GB2516487A

GB2516487A - Marine transfer system

Info

Publication number: GB2516487A
Application number: GB1313227.9A
Authority: GB
Inventors: George Swietlik; Christopher Duggan
Original assignee: AKD ENGINEERING Ltd
Current assignee: AKD ENGINEERING LIMITED
Priority date: 2013-07-04
Filing date: 2013-07-04
Publication date: 2015-01-28
Also published as: EP2829468A3; GB201313227D0; EP2829468A2

Abstract

A marine transfer system 1 for securing a marine vessel 2 to a structure 4 comprises a platform assembly 6 configured to carry personnel and/or materials, a bumper member 8 configured to contact the structure and a gripping assembly 10 configured to selectively engage the structure to secure the marine transfer system to the structure. The gripping assembly comprises one or more gripping elements (12, Fig 2b) coupled to the bumper member and a force transfer mechanism (14, Fig 2b) that operatively connects the bumper member to the gripping elements. In other embodiments the transfer system also comprises a gangway assembly 18 configured to carry personnel and/or materials and a support assembly (20, Fig 4) configured to support the gangway assembly and permit vertical movement with respect to the marine vessel.

Description

Marine transfer system This invention relates to a marine transfer system and method and specificafly, but not exclusively, relates to a marine transfer system for transferring personnel and/or materials between a marine vessel and a structure.

Background

The transfer of personnel and materials from a marine vessel to other structures, such as offshore wind turbines, is an important consideration for the offshore industry. In particular, there are a number of factors to consider when determining the safety and the efficiency of the transfer, especially in adverse weather conditions. As such, transferring personnel and/or materials from the marine vessel to the structure is one of the most hazardous operations undertaken during the construction and maintenance of an offshore wind turbine.

Transfer of personnel and materials occurs on a regular basis after the initial installation as part of the servicing/maintenance of the turbine and personnel may be required to carry heavy loads from the marine vessel to the structure. The mast of the turbine has access ladders for personnel to climb onto from the marine vessel as a means of reaching the nacelle, where the turbine mechanisms, gearboxes and generators are housed. Currently there is a risk of personal injury and material damage as the personnel involved must judge the safest time to step from the front of the marine vessel to the rungs of the ladder on the mast as the marine vessel moves about in the sea.

Moreover, there exists an operating window outside of which the safe transfer of personnel and/or materials is not possible. Currently, the marine vessels used for transfer purposes must satisfy the UK MCA Small Commercial Vessels Code. This means that in seas above 1 m (sea state 3 on the Beaufort scale), which is a common occurrence, the vessels do not provide enough stability to allow personnel to safely step from the vessel to the ladder on the mast of the turbine. As weather conditions worsen, the increased rotational (pitch, roll and yaw) and translational (sway, heave and surge) motions of the vessel reduces safety even further. As such, the operational window in which maintenance/servicing is possible becomes heavily dependent upon weather conditions.

A known procedure for personnel and/or materials transfer is to engage the marine vessel against a structure on the mast of the turbine and apply a large amount of thrust to maintain engagement with the structure. However, legislative policies, such as The Energy Efficiency Design ndex (EEDI) and the Ship Energy Efficiency Management Plan (SEEMP), are driving for a reduction in the overall emissions generated by marine vessels. It is undesirable therefore to sustain prolonged periods of full throttle in order to maintain engagement of the marine vessel with the structure. Hence, current marine vessels are specifically designed to be small and lightweight, to reduce emissions and to allow the vessel to attend to several turbines within the operating window. For this reason, there are specific constraints regarding the size and weight of a marine transfer system for a marine vesseL The offshore wind industry is currently implementing the use of marine vessels to service and maintain the current (Phase 2) wind turbines. However, the next stage of wind turbines (Phase 3) to be installed around the coast of the UK and elsewhere will be in deeper water with larger swell (sea state 5 on the Beaufort scale) and further offshore than the Phase 2 turbines. This provides further restrictions on the operating window in which a marine vessel and its transfer system must operate.

It is known to provide a marine transfer system for a marine vessel that allows for the transfer of personnel and/or materials to a structure during adverse weather conditions.

However, such systems are often heavy, large and expensive as they implement hydraulic/robotic mechanisms with complex feedback systems. See for example US2O1 1/0038691 Al and GB2480408 A. Furthermore, as such systems are mounted to the front of the marine vessel, the visibility from the cabin of the marine vessel may be significantly impaired when using current marine transfer systems.

The present invention therefore seeks to address these issues.

Statements of Invention

According to a first aspect of the present invention there is provided a marine transfer system for transferring personnel and/or materials between a marine vessel and the structure. The marine transfer system is configured to secure the marine vessel to the structure. The marine transfer system comprises: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; a bumper member movably coupled to the platform assembly, wherein the bumper member is configured to contact the structure and is movable relative to the platform assembly between a first position and a second position; and a gripping assembly. The gripping assembly comprises: one or more gripping elements, e.g. latching elements, coupled to the bumper member, wherein the gripping elements are configured to selectively engage the structure to secure the marine transfer system to the structure; and a force transfer mechanism that operatively connects the bumper member to the gripping elements, the force transfer mechanism being configured to actuate the gripping elements from an open position to a closed position in which the marine transfer system is secured to the structure upon movement of the bumper member from the first position to the second position.

The marine transfer system may further comprise: a gangway assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a support assembly configured to support the gangway assembly and permit vertical movement with respect to the marine vessel. The support assembly may comprise: a winch assembly; and one or more cables coupled to the support assembly and/or the gangway assembly. The cables may be wound round the winch assembly so that the winch assembly is operable to adjust the length of unwound cable to maintain a tension force in the cable and permit the vertical movement of the gangway assembly with respect to the marine vessel.

The gripping assembly may be further configured to couple the platform assembly to the structure. The gripping assembly may be further configured such that when an upward force is applied to the platform assembly, the one or more gripping elements move into a first position relative to the structure in which the gripping assembly is able to slide upwards with respect to the structure, The gripping assembly may be further configured such that when the upward force is not applied to the platform assembly, the one or more gripping elements move into a second position relative to the structure in which the gripping assembly grips the structure and prevents downwards movement of the gripping assembly with respect to the structure.

According to a second aspect of the present invention there is provided a marine transfer system for transferring personnel and/or materials between a marine vessel and a structure.

The marine transfer system comprises: a gangway assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a support assembly configured to support the gangway assembly and permit vertical movement of the gangway assembly with respect to the marine vessel. The support assembly comprises: a winch assembly; and one or more cables coupled to the support assembly and/or the gangway assembly, the cables being wound round the winch assembly so that the winch assembly is operable to adjust the length of unwound cable to maintain a tension force in the cable and permit the vertical movement of the gangway assembly with respect to the marine vessel.

The marine transfer system may further comprise: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a gripping assembly configured to couple the platform assembly to the structure. The gripping assembly may comprise one or more gripping elements. The gripping assembly may be configured such that when an upward force is applied to the platform assembly, the one or more gripping elements move into a first position relative to the structure in which the gripping assembly is able to slide upwards with respect to the structure. The gripping assembly may be further configured such that when the upward force is not applied to the platform assembly, the one or more gripping elements move into a second position relative to the structure in which the gripping assembly grips the structure and prevents downwards movement of the gripping assembly with respect to the structure.

The marine transfer system may further comprise: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; a bumper member movably coupled to the platform assembly, wherein the bumper member may be configured to contact the structure and is movable relative to the platform assembly between a first position and a second position; and a gripping assembly. The gripping assembly may further comprise: one or more gripping elements coupled to the bumper member, wherein the gripping elements may be configured to selectively engage the structure to secure the marine transfer system to the structure; and a force transfer mechanism that operatively connects the bumper member to the gripping elements. The force transfer mechanism may be configured to actuate the gripping elements from an open position to a closed position in which the marine transfer system is secured to the structure upon movement of the bumper member from the first position to the second position.

According to a third aspect of the present invention there is provided a marine transfer system for transferring personnel and/or materials between a marine vessel and a structure.

The marine transfer system is configured to couple a marine vessel to a structure. The marine transfer system comprises: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a gripping assembly configured to couple the platform assembly to the structure. The gripping assembly comprises one or more gripping elements, wherein the gripping assembly is configured such that when an upward force is applied to the platform assembly, the one or more gripping elements move into a first position relative to the structure in which the gripping assembly is able to slide upwards with respect to the structure. The gripping assembly is further configured such that when the upward force is not applied to the platform assembly, the one or more gripping elements move into a second position relative to the structure in which the gripping assembly grips the structure and prevents downwards movement of the gripping assembly with respect to the structure.

The marine transfer system may further comprise: a bumper member movably coupled to the platform assembly, wherein the bumper member may be configured to contact the structure and may be movable relative to the platform assembly between a first position and a second position. The one or more of the gripping are elements may be coupled to the bumper member may be configured to selectively engage the structure to secure the marine transfer system to the structure. The gripping assembly may further comprise: a force transfer mechanism that operatively connects the bumper member to the gripping elements. The force transfer mechanism may be configured to actuate the gripping elements from an open position to a closed position in which the marine transfer system is secured to the structure upon movement of the bumper member from the first position to the second position.

According to the first, second and third aspects of the present invention the marine transfer system for transferring personnel and/or materials between a marine vessel and a structure may comprise any of the additional features as set out below.

The structure may be part of a wind turbine, an offshore platform, a harbour wall or part of another marine vessel.

The force transfer mechanism may comprise a hydraulic, pneumatic, mechanical and/or electronic system. For example, the movement of the bumper member may be transmitted fluidically, mechanically and/or electronically, e.g. via one or more sensors and one or more actuators.

The bumper member may be slidably coupled to the platform assembly. The bumper member may comprise a resilient member configured to deform upon contact with the structure. The bumper member may comprise a first biasing mechanism configured to bias the bumper member towards the first position of the bumper member. The first biasing mechanism may comprise one or more first spring elements configured to move the bumper member from the second position of the bumper member to the first position of the bumper member.

The platform assembly may be further configured to engage the gangway assembly.

The gangway assembly may be further configured to engage the platform assembly and/or a deck of the marine vessel. The gangway assembly may be slidably or pivotably coupled to the platform assembly and/or the deck of the marine vessel. The gangway assembly may comprise one or more gangways.

The support assembly may comprise a plurality of winch assemblies. The or each winch assembly may comprise a first spool and a second spool provided on a common shaft, the first and second spools being adapted to receive first and second points of the cable respectively. The or each winch assembly may comprise spools of different diameters. The cable may wound in a first direction on the first spool and in a second direction on the second spool and the first direction is the same as the second direction. The cable may wound in different directions on the spools. The winch assembly may comprise a sensor configured to detect the tension in the cable. The winch assembly may comprise a clutch.

The marine transfer system may further comprise a control means, the control means being configured to control the tension in the one or more cables and the vertical movement of the gangway assembly with respect to the marine vessel.

The first and/or second gripping elements may comprise jaw members and/or hook members. The gripping assembly may comprise two or more gripping elements spaced apart from one another. The gripping assembly may comprise a pair of gripping elements configured to engage a first portion and a second portion of the structure. The gripping elements may be spaced apart vertically. The gripping elements may be spaced apart laterally.

The gripping assembly may comprise first and second gripping elements configured such that when the gripping assembly is coupled to the structure the coupling between the first gripping element and the structure has a first degree of play and the coupling between the second gripping element and the structure has a second degree of play that is greater than the first degree of play.

The second gripping element may be disposed above the first gripping element. The gripping elements may be pivotably coupled to the gripping assembly.

The gripping assembly may further comprise a gripping mechanism configured to adjust a gripping force of the gripping elements. The gripping mechanism may comprise one or more pneumatic, hydraulic and/or electro-mechanical devices configured to actuate the gripping elements. The gripping assembly may further comprise one or more sensing devices configured to determine the motion of the boat and provide a signal to the gripping mechanism. The gripping mechanism may at least partially comprise the force transfer mechanism, i.e. the gripping mechanism may be provided as part of the force transfer mechanism such that the one or more sensing devices may be configured to provide a signal to the force transfer system for the purpose of adjusting the gripping force of the gripping elements. The gripping force of the gripping elements may be adjusted to allow the gripping assembly to slide upwards with respect to the structure.

The gripping assembly may further comprise a second biasing mechanism configured to bias the gripping elements towards the second position of the gripping elements. The second biasing mechanism may comprise one or more second spring elements configured to act against the upwards force.

The support assembly may comprise one or more support members configured to support the gangway assembly on the marine vessel. The support assembly may comprise first and second support members each comprising first and second ends. The first ends of the first and second support members may be pivotably and/or slidably coupled to the gangway assembly and the second ends of the first and second support members may be pivotably and/or slidably coupled to the deck of the marine vessel. The first and second support members may be pivotably and/or slidably coupled together at a point between their respective first and second ends. The support assembly may comprise one or more coupling elements, e.g. pulleys, provided on points of the support assembly such as the support members. The points at which the coupling elements are provided on the support assembly may be movable with respect to the marine vessel.

The one or more cables may coupled to the one or more coupling elements. The coupling element may comprise a pulley wheel or guide. The cable may be wound one or more times around the coupling element. The one or more cables may be configured such that a first point of the cables connected to the winch assembly and a second point of the cables connected to the winch assembly, a further winch assembly or an anchor point. The tension force in the one or more cables may provide structural rigidity to the support assembly.

Further coupling elements may be provided at other points on the marine vessel 2, e.g. on the deck 3.

According to a further aspect of the present invention there is provided a method of transferring personnel and/or materials between a marine vessel and a structure. The method comprises: engaging a marine transfer system with the structure; gripping the structure with a gripping assembly of the marine transfer system to secure the marine transfer system to the structure; permitting upward movement of the gripping assembly with respect to the structure; preventing downward movement of the gripping assembly with respect to the structure; and supporting a gangway assembly of the marine transfer system, the gangway assembly at one end being operatively connected to the gripping assembly and being configured to carry personnel and/or materials between the marine vessel and the structure.

The method of transferring personnel and/or materials between the marine vessel and the structure may further comprise: de-gripping the structure; disengaging the marine transfer system from the structure; and lowering the gangway assembly towards the deck 3 of the marine vessel.

List of Figures For a better understanding of the present disclosure, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 shows a marine transfer system for a marine vessel in an unengaged configuration with a structure.

Figures 2a and 2b show a platform assembly, a bumper member and a gripping assembly of the marine transfer system in an unengaged configuration with the structure.

Figures 3a and 3b show the platform assembly, the bumper member and the gripping assembly of the marine transfer system in an engaged configuration with the structure.

Figure 4 shows an embodiment of the gangway assembly and support assembly for the marine vessel in a first supported position.

Figure 5 shows the embodiment of the gangway assembly and support assembly for the marine vessel in a second supported position.

Figure 6 shows a further embodiment of the gangway assembly and support assembly for the marine vessel in a first supported position.

Figure 7 shows the platform assembly and a gripping assembly for the marine vessel in a first position relative to the structure.

Figure 8 shows the platform assembly and a gripping assembly for the marine vessel in a second position relative to the structure.

Detailed Description

A marine transfer system 1 according to an example of the present invention is shown in figure 1. The marine transfer system 1 is suitable for securing a marine vessel 2 to a structure 4, such as an offshore wind turbine, for the purpose of transferring personnel and/or materials from the marine vessel 2 to the structure 4 in a safe and efficient manner.

The marine transfer system 1 comprises a platform assembly 6 configured to carry personnel and/or materials and may comprise a platform, a framework and/or railings. In the example shown in figures 1, 4 and 5, the platform assembly 6 is configured to engage a gangway assembly 18. The platform assembly may however be configured to engage a deck S of the marine vessel 2 or any other appropriate structure and/or device.

The marine transfer system 1 comprises a bumper member 8 that is movably coupled to the platform assembly 6. The bumper member 8 is configured to contact the structure 4 and is movable relative to the platform assembly 6 between a first position and a second position.

In the example shown in figures 1 to 7, the bumper member 8 is configured to slide relative to the platform assembly 6, e.g. by virtue of protruding portions 7 that are free to slide in receiving portions 9. The bumper member 8 may however be configured to move relative to the platform assembly 6 by any other appropriate means.

The marine transfer system 1 comprises a gripping assembly 10, comprising one or more gripping elements 12 configured to selectively engage the structure 4 for the purpose of securing the marine transfer system 1 to the structure 4. In the example shown in figures 1 to 7, the gripping elements 12 are pivotably coupled to the bumper member 8 or in an alternative arrangement they may be coupled by any other appropriate means. In the example shown in figures 2a to 3b, the gripping assembly comprises two pairs of gripping elements vertically spaced apart from each other. Each pair of gripping elements 12 is configured to engage a first and second portion of the structure 4. The gripping elements 12 may comprise jaw/hook members configured to engage the structure 4. The gripping elements 12 may be configured to exert a lateral force on the structure 4 such that the lateral force applied to the first portion of the structure 4 is balanced by the lateral force applied to the second part of the structure 4, i.e. the net lateral force applied to the structure 4 by a pair of gripping elements 12 is substantially zero.

The gripping assembly 10 further comprises a force transfer mechanism 14 that operatively connects the bumper member 8 to the gripping elements 12. The force transfer mechanism 14 is configured to actuate the gripping elements 12 from an open position to a closed position upon movement of the bumper member 8 from the first position to the second position. In the example shown in figures 1 to 7, the force transfer mechanism 14 comprises a hydraulic system but may comprise any other appropriate system that is configured to actuate the gripping elements 12 consequent to the movement of the bumper member 8.

Figures 2a and 2b show the marine transfer system 1 with the bumper member 8 in the first position and the gripping elements 12 in the open position. As the marine vessel 2 approaches the structure 4, the bumper member 8 contacts the structure 4. The bumper member 8 may comprise a resilient member 16 configured to deform upon contact with the structure 4. Further movement of the marine vessel 2 towards the structure 4 causes the bumper member 8 to slide from the first position to the second position, i.e. towards the platform assembly 6. As the bumper member 8 slides from the first position to the second position, the force transfer mechanism 14 converts the movement of the bumper member 8 to movement of the gripping elements 12, causing the gripping elements 12 to move, e.g. pivot, from an open position to a closed position.

Figures 3a and 3b show the marine transfer system 1 engaged with the structure 4. The structure is gripped between the bumper member 8 and the gripping elements 12. The bumper member 8 is in the second position and the gripping elements 12 are in the closed position in which the marine transfer system 1 is secured to the structure 4. The gripping elements 12 may be configured to not interfere with any feature of the structure 4, e.g. a supporting element 4a of the structure 4, in a way that may cause damage to and/or impair the function of the structure 4 and/or gripping elements 12 as the gripping assembly 10 grips the structure.

The force transfer mechanism 14 may comprise a release system to allow the gripping elements 12 to return from the closed position to the open position and therefore permit the marine transfer system 1 to disengage the structure 4. The release mechanism may be operated by personnel on the platform assembly 6 and/or remotely from the marine vessel 2 and/or the structure 4. For the example where the force transfer mechanism 14 comprises a hydraulic system, the release system may comprise a pressure release valve.

The bumper member 8 may comprise a first biasing mechanism configured to bias the bumper member 8 towards the first position. The first biasing mechanism may comprise one or more first spring elements, or any other appropriate mechanism, that act to move the bumper member 8 from the second position to the first position. Thus, the first biasing mechanism may be configured to cause the gripping elements 12 to move from the closed position to the open position upon movement of the bumper member 8 from the second position to the first position. In this manner, the gripping assembly 10 is reset upon disengagement from the structure 4.

The gripping assembly 10 for the marine transfer system 1 as presently disclosed secures the marine vessel 2 to the structure 4. As such, the marine vessel 2 need only apply low amounts of thrust to keep the marine vessel 2 engaged with the structure 4, which reduces the overall emissions produced during the transfer of personnel and/or materials between the marine vessel 2 and the structure 4. Furthermore, the gripping assembly 10 requires no further power once engaged with the structure 4, which maximizes the overall efficiency of the marine transfer system 1.

The marine transfer system 1 further comprises the gangway assembly 18 configured to carry personnel and/or materials. The gangway assembly 18 may be configured to engage the platform assembly 6 and/or the deck 3 of the marine vessel 2. The gangway assembly 18 may be pivotably and/or slidably coupled to the platform assembly 6 and/or the deck 3 of the marine vessel 2. The gangway assembly 18 may comprise one or more gangways 17, 19 and in the example shown in figures 1, 4 and 5, the gangway assembly 18 comprises a first gangway 17 and a second gangway 19. The first gangway 17 may be coupled to the second gangway 19 such that the first and second gangway 17, 19 may articulate relative to each other. The second gangway 19 may be provided to the side of the cabin 5 of the marine vessel 2 as shown in figures 4 and 5. Consequently, the weight of the marine transfer system 1 is more evenly distributed along the deck 3 of the marine vessel 2, thereby reducing the weight acting at the bow of the marine vessel 2. The gangway assembly 18 may be foldable into a collapsed position on the deck 3 of the marine vessel 2 when not in use.

The marine transfer system 1 further comprises a support assembly 20 configured to support the gangway assembly 18 and permit vertical movement of the gangway assembly 18 with respect to the marine vessel 2. The support assembly 20 may comprise one or more support members 22 configured to connect the marine vessel 2 to the gangway assembly 18.

In the example shown in figures 1 4 and 5, the support assembly 20 comprises first and second movable, elongate support members 22a, 22b, but in an alternative arrangement the support members 22a, 22b may have any other shape or form. The support members 22a, 22b have first ends 22a', 22b' coupled to the gangway assembly 18 and second ends 22a", 22b" coupled to the deck 3 of the marine vessel 2. The first ends 22a', 22b' of the first and second support members 22a, 22b may be pivotably and/or slidably coupled to the gangway assembly 18, e.g. the first and second gangways 17, 19 respectively. The second ends 22a", 22b' of the first and second support members 22a, 22b may be pivotably and/or slidably coupled to the deck 3 of the marine vessel 2. The first and second support members 22a, 22b may be pivotably and/or slidably coupled together at a point between their respective first and second ends 22a', 22a", 22b', 22b", e.g. by virtue of a bearing 23 provided in slots 25a, 25b in the first and second support members 22a, 22b.

In the example shown in figures 1, 4 and 5, the first end 22a' of the first support member 22a is pivotably and slidably coupled to the gangway assembly 18 and the second end 22a" of the first support member 22a is pivotably coupled to the deck 3 of the marine vessel 2. The first end 22b' of the second support member 22b is pivotably coupled to the gangway assembly 18 and the second end 22b" of the second support member 22b is pivotably and slidably coupled to the gangway assembly 18.

It is appreciated, however, that the support assembly 20 may comprise any number of support members 22 configured to couple the gangway assembly 13 to the deck 3 of the marine vessel 2. For example, the arrangement of the support members 22 as shown in the present example may be duplicated on a plane in front of or behind that shown in figures 4 and 5, such that the gangway assembly 18 may comprise a double support assembly 20 arrangement.

The support assembly 20 may comprise one or more coupling elements 24 provided on points of the support assembly 20. In the example shown in figures 1, 4 and 5, the support assembly 20 comprises a plurality of coupling elements 24 provided on movable points of the support assembly 20. The coupling elements 24 are provided at the ends of the support members 22, although it may be appreciated that the couphng elements 24 may be provided at any point on the support assembly 20.

The support assembly 20 comprises a winch assembly 26 and one or more cables 32. The one or more cables 32 are coupled to the support assembly 20 andior the gangway assembly 18 and wound round the winch assembly 26 so that the winch assembly 26 is operable to adjust the length of unwound cable 32 for the purpose of maintaining a tension force in the cable 32 in order to permit the vertical movement of the gangway assembly 18 with respect to the marine vessel 2.

The winch assembly 26 may comprise one or more sensors configured to detect the tension in the one or more cables 32. The marine transfer system 1 may further comprise a control means configured to control the tension in the one or more cables 32 and the vertical movement of the gangway assembly 18 with respect to the marine vessel 2.

The one or more cables 32 may be coupled to the plurality of coupling elements 24. The coupling elements 24 may comprise pulleys or guides configured to redirect the cables 32.

The cable 32 may be wound around at least one of the coupkng elements 24 one or more times. The one or more cables 32 may comprise a first point of the cables 32 that is connected to the winch assembly 26 and a second point of the cables 32 that is connected to the winch assembly 26 or an anchor point.

In the example shown in figures 1, 4 and 5, the winch assembly 26 comprises a first spool 28 and a second spool 30 provided on a common shaft. The cable 32 is coupled to the plurality of coupling elements 24, the coupling elements 24 being moveable and provided at the first and second ends of the support members 22. The first point of the cable 32 is coupled to the first spool 28 and the second point of the cable 32 is coupled to the second spool 28. The cable is wound in the same direction on the first and second spools 28, 30 such that rotation of the winch assembly 26 in one direction causes the cable 32 to un-wind from the first and second spools 28, 30 and rotation of the winch assembly 26 in the other direction causes the cable 32 to wind onto the first and second spools 28, 30, thereby adjusting the length of the unwound cable 32 that couples the plurality of coupling elements 24 of the support assembly 20, The winch assembly 26 is, therefore, operable to adjust the length of the unwound cable for the purpose of maintaining a tension force in the cable 32 in order to provide structural rigidity to the support assembly 20 and permit the vertical movement of the gangway assembly 18 with respect to the marine vehicle 2. In the example shown in figures 1, 4 and 5, the cable 32 is coupled to the plurality of coupling elements 24. However, in an alternative embodiment (not shown) the couphng elements 24 may comprise one or more pulley wheels wherein the cable 32 may be wound one or more times around at least one of the pulley whe&s for the purposes of reducing the stress in the cable 32 at a point where the cable 32 is coupled to the coupling element 24, providing a mechanical advantage and/or reducing the overall spooling requirements of the first and second spools 28, 30 of the winch assembly 26.

The winch assembly 26 may be operated manually from a remote location, for example from the cabin 5 of the marine vessel 2 or from the platform assembly 6 and/or gangway assembly 18. The winch assembly 26 may also be controlled automatically, for example by a control system.

Figure 4 shows the marine transfer system 1 of the marine vessel 2 secured to the structure 4 when the marine vessel 2 is at the crest of a wave with the support assembly 20 in a first position contracted towards the deck 3 of the marine vessel 2. Figure 5 shows the marine transfer system 1 of the marine vessel 2 secured to the structure 4 when the marine vessel 2 is at the trough of a wave with the support assembly 20 in a second position extended away from the deck 3 of the marine vessel 2, As the marine vessel 2 heaves with the motion of the sea, the support assembly 20 repeatedly contracts towards and extends away from the deck 3 of the marine vessel 2. The structural rigidity of the support assembly 20 may result from the tension in the cable 32. Therefore, as the support assembly contracts towards the deck 3 of the marine vessel 2, the sensor of the winch assembly 26 detects a reduction in the tension of the cable 32 and the control system operates the winch assembly 26 such that cable 32 is wound onto the first and second spools 28, 30 in order to maintain the tension in the cable 32, thereby preserving the structural integrity of the support assembly 20 as the marine vessel 2 rises to the crest of the wave.

Conversely, as the support assembly 20 extends away from the deck 3 of the marine vessel 2, the sensor of the winch assembly 26 detects an increase in the tension of the cable 32 and the control system operates the winch assembly 26 such that cable 32 is un-wound from the first and second spools 28, 30 in order to maintain the tension in the cable 32, thereby preserving the structural integrity of the support assembly 20 as the marine vessel falls to the trough of the wave.

In another example (not shown), the winch assembly 26 may comprise a single spool. The cable 32 may be wound round the spool such that first point of cable 32 is coupled to the spool. The second point of the cable 32 may be coupled to the anchor point. The length of un-wound cable 32 may be connected to one or more coupling &ements 24 of the support assembly 20.

In another example (not shown), the winch assembly 26 may comprise a plurality of winches and/or a plurality of anchor points that may be configured to support the gangway assembly 18.

In the example shown in figures 1, 4 and 5, the first and second spools 28, 30 have the same diameter. Thus the rate at which cable 32 is wound/un-wound is the same for the first and second spoois 28, 30. However, in another example, the diameter of the first spool 28 may be different from the diameter of the second spooi 30, in which case, the rate at which cable 32 is wound/un-wound is different for each spool. Thus, by providing spools of different diameter, a gearing may be set up that allows for cable 32 to be wound/un-wound at different rates between the spools 28, 30. Furthermore, such a set-up allows for the cable 32 to be wound round the spools 28, 30 in opposing directions.

The support assembly 20 for the marine transfer system 1 as disclosed in the present invention is supported by virtue of the tensioned cables 32 and the winch assembly 26. The height of the gangway assembly 18 above the deck 3 of the marine vessel may be controlled therefore by adjusting the tension in the cables 32 using the appropriate sensors and control system (not shown) to operate the winch assembly 26. This allows for the rapid adjustment of the tension in the cables 32 to provide constant support for the motion-compensated gangway assembly 18 in response to the heave of the marine vessel 2. Owing to its simplicity, the reliability and service issues of hydraulic/robotic support systems may be avoided. The marine transfer system 1 operates on low power requirements and the simple means of self-adjustment requires minimum input from an operator whilst transfers take place. When not in use, the gangway assembly 18 may be folded into a collapsed position such that the gangway assembly 18 may be stowed in a position that does not obscure the visibility from the cabin 5 of the marine vessel 2. Consequent to the simplicity of the present invention, the marine transfer system 1 is light-weight, which results in less weight borne at the bow of the marine vessel, which improves the performance of the marine vessel 2.

Furthermore, the overall reduction in weight of the marine vessel 2 results in an improved efficiency and reduced emissions.

In addition, the invention as presently disclosed provides an improved operation and maintenance capability in higher sea states, which increases the efficiency of the transfer of personnel and/or materials between the marine vessel 2 and the structure 4. Due to the configuration of the support assembly 20, such transfers wUl be able to take place in conditions of up to 2 m significant wave height (Beaufort Scale 4-5) and the marine transfer system 2 may be used in the deeper water wind farms (Phase 3) where transfer times between offshore wind turbines becomes a greater consideration.

Figure 6 shows a further embodiment of the support assembly 20 in which the marine transfer system 1 of the marine vessel 2 is secured to the structure 4 when the marine vessel 2 is at the crest of a wave with the support assembly 20 in a first position contracted towards the deck 3 of the marine vessel 2. The further embodiment of the support assembly 20 may comprise similar features to those described above, the features and benefits of which apply equally to the further embodiment described below. In the further embodiment of the support assembly 20, the support assembly 20 may comprise a single movable elongate support member 22 that may have a first end 22' pivotably and/or slidably coupled to the gangway assembly 18 and a second end 22' pivotably and/or slidably coupled to the deck 3 of the marine vessel 2. The coupling elements 24 may be provided at the first end 22' of the single support member 22, although it may be appreciated that the coupling elements 24 may be provided at any point on the support assembly 20. For the embodiment shown in figure 6 and any other embodiment, coupling elements 24 may be provided at other points of the marine vessel 2, for example, on the platform assembly 6 and/or on the deck 3. The support assembly 20 may comprise the winch assembly 26 and one or more cables 32. The one or more cables 32 may be coupled to the coupling elements 24 on the single support member 22 and optionally the deck 3 of the marine vessel 2 and wound round the winch assembly 26.

The coupling element 24 provided on the deck 3 may comprise the anchor point for the cable 32. The first point of the cables 32 may be connected to the winch assembly 26 and the second point of the cables 32 may be connected to the winch assembly 26 or the anchor point. In the embodiment shown in figure 6 the first and second points of the cable 32 are coupled to the winch assembly 26, the cable extending around the coupling elements 24 provided at the first end 22' of the single support member 22 and on the deck 3 of the marine vessel. It is appreciated however that the cable 32 may not be coupled to the coupling element 24 on the deck 3. The winch assembly 26 may be operable therefore to adjust the length of the unwound cable 32 for the purpose of maintaining a tension force in the cable 32 in order to provide structural rigidity to the support assembly 20 and permit the vertical movement of the gangway assembly 18 with respect to the marine vehicle 2.

As mentioned above, the gripping assembly 10 further comprises one or more gripping elements 12. The gripping elements 12 are configured such that when an when an upward force is applied to the platform assembly 6, the one or more gripping elements 12 move into a first position relative to the structure 4 in which the gripping assembly 10 is able to slide upwards with respect to the structure 4 (for example, as shown in figure 7). The gripping assembly 10 is further configured such that when the upward force is not applied to the platform assembly 6, the one or more gripping elements 12 move into a second position relative to the structure 4 in which the gripping assembly 10 grips the structure 4 and prevents downwards movement of the gripping assembly 10 with respect to the structure 4 (for example, as shown in figure 8). The gripping assembly 10 may comprise two or more gripping elements 12 spaced apart from each other. The gripping assembly 10 may comprise a pair of gripping elements 12 configured to engage a first portion and a second portion of the structure 4. The gripping elements 12 may be configured to not interfere with any feature of the structure 4, e.g. a supporting element 4a of the structure 4, in a way that may cause damage to and/or impair the function of the structure 4 and/or gripping elements 12 as the gripping assembly 10 slides up the structure 4.

The gripping assembly 10 may further comprise a second biasing mechanism configured such that the gripping elements 12 are biased towards the second position, i.e. as the upwards force is applied to the platform assembly, the upwards force acts against a biasing force. The biasing force may be selectable such that the upwards force required to cause the gripping elements 12 to move from the second position to the first position may be set at a desired level. The second biasing mechanism may comprise one or more second spring elements, or any other appropriate mechanism, that cause the gripping elements 12 to be biased towards the second position. The gripping elements may additionally or alternatively be biased into their open position by a further biasing mechanism.

In the example shown in figures 1, 7 and 8, the gripping assembly comprises two pairs of gripping elements 12 that are vertically spaced apart from each other. The gripping assembly 10 comprises first and second gripping elements 12a, 12b configured such that when the gripping assembly 10 is coupled to the structure 4 the coupling between the first gripping element 12a and the structure 4 has a first degree of play and the coupling between the second gripping element 12b and the structure has a second degree of play that is greater than the first degree of play, i.e. the coupling between the second gripping element 12b and the structure 4 is looser than the coupling between the first gripping element 12a and the structure 4.

The variation in the degree of play between the first gripping element 12a and the second gripping element 12b may be achieved by: off-setting the pivot axis of the second gripping element 12b with respect to the pivot axis of the first gripping element 12a; making the second gripping element 12b longer than the first gripping element 12a; tapering the thickness of the bumper member 8 from a thicker cross-section towards the bottom of the bumper member 8 to a thinner crosssectTion towards the top of the bumper member 8; and/or any other alternative means by which the coupling between the second gripping element 12b and the structure 4 is looser than the coupling between the first gripping element 12a and the structure 4.

Figures 6 and 7 show the gripping assembly 10 coupled to the structure 4. It is appreciated that when the gripping assembly 10 is coupled to the structure 4, the marine vessel 2 will be heaving with the motion of the waves. Consequently, as the marine vessel 2 falls to the trough of a wave, the weight of the marine vessel 2 borne by the coupling between the gripping assembly 10 and the structure 4 increases. By virtue of this increased loading on the coupling, a gripping force of the first and second gripping elements 12a, 12b is sufficient to resist the downward movement of the gripping assembly 10 with respect to the structure 4.

Conversely, as the marine vessel 2 rises to the crest of the wave, an upward force F is applied to the marine vessel 2 by the wave. The upward force F may be transmitted through the deck of the marine vessel 3 to the marine transfer system 1 such that the upward force F acts on the marine transfer system 1 when the gripping assembly 10 is coupled to the structure 4. Figure 7 shows the gripping elements 12a, 12b in the first position, i.e. when the marine vessel is rising to the crest of the wave, with the upward force F applied to the marine transfer system 1, and consequently the platform assembly 6. When the upward force F is applied to the platform assembly 6, the increased degree of play in the second gripping element 12b allows the platform assembly 6 and the gripping assembly 10 to pivot about the first gripping element 12a. As the platform assembly 6 and the gripping assembly 10 pivot, the gripping force of the second gripping element 12b reduces such that the combined gripping force between the first and second gripping elements 12a, 12b is insufficient to resist the upwards force F applied to the platform assembly 6. Consequently, the gripping assembly 10 slides upwards with respect to the structure 4.

Figure 8 shows the gripping elements 12a, 12b in the second position, i.e. when the marine vessel is falling to the trough of the wave, with the upward force F not applied to the platform assembly 6. The gripping force of the second gripping element 12b is greater in the second position. The combined gripping force of the first and second gripping elements 12a, 12b is sufficient to support the weight of the marine transfer system 1 and resist the downward movement of the gripping assembly 10 with respect to the structure 4.

In another embodiment (not shown) the gripping elements 12 may comprise one or more wedge elements configured to engage the structure 4. The gripping elements 12 may be configured such that when the upward force F is applied to the platform assembly 6, the wedge elements are forced into a iocking position, thereby acting to grip the structure 4.

Conversely, when the upward force F is not applied to the platform assembly 6, the wedge elements may move out of the locking position, thereby acting to release the grip on the structure 4. The gripping elements may comprise one or more resilient elements that are configured to grip the structure 4 upon compression by one or more of the wedge elements.

In another embodiment (not shown) the gripping assembly 10 may further comprise a gripping mechanism configured to actuate the gripping elements 12 consequent to the marine vessel 2 rising and fatling with the motion of the waves. The gripping mechanism may comprise one or more pneumatic, hydraulic and/or electro-mechanical devices configured to actuate the gripping elements 12. The gripping mechanism may at least partially comprise the force transfer mechanism 14 that operatively connects the bumper member 8 to the gripping elements 12. The gripping mechanism may further comprise one or more sensing devices, e.g. an accelerometer or a force transducer, configured to detect the motion of the marine vessel 2. The sensing device may be configured to determine the required gripping force of the gripping elements 12 and provide a signal to the gripping mechanism. In this manner, the gripping mechanism may be operable to adjust the gripping force of the gripping elements. For example, the gripping mechanism may be configured such that when the marine vessel is rising to the crest of the wave, with the upward force F applied to the marine transfer system 1, the gripping mechanism actuates the gripping elements 12 into the first position in which the gripping force of the gripping elements 12 is insufficient to resist the upwards force F applied to the marine transfer system 1.

Consequently, the gripping assembly 10 slides upwards with respect to the structure 4.

Conversely, the gripping mechanism may be configured such that when the marine vessel is fatling to the trough of the wave, with the upward force F not applied to the marine transfer system 1, the gripping mechanism actuates the gripping elements 12 into the second position in which the gripping force of the gripping elements 12 is sufficient to support the weight of the marine transfer system 1 and resist the downward movement of the gripping assembly 10 with respect to the structure 4.

Reference numerals I marine transfer system 2 marine vessel 3 deck of the marine vessel 4 structure 4 supporting element of the structure cabin of the marine vessel 6 platform assembly 7 protruding portions 8 bumper member 9 receiving portions gripping assembly 12 gripping elements 14 force transfer mechanism 16 resilient member 17 first gangway 18 gangway assembly 19 second gangway support assembly 22 support member 22' first end of support member 22" second end of support member22a first support member 22a' first end of first support member 22a" second end of first support member 22b second support member 22b' first end of second support member 22b" second end of second support member 23 bearing 24 coupling element 25a slot in first support member 25b slot in second support member 26 winch assembly 28 first spool second spool 32 cable

Claims

Claims 1 A marine transfer system for securing a marine vessel to a structure, the marine transfer system comprising: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; a bumper member movably coupled to the platform assembly, wherein the bumper member is configured to contact the structure and is movable relative to the platform assembly between a first position and a second position; and a gripping assembly, the gripping assembly comprising: one or more gripping elements coupled to the bumper member, wherein the gripping elements are configured to selectively engage the structure to secure the marine transfer system to the structure; and a force transfer mechanism that operatively connects the bumper member to the gripping elements, the force transfer mechanism being configured to actuate the gripping elements from an open position to a closed position in which the marine transfer system is secured to the structure upon movement of the bumper member from the first position to the second position.
2. A marine transfer system according to claim 1, the marine transfer system further comprising: a gangway assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a support assembly configured to support the gangway assembly and permit vertical movement with respect to the marine vessel, the support assembly comprising: a winch assembly; and one or more cables coupled to the support assembly and/or the gangway assembly, the cables being wound round the winch assembly so that the winch assembly is operable to adjust the length of unwound cable to maintain a tension force in the cable and permit the vertical movement of the gangway assembly with respect to the marine vessel.
3. A marine transfer system according to claim 1 or 2, wherein the gripping assembly is configured to couple the platform assembly to the structure, wherein the gripping assembly is configured such that when an upward force is applied to the platform assembly, the one or more gripping elements move into a first position relative to the structure in which the gripping assembly is able to slide upwards with respect to the structure; and wherein the gripping assembly is further configured such that when the upward force is not applied to the platform assembly, the one or more gripping elements move into a second position relative to the structure in which the gripping assembly grips the structure and prevents downwards movement of the gripping assembly with respect to the structure.
4. A marine transfer system for transferring personnel and/or materials between a marine vessel and a structure, the marine transfer system comprising: a gangway assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a support assembly configured to support the gangway assembly and permit vertical movement of the gangway assembly with respect to the marine vessel, the support assembly comprising: a winch assembly; and one or more cables coupled to the support assembly and/or the gangway assembly, the cables being wound round the winch assembly so that the winch assembly is operable to adjust the length of unwound cable to maintain a tension force in the cable and permit the vertical movement of the gangway assembly with respect to the marine vessel.
5. A marine transfer system according to claim 4, the marine transfer system further comprising: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a gripping assembly configured to couple the platform assembly to the structure, the gripping assembly comprising one or more gripping elements, wherein the gripping assembly is configured such that when an upward force is applied to the platform assembly, the one or more gripping elements move into a first position relative to the structure in which the gripping assembly is able to slide upwards with respect to the structure; and wherein the gripping assembly is further configured such that when the upward force is not applied to the platform assembly, the one or more gripping elements move into a second position relative to the structure in which the gripping assembly grips the structure and prevents downwards movement of the gripping assembly with respect to the structure.
6. A marine transfer system according to claim 4 or 5, the marine transfer system further comprising: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; a bumper member movably coupled to the platform assembly, wherein the bumper member is configured to contact the structure and is movable relative to the platform assembly between a first position and a second position; and a gripping assembly, the gripping assembly further comprising: one or more gripping elements coupled to the bumper member, wherein the gripping elements are configured to selectively engage the structure to secure the marine transfer system to the structure; and a force transfer mechanism that operatively connects the bumper member to the gripping elements, the force transfer mechanism being configured to actuate the gripping elements from an open position to a closed position in which the marine transfer system is secured to the structure upon movement of the bumper member from the first position to the second position.
7. A marine transfer system for coupling a marine vessel to a structure, the marine transfer system comprising: a platform assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a gripping assembly configured to couple the platform assembly to the structure, the gripping assembly comprising one or more gripping elements, wherein the gripping assembly is configured such that when an upward force is applied to the platform assembly, the one or more gripping elements move into a first position relative to the structure in which the gripping assembly is able to slide upwards with respect to the structure; and wherein the gripping assembly is further configured such that when the upward force is not applied to the platform assembly, the one or more gripping elements move into a second position relative to the structure in which the gripping assembly grips the structure and prevents downwards movement of the gripping assembly with respect to the structure.
8. A marine transfer system according to claim 7, the marine transfer system further comprising: a bumper member movably coupled to the platform assembly, wherein the bumper member is configured to contact the structure and is movable relative to the platform assembly between a first position and a second position; wherein one or more of the gripping are elements coupled to the bumper member are configured to selectively engage the structure to secure the marine transfer system to the structure; the gripping assembly further comprising: a force transfer mechanism that operatively connects the bumper member to the gripping elements, the force transfer mechanism being configured to actuate the gripping elements from an open position to a closed position in which the marine transfer system is secured to the structure upon movement of the bumper member from the first position to the second position.
9. A marine transfer system according to claim 7 orB, the marine transfer system further comprising: a gangway assembly configured to carry personnel and/or materials between the marine vessel and the structure; and a support assembly configured to support the gangway assembly and permit vertical movement with respect to the marine vessel, the support assembly comprising: a winch assembly; and one or more cables coupled to the support assembly and/or the gangway assembly, the cables being wound round the winch assembly so that the winch assembly is operable to adjust the length of unwound cable to maintain a tension force in the cable and permit the vertical movement of the gangway assembly with respect to the marine vessel.
10. A marine transfer system according to any of the preceding claims when dependent on claims 1, 6 or 8, wherein the force transfer mechanism is a hydraulic or pneumatic system.
11, A marine transfer system according to any of the preceding claims when dependent on claims 1, 6, 8 or 10, wherein the bumper member is slidably coupled to the platform assembly.
12. A manne transfer system according to any of the preceding claims when dependent on claims 1, 6, 8, 10 or 11, wherein the bumper member comprises a resilient member configured to deform upon contact with the structure.
13. A marine transfer system according to any of the preceding claims when dependent on claims 2, 5, 6, or 9, wherein the platform assembly is further configured to engage the gangway assembly.
14. A marine transfer system according to any of the preceding claims when dependent on claims 2, 5, 6, or 9, wherein the gangway assembly is further configured to engage the platform assembly and/or a deck of the marine vessel.
15. A marine transfer system according to any of the preceding claims when dependent on claims 2, 5, 6, or 9, wherein the gangway assembly is stidably or pivotably coupled to the platform assembly and/or the deck of the marine vessel.
16. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the support assembly comprises a plurality of winch assemblies.
17. A marine transfer system according to any of the preceding claims, wherein the structure is part of a wind turbine, an offshore platform, a harbour wall or part of another marine vessel.
18. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the or each winch assembly comprises a first spool and a second spool provided on a common shaft, the first and second spools being adapted to receive first and second points of the cable respectively.
19. A marine transfer system according to claim 18, wherein the cable is wound in a first direction on the first spool and in a second direction on the second spool and the first direction is the same as the second direction.
20. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the winch assembly comprises a sensor configured to detect the tension in the cable.
21, A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the marine transfer system further comprises a control means, the control means being configured to control the tension in the one or more cables and the vertical movement of the gangway assembly with respect to the marine vessel.
22. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the gangway assembly comprises one or more gangways.
23. A marine transfer system according to any of the preceding claims when dependent on claims 1 6 or 8, wherein the first and/or second gripping elements comprise jaw members and/or hook members.
24. A marine transfer system according to any of the preceding claims when dependent on claims 1, 6 or 8, wherein the gripping assembly comprises two or more gripping elements spaced apart from one another.
25. A marine transfer system according to any of the preceding claims when dependent on claims 1, 6 or 8, wherein the gripping assembly comprises a pair of gripping elements configured to engage a first portion and a second portion of the structure.
26. A marine transfer system according to claim 24 or 25, wherein the gripping elements are spaced apart vertically.
27. A marine transfer system according to any of the claims 24 to 26, wherein the gripping elements are spaced apart laterally.
28. A marine transfer system according to any of the preceding claims when dependent on claims 3, 5 or 7, wherein the gripping assembly comprises first and second gripping elements configured such that when the gripping assembly is coupled to the structure the coupling between the first gripping element and the structure has a first degree of play and the coupling between the second gripping element and the structure has a second degree of play that is greater than the first degree of play.
29. A marine transfer system according to claim 28, wherein the second gripping element is disposed above the first gripping element.
30. A marine transfer system according to any of the preceding claims when dependent on claims 3, 5 or 7, wherein the gripping elements are pivotably coupled to the gripping assembly.
31. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the support assembly comprises one or more support members configured to support the gangway assembly on the marine vessel.
32. A marine transfer system according to claim 31, wherein the support assembly comprises first and second support members each comprising first and second ends.
33. A marine transfer system according to claim 32, wherein the first ends of the first and second support members are pivotably and/or slidably coupled to the gangway assembly and the second ends of the first and second support members are pivotably and/or slidably coupled to the deck of the marine vessel.
34. A marine transfer system according to claim 32 or 33, wherein the first and second support members are pivotably and/or slidably coupled together at a point between their respective first and second ends.
35. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the support assembly comprises one or more coupling elements provided on points of the support assembly.
36. A marine transfer system according to claim 35, wherein the points at which the coupling elements are provided on the support assembly are movable with respect to the marine vessel.
37. A marine transfer system according to claim 35 or 36, wherein the one or more cables are coupled to the one or more coupling elements.
38. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the one or more cables are configured such that a first point of the cables connected to the winch assembly and a second point of the cables connected to the winch assembly, a further winch assembly or an anchor point.
39. A marine transfer system according to any of the preceding claims when dependent on claims 2, 4 or 9, wherein the tension force in the one or more cables provides structural rigidity to the support assembly.
40. A marine transfer system according to any of the preceding claims when dependent on claims 3, 5 or 7, wherein the gripping assembly further comprises a gripping mechanism configured to adjust a gripping force of the gripping elements.
41. A marine transfer system according to claim 40, wherein the gripping assembly further comprises one or more sensing devices configured to determine the motion of the boat and provide a signal to the gripping mechanism.
42. A marine transfer system according to any of the preceding claims when dependent on claims 1, 6 or 8, wherein the bumper member comprises a first biasing mechanism configured to bias the bumper member towards the first position of the bumper member.
43. A marine transfer system according to any of the preceding claims when dependent on claims 3, 5 or 7, wherein the gripping assembly further comprises a second biasing mechanism configured to bias the gripping elements towards the second position of the gripping elements.
44. A marine vessel comprising the marine transfer system as claimed in claims 1, 4 or 7.
45. A method of transferring personnel and/or materials between a marine vessel and a structure, the method comprising: engaging a marine transfer system with the structure; gripping the structure with a gripping assembly of the marine transfer system to secure the marine transfer system to the structure; permitting upward movement of the gripping assembly with respect to the structure; preventing downward movement of the gripping assembly with respect to the structure; and supporting a gangway assembly of the marine transfer system, the gangway assembly at one end being operatively connected to the gripping assembly and being configured to carry personnel and/or materials between the marine vessel and the structure.
46. A method of transferring personnel and/or materials between the marine vessel and the structure according to claim 45, wherein the method further comprises: de-gripping the gripping assembly of the marine transfer system from the structure; disengaging the marine transfer system from the structure; and lowering the gangway assembly towards the deck of the marine vessel.
47. A marine transfer system as described herein, with reference to, and as shown in the accompanying drawings.
48. A method of transferring personnel and/or materials between the marine vessel and the structure as described herein, with reference to, and as shown in the accompanying drawings.