GB2610418A

GB2610418A - Floatation apparatus and method of operating the same

Info

Publication number: GB2610418A
Application number: GB2112602.4A
Authority: GB
Inventors: Millorit Andrew
Original assignee: Dryberth Ltd
Current assignee: Dryberth Ltd
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2023-03-08
Anticipated expiration: 2041-09-03
Also published as: GB2610418B; GB202112602D0

Abstract

An apparatus 2 for providing a berth for a vessel (4, Fig 1) in water has a variable buoyancy and comprises first 104 and second 106 primary buoyant members spaced apart from each other and each comprising a chamber 108 and 110 therein and comprising a water port (150, Fig 3) to allow water to enter and leave the chamber and a support assembly 120 for supporting the vessel and comprising one or more support members 124a, 124b, 128a, 128b extending between the first and second primary buoyant members. The apparatus has a floating position, in which a vessel resting on the support assembly is supported by the apparatus to be at least partially out of the water, and a submerged position, in which the apparatus is sufficiently submerged to allow the vessel to be moved relative to the support assembly, thereby moving the support assembly into and out of a position beneath the vessel. A method for using the apparatus is also disclosed.

Description

FLOATATION APPARATUS AND METHOD OF OPERATING THE SAME

The present invention relates to a floatation apparatus, in particular an apparatus for supporting a vessel in water, more particularly to an apparatus for raising and lowering a vessel in a body of water, for example to provide a dry berth for the vessel. The present invention also provides a method of operating a floatation apparatus, more particularly a method for raising and lowering a vessel in a body of water. The present invention is especially advantageous in providing a long term dry mooring for water-borne vessels, such as pleasure boats and yachts.

It is a common requirement to remove water-borne vessels of all sizes from the water from time to time, for example for maintenance or for storage. For smaller vessels, such as pleasure boats and yachts, it is a common practice to lift the vessel into and out of the water using a crane or a gantry. However, cranes or gantries are expensive items of equipment, require regular maintenance and occupy much needed space in boat yards and marinas. Therefore, there is a need for a simpler and more cost-effective way of raising and lowering vessels, such as pleasure craft, into and out of the water.

GB 2005603 A discloses a floating dock. The dock comprises a pair of centrally located, rotatably mounted caissons. Arms extend from each caisson and connect each caisson to a respective outrigger float. Rotation of the caissons raises or lowers the outrigger floats and a vessel resting on them.

AU 674273 discloses a floatation device. The floatation device comprises a pair of elongate, generally cylindrical, spaced apart float members. The float members are connected by a linking means comprising a bridge formed from nylon rope. In use, a vessel is positioned on the device, with the hull of the vessel supported on either side by the float members.

WO 97/00807A discloses a docking apparatus for a water borne vessel. The apparatus comprises a pair of spaced apart, generally cylindrical, primary buoyancy bodies connected by a cradle assembly. The cradle assembly comprises a plurality of flexible sheets arranged in a V-shaped configuration. Each buoyancy body is able to be filled with water and submerged. Expelling water from the buoyancy bodies causes the apparatus to rise. In this way the apparatus may be used to raise and lower a vessel in the water.

More recently, US 2018/0319469 concerns a submersible device for lifting a boat over water. The device comprises a pair of generally cylindrical inflatable members connected by flexible cross-members. A boat is positioned on the device and is raised or lowered by inflation or deflation of the inflatable members.

WO 2018/081864 discloses an apparatus for servicing the engine and drive system of a vessel while still in the water. The apparatus comprises a receptacle for receiving the vessel. The receptacle is submerged, to allow the vessel to be positioned over the receptacle. The receptacle is then raised and water pumped out of the receptacle to provide access to the vessel and its propulsion system.

Perhaps most recently, WO 2020/163848 discloses a bladder and tie-down system for securing and storing vessels, such as boats.

There is a need for an improved apparatus for berthing vessels in the water. It would be advantageous if the apparatus could be simple and inexpensive to construct, store and transport. It would also be an advantage if the apparatus could occupy no more space around the vessel than is provided for mooring the vessel in a harbour or marina, in particular being substantially no wider and/or substantially no longer than the vessel.

In a first aspect, the present invention provides an apparatus for providing a berth for a vessel in water, the apparatus having a variable buoyancy and comprising: a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein and comprising a water port to allow water to enter and leave the chamber; a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; an air supply and removal system for providing air to and allowing air to leave the chamber in each of the first and second primary buoyant members, the system comprising: an air inlet in the chamber of each of the first and second primary buoyant members to allow air to enter the respective chamber within the primary buoyant member; an air outlet in the chamber of each of the first and second primary buoyant members to allow air to be displaced from the respective chamber within the primary buoyant member by water entering the chamber through the water port; a valve assembly for controlling the flow of air to and from the air inlet and the air outlet; the apparatus having a floating position, in which a vessel resting on the cradle is supported by the apparatus to be at least partially out of the water, and a submerged position, in which the apparatus is sufficiently submerged to allow the vessel to be moved relative to the support assembly, thereby moving the support assembly into and out of a position beneath the vessel; wherein the apparatus has a selected orientation in the submerged position relative to the vessel to be raised and lowered, the position of the air outlet of each of the first and second conduits into the chamber of the respective buoyant member prevents the apparatus from submerging further than the selected orientation.

The apparatus of the present invention provides a number of significant advantages. In particular, the apparatus is simple to assemble. The apparatus may be transported as separate assemblies or components and assembled at the location of the end user.

Further, the apparatus may be tailored to suit the vessel to be berthed. In particular, the arrangement and location of the openings of the first and second conduits may be positioned to provide the apparatus with an orientation in the submerged position that is suitable for the shape and configuration of the vessel. The apparatus may also be tailored to suit vessels having different drafts in the water.

Still further, the apparatus is compact. In particular, the apparatus can be arranged to have a footprint that is not substantially larger than that of the vessel to be berthed. This is particularly important in many harbours and marinas, especially those providing berths for pleasure craft, where the space provided for each berth is limited. In general, the apparatus of the present invention can easily be configured to fit within the standard berth for vessels.

The apparatus of the present invention may be used to provide a berth for a wide range of vessels in and out of the water. The apparatus is readily scalable and can be constructed in a wide range of different sizes to suit a range of differently sized vessels. The apparatus finds particular use in marinas and the like for the berthing of pleasure craft. As noted above, the apparatus can be sized to fit within a standard marina berth or mooring, which are generally sized for a particular length and beam of a craft. \Mien not required, the apparatus may be left in a submerged or partially submerged position at the mooring and the vessel moved in and out over the apparatus, as required without hindrance.

Terms such as 'upper', 'lower', 'upwards', 'downwards', 'above', 'below' and the like are to be understood as referring to the apparatus when in its normal orientation during use.

Similarly, the terms 'front' and 'rear' refer to the ends of the apparatus corresponding to the bow and stern of the vessel when in position on the apparatus during normal use. Generally, in many embodiments, the apparatus is used in one orientation relative to the vessel, with the front of the apparatus, corresponding to the bow of the vessel, being the relatively more buoyant end of the apparatus and remaining higher in the water when in the submerged position. In such embodiments, the vessel is moved onto and off of the apparatus from the rear of the apparatus, which generally sits lower in the water in the submerged position.

The apparatus comprises a pair of primary buoyant members. The pair of primary buoyant members comprises a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member. Each of the first and second primary buoyant members comprises a chamber therein and has an opening to allow water to enter and leave the chamber. In use, to lower the apparatus in the water, and a vessel if supported on the apparatus, water is allowed to enter the chambers of the first and second primary buoyant members, reducing their buoyancy. As described hereinbelow, the apparatus is configured to automatically submerge to the required depth and orientation without a complex control system. To raise the apparatus, and a vessel

S

supported on the apparatus, air is introduced into the chambers of the primary buoyant members, to dispel water from the chambers, increasing their buoyancy and raising the apparatus and any supported vessel.

References herein to 'air' are to be understood as references to any gas which may be introduced into the chambers of the primary buoyant members or other component of the apparatus providing buoyancy. Any suitable gas may be employed. Air is a most suitable and most preferred gas.

In general, to displace water from the chambers in the first and second primary buoyant members or other components, air is required to be supplied at a pressure above atmospheric pressure. However, it is an advantage of the apparatus of the present invention that the air need only be at a pressure slightly above atmospheric pressure, for example up to 0.3 barg (5 psig), more preferably up to 0.28 barg (4 psig), still more preferably up to 0.2 barg (3 psig), still more preferably up to 0.14 barg (2 psig). Air at a pressure of from 0.07 to 0.14 barg (1 to 2 psig), for example about 0.1 barg (1.5 psig) is suitable for many embodiments.

Each of the first and second primary buoyant members may have any suitable shape and configuration to provide the apparatus with the buoyancy required to raise the selected vessel from the water and to allow the apparatus to be submerged sufficiently to be positioned beneath the vessel. Preferably, the first and second primary buoyant members are elongate. In many preferred embodiments, the first and second primary buoyant members are tubular. The first and second primary buoyant members may have any suitable cross-sectional shape. Preferably, the first and second primary buoyant members are circular in cross-section. It is particularly preferred that the first and second primary buoyant members are hollow, elongate cylinders.

Each of the first and second primary buoyant members comprises a chamber therein. Each primary buoyant member may comprise a single chamber or a plurality of chambers. In many preferred embodiments, each primary buoyant member comprises a single chamber therein extending substantially the entire length of the primary buoyant member.

It is an advantage that the first and second primary buoyant members can be formed as tubes, especially in the form of an elongate, hollow cylinder, as this allows the first and second primary buoyant members to be sized for a particular vessel and end use. In particular, the length and diameter of the first and second primary buoyant members may be readily selected to provide the required buoyancy of the first and second primary buoyant members, and hence the apparatus as a whole.

The first and second primary buoyant members are spaced apart. The distance between the first and second primary buoyant members may be determined by the size and configuration of the hull of the vessel to be raised and lowered. In general, in use, a vessel will be supported on the apparatus with the centre line or keel of the hull of the vessel between the first and second primary buoyant members. When the apparatus is configured to raise the vessel to have the hull clear of the water, the centre line or keel of the hull of the vessel is preferably supported above the first and second primary buoyant members, more preferably above the splash zone line of the apparatus.

The first and second primary buoyant members may be a fixed distance apart. More preferably, the distance between the first and second primary buoyant members is adjustable, to allow a given apparatus to accommodate vessels having a range of different hull dimensions.

The first and second primary buoyant members are preferably rotatable about their connections, more preferably each primary buoyant member mounted so as to be rotatable about the support assembly, as described in more detail below.

Preferably, the first and second primary buoyant members are arranged to have their longitudinal axes parallel.

Each of the first and second primary buoyant members is provided with a water port. In use, water enters and leaves the chamber in the primary buoyant member through the water port. Preferably, the port comprises a single opening in the wall of the primary buoyant member, through which water both enters and leaves the chamber, as required.

The water port may consist essentially of one or more openings in the wall of the primary buoyant member. More preferably, the water port comprises a conduit connected to the or each opening in the primary buoyant member through which water entering and leaving the chamber flows, the conduit having an opening spaced apart from the primary buoyant member. Again, it is preferred that water enters and leaves the chamber through the same conduit.

The conduit may be fixed. More preferably, the conduit is moveable, such that the opening in the conduit may be moved relative to the primary buoyant member between an upper position and a lower position. With the apparatus fully buoyant and in its floating position in the water, the conduit is preferably arranged such that the opening in the conduit in its upper position is above the water and in its lower position is below the water.

With the apparatus in its floating position and the opening in the conduit in the upper position, water cannot enter the chamber in the respective primary buoyant member. With the opening in the conduit moved to its lower position, below the surface of the water, water may enter the chamber to displace air from the chamber, but only once the valve assembly is opened to allow air displaced by the entering water to leave the chamber. In this way, the valve assembly provides a fail safe mechanism, preventing water from being allowed to enter the chamber inadvertently.

The conduit may be flexible. More preferably, the conduit is rotatable relative to the primary buoyant member such that the opening in the conduit is moveable between its upper position and its lower position.

In general, the apparatus may be lowered in the water in one of or a combination of two ways. First, the water port may be moved, for example by moving or rotating the conduit, to be below the water level, thereby allowing water to enter the chamber in the primary buoyant member. Alternatively, or in addition, the buoyancy of the rear of the assembly may be reduced sufficiently to lower the water port below the surface of the water, again allowing water to enter the chamber in the buoyant member.

The apparatus further comprises a support assembly for supporting the vessel. In use, the hull of the vessel rests on the support assembly. The support assembly also serves to connect the first and second primary buoyant members together. In one embodiment, the support assembly comprises a connecting member assembly comprising at least one connecting member extending between the first and second primary buoyant members. Preferably, the connecting member assembly comprises a plurality of connecting members, spaced apart along the length of and extending between the first and second primary buoyant members. The one or more connecting members preferably extend from a lower portion of the first primary buoyant member to a lower portion of the second primary buoyant member.

In one preferred embodiment, the connecting member assembly comprises a first connecting member and a second connecting member, each extending between the first and second primary buoyant members, preferably with the first and second connecting members respectively located forward and rearward of the centres of the first and second primary buoyant members. The first and second connecting members may be arranged symmetrically or asymmetrically forward of and rearward of the centres of the first and second primary buoyant members.

As noted above, one function of the support assembly is to connect the first and second primary buoyant members together. Preferably, the first and second primary buoyant members are connected to the support assembly to have their longitudinal axes extend parallel to one another. The first and second primary buoyant members may be rigidly connected to the support assembly. More preferably, the first and second primary buoyant members are pivotably connected to the support assembly, allowing the first and second primary buoyant members to be rotated laterally inwards and outwards about the pivot connection. In one preferred embodiment, the first and second primary buoyant members are each pivotably connected to the or each connecting member of the support assembly.

Having the first and second primary buoyant members pivotably connected to the support assembly provides a number of advantages. First, the width of the support assembly, in particular the distance between the hull support members mounted to the first and second primary buoyant members can be varied. This allows the support assembly to be adapted to different hull geometries. In addition, the pivot connection allows for the primary buoyant members to be easily disconnected from the cradle and reconnected, in turn easing the assembly and disassembly of the apparatus, for example for storage or transport.

The support assembly preferably comprises a hull support assembly comprising one or more hull support members. In use, the hull of the vessel berthed on the apparatus rests on the one or more hull support members of the hull support assembly. The one or more hull support members may be oriented and/or shaped to accommodate the hull of the vessel. The one or more hull support members are preferably mounted to the first and second primary buoyant members, preferably to the upper portions of the first and second primary buoyant members.

The hull support assembly preferably comprises one or more hull support connecting members. The or each hull support connecting member extends between the first and second primary buoyant members and provides a support for the hull of the vessel being berthed. In one preferred embodiment, the or each hull support connecting member is connected to and extends between two hull support members. In such embodiments, the hull support connecting member may comprise the hull support members, preferably with a hull support member at each end. Preferably, the hull support connecting member is shaped to accommodate the hull of the vessel, more preferably having a V-shaped upper surface. The or each hull support connecting member is preferably flexible, more preferably resilient, allowing the member to change its shape under the weight of the vessel being berthed, to more closely conform to the shape of the hull of the vessel.

In one embodiment, the hull support assembly comprises one or more front hull support members located forward of the centre of the first and second primary buoyant members. In one preferred embodiment, the hull support assembly comprises a first front hull support member mounted to the first primary buoyant member and a second front hull support member mounted to the second primary buoyant member opposite the first front hull support member. The first and second front hull support members are preferably oriented to accommodate the hull of the vessel, more preferably having their upper surfaces for contacting the hull of the vessel lying on the arms of a V-shape. The front hull support members are preferably moveable laterally, to allow their position to be adjusted to accommodate different hull designs. The front hull support members are preferably pivotably mounted, to allow their orientation to be adjusted to accommodate vessels with hulls of different shapes and sizes.

In one preferred embodiment, a hull support connecting member extends between the first and second front support members. The hull support connecting member may comprise the first and second front hull support members, preferably with a hull support member at each end. Preferably, the front hull support connecting member is shaped to accommodate the hull of the vessel, more preferably having a V-shaped upper surface.

In one embodiment, the hull support assembly comprises one or more rear hull support members located rearwards of the centre of the first and second primary buoyant members. In one preferred embodiment, the hull support assembly comprises a first rear hull support member mounted to the first buoyant member and a second rear hull support member mounted to the second primary buoyant member opposite to the first rear hull support member. The first and second rear hull support members are preferably oriented to accommodate the hull of the vessel, more preferably having their upper surfaces for contacting the hull of the vessel lying on the arms of a V-shape. The rear hull support members are preferably moveable laterally, to allow their position to be adjusted to accommodate different hull designs. The rear hull support members are preferably pivotably mounted, to allow their orientation to be adjusted to accommodate vessels with hulls of different shapes and sizes.

A hull support connecting member may extend between the first and second rear hull support members. The hull support connecting member may comprise the first and second rear hull support members, preferably with a hull support member at each end. Preferably, the rear hull support connecting member, if present, is shaped to accommodate the hull of the vessel, more preferably having a V-shaped upper surface. In many preferred embodiments, a rear hull support connecting member is not employed.

The upper surfaces of the one or more hull support members and the one or more hull support connecting members, if present, may be provided with a material, such as rubber or flexible polymer, to prevent the hull of the vessel being damaged.

In one preferred embodiment, the or each hull support connecting member is flexible, preferably resilient, in particular sufficiently flexible that it will flex to accommodate the shape of the hull of the vessel, when the weight of the vessel is applied to the or each hull support connecting member. In the preferred embodiment in which the or each hull support connecting member is generally V-shaped, the hull support member is preferably sufficiently flexible to allow the angle between the arms of the 'V to change as the weight of the vessel bears on the hull support connecting member.

In embodiments in which the first and second primary buoyant members are pivotably connected to the support assembly, this provides a number of effects. First, as the or each hull support connecting member flexes, each of the first and second primary buoyant members pivots about its connection to the support assembly, in turn adjusting the position of the hull support members mounted on the primary buoyant members to conform to the shape of the hull of the vessel. Further, in embodiments in which secondary buoyant members are provided, as described hereinbelow, the action of the first and second primary buoyant members pivoting about the support assembly as the weight of the vessel is applied to the hull support members and/or hull support connecting members moves the secondary buoyant members inwards towards the hull of the vessel. This acts to further support and hold the vessel. This also reduces or avoids the need to provide the vessel with buffers or bumpers along the sides of the hull, as is common practice when mooring vessels in a marina or harbour.

The pair of primary buoyant members may provide substantially all the buoyancy of the apparatus. In one preferred embodiment, the apparatus comprises a pair of secondary buoyant members comprising a first secondary buoyant member spaced apart from the first primary buoyant member and a second secondary buoyant member spaced apart from the first secondary buoyant member. The pair of secondary buoyant members is preferably disposed above the pair of primary buoyant members. In one preferred embodiment, the first and second secondary buoyant members each lies respectively above the first and second primary buoyant members, more preferably above and laterally outwards from the longitudinal centre line of the first and second primary buoyant members. Each secondary buoyant member may be connected to the respective primary buoyant member of the first pair by connecting arms, preferably extending from an upper portion of the respective primary buoyant member.

Each secondary buoyant member may be pivotably mounted, so as to be moveable laterally inwards and outwards, to accommodate vessels of different sizes. In embodiments in which the primary buoyant members are pivotably mounted to the support assembly, as described above, the secondary buoyant members are preferably rigidly mounted to a respective primary buoyant member. In this way, the secondary buoyant members are moved inwards and outwards, as the primary buoyant members pivot about the support assembly, as described above.

Each of the first and second secondary buoyant members may have any suitable shape and configuration to provide the apparatus with the buoyancy required. Preferably, the first and second secondary buoyant members are elongate. In many preferred embodiments, the first and second secondary buoyant members are tubular. The first and second secondary buoyant members may have any suitable cross-sectional shape.

Preferably, the first and second secondary buoyant members are circular in cross-section.

It is particularly preferred that the first and second secondary buoyant members are hollow, elongate cylinders.

Each of the first and second secondary buoyant members comprises a chamber therein. Each secondary buoyant member may comprise a single chamber or a plurality of chambers. In many preferred embodiments, each secondary buoyant member comprises a single chamber therein extending substantially the entire length of the secondary buoyant member. Preferably, the chambers are sealed to contain a body of air and the ingress of water into the chambers is prevented. In use, it is preferably not required to flood the chambers of the secondary buoyant members, but rather to maintain the buoyancy of the secondary buoyant members and to rely on changing the buoyancy of the pair of primary buoyant members to raise and lower the apparatus and the vessel in the water.

It is an advantage that the first and second secondary buoyant members can be formed as tubes, especially in the form of an elongate, hollow cylinder, as this allows the first and second secondary buoyant members to be sized for a particular vessel and end use. In particular, the length and diameter of the first and second secondary buoyant members may be readily selected to provide the required buoyancy of the first and second secondary buoyant members, and hence the apparatus as a whole.

The first and second secondary buoyant members are spaced apart. The distance between the first and second secondary buoyant members may be determined by the size and configuration of the hull of the vessel to be raised and lowered. In general, in use, a vessel will be supported on the apparatus with the centre line or keel of the hull of the vessel between the first and second secondary buoyant members. When the apparatus is configured to raise the vessel to have the hull clear of the water, the centre line or keel of the hull of the vessel may be supported below the first and second secondary buoyant members. In this way, the first and second secondary buoyant members of the second pair will lie on either side of the hull of the vessel.

Preferably, the first and second secondary buoyant members are arranged to have their longitudinal axes parallel. More preferably, the first and second secondary buoyant members are arranged to have their longitudinal axes parallel to the longitudinal axes of the primary buoyant members.

The secondary buoyant members perform a number of functions. First, they provide additional buoyancy and function to keep the apparatus at the required depth when the apparatus is submerged, for example to allow a vessel to be moved onto or off of the apparatus. In particular, the secondary buoyant members provide a counterbalance as the primary buoyant members fill with water and sink. Further, when arranged in the preferred embodiments described above, the secondary buoyant members act as guides to position the vessel centrally over the apparatus. Still further, as described in more detail below, the secondary buoyant members can provide support for the valve assembly.

The apparatus further comprises an air supply and removal system for providing air to and removing air from the chamber in each of the first and second primary buoyant members.

The air supply and removal system comprises an air inlet in each of the first and second buoyant members to allow air to enter the respective chamber within the primary buoyant member. In use, when the apparatus is submerged and it is desired to raise the apparatus, and any vessel above the apparatus, air is supplied to the air inlet of the chambers of both the first and second primary buoyant members. This supply of air displaces water in the chambers of the primary buoyant members and forces water out of the chamber through the water port in each of the first and second primary buoyant members, increasing the buoyancy of the apparatus.

The air supply and removal system further comprises an air outlet in each of the first and second primary buoyant members to allow air to be expelled from the respective chamber within the primary buoyant member, in particular to be displaced by water entering the chamber through the water port. In use, when the apparatus is in its floating position and it is desired to lower the apparatus in the water, and any vessel above the apparatus, air is allowed to leave the chambers of both the first and second primary buoyant members through their respective air outlet. This in turn allows water to enter the chamber through the water port in each of the first and second primary buoyant members, decreasing the buoyancy of the apparatus.

In a particularly preferred embodiment, the air inlet and the air outlet of each primary buoyant member employ the same opening, such that air enters and leaves the primary buoyant member along the same flowpath, that is along the same conduit.

The air supply and removal system further comprises a valve assembly for controlling the flow of air to and from the air inlet and the air outlet. The valve assembly may comprise any suitable arrangement of valves to control the flow of air into and out of the chamber in each primary buoyant member. The valve assembly may comprise a single valve controlling the flow of air to or from both primary buoyant members. More preferably, each primary buoyant member is provided with a respective valve for controlling the flow of air. In a preferred embodiment, the flow of air both to and from the chamber within a primary buoyant member is controlled by the same valve. The valves for controlling the flow of air to and from the chambers in the primary buoyant members are preferably variable, to allow the flow rate of air to be controlled, thereby providing a means to control the rate at which the apparatus, and any vessel supported thereon, is raised or lowered in the water. This also allows the stability of the apparatus from side to side to be adjusted and maintained, for example to hold the vessel in a level orientation.

The valve assembly may be mounted directly on the primary buoyant members.

More preferably, the valve assembly is spaced apart from the primary buoyant members and the air supply and removal system comprises a conduit assembly connecting the valve assembly with the chamber within each primary buoyant member. The conduit assembly comprises one or more conduits extending from the valve assembly and opening into the chamber within a respective primary buoyant member. The conduit assembly may comprise a conduit connecting the valve assembly to each of the air inlet and air outlet of each primary buoyant member. More preferably, the conduit assembly comprises a single conduit for both supplying air to and removing air from the chamber in each primary buoyant member.

In one embodiment, the one or more conduits extending to each primary buoyant member extends from the valve assembly externally of the primary buoyant member to an opening in the wall of the primary buoyant member, through which air enters and/or leaves the chamber.

More preferably, the one or more conduits extending to each primary buoyant member comprises a first conduit portion extending from the valve assembly externally of the primary buoyant member to an opening in the wall of the respective primary buoyant member; and a second conduit portion extending from the opening in the wall of the primary buoyant member within the chamber of the primary buoyant member. The second conduit portion has a conduit opening spaced apart from the opening in the wall of the primary buoyant member, through which air enters and/or leaves the chamber. This provides the advantage that the primary buoyant member may be formed with one or more openings in its wall and the position of the conduit opening through which air enters and/or leaves the chamber determined solely by the length and shape of the second conduit portion. This in turn allows the attitude and depth of the apparatus in the submerged position to be determined simply by the design of the second conduit portion, with the other components being of a standardised design.

In one preferred embodiment, the second conduit portion extends from the opening in the wall of the primary buoyant member longitudinally within the chamber, more preferably from the opening in the wall of the primary buoyant member towards the front of the apparatus. In this way, the conduit opening is forward of the opening in the wall of the primary buoyant member.

In a particularly preferred embodiment, the air supply and removal assembly comprises a conduit assembly comprising a conduit extending from the valve assembly to each primary buoyant member, the conduit comprising a first conduit portion and a second conduit portion, whereby air entering and leaving the chamber in the primary buoyant member flows along the same conduit.

The components of the valve assembly, such as the one or more valves, may be located in any suitable position on the apparatus. In embodiments in which the apparatus comprises a pair of secondary buoyant members, as described above, it is preferable that the valve assembly is mounted on a secondary buoyant member. This allows the valve assembly to be readily accessible to an operator and remain above the water when the apparatus is lowered, for example from a jetty or walkway besides the berth. In a particularly preferred embodiment, each of the secondary buoyant members is provided with a valve assembly support or a set of one or more valves making up the valve assembly. In use, one valve assembly or set of valves will be used and the other is redundant. Depending upon the orientation of the apparatus relative to an adjacent jetty or walkway, the valves of the valve assembly may be mounted to the valve assembly support or the conduits may be connected to the one or more valves of the secondary buoyant member adjacent the jetty or walkway. Should the orientation of the apparatus relative to the jetty or the walkway be reversed, the valves of the valve assembly may be mounted to the valve assembly support or the conduits may simply be connected to the set of valves on the other secondary buoyant member.

In use, the apparatus has a floating position, in which a vessel resting on the cradle is supported by the apparatus to be at least partially out of the water, and a submerged position, in which the apparatus is sufficiently submerged to allow the support assembly to be moved relative to the vessel into and out of a position beneath the hull of the vessel. In this respect, references to movement of the apparatus or its components 'relative' to the vessel or its components is a reference to one of the vessel and the apparatus being moved in relation to the other. The apparatus may be moved into or out of position beneath the vessel while the vessel is stationary. Alternatively, and most preferred, is to keep the apparatus stationary, for example moored in the berth of the marina or harbour, and to move the vessel through the water onto and off of the apparatus.

With the apparatus in the floating position, the water port of each primary buoyant member is below the surface of the water or, depending upon the design of the water port, the conduit is moved to have its opening below the surface of the water. This provides water for entering the chambers with the primary buoyant members. To permit the water to enter the chambers and flood the primary buoyant members, the air outlet is opened, for example by opening the corresponding valve or valves of the valve assembly. This allows air present in the chamber to be displaced by water entering the water port, in turn decreasing the buoyancy of the primary buoyant members and submerging the apparatus. Water will continue to enter the chamber within each buoyant member until the water level within the chamber reaches the air outlet. In this way, the water forms a 'water lock', closing the air outlet, in turn preventing further air from leaving the chamber. Thus, the apparatus does not sink further and the depth to which the apparatus is submerged is controlled by the location of the air outlet, without requiring further actions by the operator. In one embodiment, the depth and orientation of the apparatus in the submerged position is determined by the distance between the air outlet and the front end of the chamber within the respective primary buoyant member.

The apparatus can be considered as having a selected orientation and depth in the submerged position. As noted above, these are determined by the location of the air outlet in each primary buoyant member. Typically, these will be selected according to the vessel to be raised and lowered. The depth of the apparatus in the submerged position is determined by the draught of the vessel. The attitude or orientation of the apparatus in the submerged position will be determined by the shape and configuration of the vessel, for example by the shape of the hull and other components of the vessel extending into the water, such as outboard engines at the stern of the vessel and the like. In many embodiments, when in the submerged position, the apparatus will have the rear lower in the water than the front, for example with the apparatus angled upwards from rear to front at an angle of from 5 to 100.

The position of the air outlet of each of the first and second primary buoyant members into the chamber of the respective primary buoyant member prevents the apparatus from submerging further than the selected position and also determines the orientation of the apparatus in the submerged position. It is particularly advantageous that these parameters may be selected simply by the position of just the air outlet, for example by the design of a single component, that is the second conduit portion, as discussed above.

Accordingly, in a further aspect, the present invention provides a method for raising and lowering a vessel in water, the method comprising: providing a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein; providing a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; at least partially submerging the first and second primary buoyant members by allowing water to enter the chamber through a water inlet in each primary buoyant member and air to leave the chamber through an air outlet in each primary buoyant member; controlling the depth and orientation of the first and second primary buoyant members when at least partially submerged to a selected depth and a selected orientation by locating the air outlet in each primary buoyant member.

Once the apparatus has been submerged into the submerged position, it is positioned beneath the hull of the vessel to be raised. This may be achieved by moving the apparatus through the water, however, it is generally more convenient to move the vessel over the apparatus. In this way, the apparatus may remain moored in the berth and not moved. With the vessel in position over the apparatus, and the hull of the vessel appropriately positioned over the cradle, air is supplied to the air inlet of each of the primary buoyant members, displacing the water in the chamber, which is forced out of the water port. This increases the buoyancy of the apparatus, which rises, together with the vessel, in the water to the floating position. When the water has been evacuated from each chamber, the water port may be closed, for example by moving the conduit to have its opening above the surface of the water.

It has been found that it in some circumstances it is advantageous to provide additional variable buoyancy, in the form of a trim vessel, to the rear portion of the apparatus, that is rearwards of the centre of the first and second primary buoyant members. The variable buoyancy functions in the same way as the primary buoyant members, that is when full of air provides additional buoyancy and when partially or completely full of water provides additional ballast. The addition of further variable buoyancy in this way moves the centre of buoyancy of the apparatus. In particular, when the variable buoyancy is fully or partially full of water, the centre of buoyancy of the apparatus is moved rearwards. This alters the attitude of the apparatus in the submerged position, such that the rear of the apparatus lies lower in the water than the front. This in turn allows the apparatus to accommodate vessels having components extending into the water at the stern of the vessel, such as outboard engines. The inclusion of additional variable buoyancy to the rear portion of the apparatus also increases the buoyancy of the rear of the apparatus, which in turn allows vessels having significant weight in their stern portions, for example arising from inboard or outboard engines, to be accommodated.

In a further aspect, the present invention provides an apparatus for raising and lowering a vessel in water, the apparatus comprising: a first pair of primary buoyant members comprising a first primary buoyant member and a primary second buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein and comprising a water port to allow water to enter and leave the chamber; a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; an air supply and removal system for providing air to and removing air from the chamber in each of the first and second primary buoyant members, the system comprising: an air inlet in each of the first and second primary buoyant members to allow air to enter the respective chamber within the primary buoyant member; an air outlet in each of the first and second primary buoyant members to allow air to be displaced from the respective chamber within the primary buoyant member by water entering the chamber through the water port; a valve assembly for controlling the flow of air to and from the air inlet and the air outlet; a trim vessel having a water port to allow water to enter or leave the vessel, an air inlet to allow air to enter the trim vessel and an air outlet to allow air to leave the vessel; 10 and a buoyancy air supply and removal system, the system comprising a valve assembly for controlling the flow of air to and from the trim vessel.

The trim vessel is preferably disposed rear of the centre of the apparatus. In this way, the trim vessel provides additional buoyancy for the rear of the apparatus, which is of advantage when the apparatus is being used with vessels having significant weight at the stern, such as inboard or outboard motors. In addition, when the trim vessel is full of water, the centre of buoyancy of the apparatus is displaced rearwards relative to the centre of buoyancy of the apparatus when the trim vessel is full of air. This assists the apparatus in having a stern-down orientation in the submerged position, that is with the rear lowermost and the front uppermost The trim vessel may have any suitable shape and may be any suitable vessel for holding water and air. In one preferred embodiment, the trim vessel is generally rectangular.

Preferably, the trim vessel is located between the first and second primary buoyant members, most preferably between the rear portions of the primary buoyant members.

The trim vessel comprises a water port. In use, water is allowed to enter the trim vessel through the water port or is forced out of the trim vessel through the water port. The water port may comprise one or more openings in the trim vessel. Preferably, water enters and leaves the trim vessel through the same opening or openings.

The trim vessel comprises an air inlet. During operation, with water present in the vessel, when it is required to increase the buoyancy of the trim vessel, air is supplied to the air inlet, which is used to evacuate water from the trim vessel through the water port. The trim vessel further comprises an air outlet. During operation, when it is required to decrease the buoyancy of the trim vessel, the air outlet may be opened, allowing air in the vessel to be displaced by water entering the water port. In one preferred embodiment, the air inlet and the air outlet are both provided by the same opening in the trim vessel, such that air entering and leaving the trim vessel follows the same flowpath. This allows the air flow both to and from the trim vessel to be controlled by single valve The apparatus comprises a buoyancy air supply and removal system. The system comprises a valve assembly for controlling the flow of air to and from the trim vessel. The valve assembly may be located in any suitable position on the apparatus and, if spaced from the trim vessel, may comprise a conduit extending from the valve assembly to the air inlet in the trim vessel.

Other features of the apparatus of this aspect of the invention are as hereinbefore described.

In operation, when the apparatus is in the floating position, the trim vessel provides additional buoyancy to the apparatus, in addition to the buoyancy provided by the primary buoyancy members, preferably to the rear of the apparatus. When moving the apparatus to the submerged position, in order to provide additional ballast to the apparatus, the water port of the trim vessel is opened. Air is allowed to leave the trim vessel through the air outlet, in turn allowing water to enter the vessel through the water port and displace air from within the vessel. To increase the buoyancy of the trim vessel and move the apparatus to the floating position, air is supplied under pressure to the air inlet, forcing water out of the vessel through the water port.

The trim vessel is used to alter the buoyancy of the apparatus, more preferably the rear portion of the apparatus, as described above. The trim vessel also acts to provide lateral trim to the apparatus.

When moving the apparatus from the floating position to the submerged position, it has been found advantageous, in a first stage, to decrease the buoyancy of the trim vessel, by flooding the trim vessel with water, and thereafter, in a second stage, to allow water to enter the chambers in the first and second primary buoyant members.

In a still further aspect, the present invention provides a method for raising and lowering a vessel in water, the method comprising: providing a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein; providing a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; providing a trim vessel connected to the first and second primary buoyant members, at least partially submerging the apparatus to a first position having a first depth and a first orientation by allowing water to enter the trim vessel through a water port and air to leave the trim vessel through an air outlet; and further submerging the apparatus to a second position having a second depth and a second orientation by at least partially submerging the first and second primary buoyant members by allowing water to enter the chamber through a water port in each primary buoyant member and air to leave the chamber through an air outlet in each primary buoyant member.

The trim vessel preferably provides a fail-safe mechanism for lowering the apparatus in the water. In particular, the trim vessel is preferably arranged such that water must first be introduced into the trim vessel, reducing the buoyancy of the vessel and the apparatus sufficiently to lower the apparatus in the water to bring the water port in each primary buoyant member below the surface of the water, only then to allow water to enter the chambers within the buoyant members.

In a further aspect, the present invention provides a preferred embodiment of an apparatus for raising and lowering a vessel in water, the apparatus comprising: a pair of primary buoyant members comprising a first hollow, elongate, cylindrical, primary buoyant member and a second hollow, elongate, cylindrical, primary buoyant member spaced apart from the first primary buoyant member, the first and second primary buoyant members having their longitudinal axes parallel, each of the first and second primary buoyant members comprising a chamber therein and comprising a conduit extending from an opening in the lower portion of the primary buoyant member, the conduit having an opening to allow water to enter and leave the chamber; a support assembly for supporting the vessel and comprising a plurality of support members mounted on the upper portions of the first and second primary buoyant members and a plurality of connecting members extending between the lower portion of the first primary buoyant member and the lower portion of the second primary buoyant member, wherein the support members are arranged to have their upper surfaces lie on the arms of a V-shape to accommodate the lower portion of the hull of the vessel to be raised and lowered; and wherein the first and second primary buoyant members are pivotally connected to the connecting members; a pair of secondary buoyant members comprising a first cylindrical, elongate, secondary buoyant member and a second cylindrical, elongate, secondary buoyant member, each secondary buoyant member being arranged above and laterally outwards of the longitudinal centre line of a respective primary buoyant member and connected to a respective one of the primary buoyant members by a plurality of support members extending upwards from the respective primary buoyant member; an air supply and removal system for providing air to and and allowing air to leave the chamber in each of the first and second primary buoyant members, the system comprising: an air inlet in each of the first and second primary buoyant members to allow air to enter the respective chamber within the primary buoyant member; an air outlet in each of the first and second primary buoyant members to allow air to be displaced from the respective chamber within the primary buoyant member by water entering the chamber through the water port; a valve assembly for controlling the flow of air to and from the air inlet and the air outlet; a first conduit extending from the valve assembly to the first primary buoyant member and a second conduit extending from the valve assembly to the second primary buoyant member, each of the first and second conduits comprising a first conduit portion extending to an opening in the upper portion of the wall of the respective primary buoyant member and a second conduit portion extending from the opening in the wall of the primary buoyant member longitudinally within the chamber in the primary buoyant member, the second conduit portion having a conduit opening spaced apart from the opening in the wall of the primary buoyant member, the conduit opening providing both the air inlet and the air outlet through which air both enters and leaves the chamber; the valve assembly being mounted on one of the secondary buoyant members; the apparatus having a floating position, in which the vessel is resting on the support assembly and is supported by the apparatus to be at least partially out of the water, and a submerged position, in which the apparatus is at least partially submerged in the water to selected depth and has a selected orientation relative to the vessel and in which the apparatus is sufficiently submerged to allow the vessel to be moved relative to the apparatus to move the support assembly into and out of a position beneath the hull of the vessel; wherein in the submerged position, the position of the conduit opening of each of the second conduit portions within the chamber of the respective primary buoyant member prevents the apparatus from submerging further than the submerged position.

The apparatus of the preferred embodiment, may further comprise a trim vessel as hereinbefore described.

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 vessel supported on an apparatus according to one embodiment of the present invention; Figure 2 is a perspective view of the apparatus according to the embodiment of Figure 1; Figure 3 is a plan view from above of the apparatus of Figure 2; Figure 4 is a rear view of the apparatus of Figure 2 in the direction of the arrow A in Figure 3, Figure 5 is partial cross-sectional view of the front portion of one primary buoyant member of the apparatus of Figure 2 showing the chamber within the buoyant member; Figure 6 is a perspective view of an apparatus of a further embodiment of the present invention; Figure 7 is a plan view from above of the apparatus of Figure 6; and Figure 8 is a rear view of the apparatus of Figure 6 in the direction of the arrow B in Figure 7.

Turning first to Figure 1, there is shown a perspective view of an apparatus according to one embodiment of the present invention, generally indicated as 2, with a vessel 4 supported on the apparatus 2. The apparatus 2 is described in more detail below. The vessel 4 is just one example of the type of vessel which may be raised and lowered from the water using the apparatus of the present invention. In this example, the vessel is a rigid inflatable boat (RIB) with a pair of outboard engines mounted to the stern of the RIB.

Referring to Figure 2, there is shown a perspective view of an apparatus according to the embodiment of the present invention shown in Figure 1. The apparatus is shown in plan view from above in Figure 3 and from the rear in the direction of arrow A in Figure 4.

The apparatus, generally indicated as 2, is generally used with its front 2a oriented to the bow of the vessel and its rear 2b oriented to the stern of the vessel, as shown in Figure 1.

The apparatus 2 comprises a first primary buoyant member 104 and a second primary buoyant member 106. Both the first and second primary buoyant members 104, 106 are elongate, hollow cylinders with closed ends, providing elongate cylindrical chambers 108, 110 respectively therein. The first and second primary buoyant members 104, 106 are spaced apart and arranged with their longitudinal axes substantially parallel to one another. The first and second primary buoyant members 104, 106 are the same length and are arranged to be coterminous at the front 2a and the rear 2b of the apparatus.

The apparatus 2 further comprises a support assembly, generally indicated as 120. The support assembly 120 comprises a connecting member assembly 121 comprising spaced apart, parallel, front and rear connecting members 122a, 122b extending between the front lower portions and between the rear lower portions respectively of the first and second primary buoyant members 104, 106. The front connecting member 122a is connected at each end to a front mount 123a on the front portion of the respective primary buoyant member 104, 106 by a pivot connection 125a. Similarly, the rear connecting member 122b is connected at each end to a rear mount 123b on the rear portion of the respective primary buoyant member 104, 106 by a pivot connection 125b. In this way, each of the first and second primary buoyant members 104, 106 is pivotable about the connecting member assembly 121 of the support assembly 120 and able to rotate laterally inwards and outwards.

The support assembly 120 further comprises front support connecting member 124 having a pair of front support members 124a, 124b. The front support connecting member 124 is moveably mounted at each end to the upper portion of the front mounts 123a. The front support connecting member 124 is formed with a shallow V-shape, to accommodate the lower portion of the hull of a vessel. The front support connecting member 124 is flexible, such that as weight of a vessel is applied to the upper surface of the member, the member flexes to conform more closely to the shape of the hull of the vessel. In addition, the action of the weight of the vessel on the front support connecting member 124 is to cause the primary buoyant members 104, 106 to pivot about the support assembly 120 and rotate inwards towards the hull of the vessel.

Elongate rubber pads 126 are provided on the upper surface of each end of the front support connecting member 124.

The support assembly 120 further comprises a pair of rear support members 128a, 128b. Each rear support member 128a, 128b is moveably mounted to the upper portion of a respective rear mount 123b, such that each rear support member 128a, 128b is both moveable laterally inwards and outwards and pivotable relative to the respective rear mount 123b. The upper surfaces of the rear support members 128a, 128b are oriented to lie on an arm of a V-shape, to accommodate the hull of a vessel. Elongate rubber pads 129 are provided on the upper surface of each end of the rear support members 128a, 128b.

The apparatus 2 further comprises a first secondary buoyant member 130 and a second secondary buoyant member 132. Each secondary buoyant member 130, 132 is an elongate, hollow cylinder with closed ends. Each secondary buoyant member 130, 132 contains a sealed chamber therein holding air. Each secondary buoyant member 130, 132 is mounted to a respective primary buoyant member 104, 106 above and laterally outwards of the centre of a respective primary buoyant member 104, 106 by a pair of spaced apart mounting arms 134, each mounting arm 134 connected to an upper, outer portion of a front or rear mount 123a, 123b.

A pair of spaced apart dock guides 142 are provided on one secondary buoyant member 130 and extend downwards to a lower portion of the respective primary buoyant member 104. The dock guides 142 are provided in the side of the apparatus 2 adjacent the jetty or walkway of the berth. The dock guides 142 may be moved to the other side of the apparatus 2, as required by the arrangements of the berth. Alternatively, both sides of the apparatus 2 may be provided with dock guides 142.

Each primary buoyant member 104, 106 is provided with a water port 150. Each water port 150 comprises an opening 152 in the wall of the respective buoyant member 104, 106 located in the lower portion of the rear portion of the buoyant member. A first water conduit 154 extends laterally inwards from each opening 152. A second water conduit 156 is rotatably mounted to the end of each first water conduit 154 and extends generally perpendicular to the first water conduit. Each second water conduit 156 has a generally lazy 'S' shape and comprises an open end through which water can enter and leave. In use, each second water conduit 156 can be rotated about the respective first water conduit 154 to raise or lower the open end. In particular, the second conduit 156 may be rotated to have the open end either above or below the surface of the water.

The apparatus 2 further comprises an air supply and removal system, generally indicated as 160, for providing air to and removing air from the chamber 108, 110 in each of the first and second primary buoyant members 104, 106. The air supply and removal system comprises a valve assembly 162 comprising a pair of valves 164, 166. Each valve 164, 166 of the valve assembly 162 is mounted to one of the secondary buoyant members 130, with each valve 164, 166 having a respective support tube extending through the secondary buoyant member 130. Air is supplied to and removed from the primary buoyant members 104, 106 by a conduit assembly 168. A first conduit portion in the form of a flexible hose 170 extends from the valve 164 to an opening 172 in the top of the wall of the buoyant member 104. Similarly, a conduit portion in the form of a flexible hose 174 extends from the valve 166 to an opening 176 in the top of the wall of the buoyant member 106.

In the embodiment shown in the figures, the second secondary buoyant member 132 is provided with a set of valves 164a, 166a, in an analogous arrangement to that of the valve assembly 162 on the first secondary buoyant member 130. The hoses 170, 174 may be disconnected from the valves 164, 166 on one side of the apparatus and connected to the valves 164a, 166a on the other side of the apparatus, as required for ease of access to the valves and operation of the apparatus when in the berth.

Turning now to Figure 5, there is shown a partial cross-sectional view of the front portion of one primary buoyant member 106. As shown in Figure Sand described above, the first conduit portion 172 of the conduit assembly 168 extends to the opening 176 in the top portion of the wall of the primary buoyant member 106. A second conduit portion 180 extends longitudinally within the chamber 110 in the primary buoyant member 106 from the opening 176 towards the front of the primary buoyant member 106. The second conduit portion 180 has a conduit opening 182 at its end. As will be seen, in the embodiment shown in Figure 5, the conduit opening 182 is positioned slightly rearwards of the front end of the primary buoyant member 106. The position of the conduit opening 182 may be varied by varying the length of the second conduit portion.

The conduit assembly 168 comprises a second conduit portion extending within the chamber of the other primary buoyant member 104, in the same manner as shown in Figure 5.

In operation, the apparatus 2 of Figures 2 to 5 is first deployed in its floating position at the surface of the water, for example in a berth in a harbour or marina. When it is desired to berth a vessel, the valves 164, 166 are opened, thereby connecting the chamber within each primary buoyant member 104, 106 to atmosphere through the respective first and second conduit portions 172, 176, 180 of the conduit assembly 168. Both second water conduits 156 are rotated to have their open ends below the surface of the water. In this position, water enters the chambers 108, 110 within each primary buoyant member 104, 106, displacing air through the conduit assembly 168. As water enters the chambers 108, 110, the apparatus 2 sinks in the water, with the rear end of the apparatus sinking first and furthest. The apparatus 2 continues to sink until the water level in each chamber 108, 100 reaches the conduit openings 182 in the second conduit portions. At this point, the water forms a water lock, whereby the air remaining in each chamber is trapped and water stops flowing into the chambers. The apparatus 2 has reached its submerged position and does not sink further. The orientation of the apparatus 2 of this embodiment in the submerged position is with the rear of the apparatus lower in the water than the front and the apparatus generally angled at an upwards angle of from 5 to 10° from front to rear. The point at which the water forms a water lock and prevents further water entering and air leaving the chambers is determined by the position of the conduit openings 182 within the chambers. More particularly, in the embodiment shown, the point at which the water forms a water lock, and hence the position and orientation at which the apparatus stops sinking, is determined by the distance between the conduit openings 182 and the front end of the chambers 108, 110.

As noted above, the apparatus sinks at the rear at an attitude of from 5 to 10°, with the front uppermost. As a result, in this orientation, the conduit openings 182 are positioned to the rear and below the front end of the respective chamber 108, 110. Moving the conduit opening 182 away from the front end of the respective chamber 108, 110 causes the water lock to be formed earlier during the operation. Similarly, moving the conduit opening 182 towards the front end of the respective chamber 108, 110 delays the water lock forming, in turn causing the apparatus to sink lower in the water.

With the apparatus 2 in the submerged position, the vessel may be moved through the water to position the hull of the vessel over the support assembly 120. Alternatively, but less preferred, the apparatus may be moved through the water to a position beneath the hull of the vessel. With the vessel in position over the support assembly 120 of the apparatus, a supply of pressurised air is connected to the valves 164, 166. The air is supplied under sufficient pressure to displace the water within the chambers 108, 110 and force the water to leave through the water ports. In this respect, it is sufficient to provide the air at a pressure slightly above atmospheric pressure, that is about 1 or 2 psig (about 0.07 or 0.14 barg).

As water is displaced from within the primary buoyant members 104, 106, the apparatus 2 rises into the floating position, with the vessel raised at least partially out of the water. With the apparatus in the floating position, the valves 164, 166 are closed and the second water conduits 156 are rotated to have their openings raised above the surface of the water.

The depth and orientation of the apparatus 2 in the submerged position may be controlled by varying the position of the conduit openings 182 in the chamber 108, 110 of each primary buoyant member, as described above.

Turning to Figures 6 to 8, there is shown an apparatus according to a further embodiment of the present invention. The apparatus, generally indicated as 202, has the same general arrangement and configuration as that of the embodiment of Figures 1 to 5 as described above. Components of the apparatus 202 of Figures 6 to 8 that are same as those of the apparatus 2 of Figures 1 to 5 are indicated using the same reference numerals and are as described hereinbefore.

The apparatus 202 further comprises a secondary buoyancy system, generally indicated as 204. The secondary buoyancy system 204 comprises a generally rectangular trim vessel 206 mounted between the rear portions of the first and second primary buoyant members 104, 106. The trim vessel 206 comprises a water port 208 on its underside, as shown in Figure 8, which opens the chamber within the trim vessel to the water. A conduit, in the form of a flexible hose 210 extends from the upper front portion of the trim vessel 206 to a ballast valve 212 comprised in the valve assembly 162 and mounted to the secondary buoyant member 130 adjacent the valves 164, 166.

In operation, when it is required to move the apparatus 202 from the floating position to the submerged position, the ballast valve 212 is opened, connecting the interior of the trim vessel 206 with the atmosphere through the hose 210. This allows water to enter the trim vessel 206 through the water port 208 and displace air through the hose 210 and the valve 212. When the trim vessel 206 is filled with water, the ballast valve 212 may be closed or may be left open. Filling the trim vessel 206 with water decreases the buoyancy of the rear of the apparatus 202, causing the rear of the apparatus to sink. Thereafter, the procedure described above is followed, to move the apparatus into its submerged position.

To return the apparatus 202 to its floating position, a supply of air is connected to the ballast valve 212 and the valve opened. The air enters the trim vessel 206, displacing the water, which is forced to leave the trim vessel through the water port 208. This may be carried before, during or, most preferably, after air is supplied to the primary buoyant members, as described above.

In this embodiment, the second water conduits 156 may be locked in a position with their openings above the surface of the water with the apparatus 202 in the floating position. In this way, it is required to first flood the trim vessel 206 first, in order to sink the rear of the apparatus 202 sufficiently for the openings in the second water conduits 156 to be below the water surface and allow water to enter the chambers in the first and second primary buoyant members 104, 106. This provides a fail-safe mechanism, by which the apparatus 202 may only be moved from the floating position to the submerged position in a two-stage operation: in a first stage flooding the trim vessel 206 with water; and, in a second stage, flooding the chambers in the primary buoyant members 104, 106 with water.

Claims

CLAIMS1. An apparatus for providing a berth for a vessel in water, the apparatus having a variable buoyancy and comprising a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein and comprising a water port to allow water to enter and leave the chamber; a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary 10 buoyant member; an air supply and removal system for providing air to and allowing air to leave the chamber in each of the first and second primary buoyant members, the system comprising: an air inlet in the chamber of each of the first and second primary buoyant members to allow air to enter the respective chamber within the primary buoyant member; an air outlet in the chamber of each of the first and second primary buoyant members to allow air to be displaced from the respective chamber within the primary buoyant member by water entering the chamber through the water port; a valve assembly for controlling the flow of air to and from the air inlet and the air outlet; the apparatus having a floating position, in which a vessel resting on the cradle is supported by the apparatus to be at least partially out of the water, and a submerged position, in which the apparatus is sufficiently submerged to allow the vessel to be moved relative to the support assembly, thereby moving the support assembly into and out of a position beneath the vessel; wherein the apparatus has a selected orientation in the submerged position relative to the vessel to be raised and lowered, the position of the air outlet of each of the first and second conduits into the chamber of the respective buoyant member prevents the apparatus from submerging further than the selected orientation.
2. The apparatus according to claim 1, wherein one or both of the first and second primary buoyant members is pivotably connected to the support assembly.
3. The apparatus according to either of claims 1 or 2, wherein support assembly comprises a hull support assembly comprising one or more hull support members.
4. The apparatus according to any preceding claim, wherein the support assembly comprises one or more hull support connecting members, the or each hull support connecting member being resilient.
5. The apparatus according to any preceding claim, wherein the air inlet and the air outlet in the chamber of each of the first and second primary buoyant members are provided by a single opening in the primary buoyant member.
6. The apparatus according to claim 5, wherein air entering and leaving the chamber in each of the first and second primary buoyant members flows along the same flowpath.
7. The apparatus according to any preceding claim, wherein the air supply and removal system comprises a conduit extending from the valve assembly to each chamber of the first and second primary buoyant members, in use air flowing through the conduit to enter and/or leave the chamber in the primary buoyant member.
8. The apparatus according to claim 7, wherein a portion of the conduit extends within the chamber in each primary buoyant member, the portion of the conduit having an opening within the chamber to allow air to enter and/or leave the chamber.
9. The apparatus according to claim 8, wherein the portion of the conduit extends within the chamber from an opening in the primary buoyant member towards the front of the primary buoyant member, whereby the orientation and depth of the apparatus in the submerged position is determined by the position of the opening relative to the front of the primary buoyant member.
10. The apparatus according to any preceding claim, further comprising a pair of secondary buoyant members comprising a first secondary buoyant member spaced apart from the first primary buoyant member and a second secondary buoyant member spaced apart from the first secondary buoyant member.
11. The apparatus according to claim 10, wherein the first and second secondary buoyant members each lie respectively above and laterally outwards from the longitudinal centre line of the first and second primary buoyant members.
12. The apparatus according to either of claims 10 or 11, wherein the valve assembly is mounted on one of the first and second secondary buoyant members.
13. The apparatus according to any preceding claim, further comprising: a trim vessel having a water port to allow water to enter or leave the vessel, an air inlet to allow air to enter the trim vessel and an air outlet to allow air to leave the vessel; and a buoyancy air supply and removal system, the system comprising a valve assembly for controlling the flow of air to and from the trim vessel.
14. A method for raising and lowering a vessel in water, the method comprising: providing a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein; providing a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; at least partially submerging the first and second primary buoyant members by allowing water to enter the chamber through a water inlet in each primary buoyant member and air to leave the chamber through an air outlet in each primary buoyant member; controlling the depth and orientation of the first and second primary buoyant members when at least partially submerged to a selected depth and a selected orientation by locating the air outlet in each primary buoyant member.
15. The method according to claim 14, further comprising altering the position of the first and second primary buoyant members relative to the support assembly.
16. The method according to claim 15, wherein the first and second primary members are rotated relative to the support assembly.
17. The method according to any of claims 14 to 16, wherein the support assembly comprises one or more hull support members and/or one or more hull support connecting members, the method further comprising adjusting the shape or orientation of the one or more hull support members and/or the one or more hull support connecting members to conform to the shape of the hull of the vessel.
18. The method according to any of claims 14 to 17, wherein the air outlet is disposed within the chamber of each of primary buoyant member, the method comprising locating the air outlet within the chamber to provide the desired orientation and depth of the apparatus when submerged.
19. The method according to any of claims 14 to 18, wherein the apparatus is inclined with the front uppermost when submerged, the depth and angle of inclination being selected by positioning the air outlet of each primary buoyant member relative to the front of the primary buoyant member to form a water lock in the front portion of the chamber of the primary buoyant member.
20. An apparatus for raising and lowering a vessel in water, the apparatus comprising: a pair of primary buoyant members comprising a first hollow, elongate, cylindrical, primary buoyant member and a second hollow, elongate, cylindrical, primary buoyant member spaced apart from the first primary buoyant member, the first and second primary buoyant members having their longitudinal axes parallel, each of the first and second primary buoyant members comprising a chamber therein and comprising a conduit extending from an opening in the lower portion of the primary buoyant member, the conduit having an opening to allow water to enter and leave the chamber; a support assembly for supporting the vessel and comprising a plurality of support members mounted on the upper portions of the first and second primary buoyant members and a plurality of connecting members extending between the lower portion of the first primary buoyant member and the lower portion of the second primary buoyant member; wherein the support members are arranged to have their upper surfaces lie on the arms of a V-shape to accommodate the lower portion of the hull of the vessel to be raised and lowered; and wherein the first and second primary buoyant members are pivotally connected to the connecting members; a pair of secondary buoyant members comprising a first cylindrical, elongate, secondary buoyant member and a second cylindrical, elongate, secondary buoyant member, each secondary buoyant member being arranged above and laterally outwards of the longitudinal centre line of a respective primary buoyant member and connected to a respective one of the primary buoyant members by a plurality of support members extending upwards from the respective primary buoyant member; an air supply and removal system for providing air to and removing air from the chamber in each of the first and second primary buoyant members, the system comprising: an air inlet in each of the first and second primary buoyant members to allow air to enter the respective chamber within the primary buoyant member; an air outlet in each of the first and second primary buoyant members to allow air to be displaced from the respective chamber within the primary buoyant member by water entering the chamber through the water port; a valve assembly for controlling the flow of air to and from the air inlet and the air outlet; a first conduit extending from the valve assembly to the first primary buoyant member and a second conduit extending from the valve assembly to the second primary buoyant member, each of the first and second conduits comprising a first conduit portion extending to an opening in the upper portion of the wall of the respective primary buoyant member and a second conduit portion extending from the opening in the wall of the primary buoyant member longitudinally within the chamber in the primary buoyant member, the second conduit portion having a conduit opening spaced apart from the opening in the wall of the primary buoyant member, the conduit opening providing both the air inlet and the air outlet through which air both enters and leaves the chamber; the valve assembly being mounted on one of the secondary buoyant members, the apparatus having a floating position, in which the vessel is resting on the support assembly and is supported by the apparatus to be at least partially out of the water, and a submerged position, in which the apparatus is at least partially submerged in the water to selected depth and has a selected orientation relative to the vessel and in which the apparatus is sufficiently submerged to allow the vessel to be moved relative to the apparatus to move the support assembly into and out of a position beneath the hull of the vessel; wherein in the submerged position, the position of the conduit opening of each of the second conduit portions within the chamber of the respective primary buoyant member prevents the apparatus from submerging further than the submerged position.
21. An apparatus for raising and lowering a vessel in water, the apparatus comprising: a first pair of primary buoyant members comprising a first primary buoyant member and a primary second buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein and comprising a water port to allow water to enter and leave the chamber; a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; an air supply and removal system for providing air to and removing air from the chamber in each of the first and second primary buoyant members, the system comprising: an air inlet in each of the first and second primary buoyant members to allow air to enter the respective chamber within the primary buoyant member; an air outlet in each of the first and second primary buoyant members to allow air to be displaced from the respective chamber within the primary buoyant member by water entering the chamber through the water port; a valve assembly for controlling the flow of air to and from the air inlet and the air outlet; a trim vessel having a water port to allow water to enter or leave the vessel, an air inlet to allow air to enter the trim vessel and an air outlet to allow air to leave the vessel; and a buoyancy air supply and removal system, the system comprising a valve assembly for controlling the flow of air to and from the trim vessel.
22. The apparatus according to claim 21, wherein the trim vessel is disposed between the rear portions of the first and second primary buoyant members.
23. A method for raising and lowering a vessel in water, the method comprising: providing a first primary buoyant member and a second primary buoyant member spaced apart from the first primary buoyant member, each of the first and second primary buoyant members comprising a chamber therein; providing a support assembly for supporting the vessel and comprising one or more support members extending between the first primary buoyant member and the second primary buoyant member; providing a trim vessel connected to the first and second primary buoyant members; at least partially submerging the apparatus to a first position having a first depth and a first orientation by allowing water to enter the trim vessel through a water port and air to leave the trim vessel through an air outlet; and further submerging the apparatus to a second position having a second depth and a second orientation by at least partially submerging the first and second primary buoyant members by allowing water to enter the chamber through a water port in each primary buoyant member and air to leave the chamber through an air outlet in each primary buoyant member.
24. The method according to claim 23, wherein the trim vessel is disposed in a rear portion of the apparatus, the method comprising at least partially submerging the rear portion of the apparatus to the first position.
25. The method according to either of claims 23 or 24, wherein submerging the apparatus to the first position is required before water is allowed to enter the chamber of each primary buoyant member and further submerge the apparatus to the second position.