Floating offshore platform and method for deploying a floatable offshore platform

Abstract

A floatable offshore platform for supporting a renewable energy system in a body of water is provided, the body of water having a surface and a bottom. The floatable offshore platform comprises a base portion submerged below the surface of the body of water, a top portion remaining above the surface of the body of water, one or more mooring lines securing the floatable offshore platform to the bottom of the body of water, and tensioning means for applying tension to the one or more mooring lines. The floatable offshore platform further comprises a floating configuration, the floatable offshore platform being positioned substantially floating on the surface of the body of water, the floatable offshore platform comprising a deployed configuration, the base portion submerged below the surface of the body of water and the tip portion remaining above the surface of the body of water. In use, the tensioning means is configured to apply tension to the one or more mooring lines secured between the floatable offshore platform and the bottom of the body of water such that the floatable offshore platform transitions between the floating configuration and the deployed configuration. The described platform aims to provide a partially submerged operating configuration making it safer and more efficient to deploy the floatable offshore platform.

Description

[Technical field]

[0001] The present disclosure relates to a floatable offshore platform for supporting renewable energy systems, a tensioning means for deploying such a platform, and a method for deploying a floatable offshore platform. Summary of the Invention [Problem to be solved by the invention]

[0002] Both wave energy and offshore wind energy have been considered as leading technology options for decarbonizing the global energy system. The economic viability and practical feasibility of these renewable energy systems depends heavily on the ease and cost of installation and maintenance of these offshore systems. One solution to minimize the cost of these systems is to install offshore wave and wind energy systems on floating or buoyant platforms. [Means for solving the problem]

[0003] Floatable offshore platforms have advantages in that it is typically quicker and easier to install the foundations required for a floatable offshore platform on the bottom of a body of water, and the foundations can be more easily installed at greater depths. Furthermore, a completed floatable offshore platform may be manufactured on or near land and then towed to a desired location rather than being assembled piece by piece offshore. However, there are problems with current state of the art floatable offshore platforms and the methods and apparatus used to install them offshore. Objects and aspects of the present disclosure seek to alleviate at least some of these problems with the prior art.

[0004] The present disclosure relates to a buoyant marine platform for supporting a renewable energy system in a body of water, the platform having an underwater operating configuration in which a base portion is submerged below the surface of the body of water and a top portion thereof remains above the surface of the body of water. The top portion is preferably configured to support a renewable energy system (which may include, for example, a wind turbine), a renewable energy storage device, and / or a compartment, building, or room (which may be used, for example, to house or store platform control or maintenance equipment) above the surface of the body of water at all times during use. The platform of the present disclosure includes tensioning means configured to apply tension to one or more mooring lines to place the platform in the underwater operating configuration. In some preferred embodiments, the tensioning means is configured to apply a first tension to one or more mooring lines such that the mooring lines are taut, and subsequently provide a second tension to the one or more mooring lines such that the platform is partially submerged in the body of water in the underwater operating configuration. In preferred embodiments, the second tension is applied periodically to the one or more mooring lines. Such force is preferably provided by a reciprocating tensioning device having a unidirectional mode configured to engage one or more mooring lines such that motion is restricted to a single direction. Such unidirectional motion may be provided, for example, by a claw member of the reciprocating tensioning device configured to be moved by the tensioning device in a reciprocating fashion such that one or more mooring lines are moved unidirectionally by the claw member. In embodiments in which one or more of the mooring lines include a chain, such an example of a claw member may include a chain stopper. In certain instances, the reciprocating tensioning device may be configured to apply a second tension to two such mooring lines, and in some embodiments, may be configured to apply a second tension to one of the two mooring lines independently of the other of the two mooring lines. The present disclosure further relates to a reciprocating tensioning device for use with a buoyant marine platform, a kit of parts including the platform and the tensioning device, and a method of placing the platform in an underwater operating configuration.

[0005] According to one aspect of the present disclosure, there is provided a floatable offshore platform for supporting a renewable energy system in a body of water having a surface and a bottom, the floatable offshore platform comprising a base portion submerged below the surface of the body of water, a top portion remaining above the surface of the body of water, one or more mooring lines securing the floatable offshore platform to the bottom of the body of water, and tensioning means for applying tension to the one or more mooring lines, the floatable offshore platform comprising a floating configuration in which the floatable offshore platform is positioned substantially floating on the surface of the body of water, and a displaced configuration in which the base portion is submerged below the surface of the body of water and the top portion remains above the surface of the body of water, and further wherein, in use, the tensioning means is configured to apply tension to the one or more mooring lines secured between the floatable offshore platform and the bottom of the body of water such that the floatable offshore platform transitions between the floating configuration and the displaced configuration.

[0006] In some embodiments, the tensioning means preferably comprises a pulley mounted to the platform, the pulley configured to be driven by the drive means and configured to apply a first tension to the one or more mooring lines when driven by the drive means.

[0007] In some embodiments the tensioning means is preferably configured to apply a first tension to the two mooring lines.

[0008] In some embodiments, the platform preferably further comprises a mooring line well, and the pulley is further configured to direct one or more mooring lines into the mooring line well.

[0009] In some embodiments, the mooring line well is preferably located within a hollow structural element at the top.

[0010] In some embodiments, the pulley is preferably permanently attached to the platform.

[0011] In some embodiments, the drive means is preferably a motor, the motor removably engaging the pulley.

[0012] In some embodiments, the tensioning means preferably further comprises a static unidirectional mechanism having a tension mode, in which the unidirectional mechanism is configured to restrict movement of one or more mooring lines in a single direction, and a release mode, in which the unidirectional mechanism is configured to allow free movement of the mooring lines in any direction.

[0013] In some embodiments, the static unidirectional mechanism is preferably permanently attached to the platform such that the static unidirectional mechanism does not move relative to the platform.

[0014] In some embodiments, the tensioning means preferably comprises an elongated rail configured to be attached to the platform, and the static unidirectional mechanism is positioned on the rail and configured to move along the rail. Preferably, during the tensioning mode, the unidirectional mechanism is configured to move along the rail from a slack position to a taut position, during which movement tension is applied to one or more mooring lines secured between the floatable offshore platform and the bottom of the body of water, such that the floatable offshore platform transitions between the floating configuration and the deployed configuration.

[0015] In some embodiments, the tensioning means preferably further includes a reciprocating unidirectional mechanism comprising a first water ram and a second water ram, each of the first and second water rams attached to a corresponding moveable unidirectional member having a tension mode in which the unidirectional member is configured to restrict movement of one of the mooring lines in a first direction and is further configured to be moved in the first direction by the corresponding water ram to apply a second tension to the mooring line, and a release mode in which the unidirectional member is configured to be moved along the mooring line in a second direction opposite the first direction by the corresponding water ram, each unidirectional member configured to transition between the tension mode and the release mode in a reciprocating manner.

[0016] In some embodiments, each unidirectional member may be powered by a corresponding first or second hydraulic ram, preferably independently of the other unidirectional member.

[0017] In some embodiments, the one or more mooring lines preferably comprise chains and the reciprocating unidirectional mechanism is a jack chain.

[0018] In some embodiments, the reciprocating unidirectional mechanism is preferably removably attached to the platform.

[0019] In some embodiments, the tensioning means preferably further comprises an elongated rail, and the reciprocating unidirectional mechanism is preferably configured to move along the rail from a slack position to a taut position during the tensioning mode, during which movement tension is applied to one or more mooring lines secured between the floatable offshore platform and the bottom of the body of water, such that the floatable offshore platform transitions between the floating configuration and the deployed configuration.

[0020] In a preferred embodiment, the rail and reciprocating unidirectional mechanism are removably mounted to the platform. It will be understood that in an embodiment, the rail and reciprocating unidirectional mechanism are permanently mounted to the platform. In a preferred embodiment, the rail is an indexed rail or a slotted rail having a slot or groove configured to receive engagement by a complementary tooth member of the reciprocating unidirectional mechanism, the tooth member enabling movement of the reciprocating unidirectional mechanism along the rail. Preferably, the tooth member is positioned on a wheel or gear configured to be driven by a motor of the reciprocating unidirectional mechanism. It will be understood that features described as suitable for use with a reciprocating unidirectional mechanism are similarly suitable for a static unidirectional mechanism.

[0021] In some embodiments, the platform preferably further comprises a power line configured to transfer power to and from the platform when the power line is operatively engaged with the platform, the power line being configured to be moved into operative engagement with the platform by the tensioning means.

[0022] According to a further aspect of the present disclosure, there is provided a reciprocating unidirectional mechanism configured to apply tension to two mooring lines of a platform, as set forth in any one of the claims, the unidirectional mechanism comprising a first water ram and a second water ram, each of the first and second water rams attached to a corresponding movable unidirectional member having a pull mode, in which the unidirectional member is configured to restrict movement of one of the mooring lines to a first direction and is further configured to be moved in the first direction by the corresponding water ram to apply tension to the mooring lines, and a release mode, in which the unidirectional member is configured to be moved along the mooring lines in a second direction opposite to the first direction by the corresponding water ram.

[0023] In some embodiments, the reciprocating unidirectional mechanism is preferably configured to apply tension to the two mooring lines independently relative to each other.

[0024] In some embodiments, the reciprocating unidirectional mechanism is a jack chain.

[0025] In some embodiments, the reciprocating unidirectional mechanism may be mounted to a rail and configured to move along the rail, as described below.

[0026] According to a further aspect of the present disclosure, there is provided a kit of parts including a buoyant offshore platform according to an aspect of the present disclosure and a reciprocating unidirectional mechanism according to an aspect of the present disclosure.

[0027] According to a further aspect of the present disclosure, there is provided a method of positioning a floatable offshore platform to support a renewable energy system, the method comprising the steps of moving the floatable offshore platform into position along a surface of a body of water; anchoring one or more mooring lines to a bottom of the body of water; attaching the floatable offshore platform to the one or more mooring lines via tensioning means; applying a first tension to the one or more mooring lines using the tensioning means such that the one or more mooring lines are taut; and applying a second tension to the one or more mooring lines such that a portion of the floatable offshore platform is submerged in the body of water.

[0028] In some embodiments, the method preferably includes the further step of attaching a reciprocating unidirectional mechanism to the platform, and the second tensioning force is applied using the reciprocating unidirectional mechanism.

[0029] In some embodiments, the method preferably further comprises the additional step of removing the reciprocating unidirectional mechanism from the platform.

[0030] According to a further aspect of the present disclosure, there is provided a buoyant offshore platform for supporting a renewable energy system in a body of water having a surface and a bottom, the platform comprising: The floating offshore platform is A base portion that is sunk below the surface of the water body; a top that remains above the surface of the body of water; one or more lines for anchoring the buoyant offshore platform to the bottom of the body of water; and tensioning means for applying tension to one or more of the ropes; The floatable offshore platform includes an arrangement in which a base portion is submerged below the surface of the body of water and a top portion remains above the surface of the body of water; The floatable offshore platform further includes a floating configuration where the floatable offshore platform substantially floats on a surface of the body of water; The present invention is further characterized in that, during use, the tensioning means is configured to apply tension to one or more lines secured between the floatable offshore platform and a bottom of the body of water, such that the floatable offshore platform is adapted to transition between the floating configuration and the deployed configuration.

[0031] In this manner, a floatable offshore platform is provided that can be transported to a predetermined location in its floating configuration and then transitioned to its deployed configuration. Transporting the floatable offshore platform in a floating configuration is advantageous as it reduces the drag or resistance of the floatable offshore platform in the body of water.

[0032] In the configuration, one or more lines secured between the bottom of the body of water and the floatable offshore platform prevent the floatable offshore platform from floating so that the floatable offshore platform remains partially submerged.

[0033] The buoyant forces of the floatable offshore platform act in a direction substantially opposite to the direction in which the tethers are anchored between the offshore platform and the bottom of the body of water. The opposing interaction of the buoyant forces and the anchored one or more tethers causes the one or more tethers to be taut. By keeping the one or more tethers taut, the floatable offshore platform is stabilized in its deployed configuration. Thus, in the deployed configuration, the movement of the floatable offshore platform in all directions in the body of water should be substantially less than the movement of the floatable offshore platform in a floating configuration above the body of water. The stabilization of the floatable offshore platform is important for many of its intended uses, for example, as it allows it to act as a stable offshore platform for supporting wind turbines.

[0034] Preferably, in use, one or more tethers are secured between the top of the floatable offshore platform and the bottom of the body of water. Securing the tethers to the top of the floatable offshore platform is above the surface of the body of water so that installation can be more easily adjusted or performed.

[0035] Preferably, in use, the one or more tethers are removably attached to the floatable offshore platform such that the floatable platform can be released from the tethers to easily transition the floatable offshore platform from its deployed configuration to its floating configuration.

[0036] Preferably, the floatable offshore platform comprises a set of attachment points for the attachment of one or more tethers. Preferably, each attachment point in the set of attachment points is located at a different pre-defined location, and in use and in the deployed configuration, the percentage of the foundation portion that is submerged below the surface of the body of water is controlled by attaching a tether to one attachment point in the set of attachment points. Preferably, each attachment point in the set of attachment points is located at a different pre-defined location to control the percentage of the foundation portion that is submerged in the deployed configuration. In this way, one or more tethers may be attached to different locations on the floatable offshore platform. Different locations of the set of attachment points may affect the angle of the floatable platform or its submerged depth. Furthermore, the attachment points may be used to account for differences in the height of the bottom of the body of water, so that the offshore platform remains horizontal when attached by two or more tethers.

[0037] Preferably, the floatable offshore platform comprises one or more orienting members disposed on the base portion, the orienting members configured to direct one of the one or more lines between the floatable offshore platform and the bottom of the body of water. The orienting members change the angle or direction of a line of the one or more lines. The orienting member or members act to move and route the line. Preferably, the orienting member is a guide, which is a tubular member, of any shape and size to accommodate the line and the required change in direction. Preferably, the orienting member is a fairlead.

[0038] Preferably, the buoyant offshore platform includes a first orienting member configured to orient one of the one or more lines in a direction substantially horizontally parallel to a plane defined by the base portion, the base portion moving between the deployed position and the floating position through the first orienting member. Preferably, the first orienting member is configured to orient the one of the one or more lines to a position intermediate the base portion and the top.

[0039] Preferably, the buoyant offshore platform includes a second orienting member configured to orient one of the one or more lines in a direction substantially perpendicular to a plane defined by the base portion, the base portion moving between the deployed position and the floating position through the second orienting member.

[0040] Preferably, the floatable offshore platform comprises a plurality of tethers for anchoring the floatable offshore platform to the bottom of the body of water. The plurality of tethers builds redundancy and resilience into the system.

[0041] Preferably, the buoyant offshore platform comprises a plurality of orienting members, each of the plurality of orienting members being oriented by at least one of the plurality of orienting members.

[0042] Preferably the tensioning means of the floatable offshore platform is located on top of the floatable offshore platform, more preferably the tensioning means comprises at least one or more winches.

[0043] Preferably the tensioning means of the buoyant offshore platform comprises a sheave. Preferably a single continuous rope around the block transmits tension around the block and pulleys, thus providing tension between the ropes as required. The sheave pulley system has the advantage that the pulleys apply tension in a manner that provides a mechanical advantage and amplifies the force applied to the rope.

[0044] Preferably, the buoyant offshore platform further comprises a crane configured to move the tensioning means.

[0045] Preferably, the floatable offshore platform comprises an open framework, the open area framework and latticework providing an overall strength and robust construction suitable to withstand shocks around the platform, continuous fluid flow and surges, and any rough, stormy sea conditions.

[0046] According to a further aspect of the present disclosure there is provided a kit of parts comprising: The parts kit is an offshore platform according to an aspect of the present disclosure; a winch for releasably attaching to the top of the buoyant platform and for releasably attaching to the line; Including, In use, the winch is configured to submerge a base portion of the buoyant platform by hoisting the buoyant platform against the bottom of the body of water.

[0047] Preferably, the kit of parts further comprises a reeving pulley acting on the rope between the winch and the bottom.

[0048] Preferably, the kit of parts further includes a tension line extending between the line and the winch.

[0049] According to a further aspect of the present disclosure, there is provided a method of deploying an offshore platform for supporting a renewable energy system, comprising: The method comprises: moving an offshore platform comprising a buoyant platform into position along a surface of the body of water; anchoring the line to the bottom of the body of water; Attaching the buoyant platform to a tether via a winch or tensioning means; hoisting the buoyant platform against a line such that a portion of the buoyant platform is submerged in the body of water and a winch or tensioning means remains above the surface of the body of water; Includes.

[0050] Preferably, the method of deploying an offshore platform comprises the further steps of: The further step is disconnecting the line from the winch or tensioning means; attaching the line to a portion of the offshore platform above the surface of the body of water such that the offshore platform remains partially submerged in the body of water; Includes.

[0051] Preferably, the method of deploying an offshore platform comprises the further steps of: The further step is This includes using guides located on the buoyant platform to orient a line extending between the winch or tension means and the bottom of the body of water.

[0052] In a preferred embodiment, the tensioning means is any suitable tensioning means as described herein.

[0053] According to a further aspect of the present disclosure, a method of deploying an offshore platform for supporting a renewable energy system is provided, comprising: The method comprises: moving an offshore platform comprising a buoyant platform along a surface of the body of water to a desired deployment location; connecting one or more installation lines between the platform and corresponding anchors secured to the bottom of the body of water; applying tension to the one or more mounting lines using tensioning means secured to the platform such that the platform moves from a floating configuration in which the platform substantially floats on the body of water to a submerged configuration in which the platform is partially submerged in the body of water; removing the tensioning means from the platform; Includes.

[0054] In some embodiments, the method may further comprise attaching one or more permanent mooring tendons between the platform and the corresponding anchors after the tensioning step. Such embodiments preferably further comprise removing the one or more installation lines after the attaching one or more permanent mooring lines. In some embodiments, the permanent mooring tendons are rigid and may be of a fixed length, the fixed length determining the working depth of the platform. In other embodiments, the working depth may be adjustable. In a preferred embodiment, in the submerged configuration, the tensioning means remains at least partially above the surface of the body of water. In some preferred embodiments, the tensioning means remains completely above the surface of the body of water.

[0055] The method may further comprise the step of attaching a power cable to the platform, the power cable preferably being configured to transfer useful electrical energy from the platform to a remote storage device or plant.

[0056] It will be appreciated that the tensioning means may be any suitable tensioning means as described herein, and is preferably a unidirectional mechanism according to the present disclosure. In some embodiments, the method further comprises moving the second platform along the surface of the body of water to a desired deployment position, and attaching the detached tensioning means to the second platform before performing further steps of the method on the second platform. In such a way, the same tensioning means may be used to quickly, easily and safely deploy a farm of platforms, for example an offshore wind farm.

[0057] It will be understood that any feature described herein as suitable for incorporation in one or more aspects or embodiments of the present disclosure is intended to be generalizable across any and all aspects and embodiments of the present disclosure. Other aspects of the present disclosure can be appreciated by those skilled in the art in view of the detailed description, claims, and drawings of the present disclosure. The general description set forth above and the detailed description set forth below are exemplary and explanatory only and are not intended to limit the scope of the claims.

[0058] Specific embodiments will now be described, by way of example only, and with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0059] [Figure 1] 1 shows an offshore platform according to the present invention, the offshore platform being in use and in a deployed configuration; [Figure 2A] 2 shows an enlarged view of the tensioning means of the platform of FIG. 1; [Figure 2B] 2 shows an enlarged view of the tensioning means of the platform of FIG. 1; [Figure 2C] 2 shows an enlarged view of the tensioning means of the platform of FIG. 1; [Figure 3A] 2 illustrates the step-by-step process by which the offshore platform of FIG. 1 is deployed. [Figure 3B] 2 illustrates the step-by-step process by which the offshore platform of FIG. 1 is deployed. [Figure 3C] 2 illustrates the step-by-step process by which the offshore platform of FIG. 1 is deployed. [Figure 3D] 2 illustrates the step-by-step process by which the offshore platform of FIG. 1 is deployed. [Figure 3E] 2 illustrates the step-by-step process by which the offshore platform of FIG. 1 is deployed. [Figure 3F] 2 illustrates the step-by-step process by which the offshore platform of FIG. 1 is deployed. [Figure 4]FIG. 1 illustrates a close-up view of a reciprocating unidirectional mechanism according to one embodiment of the present disclosure in the form of a jack chain. [Diagram 5] FIG. 2 shows a cross-sectional view of a structural element at the top of the platform configured to store a portion of one or more mooring lines of the platform during use. [Figure 6] 5 illustrates the offshore platform of FIG. 1 in use in a deployed configuration with the reciprocating unidirectional mechanism of FIG. 4 removed from the platform. [Figure 7] 7 shows a close-up view of the unidirectional mechanism during the removal process that occurs in FIG. 6. [Figure 8] FIG. 1 shows a flow diagram illustrating steps of an example embodiment of a method for deploying a floatable offshore platform to support a renewable energy system according to one aspect of the present disclosure. [Figure 9] 1 shows an alternative embodiment of the platform of the first aspect with a unidirectional mechanism of the second aspect. [Figure 10] 10 shows an enlarged perspective view of the embodiment of FIG. 9. [Figure 11] 10 shows a side view of the embodiment of FIG. 9 moving from a floating configuration to a deployed configuration. [Figure 12A] 12 illustrates a first step in an installation sequence according to one embodiment of the present disclosure, in which the platform of FIG. 11 is placed in a desired deployment location and temporarily secured to the bottom of a body of water via anchors. [Figure 12B] 12 illustrates a first step in an installation sequence according to one embodiment of the present disclosure, in which the platform of FIG. 11 is placed in a desired deployment location and temporarily secured to the bottom of a body of water via anchors. [Figure 12C] 12 illustrates a first step in an installation sequence according to one embodiment of the present disclosure, in which the platform of FIG. 11 is placed in a desired deployment location and temporarily secured to the bottom of a body of water via anchors. [Figure 13A] 12A-12C show a further step in the installation sequence of FIGS. 12A-12C in which the platform is transitioned to an operating depth in a submersible configuration and permanently anchored to the bottom of the body of water at the operating depth via anchors. [Figure 13B]12A-12C show a further step in the installation sequence of FIGS. 12A-12C in which the platform is transitioned to an operating depth in a submersible configuration and permanently anchored to the bottom of the body of water at the operating depth via anchors. [Figure 13C] 12A-12C show a further step in the installation sequence of FIGS. 12A-12C in which the platform is transitioned to an operating depth in a submersible configuration and permanently anchored to the bottom of the body of water at the operating depth via anchors. [Figure 13D] 12A-12C show a further step in the installation sequence of FIGS. 12A-12C in which the platform is transitioned to an operating depth in a submersible configuration and permanently anchored to the bottom of the body of water at the operating depth via anchors. [Figure 14A] 12A-12C depict a further step in the installation sequence of FIGS. 12A-12C, in which the temporary fixation is removed. [Figure 14B] 12A-12C depict a further step in the installation sequence of FIGS. 12A-12C, in which the temporary fixation is removed. [Figure 15A] FIG. 12C illustrates a further step in the installation sequence of FIGS. 12A to 12C, in which an underwater power cable is attached to the platform. [Figure 15B] FIG. 12C illustrates a further step in the installation sequence of FIGS. 12A to 12C, in which an underwater power cable is attached to the platform. [Figure 16A] FIG. 15B shows an isometric view of the platform of FIGS. 12A to 15B in an underwater configuration and during maintenance. [Figure 16B] FIG. 15B shows an isometric view of the platform of FIGS. 12A to 15B in an underwater configuration and during maintenance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0060] 1 of the drawings illustrates an example embodiment of a floatable offshore platform 102 according to one aspect of the present disclosure in a deployed or in-use configuration. In the illustrated in-use or deployed configuration, the offshore platform 102 is partially submerged in a body of water 104. The position of the offshore platform 102 below a surface 106 of the body of water 104 is controlled by a number of mooring lines 108, each of which couples the offshore platform 102 to a corresponding mooring point 109 positioned in communication with a bottom 110 of the body of water 104. Buoyancy for the offshore platform 102 is provided by a number of its buoyancy tanks 112, which act against tension provided by the mooring lines 108 such that the platform 102 is stable in the illustrated underwater configuration.

[0061] The offshore platform 102 comprises an open framework 114 supported on buoyancy tanks 112. In the embodiment 100 shown, the offshore platform 102 is for supporting a renewable energy system, and in particular for supporting a wind turbine 116. Other embodiments of the offshore platform 102 according to the present disclosure are envisaged for supporting other suitable pieces of equipment.

[0062] The open framework 114 may take many viable forms, provided that in such form resistance to the movement of a medium such as water or air is minimized. Examples of such open frameworks 114 may include, for example, a lattice frame, a mesh frame, a perforated frame, a porous frame, a permeable frame, and / or a skeletal frame.

[0063] In this embodiment 100, the open framework 114 has a shape substantially similar to a triangular pyramid or tetrahedron. The base 118 of the open framework 114 is formed in part from three edge structural members 120 that extend along the sides of a triangle. The three edge structural members 120 meet at three vertices at the corners of the triangular base 118. A corresponding pair of buoyancy tanks 112 is positioned at each of the three vertices 122 and cooperate to provide a center of buoyancy at the corresponding vertex 122.

[0064] The open framework 114 further comprises three cornered structural members 124, each extending from an apex 122 of the base 118 towards an upper portion in the form of a support platform 126 located at the apex of the triangular-based pyramidal open framework 114 and supported by the three cornered structural members 124.

[0065] The open framework 114 further comprises vertical structural members (not shown) that extend vertically from the underside of the support platform 126 to the base 118 and is supported by three horizontal structural members (not shown) that each extend from a corresponding apex 122 to the center of the base 118. Stability and structural integrity of the platform 102 is provided by this open framework structure as the support platform 126 is configured to support the wind turbine 116.

[0066] The buoyancy tanks 112 can take many forms, provided that in such forms, the buoyancy tanks 112 provide sufficient buoyancy to the offshore platform 102 so that the offshore platform 102 floats on the surface 106 of the body of water 104 when not in the arrangement or in-use configuration shown, i.e., when coupled to the bottom 110 by mooring lines 108.

[0067] The support platform 126 is supported at its apex on the open framework 114 by three corner structural members 124 and vertical structural members. In this embodiment, the support platform 126 includes a socket (not shown) for receiving and retaining the tower of the wind turbine 116. Other embodiments are contemplated having different features located on the support platform 126. Additionally, embodiments may be contemplated having any suitable number of corner structural members and / or vertical structural members, each taking any suitable form.

[0068] In the depicted deployed or in-use configuration, the offshore platform 102 is tethered to the bottom 110 of the body of water 104 by six mooring lines 108. The mooring lines 108 are positioned in pairs, with each pair extending from a corresponding fixed point 109 to an apex 122 of the platform 102. The mooring lines of a pair extend from the apex 122 along corresponding angled structural members 124 and are secured to the platform by corresponding tensioning means 130.

[0069] 2A-2C, a close-up view of tensioning means 130 is shown. Tensioning means 130 comprises a chain pulley 132 and a static unidirectional chain stop 134. In the embodiment shown, pulley 132 and chain stop 134 are permanently attached to the top of the corresponding angled structural member 124. Pulley 132 is configured to be driven by a motor 136, which in the embodiment shown is removable. Each tensioning means 130 comprises a pulley 132 and a chain stop 134 as shown, and each such means 130 is configured to apply a first tension to a corresponding pair of mooring lines 108 when pulley 132 is driven by motor 136. The chain stops 134 include a release mechanism that in the example embodiment shown comprises a water ram, each configured to move a corresponding pawl member of the chain stopper from a closed position, in which the corresponding mooring line can only move in a single direction towards the pulley, to an open position in which the corresponding mooring line is free to move in either direction. The chain stops 134 in the embodiment shown 100 are therefore configured to limit movement of one of the corresponding pair of mooring lines 108 independent of the other pair of mooring lines 108. It will be understood that embodiments may include pawl members of the chain stoppers 134 that are movable between the open and closed positions by any suitable mechanism.

[0070] 3A-3G, a step-by-step deployment process is depicted for deploying the platform of FIG.

[0071] In the configuration depicted in FIG. 3A , six mooring lines 108 are pre-installed at the desired deployment location, with each mooring line attached to a corresponding fixed point 109 on the bottom 110 of the body of water 104. At one end distal to the fixed point 109, the mooring lines each include a marker buoy 140 temporarily attached thereto, which marks the location of the corresponding mooring line 108. In addition to the mooring lines 109, a power cable 138 is deployed near the desired location, with the power cable 138 also having a marker buoy 140 temporarily attached thereto. In use, the power cable 138 is attached to a renewable energy capture device, which in the embodiment described herein is a wind turbine 116, such that the output of electrical energy by the renewable energy capture device can be transmitted away from the platform 102 where it is used. The mooring lines and array cables are pre-installed in place and marked with the marker buoys. Since the platform 102 floats on the surface 106 of the body of water 104 as previously described, the offshore platform 102 is then towed to the desired location.

[0072] Referring to FIG. 3B, a placement step subsequent to that shown in FIG. 3A is shown. In the step shown, a reciprocating unidirectional mechanism 142 is positioned on the platform near each of the tensioning means 130. In the embodiment shown, the reciprocating unidirectional mechanism 142 (as described in connection with FIG. 4) takes the form of a jack chain, but other suitable mechanisms will be understood as described herein. A single guide line 144 extending from each tensioning means 130 of the platform 102 is attached to each of the mooring lines 108 in turn. After this step, as shown in FIG. 3C, the motor 136 of each pulley 132 is actuated such that the pulley applies a first tension to each of the mooring lines 108 attached thereto, such pretension being used to pull each of the mooring lines 108 taut. The pulleys 132 are configured to direct excess mooring lines 108 to a mooring line storage chamber 152 (shown in FIG. 5) located within each of the angled structural members 124. Power supply for motors 136 is provided by deployment vessel 146, although it will be understood that embodiments may use any suitable power supply means. Power cables 138 are then attached to corresponding guide lines 147, as shown in Figure 3E, using deployment vessel 146, before being lifted into engagement with a power socket (not shown) mounted on the platform, as shown in Figure 3D.

[0073] FIG 3F illustrates a deployment step subsequent to that shown in FIG 3E, in which a reciprocating unidirectional mechanism 142 is engaged with each corresponding pair of mooring lines 108 and provides a second tension to each mooring line 108 such that the platform 102 is partially submerged in the body of water 104 in a deployed or in-use configuration while being powered by a deployment vessel 146. The reciprocating unidirectional mechanism 142 reciprocates to apply the second tension in a cyclical manner. The use of such a mechanism to simultaneously apply the second tension to two mooring lines in this manner preferably provides an efficient means of deployment. The ability to apply the second tension to each line of a pair of mooring lines independent of the other preferably provides the flexibility and redundancy needed during deployment, which may be in a remote location such that access to the platform to resolve issues during deployment is limited.

[0074] 4, a close-up view of a reciprocating unidirectional mechanism 142 is shown according to one embodiment of the disclosure and will be described in conjunction with the placement process shown in FIGS. 3A-3F. The mechanism 142 shown is suitable for inclusion in a kit of parts according to further embodiments. The reciprocating unidirectional mechanism 142 includes a pair of water rams 148 each configured to move a corresponding movable chain stopper 150 in a reciprocating manner. As previously described, the water rams 148 of the mechanism 142 may be independently actuated to move the corresponding chain stopper 150 independently of the other. The chain stoppers 150 each include a release mechanism, which in the embodiment shown includes a water ram configured to move the corresponding pawl member of the respective chain stopper 150. The release mechanism is configured to switch the mechanism 142 from a tension mode in which movement of the mooring line is restricted in a direction toward the pulley, and a release mode in which free movement of the mooring line is permitted.

[0075] 5, as previously explained, the pulleys 132 of the tensioning means 130 are configured to direct excess mooring lines 108 into a cavity or chamber within the platform, which in the example shown is a mooring line storeroom 152 located within a hollow portion of each of the angled structural members 124. Such a storeroom preferably improves safety of the platform, as excess slack mooring lines could pose a hazard to deployment or maintenance crews.

[0076] 6, an example final deployment step is shown in which the reciprocating unidirectional mechanisms 142 are each successively removed from the platform 102 by the deployment vessel 146, as shown in greater detail in FIG 7. The removable nature of the mechanisms 142 preferably facilitates the deployment of several such platforms within a short period of time, which can be beneficial during changing weather patterns that would otherwise pose a hazard to the deployment vessel and crew.

[0077] 8, steps of an example method 800 according to one aspect of the present disclosure are illustrated using a flow diagram. In the illustrated embodiment 800, the method includes: moving 802 a buoyant offshore platform into position along the surface of the body of water; Anchoring one or more mooring lines to the bottom of the body of water 804; Attaching 806 the buoyant offshore platform to one or more mooring lines via tension means; applying a first tension to the one or more mooring lines using a tensioning means such that the one or more mooring lines are taut; Attaching a reciprocating unidirectional mechanism to a platform (step 810); applying a second tension to one or more mooring lines using a reciprocating unidirectional mechanism such that a portion of the buoyant offshore platform is submerged in the body of water 812; Includes.

[0078] It will be appreciated that the method 800 illustrated may be implemented using a platform, a reciprocating unidirectional mechanism, and / or a kit of parts, as described herein.

[0079] Figure 9 shows an alternative embodiment of the platform 900 according to the first aspect, the platform being substantially as previously described, but the tensioning means further comprises a rail 904 on which a reciprocating unidirectional mechanism 902 is mounted. The reciprocating unidirectional mechanism 902 is configured to move along the rail 904 during its tensioned state to tension or remove tension from the mooring line 906. The rail 904 in the illustrated embodiment is an indexed rail or a slotted rail, as seen at a larger scale in Figure 10, the rail having an elongated slot or groove along the rail configured to engage with the reciprocating unidirectional mechanism 902, for example to prevent further movement thereof under tension of the mooring line 906. The embodiment of Figure 9 is shown in use in Figure 11, together with a left side view depicting the platform 900 in a floating configuration. In the floating configuration, the reciprocating unidirectional mechanism 902 is configured to initiate a tensioning mode during which movement of the mooring line 904 through the unidirectional mechanism 902 is prohibited. During the pulling mode, the unidirectional mechanism 902 is further configured to move along the rails to apply tension to the mooring lines 904, and further configured to force the platform 900 to transition from the floating configuration shown in the left side view to the deployed configuration shown in the right side view of FIG. 11. During the transition, the base of the platform 900 is submerged below the surface of the body of water 908. In use, after transition to the deployed configuration, the rails 904 and the reciprocating unidirectional mechanism 902 are removed from the platform 900 for reuse in a subsequent deployment of the platform (not shown). Prior to removal, the mooring lines may be attached to the platform such that their length remains fixed, or a static unidirectional mechanism of the platform may prohibit further extension of the mooring lines. Embodiments in which the rails and the reciprocating unidirectional mechanism remain attached to the platform will be understood.

[0080] 12A-15B detail an installation sequence in accordance with the present invention. For illustrative purposes, the installation sequence is depicted using platform embodiment 900 as detailed in connection with FIG. 9, however, it will be understood that the installation sequence is suitable for implementation with any platform or unidirectional mechanism as described herein.

[0081] 12A-12C show the first step of the installation sequence. The platform 900 is positioned in a suitable deployment location using a deployment vessel 910 to tow the platform 900 across the surface of the body of water 908. Once in the desired deployment location, the platform 900 is positioned with each of the three vertices of the triangular platform base portion positioned on a corresponding pre-positioned anchor 912, each of the three pre-positioned anchors 912 pre-positioned in engagement with the bottom of the body of water. A deployment line 914 is coupled at one end to the platform 900 with a second end lowered from the platform 900 towards the corresponding anchor 912. A remotely operated underwater vehicle (ROV) 916 is deployed by the deployment vessel 910, the ROV 916 configured to facilitate engagement between the second end of the deployment line 914 and the corresponding anchor 912. 12C, a second end of the location line 914 comprises a connector 918 configured to engage a corresponding central connector 920 disposed on the anchor 912. In the example embodiment shown, the location line connector 918 and the anchor connector 920 comprise subsea mooring connectors (SMCs), such as, for example, BallGrubb™ connectors. It will be understood that in embodiments any suitable connectors are used to temporarily or permanently attach the location line 914 to the corresponding anchor 912. In the particular embodiment shown, the location line 914 is attached to the platform 900 and the anchor 912 in a temporary manner.

[0082] 12C, an anchor 912 of an embodiment of the invention comprises two additional connectors 922 positioned on either side of a central connector 920. These two additional connectors 922 are each configured to engage a connector on a second end of a permanent mooring tendon that couples the anchor 912 to the platform 900, as described in connection with FIGS.

[0083] 13A-13D, a further step in the installation sequence is shown in which tension is applied to the installation lines 914 as described herein using the unidirectional mechanism 902 and rails 904 to transition the platform 900 from the floating configuration shown in FIGS. 11 and 12A to the submerged configuration shown in FIGS. 11 and 13A. Any mode of tensioning using any suitable tensioning means described herein may be used. Once at the desired operating depth in the submerged configuration, the ROV 916 is used to facilitate engagement of the permanent mooring tendons 924, which extend from the platform to corresponding further connectors 922 on the corresponding anchors 912 as shown in FIGS. 13C and 13D. Any suitable connector may be used, including a suitable subsea mooring connector (SMC), such as a BallGrubb™ connector. In the particular embodiment shown, the permanent anchoring tendons 924 define an anchoring working depth of the platform 900 that is determined by the anchoring length of the anchoring tendons 924. It will be understood that in embodiments the working depth may be adjusted by extending or retracting a portion of the anchoring tendon between the platform 900 and the corresponding anchor 912, such as with a winch and / or tensioning means as described herein.

[0084] 14A and 14B, a further step in the installation sequence is shown, which includes actuating the tensioning means 902 by the deployment vessel 910 as shown in FIG. 14A to release tension from the installation lines 914 so that only the permanent mooring tendons 924 bear all tension applied thereon by the buoyant platform 900. The platform 900 is then supported in a submerged configuration by the mooring tendons 924 at an operating depth, which in the example shown is determined by the length of the mooring tendons 924. A second end of the installation lines 914 is disengaged from the corresponding anchors 912 as shown in FIG. 14B, either remotely or using an ROV 916. The temporary installation lines 914 are then retrieved by the deployment vessel 910. In the example shown, the tensioning means including the unidirectional mechanism 902 is also retrieved by the deployment vessel 910 for use in further deployment of the platform. In the example shown, rails 904 are also retrieved by deployment vessel 910 for reuse in installing additional platforms.

[0085] 15A and 15B show further steps in the installation sequence, including securing a subsea power cable 928 to the platform 900 for transferring electrical energy from the platform 900. The cable 928 is laid towards the platform 900 as shown in FIG. 15A, and cable attachments are secured to the cable 928 including buoyancy modules and bending stiffeners 930 to stabilize the cable 928 in the water. A messenger line (not shown) through a J-tube is coupled to the cable 928 from a winch (not shown) located on the platform 900, which then pulls the cable 928 into place for coupling to a corresponding port on the platform. Ten turbines 932 are installed to provide a fully deployed platform as shown in FIG. 15B.

[0086] Figures 16A and 16B show an enlarged isometric view of the platform 900 after the pulling step with the tensioning means 902 and before the removal of the tensioning means 902, 904 by the deployment vessel 910. As can be seen in particular from the views of Figures 16A and 16B, in the example described the platform 900 is compatible with existing maintenance options and provides access to the personnel transfer vessel (CTV) via a landing and ladder on the diagonal piers of the platform 900. The lower part of the top of the platform 900 supporting the turbine 932 is provided to stay above the surface of the body of water in the underwater configuration. This part has, in the example shown in Figures 16A and 16B, an example of a suitable draft greater than or equal to 18m and an example of a suitable height greater than or equal to 10m to provide space for a Service Operation Vessel (SOV) or a larger vessel to the platform and turbine during installation and maintenance. The stability of the platform 900 in the submerged operating configuration, caused by the buoyancy of the platform 900 and the resulting tension in the mooring tendons 924, results in low motion in this configuration, providing compatibility with walk-to-work and lift-compensated crane access systems. Maintenance upon return to port is facilitated by simple refitting of the tensioning means and positioning system described herein, and thus simple reversal of the installation and installation process.

[0087] It will be understood that the above described embodiments are given by way of example only, and that alternatives are also contemplated within the scope of this disclosure. For example, the details of construction may be of any shape or size or of any suitable material. The number of mooring lines, platform apexes, and any other details may be varied, and tensioning options may be of any suitable means. The mooring lines in the illustrated example are chains, and the tensioning means shown are primarily adapted to chains. It will be understood that in other embodiments, the mooring lines take any suitable form, such as natural or synthetic ropes as described herein.

Claims

1. 1. A floatable offshore platform for supporting a renewable energy system in a body of water having a surface and a bottom, the floatable offshore platform comprising: a base portion that is submerged below the surface of the body of water; a leading portion that remains above the surface of the body of water; one or more mooring lines that secure the buoyant offshore platform to the bottom of the body of water; tensioning means for applying tension to said one or more mooring lines; Equipped with the floatable offshore platform further comprising a floating structure, the floatable offshore platform being positioned substantially floating on the surface of the body of water; the floatable offshore platform comprising an arrangement, the base portion being submerged below the surface of the body of water and the tip portion remaining above the surface of the body of water; and further wherein, in use, the tensioning means is configured to apply tension to the one or more mooring lines secured between the floatable offshore platform and the bottom of the body of water as the floatable offshore platform transitions between the floating configuration and the deployed configuration. A platform characterized by.

2. 2. The floatable offshore platform of claim 1, wherein the tensioning means comprises a pulley attached to the platform, the pulley configured to be driven by a drive means and further configured to apply a first tension to one or more of the mooring lines when driven by the drive means.

3. The buoyant offshore platform of claim 2 , wherein the tensioning means is configured to apply the first tension to two of the mooring lines.

4. 4. A floatable offshore platform as claimed in claim 2 or claim 3, wherein the platform further comprises a mooring line well, and the pulley is further configured to guide the one or more mooring lines into the mooring line well.

5. The floatable offshore platform of claim 4 , wherein the mooring line well is disposed within a hollow structural element of the tip section.

6. The floatable offshore platform of claim 2 , wherein the pulley is permanently attached to the platform.

7. 3. The floatable offshore platform of claim 2, wherein said drive means is a motor, and said motor is in releasable engagement with said pulley.

8. 2. The buoyant offshore platform of claim 1, wherein the tensioning means further comprises a static unidirectional mechanism having a tensioned state and a released state, wherein in the tensioned state, the static unidirectional mechanism is configured to restrict movement of one or more of the mooring lines to a single direction, and in the released state, the unidirectional mechanism is configured to allow free movement of the mooring lines in either direction.

9. The floatable offshore platform of claim 8 , wherein the static unidirectional mechanism is permanently attached to the platform such that the static unidirectional mechanism cannot move relative to the platform.

10. The tensioning means further includes a reciprocating unidirectional mechanism, the reciprocating unidirectional mechanism comprising: A first water ram pump and a second water ram pump are provided, Each of the first and second hydraulic rams is attached to a corresponding movable unidirectional member, the unidirectional member comprising: a tension state configured to limit movement of one of the mooring lines relative to a first direction and further configured to be actuated by the corresponding hydraulic hammer in the first direction to apply a second tension to the mooring line; a released state configured to be moved along the mooring line in a second direction opposite to the first direction by the corresponding hydraulic hammer; and having each said unidirectional member being configured to transition between said tensioned state and said released state in a reciprocating manner; 2. The buoyant offshore platform of claim 1.

11. The floatable offshore platform of claim 10 , wherein each unidirectional member may be powered by the corresponding first or second hydraulic ram independently of the other unidirectional members.

12. The floatable offshore platform of claim 10 , wherein the one or more mooring lines comprise chains and the reciprocating unidirectional mechanism is a jack chain.

13. The floatable offshore platform of claim 10 , wherein the reciprocating unidirectional mechanism is removably attached to the platform.

14. A reciprocating unidirectional mechanism configured to apply tension to two mooring lines of a platform as described in claim 1, the unidirectional mechanism comprising: A first water ram pump and a second water ram pump are provided, Each of the first and second hydraulic rams is attached to a corresponding movable unidirectional member, the unidirectional member comprising: a tension state configured to limit movement of one of the mooring lines relative to a first direction and further configured to be actuated by the corresponding hydraulic hammer in the first direction to apply tension to the mooring line; a released state configured to be moved along the mooring line in a second direction opposite to the first direction by the corresponding hydraulic hammer; and The present invention is characterized by having the following.

15. The reciprocating unidirectional mechanism of claim 14 , wherein the unidirectional mechanism is configured to apply the tension to the two mooring lines independent of each other.

16. The reciprocating unidirectional mechanism of claim 14 , wherein the reciprocating unidirectional mechanism is a jack chain.

17. A buoyant offshore platform according to claim 1; 15. A reciprocating unidirectional mechanism as claimed in claim 14; Complete set of parts including.

18. 1. A method of deploying a floatable offshore platform for supporting a renewable energy system, comprising: The method comprises: moving the buoyant marine platform along the surface of the body of water into position; attaching the buoyant offshore platform to the one or more mooring lines via tensioning means; applying a first tension to the one or more mooring lines using the tensioning means such that the one or more mooring lines are taut; applying a second tension to the one or more mooring lines such that a portion of the buoyant offshore platform is submerged in the body of water; The method includes:

19. 20. The method of claim 18, said method including the additional step of attaching a reciprocating unidirectional mechanism to said platform that is adapted to be attached with said reciprocating unidirectional mechanism.

20. 20. The method of claim 19, further comprising the additional step of removing the reciprocating unidirectional mechanism from the platform.

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