WO2019145681A1

WO2019145681A1 - Floating deck assembly

Info

Publication number: WO2019145681A1
Application number: PCT/GB2019/050125
Authority: WO
Inventors: Shane Carr
Original assignee: Shane Carr Ltd
Priority date: 2018-01-24
Filing date: 2019-01-17
Publication date: 2019-08-01
Also published as: GB201801141D0; GB2570453A; GB2570453B

Abstract

A deck assembly is provided, the assembly comprising a first support assembly (4); a deck (6); a plurality of support members (8) extending between and connecting the first support assembly and the deck; and a plurality of inflatable vessels (10) disposed between the first support assembly and the deck. A floating dry dock assembly is also provided, the assembly comprising a deck assembly comprising an upper deck surface, preferably wherein the buoyancy of the deck assembly can be varied; and a plurality of buoyant vessels connected to and able to support the deck assembly; wherein each buoyant vessel is moveable vertically with respect to the deck assembly. A method for raising a vessel from water, the method comprising providing a deck assembly, preferably having variably buoyancy, the deck assembly having a plurality of buoyant vessels connected to the deck assembly, each buoyant vessel being moveable vertically with respect to the deck assembly; sinking the deck assembly below the vessel to be raised; supporting the deck assembly using the buoyant vessels at the surface of the water; manoeuvring the deck assembly below the vessel to be raised; and raising the deck assembly and the vessel to be raised.

Description

FLOATING DECK ASSEMBLY

The present invention relates to a deck assembly and to a method for its use, in particular to a floating deck assembly. The deck assembly finds use, for example as a floating dry dock.

Floating deck assemblies are known and have been used for a wide range of applications. For example, air bags supporting a frame and decking having been used for many years to bridge rivers and swamps, in particular by the military.

US 2007/0295258 discloses a transportable floatation system. The system comprises a plurality of sections each having a decked supporting structure with heavy duty floatation tubes. The sections are coupled together with pre-tensioned ropes, straps or cables.

US 2009/0241824 discloses a frameless modular floating dock comprising a plurality of buoyant support modules. An inflatable floating bridge is described and shown in CN 1051 13381 A.

A pontoon-type floating vessel is described and shown in RU 2403168.

A dry dock for boats is disclosed in US 3,991 ,695.

US 2006/0153643 discloses a modular floating dock with inflatable pontoons.

US 4,729,335 discloses a flotation assembly. JPH 01240396 discloses a method and device for fixing cargo and a structure for attaching air bags in the device.

There is a need for an improved floating deck assembly. It would be

advantageous if the assembly could be capable of being constructed in a wide range of sizes and configurations, to be adapted to a wide range of needs. It would be particularly advantageous if the assembly could be employed as a floating dry dock to recover or deploy a range of different water borne vessels or structures. It would be most helpful if the assembly could be formed from components that are readily stored, transported and assembled. It would also be advantageous if the shape and size of the assembly could be adapted to suit a wide range of different vessels and structures.

According to a first aspect of the present invention there is provided a deck assembly, the assembly comprising: a first support assembly; a deck; a plurality of support members extending between and connecting the first support assembly and the deck; and a plurality of inflatable vessels disposed between the first support assembly and the deck.

The deck assembly of the present invention is a floating deck assembly that can be constructed and assembled in a wide range of different configurations to meet a wide range of needs. The assembly can be constructed from components that are easily stored and transported. The assembly can be employed in a wide range of situations where a temporary or permanent deck is required. For examples, the assembly can be used as a jack up rig. The assembly can be used in any situation where a stationary craft/vessel employing floatation is required, for example as a semi-submersible drilling rig and the like. The assembly finds particular use as a floating dry dock, as described in more detail hereafter. In a particularly preferred embodiment, the components of the assembly are releasably connected to one another. This allows the entire assembly to be disassembled at one location and stored or shipped to another location, as required, with ease.

The deck assembly of the present invention comprises a first support assembly.

In use, the first support assembly is the lower support assembly. The first support assembly may be formed from any suitable components and have any suitable structure.

In one preferred embodiment, the first support assembly comprises a frame made up of a plurality of interconnected frame members. The interconnected frame members are preferably spaced apart to form an open frame, that is a frame having openings or space between adjacent members of the frame. In one preferred embodiment, the frame comprises a plurality of frame cells, each cell formed from a plurality of frame members. Adjacent cells are connected, preferably by sharing one or more frame members. A preferred arrangement for the frame is a plurality of frame members interconnected at right angles to form a grid comprising a plurality of generally rectangular, preferably square, cells. At least some, preferably all of the cells further comprises a frame member extending diagonally to provide rigidity to the frame.

The frame of the first support member may be a permanent construction, with the frame members permanently interconnected, for example by welding. More preferably, the frame is formed from a plurality of releasably interconnected frame modules, with each frame module comprising one or more frame members.

Any suitable system of frame members may be employed to form the frame of the first support assembly. Suitable frame systems are known in the art and are available commercially. One particularly suitable frame system is the MERO® frame system available from MERO-TSK International GmbH & Co. KG, Germany.

The deck assembly of the present invention further comprises a deck. In use, the deck overlies the first support assembly and is generally uppermost. The deck may be formed from any suitable components and have any suitable structure.

The deck comprises a decking assembly. The decking assembly comprises at least one, preferably a plurality of interconnected decking members to provide the upper surface of the deck as required for the intended use of the assembly.

The deck may consist essentially of the decking assembly, with the one or more decking members connected to the support members, which in turn connect the decking members to the first support assembly.

In a preferred embodiment, the deck comprises a second support assembly and a decking assembly. The second support assembly is connected to the support members and to the first support assembly by the aforementioned support members described in more detail below. The decking assembly overlies the second support assembly and is mounted thereto, preferably releasably.

The second support assembly may be formed from any suitable components and have any suitable structure. In one preferred embodiment, the second support assembly comprises a frame made up of a plurality of interconnected frame members. The interconnected frame members are preferably spaced apart to form an open frame, that is a frame having openings or space between adjacent members of the frame. In one preferred embodiment, the frame comprises a plurality of frame cells, each cell formed from a plurality of frame members. Adjacent cells are connected, preferably by sharing one or more frame members. A preferred arrangement for the frame is a plurality of frame members interconnected at right angles to form a grid comprising a plurality of generally rectangular, preferably square, cells. Some or all of the cells may further comprises a frame member extending diagonally to provide rigidity to the frame.

The frame of the second support member may be a permanent construction, with the frame members permanently interconnected, for example by welding. More preferably, the frame is formed from a plurality of releasably interconnected frame modules, with each frame module comprising one or more frame members.

Any suitable system of frame members may be employed to form the frame of the second support assembly. The frame system of the second support assembly is preferably the same as that employed for the first support assembly. Suitable frame systems are known in the art and are available commercially. One particularly suitable frame system is the MERO® frame system available from MERO-TSK International GmbH & Co. KG, Germany.

As noted, the deck overlies the first support assembly. The first support assembly and the deck may have the same footprint, that is the area of the first support assembly and the deck are substantially the same. The deck may be arranged symmetrically or asymmetrically to overlie the first support assembly, preferably symmetrically. In some preferred embodiments, the footprint of the deck is larger than the footprint of the first support assembly, that is the area of the deck is greater than the area of the first support assembly.

The deck assembly of the present invention further comprises a plurality of support members extending between the first support assembly and the deck. Each support member is connected to the first support member and to the deck. Preferably, the connections between each support member and the first support assembly and the deck are releasable. The support members may be formed from any suitable components and have any suitable structure. Preferably, the support members are frame components and form a frame between the first support assembly and the deck. The support members are preferably spaced apart to form an open frame, that is a frame having openings or space between adjacent members of the frame. In one preferred embodiment, the frame comprises a plurality of frame cells, each cell formed from a plurality of frame members. Adjacent cells are connected, preferably by sharing one or more frame members.

Suitable frame systems are known in the art and are available commercially. One particularly suitable frame system is the MERO® frame system available from MERO-TSK International GmbH & Co. KG, Germany.

In one preferred embodiment, the support members together form a space frame comprising the frame of the first support assembly, a plurality of spaced apart support members, and the frame of the second support assembly. Preferably, each support member extends between a cell of the frame of the first support assembly and a cell of the second support assembly.

The deck assembly of the present invention further comprises a plurality of inflatable vessels. The inflatable vessels are disposed and retained between the first support assembly and the deck. When inflated, the inflatable vessels provide the necessary buoyancy to the deck assembly.

In one preferred arrangement, one or more support members is disposed between each adjacent inflatable vessel. More preferably, each inflatable vessel is contained within a cell of the frame defined by the first support assembly, a plurality of support members and the deck. As described in more detail hereinbelow, it is particularly preferred that each inflatable vessel is retained within a cell of a space frame defined by frame members of the first support assembly, the support members and the second support assembly.

The inflatable vessels may have any suitable form. In one preferred embodiment, each inflatable vessel is generally cylindrical. The inflatable vessels may each be elongate, that is have a length greater than their width.

The inflatable vessels may be arranged in any orientation between the first support assembly and the deck. In the case of inflatable vessels that are elongate, that is have a major axis length greater than the width or diameter, the vessels may be arranged horizontally, that is with their major axes extending horizontally. However, the vessels are preferably arranged vertically within the assembly, that is with their major axes extending vertically. In the case of cylindrical inflatable vessels, each vessel is arranged with its axis vertically, that is with its end faces lower- and uppermost.

It is preferred that each inflatable vessel has a uniform cross-sectional area along at least a portion of its height, that is the direction extending from the first support assembly to the deck. In this way, each inflatable vessel maintains a constant waterplane area, that is the area of the plane passing through the vessel at the surface of the water as at least the portion of the vessel moves into and out of the water.

The inflatable vessels are preferably of a size that at least a portion of the vessel remains above the water when the deck assembly in use and the deck is above the surface of the water. In this way, the inflatable vessels and the entire deck assembly is provided with excess buoyancy. The size of the inflatable vessels may be readily determined by determining the load to be carried on the deck of the deck assembly and calculating the buoyancy required to support the load and the deck assembly with the deck out of the water at the required height above the surface of the water. Preferably, the inflatable vessels are of a size that at least 25%, more preferably at least 30%, still more preferably at least 40%, more preferably still at least 45% of the vessel remains above the water during the normal use of the deck assembly with the deck above water. An arrangement in which about 50% of each inflatable vessel remains above the surface of the water during normal operation of the deck assembly with the deck above water is particularly preferred.

A particularly preferred arrangement for the inflatable vessels is a plurality of vertically arranged cylindrical vessels.

The inflatable vessels are preferably connected to the first support assembly and/or the deck, preferably to both the first support assembly and the deck. The inflatable vessels are preferably releasably connected to the first support assembly and/or the deck.

In embodiments in which the first support assembly comprises a frame comprising a plurality of spaced apart frame members, each inflatable vessel is preferably arranged to have a frame member of the first support assembly disposed centrally below the vessel, preferably with the vessel being connected to this frame member. In embodiments in which the deck comprises a second support assembly having a frame comprising a plurality of spaced apart frame members, each inflatable vessel is preferably arranged to have a frame member of the second support assembly disposed centrally above the vessel, preferably with the vessel being connected to this frame member.

The inflatable vessels may have any form that can be inflated, to increase the buoyancy of the vessel. The inflatable vessels may be formed from any suitable material. The material may be porous. More preferably, the material of the vessels is non-porous. Suitable inflatable vessels are known in the art and are commercially available. Suitable inflatable vessels include inflatable bags. One preferred inflatable vessel is the range of Seaflex® inflatable bags available from the Unique Group.

Each inflatable vessel is preferably provided with a pressure relief system, such as a blow-off valve, to allow excess gas pressure within the vessel to be vented, for example when the deck assembly is rising through the water and the hydrostatic pressure on the vessel is reducing.

In use, a gas, most preferably air, is pumped into the inflatable vessels to provide the degree of buoyancy required to support the deck assembly and any load to be carried on the deck at the required position relative to the surface of the water. For use as a deck, the assembly is generally positioned to have the upper surface of the deck above the surface of the water. The inflatable vessels may be arranged to be inflated/deflated individually, in groups or banks of vessels or all together, depending upon the needs of the operation being performed. The ability to inflate or deflate individual vessels allows the assembly to be accurately trimmed during use, for example to maintain the upper surface of the deck horizontal.

The deck assembly of the present invention may also be used as a jack-up rig or platform. When used in this manner, the deck assembly is preferably provided with a plurality of legs extending vertically, either adjacent or through the deck of the deck assembly. In many embodiments, four equally spaced legs arranged in a rectangular or square pattern are employed. Each leg is mounted so as to be moveable vertically with respect to the deck. The legs may be moved vertically by a crane on the deck, for example. Alternatively, the legs may be self-jacking, as is known in the art. In use, the deck assembly is assembled or, more typically, floated to the location where a rig or platform is required. The legs are lowered to the bed of the body of water and the deck assembly used as a rig or platform in known manner.

The assembly may also be used as a floating dry dock, including raising a vessel or other floating structure from the water and returning the vessel to the water. In use, the inflatable vessels are inflated to a level to allow the deck assembly to be submerged below a vessel in the water. In particular, with the assembly floating, one or more of the inflatable vessels are deflated partially or wholly by an amount required to sink the assembly to have the deck at the appropriate depth under the surface of the water. The assembly is then manoeuvred beneath the vessel or structure to be raised or the vessel or structure is manoeuvred over the deck of the deck assembly. The inflatable vessels are then inflated, raising the deck assembly until the hull of the vessel is in contact with the deck. Continued inflation of the inflatable vessels raises the vessel from the water. The reverse procedure is followed to return the vessel to the water. The use of a deck assembly, such as the deck assembly of the present invention, as a floating dry dock can present problems with stability, in particular as a vessel is being raised from or lowered into the water. A particular problem arises when the load applied to the deck assembly is not uniform across the assembly, which results in an increased risk of the entire assembly and the vessel capsizing. There is therefore a need for an improved floating dry dock assembly that has increased stability.

According to a further aspect of the present invention, there is provided a floating dry dock assembly, the assembly comprising: a deck assembly comprising an upper deck surface; and a plurality of buoyant vessels connected to and able to support the deck assembly; wherein each buoyant vessel is moveable vertically with respect to the deck assembly. In the dry dock assembly of this aspect of the present invention, the buoyant vessels moveable with respect to the deck assembly provide stability to the assembly in all planes, in particular when carrying a load, such as a vessel.

The dry dock assembly comprises a deck assembly. The deck assembly may have a fixed buoyancy. More preferably, the deck assembly has a variable buoyancy. In this embodiment, the deck assembly is arranged to have a variable buoyancy, so that its position relative to the surface of the water may be varied. Any suitable deck assembly having a variable buoyancy may be employed. Preferably, the deck assembly is one according to the first aspect of the present invention and described above.

The dry dock assembly comprises a plurality of buoyant vessels connected to the deck assembly. In use, the buoyant vessels provide support to the deck assembly in the water.

The buoyant vessels may be connected directly to the deck assembly. More preferably, the buoyant vessels are disposed at positions laterally of the deck assembly. In one preferred embodiment, the dry dock assembly comprises a plurality of lateral members extending laterally from the deck assembly, each member connected at a first position thereon to the deck assembly, with a buoyant vessel being connected to each member at a second position on the lateral member.

In embodiments in which the deck assembly is a deck assembly according to the first aspect of the present invention described above, the lateral members may each be connected to any suitable position of the deck assembly. For example, each lateral member may be connected to the first support assembly and/or the support members. In one preferred embodiment, each lateral member is connected to the deck of the deck assembly. In embodiments in which the deck comprises a second support assembly and a decking assembly, each lateral member is preferably connected to the second support assembly.

In this embodiment, each lateral member is connected at a first position, preferably a first or inner end portion thereof to the deck assembly. In many preferred embodiments, each member has a first end connected to the deck assembly.

A buoyant vessel is connected to the second end portion of each lateral member. Preferably, a buoyant vessel is connected to a second position on the lateral member. The second position is most preferably spaced apart from the first position, such that the buoyant vessel is spaced from the deck assembly. Preferably, the second position is at a second or outer end portion, in particular the second end of each lateral member.

A single buoyant vessel may be connected to each lateral member. Alternatively, one or more of the lateral members may be provided with two or more buoyant vessels connected thereto. The two or more buoyant vessels may all be connected to the second position on the lateral member or may be connected to positions spaced apart on the lateral member.

Each member may have any suitable form. In one preferred embodiment, each lateral member comprises an arm assembly. Each arm assembly may comprise a single arm member. In one preferred arrangement, each arm assembly comprises a pair of arm members, more preferably arranged in a V-shape. Each V-shape arm is connected at its widest end portion to the deck assembly, with the respective buoyant vessel connected to the narrower end portion of the arm assembly.

Each buoyant vessel is moveable vertically with respect to the deck assembly. To allow the buoyant vessels to provide stability to the deck assembly, a plurality of the buoyant vessels are moveable relative to the deck assembly independently of each other, that is some or all of the plurality of buoyant vessels are moveable independently with respect to the deck assembly.

To provide stability to the deck assembly, the buoyant vessels are arranged around the deck assembly. In some embodiments, for example for deck assemblies having lower deck areas, it is sufficient for the buoyant vessels to be arranged on each of two opposing sides of the deck assembly, preferably spaced apart and in a symmetrical pattern. For larger deck assemblies and/or those intended to carry larger loads, the buoyant vessels are preferably arranged on all sides of the deck assembly.

Any suitable means may be employed to allow movement of each buoyant vessel relative to the deck assembly. For example, each buoyant vessel may be connected to the deck assembly by a tether, with the length of the tether being variable, for example by means of a winch. The tether may be inelastic. Alternatively, the tether may be elastic.

In embodiments in which the buoyancy of the deck assembly is variable, it is preferable that each buoyant vessel is free to move relative to the deck assembly under the action of the deck assembly moving up and down in the water. In this way, each buoyant vessel will move and automatically stabilise the deck assembly and keep the upper surface of the deck level.

In one preferred embodiment, each lateral member is configured to allow the relative movement of the respective buoyant vessel and the deck assembly. For example, each lateral member may be provided with a hinge or pivoted portion. More preferably, each lateral member is pivotally attached to the deck assembly at the first position on the lateral member. If this arrangement is employed, it is preferred that the movement of each lateral member relative to the deck assembly is constrained or limited, for example by a tether. The tether may be inelastic. More preferably, for many embodiments, the or each tether is elastic. The length of each tether is preferably variable, for example by means of a winch. In operation of the dry dock assembly, the orientation of each lateral member with respect to the deck assembly changes as the deck assembly moves vertically in the water. This is particularly the case in the preferred embodiment in which each buoyant vessel remains at the surface of the water with at least a portion of the vessel above the surface during the operation. Varying the length of the tether allows this change in orientation between each lateral member and the deck assembly to be accommodated.

The buoyant vessels may be any suitable vessel that can provide sufficient buoyancy to support the deck assembly and the load to be applied to the deck. Each buoyant vessel may be rigid and have a fixed buoyancy. Suitable rigid buoyant vessels are known in the art and are commercially available.

Preferably, each buoyant vessel has variable buoyancy, more preferably is an inflatable vessel. Suitable inflatable vessels are known in the art and are commercially available. Suitable inflatable vessels include inflatable bags. One preferred inflatable vessel is the range of Seaflex® inflatable bags available from the Unique Group.

The buoyant vessels may have any suitable shape. During use of the dry dock assembly, the buoyant vessels are disposed at the surface of the water and move relative to the surface, into and out of the water, as the dry dock is employed and the load applied to the buoyant vessels changes. It is preferred that each buoyant vessel is of a shape that maintains a constant water plane area during the operation, that is that during its movement relative to the surface of the water, the buoyant vessel has a constant area at the surface of the water. Therefore, the cross-sectional are of the buoyant vessel is preferably uniform along that portion of the vessel that moves in and out of the water during the operation. More preferably, the buoyant vessel has a uniform cross-sectional area along its height.

One preferred form for each buoyant vessel is cylindrical, most preferably with the cylinder arranged with its longitudinal axis extending between the end faces thereof vertical.

The buoyant vessels are preferably of a size that at least a portion of the vessel remains above the water during the entire operation of the dry dock assembly. In this way, the buoyant vessels and the entire dry dock assembly is provided with excess buoyancy. Preferably, the buoyant vessels are of a size that at least 25%, more preferably at least 30%, still more preferably at least 40%, more preferably still at least 45% of the vessel remains above the water during the operation of the dry dock assembly. An arrangement in which about 50% of each buoyant vessel remains above the surface of the water during normal operation of the dry dock assembly is particularly preferred.

In operation, the buoyant vessels of the dry dock assembly provide sufficient support for the deck assembly. The deck assembly is lowered below the surface of the water. For example, where the deck assembly has variable buoyancy, the buoyancy of the deck assembly is reduced, for example by partially or wholly deflating inflatable vessels in the deck assembly. This allows the deck assembly to sink below the surface of the water and be manoeuvred beneath a vessel or structure to be raised out of the water.

Alternatively, the deck assembly may be held in position and the vessel or structure moved to be over the deck of the deck assembly. Once in position, the deck assembly is raised, with the vessel or structure to be raised on the deck surface. For example, the buoyancy of the deck assembly is increased, raising the deck assembly and the vessel or structure out of the water, as required. During this operation, the buoyant vessels maintain the deck assembly in position and provide stability. It is preferred that the buoyant vessels are of a sufficient size that they are always at least partially above the water until the deck assembly is in the required fully raised position.

Accordingly, in a further aspect, the present invention provides a method for raising a vessel from water, the method comprising: providing a deck assembly, preferably a deck assembly having variably buoyancy, the deck assembly having a plurality of buoyant vessels connected to the deck assembly, each buoyant vessel being moveable vertically with respect to the deck assembly; sinking the deck assembly below the vessel to be raised, for example by reducing the buoyancy of the deck assembly; supporting the deck assembly using the buoyant vessels at the surface of the water; manoeuvring the deck assembly below the vessel to be raised; and raising the deck assembly and the vessel to be raised, for example by increasing the buoyancy of the deck assembly.

The dry dock assembly and method of operation can be used in relation to a wide range of vessels, water-borne craft and floating installations or structures.

References herein to such terms as‘vertical’,‘upper’,‘lower’ and the like are references to the position and orientation of the components during the normal use and operation of the assemblies of this present invention.

Embodiments of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a deck assembly of one embodiment of the present invention;

Figure 2 is a perspective view of a first support assembly of the deck assembly of

Figure 1 ;

Figure 3 is a perspective view of the first support assembly, support members and second support assembly of the deck assembly of Figure 1 ; Figure 4 is a perspective view of the deck assembly of Figure 1 showing the arrangement of the inflatable vessels therein; Figure 5 is a plan view showing the arrangement of the inflatable vessels in the deck assembly of Figure 1 ;

Figure 6 is a perspective view of a large floating deck installation comprising a plurality of the deck assemblies of Figure 1 ; Figure 7 is a perspective view of a floating dry dock assembly according to one embodiment of the present invention;

Figure 8 is a view of the dry dock assembly of Figure 7 is position below a vessel to be raised;

Figure 9 shows the dry dock assembly and vessel of Figure 8 in a partially raised position;

Figure 10 shows the dry dock assembly and vessel of Figure 9 in the fully raised position with the vessel out of the water;

Figure 1 1 is a perspective view of a dry dock assembly of a further embodiment of the present invention with a vessel loaded thereon; and Figure 12 is a perspective view of one embodiment of the deck assembly of the present invention in use as a jack-up rig or platform.

Referring to Figure 1 , there is shown a deck assembly according to one embodiment of the present invention. The deck assembly, generally indicated as 2, comprises a first support assembly 4, a deck 6 and a plurality of support members 8 extending between the first support assembly and the deck assembly. A plurality of inflatable vessels 10 are arranged between the first support assembly 4 and the deck assembly 6. The deck 6 comprises a decking assembly 12, formed from a plurality of deck members 14, and a second support assembly 16. Details of the components of the deck assembly 2 are shown in Figures 2 to 5 and are described in more detail below. Turning to Figure 2, there is shown a perspective view of the first support assembly 4 of the deck assembly 2 of Figure 1 . The first support assembly 4 is in the form of a frame comprising frame members 20 arranged in a grid having a plurality of square cells. Each cell is provided with a diagonal frame member 22 to provide rigidity to the frame.

Turning to Figure 3, there is shown a perspective view of the first support assembly 4 of Figure 1 with the plurality of support members 8 and the second support assembly 16. As can be seen, the support members 8 are each connected at one end to the first support assembly 4 and at the other end to the second support assembly 16. The second support assembly 16 is similar in form to the first support assembly and has a frame comprising frame members 30 arranged in a grid having a plurality of square cells. Together, the first support assembly 4, the second support assembly 16 and the support members 8 form an open or space frame, which serves to provide support for the deck and the load being carried on the deck. The space frame also accommodates the inflatable vessels. As can be seen, brackets 32 are provided on the frame members 20 of the first support assembly 4 and the frame members 30 of the second support assembly 16 to which the inflatable vessels are attached.

As can be seen in Figure 3, the area or footprint of the second support assembly 16 is greater than that of the first support assembly 4. As a consequence, the area of the deck is greater than the area of the first support assembly.

The space frame comprising the first support assembly 4, the second support assembly 16 and the plurality of support members 8 is formed using components of the MERO® system.

Turning to Figure 4, there is shown a perspective view of the deck assembly of Figure 1 with the deck removed and the first and second support assemblies shown in outline. Figure 4 shows the arrangement of the inflatable vessels 10 within the space frame formed by the first support assembly 4, the second support assembly 16 and the support members 8 extending therebetween. As can be seen, each inflatable vessel 10 is generally cylindrical and is mounted with its longitudinal axis arranged vertically. Shackles on each end face of the inflatable vessel 10 attach the vessel to the respective brackets 32 on the frame members of the first and second support assemblies 4, 16. Figure 5 shows a plan view of the arrangement of the inflatable vessels 10 in the assembly of Figure 4. As can be seen, the inflatable vessels 10 are arranged in a close- packed formation. Each vessel 10 is held within a generally square cell of the space frame, with a frame member disposed above and below each vessel.

Each inflatable vessel is a Seaflex® inflatable bag available from the Unique Group. The bags are available in a range of different sizes. The size and number of inflatable vessels can be selected to meet the duty required of the deck assembly when in use.

The deck assembly shown in Figures 1 to 5 is assembled from individual components, including the frame members and deck members. These components are releasably connected, allowing the entire assembly to be disassembled, stored, transported and readily assembled for use in a new location, as required. The components of the assembly may be sized to fit within standard shipping containers, that is containers according to ISO 668 and ISO 1496.

The deck assembly 2 of Figure 1 is shown having a generally rectangular configuration, providing a generally rectangular deck. It is to be understood that the components of the assembly can be combined and assembled to form deck assemblies of other shapes and configurations.

In addition, the deck assembly 2 of Figure 1 can be employed on a modular basis and used as a module in a larger floating deck installation. For example, shown in Figure 6 is a large, generally rectangular floating deck installation 40 comprising 28 modules, each module being a deck assembly 2 of Figure 1. Again, it will be appreciated that the modules may be combined and connected together in other configurations.

In use, the deck assembly is assembled. Once assembled, the assembly is deployed in the water. With the inflatable vessels inflated, the assembly floats with the deck above the surface of the water. Deflation of some or all of the inflatable vessels allows the deck assembly to sink. In particular, the deck assembly may be sunk to have the deck below the surface of the water. In this condition, the deck assembly can be manoeuvred into position below a vessel or craft to be raised. The inflatable vessels may then be reinflated, thereby raising the deck assembly and the vessel or craft. Figure 7 shows a floating dry dock assembly according to one embodiment of the present invention. The dry dock assembly is shown deployed in water.

The dry dock assembly, generally indicated as 102, comprises a deck assembly 2 as shown in Figures 1 to 5 and described above. It is to be understood that the deck assembly 2 could be replaced with another deck assembly having a variable buoyancy and able to be raised and lowered in the water.

The dry dock assembly 102 further comprises arm assemblies 104 connected to the second support assembly 16 of the deck assembly 2. Each arm assembly 104 comprises a pair of arms 106 arranged in a V-shape, with the wide portion of the V-shape adjacent the deck assembly 2. Each arm 106 is pivotally mounted to the second support assembly 16. An inflatable vessel 108 is attached to the distal end of each arm assembly 104.

As can be seen, each inflatable vessel 108 is generally cylindrical and is mounted with its longitudinal axis arranged vertically. Shackles on the lower end face of the inflatable vessel 108 attach the vessel to the arms 106. Each inflatable vessel is a

Seaflex® inflatable bag available from the Unique Group. The bags are available in a range of different sizes. The size and number of inflatable vessels can be selected to meet the duty required of the deck assembly when in use.

Each arm assembly 104 is restrained by a tether 1 10 extending from the distal end of the arm assembly to the first support assembly of the deck assembly 2. The length of each tether is variable, for example by means of a winch (not shown for clarity). In operation of the dry dock assembly, the orientation of each arm assembly 104 with respect to the deck assembly changes as the deck assembly moves vertically in the water. This is particularly the case in the preferred embodiment in which each buoyant vessel remains at the surface of the water with at least a portion of the vessel above the surface during the operation. Varying the length of the tether allows this change in orientation between each arm assembly and the deck assembly to be accommodated.

In the embodiment shown in Figure 7, there are four arm assemblies 104 and inflatable vessels 108 arranged symmetrically on opposing sides of the deck assembly 2.

It will be understood that the number and position of the arm assemblies and buoyant vessels is selected to meet the demands of the dry dock assembly, in particular the load to be raised and lowered.

The operation of the dry dock assembly is as follows:

In the position shown in Figure 7, the inflatable vessels 10 of the deck assembly 2 are deflated to lower the deck assembly in the water such that the deck or upper surface is below the surface of the water. Figure 8 shows the dry dock assembly in this condition in a position below a vessel 200 to be raised out of the water.

The inflatable vessels of the deck assembly 2 are inflated, increasing the buoyancy of the deck assembly and raising the deck into contact with the hull of the vessel 200. This position is shown in Figure 9.

Continued inflation of the inflatable vessels of the deck assembly 2 raises the deck and the vessel 200 above the surface of the water, as shown in Figure 10. During this operation, the inflatable vessels 108 provide buoyancy to the entire installation. More particularly, by being arranged laterally of the deck assembly 2, the inflatable vessels 108 provide increased stability to the entire installation.

The vessel 200 is returned to the water by reversing the procedure described above.

It is to be noted that during the operation to raise or lower the vessel 200, the inflatable vessels 108 laterally of the deck assembly are maintained at the surface of the water, with at least a portion of the vessel extending above the surface.

As noted above, the configuration of the deck assembly and the number and shape of the inflatable vessels 1 10 employed laterally of the deck assembly can be varied to match the size and weight of the vessel to be lifted. Figure 1 1 shows an alternative embodiment of the dry dock assembly, with 22 inflatable vessels arranged laterally on all sides of the deck assembly.

Finally, referring to Figure 12, there is shown a deck assembly of the present invention in use as a jack-up rig or platform. The deck assembly 2 has the general configuration of the assembly shown in Figures 1 to 6 and described above. The deck assembly 2 is provided with four legs 204 extending through the deck of the assembly. Each leg 204 is supported by a frame 206 extending upwards from the deck and is moveable vertically relative to the deck. Each frame 206 extends through the deck and is mounted to the first support assembly of the deck assembly 2, as shown in Figure 12.

In use, with the legs 204 in the raised position, the deck assembly 2 is moved into position in the water. The legs 204 are lowered to the bed of the water into the position shown in Figure 12, for example by a crane 208. Alternatively, the legs 204 may be of the self-jacking arrangement known in the art. The deck assembly may then be used as a rig or platform for operations known in the art, such as drilling. Alternatively, the deck may be raised and lowered relative to the legs to recover or deploy a vessel in the water.

Claims

1. A deck assembly, the assembly comprising : a first support assembly; a deck; a plurality of support members extending between and connecting the first support assembly and the deck; and a plurality of inflatable vessels disposed between the first support assembly and the deck.

2. The deck assembly according to claim 1 , wherein the first support assembly comprises a frame formed from a plurality of interconnected frame members.

3. The deck assembly according to claim 2, wherein the frame is an open frame.

4. The deck assembly according to either of claims 2 or 3, wherein the frame comprises a plurality of frame cells.

5. The deck assembly according to any of claims 2 to 4, wherein the frame comprises a plurality of releasably interconnected frame modules, each module comprising one or more frame members.

6. The deck assembly according to any preceding claim, wherein the deck comprises a decking assembly comprising one or more decking members.

7. The deck assembly according to any preceding claim, wherein the deck comprises a second support assembly, the second support assembly being connected to the support members and the decking assembly overlying and connected to the second support assembly.

8. The deck assembly according to claim 7, wherein the second support assembly comprises a frame formed from a plurality of interconnected frame members.

9. The deck assembly according to claim 8, wherein the frame is an open frame.

10. The deck assembly according to either of claims 8 or 9, wherein the frame comprises a plurality of frame cells.

1 1 . The deck assembly according to any of claims 8 to 10, wherein the frame comprises a plurality of releasably interconnected frame modules, each module comprising one or more frame members.

12. The deck assembly according to any preceding claim, wherein the deck and the first support assembly have the same footprint.

13. The deck assembly according to any of claims 1 to 1 1 , wherein the footprint of the deck is larger than the footprint of the first support assembly.

14. The deck assembly according to any preceding claim, wherein each of the plurality of support members extending between the first support assembly and the deck is releasably connected to the first support assembly and the deck.

15. The deck assembly according to any preceding claim, wherein the support members are frame components and form a frame between the first support assembly and the deck.

16. The deck assembly according to claim 15, wherein the frame is an open frame.

17. The deck assembly according to either of claims 15 or 16, wherein the frame comprises a plurality of frame cells.

18. The deck assembly according to any of claims 15 to 17, wherein the support members, the first support assembly and the second support assembly together form a space frame.

19. The deck assembly according to claim 18, wherein the space frame comprises a plurality of cells, with each inflatable vessel being arranged within a cell of the space frame.

20. The deck assembly according to any preceding claim, wherein each inflatable vessel is cylindrical.

21 . The deck assembly according to any preceding claim, wherein the inflatable vessel is arranged vertically.

22. The deck assembly according to any preceding claim, wherein each inflatable vessel is sized such that 50% of each inflatable vessel is above the surface of the water in use with the deck assembly above water,.

23. The deck assembly according to any preceding claim, wherein the inflatable vessel is a bag.

24. The deck assembly according to any preceding claim, wherein each inflatable vessel has a uniform cross-sectional are along its height.

25. The use of a deck assembly according to any preceding claim for raising a vessel or other structure from water or deploying a vessel or other structure in water, as a jack up rig, or as a semi-submersible drilling rig.

26. A floating dry dock assembly, the assembly comprising: a deck assembly comprising an upper deck surface; and a plurality of buoyant vessels connected to and able to support the deck assembly; wherein each buoyant vessel is moveable vertically with respect to the deck assembly.

27. The floating dry dock assembly according to claim 26, wherein the buoyancy of the deck assembly can be varied.

28. The floating dry dock assembly according to either of claims 26 or 27, wherein the deck assembly is a deck assembly according to any of claims 1 to 24.

29. The floating dry dock assembly according to any of claims 26 to 28, wherein each buoyant vessel is disposed at a position laterally of the deck assembly.

30. The floating dry dock assembly according to claim 29, further comprising a plurality of lateral members extending laterally from the deck assembly, each member connected at a first position thereon to the deck assembly and having a buoyant vessel attached at a second position on the lateral member.

31 . The floating dry dock assembly according to claim 30, wherein the second position on each lateral member is spaced apart from the first position, such that the buoyant vessel is spaced from the deck assembly.

32. The floating dry dock assembly according to either of claims 30 or 31 , wherein a single buoyant vessel is connected to each lateral member.

33. The floating dry dock assembly according to any of claims 30 to 32, wherein each lateral member comprises an arm assembly.

34. The floating dry dock assembly according to claim 33, wherein each arm assembly comprises a single arm.

35. The floating dry dock assembly according to claim 33, wherein each arm assembly comprises a plurality of arms.

36. The floating dry dock assembly according to claim 35, wherein each arm assembly comprises a first arm and a second arm, the first and second arms being arranged in a V- shape.

37. The floating dry dock assembly according to claim 36, wherein the first and second arms are connected to the deck assembly at the widest portion of the V-shape.

38. The floating dry dock assembly according to any of claims 30 to 37, wherein each lateral member is provided with a hinge or pivot portion.

39. The floating dry dock assembly according to claim 38, wherein each lateral member is pivotally attached to the deck assembly at the first position on the lateral member.

40. The floating dry dock assembly according to either of claims 38 or 39, wherein movement of the lateral member relative to the deck assembly is constrained.

41 . The floating dry dock assembly according to claim 40, wherein the movement of the lateral member relative to the deck assembly is constrained by a tether.

42. The floating dry dock assembly according to claim 41 , wherein the tether is elastic.

43. The floating dry dock assembly according to any of claims 26 to 42, wherein each buoyant vessel is rigid and has a fixed buoyancy.

44. The floating dry dock assembly according to any of claims 26 to 43, wherein each buoyant vessel has a variable buoyancy.

45. The floating dry dock assembly according to claim 44, wherein each buoyant vessel is an inflatable bag.

46. The floating dry dock assembly according to any of claims 26 to 45, wherein each buoyant vessel is shaped to maintain a constant water plane area during use.

47. The floating dry dock assembly according to any of claims 26 to 46, wherein each buoyant vessel is generally cylindrical.

48. The floating dry dock assembly according to any of claims 26 to 47, wherein each buoyant vessel is sized such that 50% of each buoyant vessel is above the surface of the water in use.

49. A method for raising a vessel from water, the method comprising: providing a deck assembly, the deck assembly having a plurality of buoyant vessels connected to the deck assembly, each buoyant vessel being moveable vertically with respect to the deck assembly; sinking the deck assembly below the vessel to be raised; supporting the deck assembly using the buoyant vessels at the surface of the water; manoeuvring the deck assembly below the vessel to be raised; and raising the deck assembly and the vessel to be raised.

50. The method according to claim 49, wherein the deck assembly is sunk by reducing the buoyancy of the deck assembly.

51 . The method according to either of claims 49 or 50, wherein the deck assembly is raised by increasing the buoyancy of the deck assembly.

52. The method according to any of claims 49 to 51 , wherein the deck assembly is a deck assembly according to any of claims 1 to 24.

53. The method according to any of claims 49 to 52, wherein each buoyant vessel is spaced apart laterally from the deck assembly.

54. The method according to any of claims 49 to 53, wherein each buoyant vessel maintains a constant water plane area.

55. The use of an assembly according to any of claims 26 to 48 as a floating dry dock.