Patent Description:
Offshore structures, such as floating structures or platforms, can be moored by mooring lines, such as mooring chains. This may include attaching at least one mooring line to the structure to be moored and directly, or indirectly, coupling each mooring line to another structure, such as an anchor or pile located on the seabed.

A tension may be applied to each of the mooring lines. A necessary tension can be applied to each mooring line by, for example, the use of a tensioning apparatus. The tensioning apparatus may be adapted for use by a winch, or the like. The application of tension may serve to moor the floating structure or platform in a desired position.

When an appropriate tension has been applied to a mooring line, a locking mechanism may be locked to maintain the mooring line in tension. Similarly, when a tension has to be removed from the mooring line, for example, when movement of the floating structure or platform is desired, the locking mechanism may be unlocked.

The tensioning apparatus may be located on, or coupled to, the floating structure or platform. In such an arrangement, the mooring chain and/or tensioning apparatus may be prone to wear and/or failure due to out-of-plane stresses caused by movement of the floating structures or platforms relative to the mooring chain.

The tensioning apparatus may be located on, or coupled to, the mooring chain and may direct a free end or the mooring chain towards the surface to enable adjustment of the tension in the mooring line(s) e.g. by a winch located on a vessel.

During tensioning of the mooring line, bending strain can act on the mooring line due to the mooring line being pulled and/or bent around the tensioning apparatus. This can lead to increased wear and/or damage to the mooring chain and/or to the apparatus. In order to minimise the strain on the mooring line, the size of the tensioning apparatus may be increased to accommodate larger angles for guiding the mooring line towards the surface. However, this can lead to an increased cost and weight of the tensioning apparatus. Further, the increased weight of the tensioning apparatus also increases a loading upon the mooring chain, subsequently requiring an even greater tension to maintain a desired angle of inclination of the mooring chain. It is an object of at least one embodiment of at least one aspect of the present invention to obviate or at least mitigate at least one problem in the prior art. It is an object of at least one embodiment of at least one aspect of the present invention to provide a technically simple and/or commercially more cost effective apparatus and method for mooring than in the prior art.

<CIT> describes a method of and apparatus for offshore mooring, wherein a clamping apparatus includes a clamping mechanism and a pulley. A mooring line connected to an anchor or a pendant line connected to a vessel to be moored extends through the clamping mechanism and around the pulley of the clamping apparatus. The distal end of the line extending through the clamping apparatus is connected to an anchor handling vessel. The anchor handling vessel is employed to apply a predetermined tension to the pendant line and the preset mooring line. A remote operated vehicle is then employed to actuate the clamping apparatus and to disengage the anchor handling vessel.

<CIT> describes floating platform having a mooring line which passes through coupling apparatus tethered to suction anchor. The coupling apparatus allows the effective length of the mooring line between the platform and the anchor to be adjusted using a vessel independent of the platform. The vessel pulls the mooring line through the coupling apparatus, reducing the effective length of mooring line, until the floating platform is in a desired position. The coupling apparatus includes a locking device to prevent the effective length of the mooring line from changing once the floating platform is in the desired position.

<CIT> describes an anchor line installation method for mooring an offshore structure to a mooring line comprising the steps of: providing a mooring line, with one end connected to the sea bed and comprising at a free end a connector member, lifting the free end onto a deck of an anchor line handling vessel, connecting on the anchor line handling vessel a chain tensioner with a connection side to the connector member, providing a working chain into the entry side of the chain tensioner, the working chain having a relatively short tensioning chain part and a relatively long installation chain part, holding a free end of the installation chain part connected to the anchor line handling vessel while lowering the chain tensioner below water level, picking up a free end of a pendant attached on one end to the offshore structure that is to be moored, and attaching the free end of the pendant to the free end of the installation chain part in an interconnect position on the anchor line handling vessel and, placing the interconnect position overboard from the anchor handling vessel, connecting a lifting cable of a lifting device on the anchor line handling vessel to the tensioning chain part below water level, and exerting an upward tensioning force on the tensioning chain part via the lifting cable.

According to a first aspect of the present invention there is provided a mooring apparatus according to claim <NUM>.

By this apparatus a mooring line may be tensioned.

The apparatus may be known as a "Mid-Line Tensioner".

The lock or lock means may comprise a mooring line lock, e.g. capable of locking or retaining the first mooring line.

The lock may be disposed between the second mooring line and the guide portion and/or between the arrangement and the guide portion.

In use, at least a portion of the first mooring line may be disposed, locked and/or secured between the lock and the guide portion.

The lock may be adapted to secure and/or lock the first mooring line between the lock and an outer peripheral/circumferential portion of guide portion.

The lock may be hingedly or pivotably connected to the arrangement.

At least a portion of at least one or both of the mooring lines may be a chain, wire, rope, or the like. According to the invention as claimed, at least a portion of the first mooring line is a chain. At least a portion of the second mooring line may be a second chain.

The guide portion may be a wheel and/or may be substantially circular, such as mooring line wheel or a chain wheel which is rotatable relative to the arrangement, such as around a central axis of the guide portion. The guide portion may be a sprag wheel. The guide portion may be a sheave. The guide portion may be a toothed wheel, such as a cogwheel or the like.

In use, at least a portion of the first mooring line or at least one link of the first chain may be subject to a mooring tension, while the at least a portion of the first mooring line or the at least one link of the first chain is in contact with the guide portion or chain wheel. At least at least a portion of the first mooring line or at least one link of the first chain may be under a full mooring tension while the at least a portion of the first mooring line or the at least one link of the first chain is in contact with the chain wheel.

In use, at least a portion of the first mooring line may be in a position between the lock or lock means and the guide portion. In use, the at least a portion of the first mooring line may be subject to the mooring tension. In use, a portion of the first mooring line that is pulled through, threaded through, or wound around, the apparatus, or in contact with the guide portion or chain wheel and or the lock, may be under the mooring tension.

The guide portion may comprise a plurality of circumferentially arranged teeth, indentations, pockets, grooves, recesses, or the like. Each tooth, indentation, pocket, groove, recess, or the like, may be arranged to cooperate with at least a portion of the first mooring line, such as a link or links of the first chain. A dimension of each of the plurality of circumferentially arranged teeth, indentations, pockets, grooves, recesses, or the like, may be selected to correspond to a dimension of a portion of a mooring line. The dimension of each of the plurality of circumferentially arranged teeth, indentations, pockets, grooves, recesses, or the like, may be selected to correspond to a dimension of a link of the first chain.

The guide portion may be adapted to create the mooring tension in the first mooring line and/or the second mooring line by pulling at least one portion of the first mooring line towards the second mooring line.

In use, when the lock is in an engaged position, the guide portion may be subject to at least a portion of a mooring tension in the first mooring line.

The mooring tension may be greater than a tension caused by the weight of the mooring line itself and/or the weight of the apparatus on the mooring line and/or the influence of a surrounding environment upon the mooring line(s) or apparatus. The mooring tension may be greater than a self-induced tension.

The arrangement may comprise a plurality of parts. The arrangement may be arranged relative to or around at least a portion of the guide portion. The arrangement may be arranged symmetrically around the guide portion. In use, the arrangement may be detachably connected to the second mooring line. In use, the arrangement may be detachably connected to at least one link of the second chain. In use, the arrangement.

may be detachably connected to the second mooring line by means of a pin, such as a locking pin, a bolt, an elongate object, or the like.

The guide portion may be rotatably mounted on the arrangement. The guide portion may be rotatably mounted on the arrangement by means of an axle, a hub, a pin, a cylindrical element, or the like. The guide portion may be arranged to be movable around or about an axis of the apparatus.

The arrangement may comprise at least one stop-block, ridge, flange, protrusion, or the like, to limit a degree of movement of the lock.

The lock may be adapted to have a first position. The lock may be adapted to have a second position. The first position may be an engaged or lock position. The second position may be a disengaged position. The lock may be movable, actuable and/or operable between the first and/or second positions and vice versa.

In the engaged position, the lock may restrain a portion of the first mooring line. Beneficially, the provision of such a lock removes a need to maintain a mooring tension on at least a portion of the first mooring line. The portion of the first mooring line may be in contact with the guide portion. In the engaged position, the lock may abut at least one portion of the first mooring line.

In the engaged position, the lock or chain stopper may restrain at least a portion of the first mooring line or one link of the first chain. The at least a portion of the first mooring line or one link of the first chain may be in contact with the guide portion or chain wheel. In the engaged position, the lock or chain stopper may abut at least a portion of the first mooring line or at least one link of the first chain, wherein the at least a portion of the first mooring line or at least one link of the first chain is in contact with the guide portion or chain wheel.

In the engaged position, the lock may restrain the guide portion. In the engaged position, the lock may abut at least one portion of the guide portion.

The guide portion may comprise a plurality of circumferentially arranged teeth, indentations, castellations, or the like. The lock may be adapted to act upon and/or engage with, the at least a portion of the guide portion when the lock is in the engaged position.

The first chain and/or the second chain may be mooring chains. The first chain and/or the second chain may be a short link chain, a stud link chain, a twisted link chain, or the like. In use, a portion of the second chain may be connected to an anchor, a pile, such as a suction pile, a subsea structure, or the like. In use, the second chain may be connected to a subsea formation or floor of a body of water.

The lock may be adapted to be locked in the engaged position. The lock may be adapted to be locked in the engaged position by a locking pin. The lock may be adapted to be releasably locked in the disengaged position or the engaged position.

The lock may be adapted to be locked in the disengaged position. The lock may be adapted to be locked in the disengaged position by a locking pin.

The lock may comprise at least one hole. The locking pin may be removably insertable into the at least one hole. The arrangement may comprise at least one hole. The lock may be locked in a position by insertion of a locking pin through the at least one hole in the arrangement and/or the at least one hole in the lock.

The arrangement may comprise at least one shoulder, ridge or flange. The lock may be locked in a position by insertion of a locking pin through the at least one hole in the lock, wherein the locking pin may abut the at least one shoulder, ridge or flange of the arrangement.

Alternatively, the lock may comprise at least one shoulder, ridge or flange. The lock may be locked in a position by insertion of a locking pin through the at least one hole in the arrangement, wherein the locking pin may abut the at least one shoulder, ridge or flange of the lock.

The locking pin may be an elongate element or object. The locking pin may be a bolt, or the like.

The apparatus may comprise an arrangement, such as a lock positioning apparatus, for biasing the lock to an engaged position. The apparatus may comprise a lock positioning apparatus. The lock positioning apparatus may be adapted to move the lock between a disengaged position and an engaged position. The lock positioning apparatus may be adapted to move the lock from the disengaged position to the engaged position. The lock positioning apparatus may be adapted to predispose the lock to the engaged position. The lock positioning apparatus may be connected to the arrangement. The lock positioning apparatus may be hingedly or pivotably connected to the arrangement. The lock positioning apparatus may be connected to the lock. The lock positioning apparatus may be hingedly or pivotably connected to the arrangement and/or the lock. The lock positioning apparatus may be connected to the arrangement and/or the lock by an elongate element, such as a pin.

The lock positioning apparatus may comprise a spring, such as a coil spring or the like. The lock positioning apparatus may comprise a piston. The lock positioning apparatus may comprise a cylinder. The lock positioning apparatus may comprise an air spring. The lock may comprise a spring cylinder. The lock may comprise a damper or shock absorber.

The lock positioning apparatus may be configured to cause the lock to tend towards the engaged position.

The apparatus may be adapted to allow the first mooring line to be pulled through, threaded through, or wound around, the apparatus in a first direction. The apparatus may be adapted to inhibit movement of the first mooring line in a direction opposite to the first direction. The lock and/or the lock positioning apparatus may be adapted to allow the first mooring line to be pulled through, threaded through, or wound around, the apparatus in a first direction. The lock and/or the lock positioning apparatus may be adapted to inhibit movement of the first mooring line in a direction opposite to the first direction. The apparatus may be adapted to permit unidirectional movement of the mooring line around and/or through the apparatus.

The lock may be movable between the first and second positions by a mooring line as the mooring line is pulled through, threaded through, or wound around, the apparatus. The lock may be movable between the first and second positions by a mooring line as a mooring line is pulled or wound around the guide portion. The lock may be movable between the first and second positions by a mooring line as a mooring line is in contact with the guide portion, and the guide portion rotates around the axis.

The lock may be adapted to be predisposed to the engaged position. The lock may be adapted to pivot around an axis. The lock may comprise a mooring line engaging surface. The lock may be adapted to pivot between the disengaged position and the engaged position. In the engaged position the mooring line engaging surface may be adapted to act directly on at least a portion of the mooring line. In the engaged position the mooring line engaging surface may be adapted to act directly on at least a portion of the guide portion. In the disengaged position the mooring line engaging surface may be adapted to act directly on at least a portion of the first mooring line. In the engaged position, a mooring line engaging surface of the lock may be pivoted in a direction towards the guide portion. In the disengaged position, a mooring line engaging surface of the lock may be pivoted in a direction away from the guide portion. The mooring line engaging surface of the lock in a disengaged position may be in a location that is further from the guide portion than the mooring line engaging surface of the lock in an engaged position. The mooring line engaging surface may be adapted to conform to a shape of a portion of the mooring line. The mooring line engaging surface may comprise at least one seat. The at least one seat may conform to the shape of at least a portion of the first mooring line and/or the guide portion. In the engaged position the mooring line engaging surface may contact at least a portion of the mooring line at a plurality of points.

The lock or chain stopper may be adapted to be predisposed to the engaged position. The lock or chain stopper may be adapted to pivot around an axis. The lock or chain stopper may comprise a chain engaging surface. The lock or chain stopper may be adapted to pivot between a disengaged position and the engaged position. In the engaged position the chain engaging surface may be adapted to act directly on at least one link of the first chain. In the engaged position the chain engaging surface may be adapted to act directly on at least a portion of the chain wheel. In the disengaged position the chain engaging surface may be adapted to act directly on at least one link of the first chain. In the engaged position, a chain engaging surface of the lock or chain stopper may be pivoted in a direction towards the chain wheel. In the disengaged position, a chain engaging surface of the lock or chain stopper may be pivoted in a direction away from the chain wheel. The chain engaging surface of the lock or chain stopper in a disengaged position may be in a location that is further from the chain wheel than the chain engaging surface of the lock or chain stopper in an engaged position. The chain engaging surface may be adapted to conform to the shape of a link of the chain. The chain engaging surface may comprise at least one seat. The at least one seat may conform to the shape of at least a portion of a link of the chain. In the engaged position the chain engaging surface may contact a link of a chain at a plurality of points.

Movement of the first mooring line through the apparatus in a first direction may urge rotation of the guide portion in a first rotational direction. Movement of the first mooring line through the apparatus in a second direction may urge rotation of the guide portion in a second rotational direction. In use, the first mooring line may be engaged and/or meshed and/or interconnected with the guide portion. In use, at least one link of the first chain may be engaged with at least one tooth and/or at least one indentation, groove, pocket, recess, or the like of the chain wheel.

The apparatus may be submerged in use. The apparatus may be suitable for offshore and/or subsea/underwater operations. A length of the first mooring line extending from the apparatus to a floating structure may be sufficiently long such that, in use, the apparatus may be submerged. A length of the first mooring line extending from the apparatus to a floating structure may be sufficiently long such that, in use, a vessel may interact with the apparatus while remaining at a safe distance from the floating structure.

Beneficially, due to a mid-mooring line position of such an apparatus, a degree of out-of-plane bending applied to the apparatus may be reduced or sought to be minimized, in use. That is, in comparison to an apparatus wherein a mooring lie or chain stopper is positioned below a guide or chain wheel, leaving the mooring line or chain around the guide or chain wheel slack, and the entire apparatus is located in the proximity of a floating structure or vessel hull, the present invention is not subject to the relative motions that may be found between the mooring line and the structure/hull. Such relative motions may result in failure of the mooring line or mooring chain due to wear between a portion of the mooring line and the guide, or between chain links and wheel pockets. As such, the present invention does not require a locking mechanism located separately from the guide apparatus. Further, such an arrangement permits an implementation of a smaller, lighter and cheaper to manufacture and maintain solution. The provision of a smaller and/or lighter apparatus also minimises the tension applied to the mooring line by the apparatus itself.

Beneficially, the provision of a mooring line mounted apparatus for tensioning the mooring line, rather than an apparatus mounted on a vessel or anchor, provides mechanical advantage. That is, the mechanical advantage of the chain wheel, or sheave, may be used to apply a greater tension to the second mooring line. In use, this may be useful for pre-stretching mooring lines comprising at least in part a polymeric material, e.g. polyester, or the like. By pre-stretching the line, an amount of re-tensioning required over the life of the apparatus may be reduced.

The guide portion or chain wheel may comprise a plurality of circumferentially arranged cams.

The lock or chain stopper may comprise at least one finger or extension element. In use, the at least one extension element may be arranged to interact with the plurality of cams during rotation of the guide portion or chain wheel.

In use, as the guide portion or chain wheel rotates, each cam of the plurality of cams may be adapted to move the extension elements from a first position to a second position.

The transition of the at least one finger or extension element from the first position to the second position may cause the lock or chain stopper to transition from the engaged position to the disengaged position.

In use, the cams may be adapted to hold the lock or chain stopper in a disengaged position until the guide portion or chain wheel has rotated beyond a point where a restrained portion of the mooring line or a restrained chain link may be or become jammed by the lock or by the chain stopper.

Advantageously, such an arrangement prevents a "bite-point" between the mooring line or chain and the lock or chain stopper occurring, preventing damage to the mooring line or chain, or to the apparatus.

According to a second aspect of the present invention, there is provided a system for tensioning a mooring line, the system comprising the mooring apparatus according to the first aspect.

The system may comprise a first mooring line. The system may comprise a second mooring line.

The system may comprise at least one structure, such as a floating structure, an offshore structure, a floating platform or the like.

A portion of the first mooring line may be threaded or threadable through the apparatus.

A first portion of the first mooring line may be configured to be connected or connectable to the structure.

The system may comprise a buoy. The system may comprise a floating vessel. The system may comprise a winch and/or a pulley. The winch and/or pulley may be located on or in the floating vessel. The buoy may be a submersible buoy, a semisubmersible buoy, a submerged turret production buoy, a submerged turret loading buoy or the like.

A second portion of the first mooring line may be configured to be connected to the buoy and/or the floating vessel and/or the winch and/or the pulley. The winch and/or pulley may be adapted to set, adjust or increase a tension in the first mooring line.

A first portion of the second mooring line may be connected to at least a portion of the apparatus. The first portion of the second mooring line may be connected to the arrangement. The first portion of the second mooring line may be releasably connected to the arrangement.

The system may comprise an anchor. The anchor may comprise an anchoring point. The anchor may be a pile, such as a suction pile or the like. The anchor may be a subsea formation. The anchor may be adapted for use on a seabed.

A second portion of the second mooring line may be connected to the anchor or to the anchoring point.

According to a third aspect of the present invention there is provided a method of tensioning a mooring line, wherein the method comprises:
providing a system for tensioning a mooring line according to the second aspect of the present invention, the method further comprises:
applying a pulling force to a first portion of a first mooring line in a direction away from the apparatus.

The pulling force may cause the apparatus to pull at least one other portion of the first mooring line towards a second mooring line.

The pulling force may cause the apparatus to pull at least one other portion of the first mooring line towards the apparatus.

When an appropriate or desired tension has been applied to the mooring line, the lock may be locked in the engaged position.

When an appropriate or desired tension has been applied to the mooring line, the first portion of the first mooring line may be attached to a buoy or the like.

When an appropriate tension has been applied to the mooring line, at least a portion of the first portion of the first mooring line may be cut away and/or removed and/or secured to the apparatus and/or secured to the first and/or second mooring lines.

According to a fourth aspect of the present invention there is provided a method for releasing tension in a mooring line, the method comprising:
providing a system for tensioning a mooring line according to the second aspect of the present invention, the method further comprising:.

The step of retaining the lock in the disengaged position may require removal and/or repositioning and/or insertion of at least one locking pin.

It should be understood that the features defined above in accordance with any aspect of the present invention or below relating to any specific embodiment of the invention may be utilised, either alone or in combination with any other defined feature, in any other aspect or embodiment or to form a further aspect or embodiment of the invention.

These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, which are:.

Referring firstly to <FIG> of the accompanying drawings, there are shown two examples of prior art interfaces between a hull of a floating platform and a mooring line.

<FIG> shows an apparatus <NUM> wherein, in use, a mooring chain (not shown) remains in tension around a chain wheel <NUM>. It is known that such an interface may result in failure of the mooring chain due to wear between the chain links of the mooring chain and wheel pockets 15a, 15b, 15c and out-of-plane bending stress in the chain links due to insufficient lever arm to rotate the pillar bearings <NUM>.

<FIG> shows an exemplary representation of a further prior art apparatus <NUM>. <FIG> shows a design of fairlead with a mooring chain stopper <NUM> located below a chain wheel <NUM>. Such an arrangement leaves the mooring chain <NUM> around the chain wheel <NUM> slack. However, such an arrangement may also result in failure of the mooring chain <NUM> due to, at least, out-of-plane bending stresses in the chain links due to insufficient lever arm to rotate the pillar bearings <NUM>. Further, such an arrangement is significantly large, heavy and expensive to manufacture, install and maintain.

In contrast, an apparatus located on the mooring line in a mid-water position is subject to none of the relative motions found at an interface between the hull of a floating platform and the mooring line. In an embodiment of the present invention, the chain links located on a mooring line tensioner are static relative to one another, as will now be described in more detail with reference to <FIG>.

<FIG> shows a perspective view of a mooring apparatus, generally denoted <NUM>, according to a first embodiment of the present invention. The mooring apparatus comprises a guide portion <NUM> for guiding a portion of a first mooring line <NUM>. The apparatus also comprises an arrangement <NUM> for connecting or coupling the mooring apparatus <NUM> to a second mooring line <NUM>. The mooring apparatus <NUM> also comprises a lock <NUM>. The guide portion <NUM> is moveably connected to the arrangement <NUM>, and the lock <NUM> also is connected to the arrangement <NUM>. By this mooring apparatus <NUM>, a mooring line (first mooring line <NUM>) may be tensioned. One would appreciate that in other embodiments encompassing the inventive concept of the present invention, such an apparatus may be submerged in use. The apparatus is suitable for offshore and/or subsea operations.

Beneficially, due to a mid-mooring line position of such a mooring apparatus <NUM>, a degree of out-of-plane bending stress applied to the mooring apparatus <NUM> is minimized in use. That is, in comparison to a prior art apparatus <NUM>, wherein a chain stopper <NUM> is positioned below a chain wheel <NUM>, leaving the chain <NUM> around the chain wheel <NUM> slack, and the entire apparatus <NUM> is located in the proximity of a floating structure or vessel hull, the present invention is not subject to the relative motions that may be found between the mooring line and the structure/hull. Such relative motions may result in failure of the mooring chain due to wear between chain links and wheel pockets. As such, the present invention does not require a locking mechanism located separately from the guide apparatus. Further, such an arrangement permits an implementation of a smaller, lighter and cheaper to manufacture and maintain solution. The provision of a smaller and/or lighter apparatus also minimises the tension applied to the mooring line by the apparatus itself.

In the embodiment shown in <FIG>, at least a portion of the mooring lines <NUM>, <NUM> is a chain. A portion of the first mooring line <NUM> is a first chain <NUM>. At least a portion of the second mooring line <NUM> is a second chain <NUM>.

The guide portion <NUM> is a wheel, e.g. chain wheel. The guide portion <NUM> comprises a plurality of circumferentially arranged pockets <NUM>. A dimension of each of the plurality of circumferentially arranged pockets <NUM> is selected to correspond to a dimension of a link <NUM> of the first chain <NUM>.

The guide portion <NUM> is adapted to create a mooring tension in a first mooring line <NUM> and/or a second mooring line <NUM> by pulling at least one portion of the first mooring <NUM> line, e.g. towards the second mooring line <NUM>.

In use, when the lock <NUM> is in an engaged position, the guide portion <NUM> is subject to at least a portion of a mooring tension in the first mooring line <NUM>. This differs from prior art mooring apparatuses, where typically the lock is subject to the full mooring tension.

The arrangement <NUM> comprises a plurality of parts <NUM>, 95A, 95B. The arrangement <NUM>, 95A, 95B is arranged around the guide portion <NUM>. The arrangement <NUM>, 95A, 95B is arranged symmetrically around the guide portion <NUM>.

The arrangement <NUM> is detachably connected to the second mooring line <NUM>. The arrangement <NUM> is detachably connected to one link <NUM> of the second chain <NUM> by means of a pin <NUM>. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, such a pin may be a locking pin, a bolt, an elongate object, or the like.

The guide portion <NUM> is rotatably mounted on the arrangement 95A, 95B by means of an axle <NUM>. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, the axle may be a hub, a pin, a cylindrical element, or the like. The guide portion <NUM> is arranged to be movable around or about an axis X of the apparatus <NUM>.

Referring now to <FIG>, there is shown a cross-sectional view of the embodiment shown in <FIG>. The arrangement <NUM> comprises a stop block <NUM> to limit a degree of movement of the lock <NUM>.

The lock <NUM> is shown in a first, engaged position. The lock <NUM> may be movable, actuable and/or operable between the first position and a second position.

In the engaged position, the lock <NUM> restrains a portion <NUM> of the first mooring line <NUM>. Beneficially, the provision of such a lock <NUM> removes a need to maintain a mooring tension on at least a portion <NUM> of the first mooring line <NUM>. The portion <NUM> of the first mooring line <NUM> is in contact with the guide portion <NUM>. In the engaged position, the lock <NUM> abuts the portion <NUM> of the first mooring line <NUM>.

In the embodiment shown, the lock <NUM> is a chain stopper <NUM>. One will appreciate that in alternative embodiments, the lock <NUM> may be a mooring line stopper.

In the engaged position, the chain stopper <NUM> restrains at least one link <NUM> of the first chain <NUM>. The at least one link <NUM> of the first chain <NUM> is in contact with the chain wheel <NUM>. In the engaged position, the chain stopper <NUM> abuts at least one link <NUM> of the first chain <NUM>, wherein the at least one link <NUM> of the first chain <NUM> is in contact with the chain wheel <NUM>.

In use, at least one link <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the first chain <NUM> is subject to the mooring tension, while the at least one link <NUM> of the first chain <NUM> is in contact with the chain wheel <NUM>. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, at least one link <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the first chain <NUM> may be under a full mooring tension while the link <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the first chain <NUM> is in contact with the chain wheel <NUM>.

In the embodiment shown, the first chain <NUM> and/or the second chain <NUM> are mooring chains. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, the first chain <NUM> and/or the second chain <NUM> may be a short link chain, a stud link chain, a twisted link chain, or the like. In use, a portion of the second chain <NUM> is connected to an anchor, a pile, such as a suction pile, a subsea structure, or the like, as will be described with reference to <FIG> and <FIG>.

Referring now to <FIG>, there is shown a further perspective view of the embodiment of <FIG>. The lock <NUM> is adapted to be locked in the engaged position by a locking pin <NUM>. The lock <NUM> is adapted to be releasably locked in the disengaged position or the engaged position.

The lock <NUM> is adapted to be locked in the disengaged position by a locking pin <NUM> (see locking pin <NUM>, <FIG>).

The lock comprises a hole <NUM>. The locking pin 82may be inserted in the hole <NUM>. The arrangement <NUM> comprises a plurality of holes 135A, 135B. The lock <NUM> can be locked in a position by insertion of a locking pin <NUM> through the at least one hole 135A, 135B in the arrangement <NUM> and/or the at least one hole <NUM> in the lock <NUM>.

The arrangement <NUM> comprises a shoulder <NUM>. The lock <NUM> can be locked in a position by insertion of a locking pin 82through the hole <NUM> in the lock, wherein the pin abuts the shoulder <NUM> of the arrangement <NUM>.

The locking pin is described below with reference to <FIG>.

One will appreciate that in an alternative embodiment the lock <NUM> may comprise at least one shoulder, ridge or flange and the lock <NUM> may be locked in a position by insertion of a locking pin through the at least one hole 135A, 135B in the arrangement, wherein the pin may abut the at least one shoulder <NUM>.

Referring now to <FIG>, there is shown a magnified portion of the cross-sectional view of the embodiment of <FIG>. The apparatus <NUM> comprise a lock positioning apparatus <NUM>. The lock positioning apparatus <NUM> is adapted to move the lock <NUM> between a disengaged position and an engaged position. The lock positioning apparatus <NUM> is adapted to move the lock <NUM> from the disengaged position to the engaged position. A shown in <FIG>, the lock positioning apparatus <NUM> is adapted to predispose the lock <NUM> to the engaged position. The lock positioning apparatus <NUM> is pivotably connected to the arrangement <NUM> and the lock <NUM> by elongate elements 155A, 155B. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, elongate elements 155A, 155B may be pins, axles, or the like.

The lock positioning apparatus <NUM> comprises a coil spring <NUM>. The lock positioning apparatus <NUM> comprise spring cylinder <NUM>. The lock positioning apparatus <NUM> is adapted to cause the lock <NUM> to tend towards the engaged position.

Referring now to <FIG>, there is shown a perspective view of a cross-section across line A-A of the apparatus of <FIG>. The guide portion <NUM> is rotatably mounted on the arrangement 95A, 95B by means of an axle <NUM>. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, the axle may be a hub, a pin, a cylindrical element, or the like. The guide portion <NUM> is arranged to be moveable around or about an axis X of the apparatus. The guide portion <NUM> rotates freely around axis X on bearings, such as maintenance free composite bearings <NUM>.

The lock <NUM> is adapted to pivot around an axis <NUM>. The lock <NUM> comprises a mooring line engaging surface <NUM>. The lock <NUM> is adapted to pivot between the disengaged position and the engaged position. In the engaged position the mooring line engaging surface <NUM> is adapted to act directly on at least a portion of the mooring line <NUM>. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, in the engaged position the mooring line engaging surface <NUM> is adapted to act directly on at least a portion of the guide portion <NUM>.

In the engaged position, a mooring line engaging surface <NUM> of the lock <NUM> is pivoted in a direction towards the guide portion <NUM>. In the disengaged position, the mooring line engaging surface <NUM> of the lock <NUM> is pivoted in a direction away from the guide portion <NUM>. The disengaged position is described in more detail below with reference to <FIG>.

It can be seen from <FIG> that the mooring line engaging surface <NUM> is adapted to conform to a shape of a portion of the mooring line <NUM>. The mooring line engaging surface <NUM> comprises a seat. The seat conforms to the shape of a portion of the first mooring line <NUM>.

Referring now to <FIG>, there is shown a further perspective view of the apparatus of <FIG>. <FIG> shows the apparatus <NUM> in use.

The apparatus <NUM> is adapted to allow the first mooring line <NUM> to be pulled through the apparatus <NUM> in a first direction shown by arrow <NUM>. The apparatus <NUM> is adapted to inhibit movement of the first mooring line <NUM> in a direction opposite to the first direction shown by arrow <NUM>. The lock <NUM> and the lock positioning apparatus <NUM> are adapted to allow the first mooring line <NUM> to be pulled through the apparatus <NUM> in the first direction <NUM>. The lock <NUM> and the lock positioning apparatus <NUM> are adapted to inhibit movement of the first mooring line <NUM> in a direction <NUM> opposite to the first direction <NUM>. As such, it can be seen that the apparatus <NUM> is adapted to permit unidirectional movement of the mooring line through the apparatus <NUM>.

The lock <NUM> is movable between the first and second positions by the mooring line <NUM> as the mooring line <NUM> is pulled through the apparatus <NUM>. The lock <NUM> is movable between the first and second positions by the mooring line <NUM> as a mooring line <NUM> is pulled around the guide portion <NUM>. The lock <NUM> is movable between the first and second positions by the mooring line <NUM> while the mooring line <NUM> is in contact with the guide portion <NUM>, and the guide portion <NUM> rotates around the axis X.

It can be seen that movement of the first mooring line <NUM> through the apparatus <NUM> in a first direction <NUM> urges rotation of the guide portion <NUM> in a first rotational direction 215A. Movement of the first mooring line through the apparatus in a second direction <NUM> urges rotation of the guide portion in a second rotational direction 215B.

Referring now to <FIG>, there is shown a side view of the apparatus <NUM> of <FIG>. In <FIG>, the lock <NUM> is shown in a disengaged position. In the disengaged position, a mooring line engaging surface of the lock <NUM> is pivoted in a direction away from the guide portion <NUM>.

In the exemplary embodiment of <FIG>, the lock <NUM> has been transitioned to the disengaged position by movement of a portion of the mooring chain <NUM>. In use, the angle α of the mooring chain <NUM> relative to the guide portion <NUM> is changed, such that the portion of the mooring chain <NUM> acts upon the lock <NUM> and urges the lock <NUM> towards the disengaged position. The angle α is increased to urge the lock <NUM> towards the disengaged position.

The lock <NUM> is shown retained in the disengaged position by a locking pin <NUM>.

Subsequently, and as shown in <FIG>, in use the angle α of the mooring chain <NUM> relative to the guide portion <NUM> may be reduced, allowing the chain <NUM> to freely move through the apparatus <NUM>. As such, tension in the mooring line <NUM>, <NUM> may be reduced.

<FIG> shows a side view of a further embodiment of the present invention, generally denoted 50a. This embodiment differs from that of the embodiment shown in <FIG> by a further arrangement 76a affixed to the lock 75a. In the embodiment of <FIG>, the further arrangement 76a is a padeye, the padeye being suitable for connection to a wire 78a or the like. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, the further arrangement 76a may be a hook, a fastener or any other component or apparatus suitable for connection to a wire, a rope, a chain or the like.

In the embodiment shown in <FIG>, an opening 77a in the further arrangement 76a is positioned such that, in use, a pulling force applied in a direction away from the apparatus 50a, in an generally upwards direction as shown in <FIG>, causes the lock 75a to pivot from an engaged position to a disengaged position. As such, the apparatus 50a may be operated remotely by, for example, a pulling force being applied to the wire 78a. The pulling force may be applied by a floatation device, such as a buoy or the like. Advantageously, such an arrangement may dispense with a requirement to insert a locking pin to retain the lock 75a in the disengaged position. Advantageously, such an arrangement does not require an angle of incidence of the mooring line 61a to be changed to transition the lock between the engaged and disengaged position.

Referring now to <FIG>, there is shown a view of a portion of an exemplary embodiment of the present invention, generally denoted 50b. <FIG> shows a chain 61b and a chain stopper 76b. The chain stopper 76b is arranged at a "bite point". The "bite point" is an arrangement wherein a corner 79b of the lock 75b is located against a curved portion 62b of a link in the chain 61b. In the event of a change of direction of a chain through the apparatus, the lock may jam against a side of the chain link, potentially damaging the chain and/or the lock.

<FIG> shows a further embodiment of the present invention, generally denoted 50c. Chain wheel 55c comprises five circumferentially arranged cams 405a, 405b, 405c, 405d, 405e. One will appreciate that there may be fewer cams, such three or four cams, or a greater quantity of cams, such as six or more. The quantity of cams may be selected based on dimensions of the chain and/or dimensions of the chain wheel.

Chain stopper 75c comprises a pair of extension elements <NUM>, <NUM>'. In use, the extension elements <NUM>, <NUM>' are arranged to interact with the cams 405a, 405b, 405c, 405d, 405e during rotation of the chain wheel 55c. In use, as the chain wheel 55c rotates in a direction shown by the arrow in <FIG>, each cam 405a, 405b, 405c, 405d, 405e sequentially interacts with the extension elements <NUM>, <NUM>'. In use, as the chain wheel 55c rotates, each cam 405a, 405b, 405c, 405d, 405e nudges the extension elements <NUM>, <NUM>' from a first position to a second position. The transition of the extension elements <NUM>, <NUM>' from the first position to the second position causes the chain stopper <NUM> to transition from the engaged position to the disengaged position. <FIG> shows the chain stopper 76c held in the disengaged position by the extension elements <NUM>, <NUM>'. As such, occurrence of the "bite point" is avoided. That is, the effect of the cams 405a, 405b, 405c, 405d, 405e on the chain wheel 55c interacting with the extension elements <NUM>, <NUM>' attached to the chain stopper 76c is to hold the chain stopper 75c in a disengaged position until the chain wheel 55c has rotated approximately <NUM> degrees past a point where a restrained chain link is locked by the chain stopper 76c. This means that the chain link to be restrained is well clear of the chain stopper 76c at a point where the extension elements <NUM>, <NUM>' slip off the cam 405a, 405b, 405c, 405d, 405e on the chain wheel 55c and allows the chain stopper 76c to drop. The extension elements <NUM>, <NUM>' in no way hinder the chain wheel 55c as it is reversed to sit the chain link into the chain stopper 76c once the chain stopper 76c has dropped. <FIG> provides a top view of the embodiment of <FIG> provides a perspective view of the embodiment of <FIG> with the lock in the engaged position. The extension elements <NUM>, <NUM>' may be an integral part of the chain stopper 76c, or they may be affixed to the chain stopper 76c.

Referring now to <FIG>, there is shown a system, generally denoted <NUM>, for tensioning a mooring line <NUM>, <NUM> comprising the mooring apparatus <NUM> of <FIG>. The system comprises a first mooring line <NUM>. The system <NUM> comprises a second mooring line <NUM>. The system <NUM> comprise a floating structure <NUM>, which one will appreciate may be an offshore structure, a floating platform, a vessel or the like.

A portion <NUM> of the first mooring line <NUM> has been threaded through the apparatus <NUM>. A first portion <NUM> of the first mooring line <NUM> is connected to the floating structure <NUM>. The system comprises a floating vessel <NUM>. The system comprises a winch <NUM>. The winch <NUM> is located on or in the floating vessel <NUM>.

The second portion <NUM> of the first mooring line <NUM> is adapted to be connected to the winch <NUM>. The winch <NUM> is adapted to set, adjust or increase a tension in the first mooring line <NUM>.

A first portion of the second mooring line <NUM> is connected to at least a portion of the apparatus <NUM>. The first portion of the second mooring line <NUM> is connected to the arrangement <NUM>. The first portion of the second mooring line may be releasably connected to the arrangement <NUM>.

The system <NUM> comprises an anchor <NUM>. One will appreciate that in other embodiments encompassing the inventive concept of the present invention, the anchor may be a pile, such as a suction pile or the like, or the anchor may be a subsea formation. A second portion of the second mooring line <NUM> is connected to the anchor <NUM> or to an anchoring point.

It will be appreciated that in other embodiments encompassing the inventive concept of the present invention, the mooring apparatus may be used, or dispositioned, in a different or an opposite orientation. That is, in use, a first portion of the second mooring line may be connected to an anchor, a pile (such as a suction pile), a subsea structure, or the like, and a second portion of the second mooring line may be threaded through the apparatus <NUM> and, for example, connected to the winch <NUM>. In this embodiment, the arrangement may be detachably connected to the first mooring line, and the first mooring line may be connected to a floating structure or vessel hull.

Referring now to <FIG>, there is shown a system, generally denoted <NUM>. <FIG> shows the system <NUM> after the mooring line <NUM>, <NUM> has been tensioned to a mooring tension.

A portion <NUM> of the first mooring line <NUM> has been threaded through the apparatus <NUM>. The system <NUM> comprises a buoyancy module <NUM>. The portion <NUM> of the first mooring line <NUM> is configured to be connected to the buoyancy module <NUM>. Beneficially, the buoyancy module <NUM> holds an excess portion of the first mooring line <NUM> away from the apparatus <NUM>.

It will be appreciated that the embodiments of the present invention herebefore described are given by way of example only and are not meant to limit the scope of thereof in any way.

Claim 1:
A mooring apparatus (<NUM>), comprising:
a guide portion (<NUM>) for guiding a portion of a first mooring line (<NUM>),
an arrangement (<NUM>) for connecting or coupling the apparatus to a second mooring line (<NUM>), and
a lock (<NUM>), wherein
the guide portion is moveably connected to and rotatably mounted on the arrangement, and
the lock is connected to, attached to or provided on the arrangement,
wherein at least a portion of the first mooring line is a chain, characterized in that when in an engaged position the lock (<NUM>) restrains and/or abuts at least one link of the chain , the at least one link of the chain is in contact with the guide portion (<NUM>).