according to one or more of the embodiments dis- closed in these specifications. The method comprises steps of: - proving the roll and pitch compensating platform to the vessel, - arranging the actuator sets in the locked configuration, and - transferring the component to the carrier frame.

Yet another objective of the disclosure is obtained by a method of operating the roll and pitch compensating platform when unloading a component from a vessel by lifting with a lifting unit. The roll and pitch compensated platform being according to one or more of the embodiments disclosed in these specifications. The method comprises steps of: - connect the lifting unit to the top part of the component, - proving a pretension to the component with the lifting unit, preferably with a heave compensator, - unlock the actuator sets from the locked configuration, and - raise the component from the carrier surface using the lifting unit.

DK 181248 B1 11

Yet another object of the invention can be obtained by using the using the valves with a throttle effect to unlock the actuators by opening the valves for the hydraulic fluid to flow free within the closed circuits to dampen the regulation for adjusting the carrier frame into the horizontal position with the passive regulation achieved by the throttle effect.

According to further aspects, the roll and pitch compensating platform and/or the roll and pitch compensating system may comprise a control system.

This may include one or more of the following items: e Control cabinet designed for offshore use and configured to be installed as an integrated part of the base frame. The cabinet may include all necessary electri- cal components like Power supply’s, Relays, Circuit breakers, PLC system etc. e The control system may be based on a PLC system, with integrated safety func- tionality. e Human user interface (HMI). The control system may equipped with a graphic user interface for presentation of status, diagnostic and parameter input. In ad- dition to the HMI may be a remote control with safety functionality included, the remote controller may be used for all ordinary operating of the platform functionality. e Battery unit(s), for monitoring of battery status and health status.

The control system may include necessary software functionality including hardware interface for stable and safe operating of following equipment units: e Hydraulic power unit(s) / accumulator racks. e Necessary functionality and In/Output for redundancy operation and monitoring for the two hydraulic power units. E.g. monitoring of oil temperature, oil level, oil pressure etc. Controlling of valves and auxiliary equipment like cooling fans etc. e Digital and analogue output for valve control of the multiple actuators (the hy- draulic roll and pitch actuators). e Position feedback of respectively the first and second suspension axis, which may be used for monitoring of roll and pitch axis movements and positions.

DK 181248 B1 12 e Position limit monitoring at the roll and pitch axis, which may be used to mon- itor that the axes are within their legal operating area. e Motion Reference Unit (MRU) for roll and pitch axis. The MRU may be ar- ranged at the carrier frame and may be used for monitoring of the carrier frame position related to an absolute horizontal plane. e Digital output for all locking or clamping mechanisms. e Digital input for position feedback (Locked / Unlocked) of all locking or clamp- ing mechanisms. e Emergency system with any necessary emergency push button. e Interface between the RCP control system and the crane cabin. e Interface between the RCP with component to be transporter, e.g. a tower bot- tom flange.

Description of the Drawing

In the following embodiments of the present invention will be further explained with reference to the accompanying drawing, in which:

Fig. 1 illustrates one embodiment of the roll compensated platform,

Fig. 2 illustrates a vessel with a pair of RCP anchored up to a jack-up platform with a crane,

Figs. 3-6 illustrate the frames of the roll compensation platform,

Figs. 7 to 11 illustrate different embodiments of drive units,

Figs. 12 and 13 illustrate a vessel transporting a wind turbine tower section using a roll compensating platform, and

Figs. 14-31 illustrate one example of an operation of loading and unloading a wind turbine tower section to and from a roll compensating platform.

Detailed Description of the disclosure

In the different figures identical or corresponding elements will be denoted with the same reference numeral. Accordingly, each item will not be described in connection with each figure.

No Item

DK 181248 B1 13 1 roll and pitch compensating platform 2 first suspension axis 3 second suspension axis 6 locking pin 8 locking bushings base frame 12 base plane 20 carrier frame 22 carrier frame surface 10 30 middle frame 40 clamping system 42 adaptor frame 44 quick release clamping mechanism 46 sea-fastening clamping mechanism 60 actuators 62 actuator housing 64 piston 66 first set of actuators 68 second set of actuators 70 marine vessel 80 hydraulic circuit 82 valve 84 drive unit 90 pivot pin bushings 92 connection pins 100 roll and pitch compensating system

Fig. 1 illustrates one embodiment of the roll and pitch compensated platform 1 com- prising the base frame 10, the carrier frame 20 and the middle frame 30. The carrier frame 20 is suspended from the middle frame 30 along the first suspension axis 2, such that the carrier frame is allowed to tilt or pivot around the first suspension axis 2.

DK 181248 B1 14

The middle frame 30 is suspended from the base frame 10 along the second suspension axis 3, such that the middle frame is allowed to tilt or pivot around the second suspen- sion axis 3.

The carrier frame 20 is illustrated with a clamping system 40 arranged on the carrier frame surface 22. The illustrated embodiment of the clamping system 40 includes an adapter frame 42, quick release clamping mechanisms 44, and sea-fastening clamping mechanisms 46.

The carrier frame and the middle frame are suspended by pin bushings 90 and connec- tion pins 92 extending through the pivot pin bushings.

Figure 2 illustrates a vessel 70 anchored up to a jack-up platform with a crane, e.g. a wind turbine installation vessel (WTIV). The illustrated vessel comprises two roll and pitch compensating platforms 1 each carrying a wind turbine tower section. The wind turbine tower sections are lifted from the vessel by use of a tower lifting yoke in the top of the tower section.

The embodiment in figure 2 illustrates a 400ft x 100ft vessel (feeder barge).

Figure 3 illustrates an embodiment of the base frame 10 comprising ten actuators 60.

The actuators are arranged in a first set of actuators 66 and a second set of actuators 68. the actuators are connected to the base frame 10 with the actuator housing 62 in an upright position from the base frame, such that the actuators 60 can be connected re- spectively to the middle frame 30 or the carrier frame 20 via the pistons 64.

The actuators and arranged in two sets, a first set 66 and a second set 68.

The first set of actuators 66 comprises six actuators 60 configured to be connected to the base frame 10 and the carrier frame 20. The first set of actuators are arranged such that three of the six actuators can be connected to one half of the carrier frame, and the other three actuator can be connected to the other half of the carrier frame. The two halves of the carrier frame are defined by a division plane arranged perpendicular to the carrier frame along the first suspension axis (2). The division plane is not illustrated.

DK 181248 B1 15

The second set of actuators 68 comprises four actuators 60 configured to be connected to the base frame 10 and the middle frame 30. The second set of actuators are arranged such that two of the four actuators can be connected to one half of the middle frame, and the other two actuator can be connected to the other half of the middle frame. The two halves of the middle frame are defined by a division plane arranged perpendicular to the middle frame along the second suspension axis (2). The division plane is not illustrated.

In figure 3 additional units such as accumulators, drive units and tanks are illustrated.

These may be used for operating the roll and pitch compensating platform system in specific configurations.

The multiple actuators 60 are adapted to obtain a balanced position of the carrier frame and the middle frame respectively to maintain a substantially horizontal position of the carrier frame surface 22. This may be achieved by passive regulation, where the actua- tors in each set are connected in a closed circuit, such that the actuators in one actuator set provides balanced forces to the frame, to which they are connected thereby compen- sating for any roll and pitch motion of the base frame.

In another configuration, it may be beneficial to be able to set the actuators to an initial set-point where the carrier surface for example is parallel to the base frame and lock the actuators in this initial position. This could be in the case of loading a component onto the roll and pitch compensating platform, where a steady plane is preferred for placing the component in the correct position, e.g. when loading the component from quayside.

The illustrated base frame 10 furthermore comprises four locking bushings 8 configured for receiving locking pins 6. The locking bushings are provided to include an option of mechanical locking the middle frame to the base frame in a position where the tilt of the middle frame is pre-determined by the position of the holes 8 in the base frame and a corresponding set of holes in the middle frame where a set of locking pins can be arranged.

The base frame may comprise a steel support structure welded to the vessel deck.

DK 181248 B1 16

The RCP may comprise at least four actuators arranged such that two actuators corrects for roll and pitch movements of the carrier frame and two actuators corrects for roll and pitch movements of the middle frame. However, the number of actuators should be ad- justed according to the load intended to be carried, the actuators max load etc.

The RCP may furthermore include accumulator racks, hydraulic power unit (for redun- dancy), battery units, control cabinet, etc. These elements are illustrated in figure 1, here arranged at the centre of the base frame. They may be arranged in other configurations than those shown here.

In one aspect, the weight of the base frame according to the illustrated base frame may be in the magnitude of 90 tons i.e., including all the illustrated items.

The base frame may be specially designed to a given vessel. Hence, the weight and design may be subject to change according to the specific vessel.

Figure 4 illustrates one environment of the middle frame 30. The middle frame com- prises four pivot pin bushings 90 adapted for connection with respectively the base frame 10, see figure 3 and the carrier frame 20, see figure 5. The pivot pin bushings in the three frames and the connecting pins 92 accommodate for the double gimbal sus- pension of the carrier frame. The middle frame comprises twelve locking pins 6. The locking pins are arranged in a configuration where four of the locking pins are config- ured for interacting with locking bushings of the carrier frame, and the remaining eight locking pins 6 are configured for interacting with locking bushings of the base frame.

The middle frame may comprise a steel support structure.

In one aspect, the weight of the middle frame according to the illustrated embodiment may be in the magnitude of 45 tons i.e., including all the illustrated items.

The middle frame may be specially designed to the base frame and the given vessel.

Hence, the weight and design may be subject to change according to the specific vessel.

DK 181248 B1 17

Figure 5 illustrates one embodiment of the carrier frame 20. The carrier frame comprises four locking bushings 8 configured for receiving locking pins 6. The locking bushings are provided to include an option of mechanical locking the carrier frame to the middle frame in a position where the tilt of the carrier frame is locked in a pre-determined position defined by the position of the holes 8 in the carrier frame and a corresponding set of holes in the middle frame where a set of locking pins can be arranged.

The carrier frame is illustrated with four quick release clamping mechanisms 44 and six sea-fastening clamping mechanisms 46 forming part of one embodiment of a clamping system 40.

The carrier frame may comprise a steel support structure.

In one aspect, the weight of the middle frame according to the illustrated embodiment may be in the magnitude of 55 tons i.e., including all the illustrated items.

The carrier frame should be designed in accordance with the base frame, the middle frame, and the given vessel. Hence, the weight and design may be subject to change according to the specific vessel.

Figure 6 illustrates one embodiment of an adapter frame 42. The adapter frame can be comprised as part of a clamping system 40 for clamping the component to be transported to the carrier frame surface. Alternatively, it can be included as an integral part of the tower section. The illustrated adapter frame is configured for a wind turbine tower sec- tion and are configured for initially mounting onto the wind turbine tower section by bolts before loading the wind turbine tower section onto the roll and pitch compensating platform on the vessel. The illustrated adapter frame is configured to interact with the clamping mechanisms illustrated in figure 5. the adapter frame is one alternative for creating an interface between the roll and pitch compensating platform and the compo- nent to be transported. Alternatively, the component itself can be configured such that it by design comprises features adapted for interacting with the clamping system 40 of the roll and pitch compensating platform 1.

DK 181248 B1 18

The adaptor frame may comprise a steel support structure. It may be adapted with in- terfaces to clamp designs of the clamping mechanisms and alignment pins, which may be arranged in the carrier frame, see figure 5 for illustration of the alignment pins.

In one aspect, the weight of the adaptor frame according to the illustrated embodiment may be in the magnitude of 25 tons.

The adaptor frame should be designed in accordance with at least the carrier frame and the component to be transported. Hence, the weight and design may be subject to change according to the specific embodiment of the RCP.

Figure 7 illustrates a drive unit 84 for the actuators 60. The drive unit comprises a hy- draulic system including an oil tank and pressure tanks. Moreover, the drive unit com- prises multiple valves 82, which can be controlled to operate the actuators 60 in a de- sired way. Through the valves 82 it is possible to affect a movement of the actuators 60 in order to passively or actively regulate the actuators in order to control the position of the carrier frame 20.

The drive unit can be operated such that a closed circuits for each set of actuators 66,68 are established within each closed circuit, the hydraulic fluid is allowed to flow free to obtain balanced position of the middle frame or the carrier frame, respectively. Hence, this is the feature that provides the roll and pitch compensating feature.

In one embodiment, the valves 82 may be of a type where a throttle effect can be achieved when opening the valve. The throttle effect can be useful in the situation where the roll and pitch compensating platform 1 is used for transporting components in the locked position to the offshore installation with the actuators also in a set position. Once the vessel has reached the destination point of the offshore installation, and the lifting device is connected to the component, the roll and pitch compensating platform can be unlocked, to allow for passive regulation of the platform. Unlocking the actuators means opening the valves for the hydraulic fluid to flow free within the closed circuits. Using valves with a throttle effect ensures that the carrier frame slowly adjusts into the hori- zontal position to be obtained with the passive regulation without any abrupt move- ments of the carrier or middle frame.

DK 181248 B1 19

Figures 8 to 11 illustrate four different embodiments of drive units, which can be applied for controlling the operation of the clamping mechanisms 44,46 and the locking pins 6.

The embodiment in figure 8 illustrates a drive unit for controlling eight locking pins for locking the middle frame to the base frame, and the embodiment in figure 9 illustrates a drive unit for controlling four other locking pins for locking the middle frame to the carrier frame, see figure 4 for illustration of the middle frame with the locking pins 6.

The embodiment in figure 10 illustrates a drive unit for controlling six sea-fastening clamping mechanisms 44, which may be comprised in one embodiment of the clamping system 40. The embodiment in figure 11 illustrates a drive unit for controlling four quick release clamping mechanisms 46, which may be comprised in one embodiment of the clamping system 40, see figure 5 for illustration of one embodiment of the clamp- ing system 40 comprising both sea-fastening clamping mechanisms 44 and quick re- lease clamping mechanisms 46.

Figure 12 and 13 illustrate a vessel 70 transporting a wind turbine tower section using a roll and pitch compensating platform 1, where the roll and pitch compensating plat- form is in a locked state (passive, no regulation) in figure 12 and in an unlocked state in figure 13 (active, regulating). From figure 13 it is seen that the tower section pre- tensioned by the crane is held in a substantially vertical position independently of the vessel roll or pitch movements, e.g. due to waves.

Figures 14-31 illustrate one example of how an operation of loading and unloading a wind turbine tower section to and from a roll and pitch compensating platform 1 com- prised in or on a vessel 70 can be performed. The operation is described according to the embodiment of the roll and pitch compensating platform illustrated in the same fig- ures 14-31.

The tower section is mounted on a corresponding adapter frame 42. The tower adapter may be customized for each project 1.e., also for other components to be transported.

DK 181248 B1 20

Before loading the tower section to the roll and pitch compensating platform 1, the plat- form by be operated in a locked position, where the position of the carrier frame is locked relative to the base frame, either by pre-setting and locking the actuators 60 in an initial position and/or by use of locking pins 6. The locking pins 6 can be used to lock the middle frame to the base frame and/or the carrier frame, see for example figures 25 and 26, where the locking pins are arranged in complementary locking bushings 8 such that the frames are engaged accordingly.

The tower section is lifted onto the roll and pitch compensating platform comprised in or on the vessel.

When the tower is arranged with the clamping system 40 aligned, the two separate clamping systems respectively comprising quick release clamping mechanisms 44 and sea-fastening clamping mechanisms 46 will lock the tower section to the roll and pitch compensating platform 1.

In figures 18 and 19 one embodiment of the sea-fastening clamping mechanism 46 is illustrated in unlocked and locked position respectively. The embodiment comprises an actuator with a C-shaped clamp clamping the adaptor frame to the carrier frame. The sea-fastening clamps may be driven by a hydraulic system, where accumulators are used to store pressure-volume so very little pump capacity is needed.

The sea-fastening clamping mechanism 46 may be a slow operating system as the time to lock and unlock in not a critical feature for the operation. The time for operation such clamps could for example be in the range of 5-10 seconds but longer operation time up to 30 or 60 seconds would be acceptable just as a fast operation time below the 5 seconds can be implemented.

In figures 20 and 21 one embodiment of the quick release clamping mechanism 44 is illustrated in unlocked and locked position respectively.

The embodiment comprises an actuator driving a clamp arm, which interfaces with the adapter frame 42 at an angle. The clamping angle means that once the clamp pressure is removed, the clamps can be opened by lifting the tower. The actuators may be driven

DK 181248 B1 21 by a hydraulic system, where hydraulic accumulator bottles connected locally to the piston of the actuator can ensure that the clamps can be opened very quickly (<Is).

The tower is now secured to the roll and pitch compensating platform and is ready for transport.

For the illustrated embodiment of the roll and pitch compensating platform, the load, here the tower section, can only be lifted and transferred from the roll and pitch com- pensating platform when both clamping mechanisms 44,46 are unlocked.

When the vessel arrives at the installation vessel, a rigging, e.g. a quick connector is attached to the tower lifting yoke, see figure 24. Figure 24 also illustrates one example of the roll and pitch compensating system 100.

The crane can now start the lift, to build up a pre-tension, e.g. in a heave compensator, e.g. ~10-20% of load weight. When the desired force has been reached, the roll and pitch compensating platform can transition into the unlocked position.

As a first step, if the locking pins have been used, the locking pins may be moved to disengage the frames from each other, such that the carrier frame is released in both roll and pitch directions, se figures 27 and 28 for disengagement of the frames by moving the locking pins.

The actuators 60 remain locked until the locking pins are removed. After the locking pins are removed, the actuators 60 can transit into the unlocked configuration for pas- sive regulation, thereby initiating the uncoupling of roll- and pitch motions. The un- locking of the actuators 60 may be performed gradually over a set time period to avoid any abrupt movements of the carrier frame.

The roll and pitch compensating platform is now gradually achieving the uncoupling of the pitch- and roll motions over the set time period, e.g. 30-60 seconds by reducing the pressure in the actuators. For hydraulic cylinders the pressure is controlled passively by a gradually opening of one or more sets of flow valves, such that the flow valves are used as orifices to generate a pressure loss across the valves.

DK 181248 B1 22

After the set time period the roll and pitch compensating platform is uncoupled for roll and pitch motions, leaving the barge to roll and pitch while the tower remain in a vertical and nearly static position, see figure 29.

Once the roll and pitch compensating platform is in the unlocked position, the sea-fas- tening clamping mechanism can be released, such that the tower is only locked to the carrier frame by the quick release clamping mechanism.

When the condition for performing the lift is sufficient, the quick release clamping mechanism can be released. The tower section can now be lifted from the roll and pitch compensating platform with little instability to follow.

The heave compensator will swiftly remove the tower from the platform, due to stored capacity due to the applied pre-tension and/or built-in quick lift function or by reeling in the hoist wire by the crane.

The RCP can be operated to return to the locked position should the lift be aborted prior to release of the quick release clamping mechanism. This operation includes: - closing the sea-fastening clamping mechanism if included in the RCP to be used, - rightening the carrier frame to be substantial parallel to base frame or the vessel deck such that the component to be transported, e.g. a wind turbine tower section to be per- pendicular to base frame or the vessel deck; actuators with position control may be used to rightening the carrier frame and the middle frame, and - engaging the base frame, the middle frame and the carrier frame by use of the locking pins.

Claims

DK 181248 B1 23 PATENT CLAIM

1. A roll and height compensating platform (1) for stabilizing wind turbine elements on a vessel (70) floating on a sea surface, which roll and height compensating platform (1) comprises: - a base frame (10), - a support frame ( 20) with a surface (22) configured to support a component, e.g. a wind turbine element, - multiple actuators (60) and - a drive unit (84), wherein the actuators of a set of actuators are connected to the drive unit (84), and wherein each set of actuators is adapted to be operated in - a locked configuration, with each actuator locked in a set position, and - an unlocked configuration with the actuators adapted to provide a balanced position of the connected support frame such that the support frame surface (22) is placed in a substantially horizontal position independent of the orientation of the base frame, characterized by , that the roll and height compensating platform (1) further comprises - an intermediate frame (30), where the support frame (20) is suspended in the intermediate frame (30) along a first suspension axis (2), and the intermediate frame (30) is suspended in the base frame (10) along another suspension axis (3), so that the base frame (10) and the intermediate frame (30) form a double cardan suspension for the support frame (20) and the one where the roll and height compensating platform (1) is arranged to be placed on the vessel with the base frame (10) in a fixed position with the support frame surface (20) facing away from the base frame, a first set of actuators (66) comprising at least two actuators (60) connecting the support frame (20) with the base frame (10), with an actuator connected to one half of the support frame and another actuator connected to another half of the support frame, the two halves of the support frame (10) being defined by a division plane arranged perpendicular to the support frame along the first suspension axis (2), and a second set of actuators (68) comprising at least two actuators (60) connecting the intermediate frame (30) to the base frame (10) with one actuator connected to one half of the intermediate frame and another actuator connected to a second half of the intermediate frame, where the two halves of the intermediate frame frame (30) are defined by a dividing plane placed perpendicular to the intermediate frame along the second suspension axis (3), so that the first set of actuators is

DK 181248 B1 24 arranged to perform a rocking movement of the support frame and the second set of actuators. actuators are adapted to effect e a rocking movement of the intermediate frame relative to the bottom frame (10), each set of actuators being further adapted to be operated in - an unlocked configuration with the actuators further adapted to provide a balanced position of the connected middle frame.

2. The roll and height compensating platform (1) of claim 1, wherein the drive unit (84) is configured to dampen the movement of the actuator in the actuator set when the actuators transition from the locked configuration to the unlocked configuration configuration.

3. Roll and height compensating platform (1) according to any one of the preceding claims, wherein the drive unit (84) is configured to control a time interval for transition from the locked configuration to the unlocked configuration, which time interval is in the range of 10-120 seconds, preferably 20-90 seconds, more preferably 30-60 seconds.

4. Roll and height compensating platform (1) according to one or more of the preceding claims, where the base frame (10) forms part of the vessel (70).

5. Roll and height-compensating platform (1) according to one or more of the preceding claims, wherein the base frame (10) and the support frame (20) each comprise two pivot bushings (90) and the intermediate frame (30) comprises four pivot bushings (90), and where the base frame (10) and the support frame (20) are pivotally connected to the intermediate frame (30) via four connecting steps (92), which are placed partly in the pivot bushings of the intermediate frame and partly in the pivot bushings of the base frame (10) or the support frame (20).

6. Roll and height compensating platform (1) according to one or more of the preceding claims, wherein the plurality of actuators (60) are hydraulic piston-cylinder units and the drive unit comprises valves configured for a gradually opening function over time such as a ball valve or a throttle valve.

Roll and height compensating platform (1) according to one or more of the preceding claims, comprising a clamping system (40) with an adapter frame (42) configured to be mounted on the component to be transported on the vessel and a

DK 181248 B1 25 quick-release mechanism (44) mounted on the carrier frame (20), where the quick-release mechanism (44) is operated in a closed position, where the clamping mechanism locks the adapter frame (42) to the carrier frame (20) and in an open position, where the adapter frame (42) is unlocked from the support frame (20) so that the component with the adapter frame mounted is free to move relative to the support frame.

8. Marine vessel (70) for transporting wind turbine elements on a sea surface, comprising one or more rolling and height-compensating platforms (1) according to one or more of the preceding claims.

9. Roll and height compensating system (100) for offshore transfer of components from a marine vessel floating on a sea surface, which roll and height compensating system (100) comprises a heave compensator, a quick release system and a roll and height compensating platform (1) according to one or more of claims 1-7.

10. Use of a roll and height compensating system (1) according to claim 9 for transferring ring components from a marine vessel floating on a sea surface to a wind turbine installation vessel (WTIV).

11. Method for operating the roll and height compensating platform (1) according to one or more of claims 1-7 when a component is loaded onto a vessel (70), which method comprises steps: - providing the roll and height compensating platform (1) on the vessel, - arranging the actuator sets in the locked configuration, and - transferring the component to the support frame (20).

12. Method for operating the roll and height compensating platform (1) according to one or more of claims 1-7 when a component is unloaded from a vessel by lifting with a lifting unit, which method comprises steps: - connect the lifting unit to the upper part of the component, - providing a bias to the component with the lifting unit, preferably with a heave compensator, - unlocking the actuator sets from the locked configuration, and - raising the component from the airfoil using the lifting unit.