GB2619041A

GB2619041A - Method and apparatus for transferring a tensioned mooring line from a winch to a deck fixture, e.g. in mediterranean mooring

Info

Publication number: GB2619041A
Application number: GB2207654.1A
Authority: GB
Inventors: Brown Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-05-25
Filing date: 2022-05-25
Publication date: 2023-11-29
Also published as: GB202207654D0

Abstract

A mooring line 8 is transferred from a winch 4, 5 to a deck fixture 6 by applying a portable clamp 20 to the tensioned mooring line and connecting the clamp to the deck fixture via a tether 10. Then, the mooring line is released from the winch so that the tension force is restrained by the clamp and tether. Then, the inboard end of the mooring line is connected to the deck fixture before releasing the tether and removing the clamp. The clamp includes first and second parts (21, 22, Fig 10) that are moveable from a clamping position to an open position to receive the mooring line without passing an end of the mooring line through the clamp.

Description

Method and apparatus for transferring a tensioned mooring line from a winch to a deck fixture, e.g. in Mediterranean mooring This invention relates to procedures for mooring a floating vessel such as a boat or a ship to a mooring line, and particularly to procedures for transferring the mooring line under tension from a winch to a fixture (e.g. a cleat or bitts) on the deck of the vessel. Such procedures are used in so-called Mediterranean mooring of large private yachts in marinas where the mooring line is connected to a fixed anchor point on the seabed.

In such procedures, the slack mooring line is brought on board the vessel, typically by passing it though a mooring chock or fairlead onto the deck of the vessel, and then wrapped around a winch drum. The winch is operated to draw in and tension the mooring line so that the mooring line can restrain the vessel against wind, wave and tide forces.

The tension force is reacted between the fixed anchor point and the buoyancy of the vessel and so depends on the size of the vessel. The mooring lines of vessels with an overall length greater than about 15m or 20m can carry large tension forces, up to tens or even hundreds of tonnes for ships.

In Mediterranean mooring in marinas and the like where fixed mooring lines are provided, the vessel is moored with the stern to the dock and the bow pointing out to sea. Vessels such as private yachts in excess of about 15m or 20m overall length are often moored in this way using a mooring line that is attached at one end to an anchor point (e.g. a concrete block or fixed chains) on the seabed. The other end of the mooring line is attached via a smaller diameter, so-called lazy line to the dock, so that the lazy line extends down the wall of the dock to the seabed and then out along the seabed to the mooring line. In such arrangements the mooring line is referred to as a ground line, or sometimes as a slime line since, in use, it will be saturated and covered in ooze from the seabed.

Generally the mooring line will be a relatively large diameter, flexible line, usually of plastics fibres, e.g. ultra-high molecular weight polyethylene (UHMWPE), polypropylene, nylon or polyester, which may be twisted or braided. Nylon or polyester lines may be used for Mediterranean moorings where the line is required to sink to the bottom when not in use; UHMWPE may be used for ships' mooring lines which are required to float to avoid fouling the propeller. Fixed mooring lines in marinas for private yachts may be from around 14mm to 45mm in diameter. Mooring lines for smaller yachts are often around 15mm -16mm in diameter, up to about 35mm -45mm for large yachts.

In Mediterranean mooring the vessel is brought in to the dock stern first and secured to the dock with stern lines. The crew can then pick up the lazy line at the dock and carry it as a slack loop along the deck to the bow.

By way of example, Figs. 1-7 illustrate a prior art mooring procedure, wherein Fig. 1 shows the bow 2 of a floating vessel 1 having a mooring chock 3 for guiding a mooring line inboard to the drum 4 of a powered winch 4, 5 mounted on the deck of the vessel. A pair of bitts 6 is arranged close to the winch.

At the bow, the slack loop of lazy line 7 is brought inboard through a fixed guide such as a mooring chock 3 or fairlead, and then hauled in until the heavier mooring line 8 comes aboard (Fig. 2.) Then, as shown in Fig. 3, the mooring line 8 is wrapped around the drum 4 of the winch, and the winch gear 5 is operated to tension the outboard part of the mooring lines against the anchor point on the seabed (not shown.) In the figures, the tensioned part of the mooring line 8 is indicated with reference numeral 8', while the slack part of the mooring line 8, inboard of the tensioned part, is indicated by reference numeral 8".

The tensioned mooring line 8 must then be transferred from the winch drum 4 to a fixture of the vessel, typically a cleat or a pair of bitts 6 mounted on the deck. This provides a secure attachment of the mooring line 8 that will remain in place until the vessel 1 leaves its mooring, and frees up the winch drum 4 for tensioning other mooring lines or other operations.

A cleat means a fixture having a pair of oppositely directed horns. Often the cleat will be fixed to a horizontal support surface, e.g. directly to the deck of the vessel, with the horns extending horizontally in opposite directions, although it can be fixed in other orientations.

A pair of bitts means a pair of posts arranged in spaced relation, usually standing up from the deck in parallel or slightly divergent orientation.

Referring again to Fig. 3, the slack, inboard parts" of the mooring line 8 can be secured to the cleat or bitts 6 by wrapping multiple turns of the line 8 about the horns or posts, e.g. in a figure-of-eight pattern, which holds securely and can be controllably released under tension. However, a special procedure is required to maintain the tension generated by the winch 4,5 in the tensioned leg 8' of the mooring line 8 (i.e. that part that extends from the winch drum 4, outboard via the mooring chock 3 or fairlead to the anchor point) while transferring the mooring line 8 from the winch drum 4 to the deck fixture 6, so that the deck fixture 6 can take up the tension.

Referring now to Fig. 4, for this purpose, another line 10, of high strength but usually smaller diameter than the mooring line 8, is first secured to the fixture 6 or to a ring (not shown) sometimes provided for that purpose at the base of the fixture. This smaller line 10 is sometimes referred to as a stopper line or simply a stopper, and in this specification, will be referred to as a tether. Often the tether 10 is made from UHMWPE.

The tether 10 may be secured to the fixture 6 by passing it around the fixture or through the ring, or by tying it at one end to the fixture 6 or the ring. The or each free end of the tether 10 is then secured to the tensioned leg 8' of the mooring line 8 by means of a specialised, elongate hitch or lashing 11 -for example, a so-called rat-tail stopper or cross lashing -as shown in Fig. 4.

Similar hitches are known in climbing, caving, arboriculture and like pursuits, for use in tying on to a vertical rope while ascending or descending, for which purpose also clamping devices or rope grips often referred to as ascenders or descenders may be used. These arrangements generally differ from the tether presently described in that, whereas ascenders and descenders and their analogues in looped cords or straps are required to be moveable along the supporting rope as the user ascends or descends, the tether 10 presently described for use during the mooring of a vessel is required to hold fast without moving.

In addition to ascenders or rope grips for use in climbing and the like, various rope clamping devices are known in the art, as taught by, for example: W02005077749 Al; US2607094 A; W02018039367 Al; FR1338789 A; DE3731383 Al; and EP0878391 A2.

Referring again to the mooring operation, as shown in Fig. 4, the tether 10 is tensioned as much as possible while securing it to the tensioned leg 8' of the mooring line 8 so that, when the mooring line 8 is released from the winch drum 4, the tension force will be transferred to the tether 10 with as little movement or relaxation as possible, as shown in Fig. 5.

In vessels more than about 15m or 20m in length, the tension force in the mooring line 8 can be sufficient to cause severe injury or even fatality if it is released suddenly. Thus, it is critically important that the hitch or lashing 11 is executed correctly.

Once the tether 10 is secured by the hitch or lashing 11 between the fixture 6 and the tensioned leg 8' of the mooring line 8, the portion of the tensioned leg 8' of the mooring line inboard of the hitch or lashing 11 is released from the winch drum 4 as shown in Fig. 5. As the inboard portion of the tensioned leg 8' of the mooring line comes off the winch drum 4 it relaxes, transferring the tension force from the tensioned leg 8 of the mooring line to the tether 10 and, via the tether 10, to the fixture 6. The hitch or lashing 11 tightens as the tether 10 takes up the load from the tensioned leg 8' of the mooring line, and if properly executed, restrains the tensioned leg 8' of the mooring line so that the tension force does not relax.

Referring now to Fig. 6, the slack portion 8" of the mooring line inboard of the hitch or lashing 11, which has been released from the winch drum 4, is now transferred to the fixture 6, typically by wrapping it in multiple turns around the bitts 6 or the horns of the cleat, e.g. in a figure-of-eight pattern as illustrated and previously described. Again, this slack, inboard leg 8" of the mooring line is tensioned as much as possible during this operation so that it will take up the tension force with as little extension as possible when the tether 10 is released.

Referring now to Fig. 7, in the final step of the mooring procedure, the tether 10 is released, transferring the tension force from the tensioned leg 8' of the mooring line to its previously slack inboard portion 8" which has been tied off to the fixture 8 and now tightens and elongates as it takes up the load. The tensioned leg 8' of the mooring lines now extends in tension all the way from the anchor point to the fixture 6, and will remain in this position until the vessel 1 is ready to leave the mooring.

When the vessel 1 is ready to leave, the slack, inboard end 8" of the mooring line (i.e. that portion inboard of the fixture 6) will be released from the fixture 6, turn by turn, until the mooring line 8 begins to slip around the fixture 6 and so relieve the tension force in the tensioned mid-portion 8'. Once the tension force is completely relieved, the now entirely slack mooring line 8 can be finally released from the fixture 6 (Fig. 2) and allowed to slip back overboard.

It will be understood that in the Mediterranean mooring procedure, or indeed in mooring more generally where a lazy line 7 or the like is provided for convenience in picking up a fixed mooring line 8, the lazy line 7 may remain attached to the inboard end of the mooring line 8 during the whole mooring procedure, and also after finally securing the mooring line 8 to the fixture 6, so that the tensioned leg 8' of the mooring line 8 and the slack lazy line 7 extend side by side overboard the vessel 1, as illustrated, and are released together as a loop when the vessel 1 eventually leaves harbour. Alternatively, the mooring line 8 may terminate at a free inboard end. Alternatively, the mooring lines may be continuous to the dock or other retrieval point, so that a single line serves both as mooring line and as lazy line. In each case the procedure for tensioning and transferring the mooring lines is the same.

Referring again to the final step of the mooring procedure, representing the transition from Fig. 6 to Fig. 7, it is not always straightforward to release the tether 10 under tension from between the fixture 6 and the tensioned legs' of the mooring line. This can be done by releasing the final knot that holds the elongate hitch or lashing 11 to the mooring line 8, allowing the hitch or lashing 11 to relax as the mooring line 8 extends; then, once the tether 10 is slack, it can be released from the fixture 6. Or, the tether 10 can be released first from the fixture 6 and then from the mooring line 8. In either case however, the tether 10 must be released while still carrying the full tension force of the mooring line 8. Moreover, the turns of the mooring line swill often overlie the tether 10 on the fixture 6. Tension and inaccessibility can make it difficult to manipulate the securing knot in the tether 10. Relaxation of the tension force in the tether 10 and extension of the previously slack, inboard portion of the mooring lines as it takes up the load to the fixture 6 can result in sudden movement between the tether 10 and the mooring line 8. If the crew member untying the tether 10 allows their fingers to become entrapped between the moving lines, severe injury can result.

It is a general object of the present invention to provide a more convenient way for carrying out the above mentioned special procedure for transferring the mooring lines from the winch drum 4 to the deck fixture 6.

Accordingly the present invention provides, in a first aspect, a method of mooring a floating vessel to a mooring line; and, in a second aspect, an apparatus for use in the method; as defined, respectively, in the independent claims. The dependent claims define optional features.

The novel method includes providing a portable clamp and a tether, and connecting the tether between the clamp and a fixture of the vessel. The clamp has first and second parts moveable between an open position and a clamping position, wherein a mooring line receiving space is defined between the first and second parts.

The method further includes: passing an inboard portion of the mooring line around a winch on board the vessel and operating the winch to generate a tension force in a tensioned mid-portion of the mooring line. And then, in the open position of the first and second parts, arranging the clamp around the tensioned mid-portion of the mooring line by introducing the tensioned mid-portion of the mooring line into the mooring line receiving space between the first and second parts without passing an end of the mooring line through the clamp. And then, moving the first and second parts from the open position to the clamping position to clamp said tensioned mid-portion to extend through the mooring line receiving space between the first and second parts. And then, releasing the inboard portion of the mooring line from the winch to transfer the tension force from the tensioned mid-portion of the mooring line, via the clamp and the tether, to the fixture of the vessel. And then, connecting the inboard portion of the mooring line to the fixture of the vessel. And then, releasing the tether to transfer the tension force from the tensioned mid-portion of the mooring line, via the inboard portion of the mooring line, to the fixture of the vessel. And then, moving the first and second parts of the clamp to the open position and removing the clamp from the mooring line.

The novel apparatus includes a portable clamp having first and second parts moveable between an open position and a clamping position, wherein a mooring line receiving space is defined between the first and second parts, wherein in the clamping position the mooring line receiving space extends along a mooring line axis.

In the open position, the mooring line receiving space is partially unbounded when considered in a plane normal to the mooring line axis, so that a tensioned mid-portion of a mooring line may be introduced into the mooring line receiving space between the first and second parts without passing an end of the mooring line through the clamp.

The first and second parts are moveable from the open position to the clamping position to clamp said tensioned mid-portion to extend along the mooring line axis through the mooring line receiving space between the first and second parts.

The clamp further includes at least one tether connector, which is configured to connect a tether to the clamp, in the clamping position of the first and second parts, to transfer a tension force from the mooring line via the clamp and the tether to a fixture of the vessel.

Further features and advantages will become apparent from the illustrative embodiments which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which: Fig.1 shows the bow deck of a floating vessel.

Figs. 2 -7 illustrate a prior art mooring procedure performed on the deck of Fig. 1 as previously described.

Figs. 8 and 9 illustrate a portable clamp in accordance with an embodiment of the invention, showing the first and second parts in the clamping position.

Fig. 10 shows the clamp with the first and second parts in the open position.

Figs. 11 and 12 are end views of the clamp showing the first and second parts, respectively in the open position (Fig. 11) and the clamping position (Fig. 12).

Fig. 13 is a side view of the clamp showing the first and second parts in the clamping position.

Fig. 14 corresponds to Fig. 13, showing how the second end portion of the tether is connected to the second connector and engaged with both of the first and second parts of the clamp which constrain the tether to a sinuous path.

Fig. 15 corresponds to Fig. 14, showing how the first end portion of the tether is also connected to the clamp via multiple turns about the first tether connector.

Fig. 16 shows how the clamp is applied to the tensioned mid-portion of the mooring line as shown in Fig. 3, and the tether pre-tensioned against the fixture 6.

Fig. 17 shows how the pre-tensioned tether is tied off with multiple turns about the first tether connector.

Fig. 18 shows how the mooring line 8 is released from the winch drum 4 to transfer the tension force via the clamp and the tether to the fixture 6.

Fig. 19 shows how the slack, inboard portion 8" of the mooring line is secured to the fixture 6.

Fig. 20 shows how the tether is released to transfer the tension force via the mooring line 8 directly to the fixture 6.

Reference numerals and characters that appear in more than one of the figures indicate the same or corresponding parts in each of them.

Referring to Figs. 8-15, in the illustrated embodiment, the portable clamp 20 has first and second parts 21, 22 which are moveable (one relative to the other) between an open position (Fig. 10, Fig. 11) and a clamping position (Figs. 8 -9 and 12-15.) A mooring line receiving space 23 is defined between the first and second parts 21, 22, which extends in the clamping position along a mooring line axis Xl.

In the open position, the mooring line receiving space 23 is partially unbounded when considered in a plane P1 normal to the mooring line axis X1, defining an opening 24 through which a tensioned mid-portion 8' of the mooring line 8 may be introduced into the mooring line receiving space 23, between the first and second parts 21, 22, without passing an end of the mooring line 8 through the clamp 20.

The first and second parts 21,22 are moveable (one relative to the other) from the open position to the clamping position to clamp the tensioned mid-portion 8' of the mooring line so that it extends along the mooring line axis X1, through the mooring line receiving space 23 between the first and second parts 21, 22.

As best seen in Fig. 12, the first and second parts 21, 22 may be configured to enclose, together, the mooring line receiving space 23 in the clamping position, when considered as projected onto a plane P1 normal to the mooring line axis X1.

The clamp 20 further includes at least one tether connector 25, 26. The or each tether connector is configured to connect the tether 10 to the clamp 20, in the clamping position of the first and second parts 21, 22, to transfer a tension force from the mooring line 8 via the clamp 20 and the tether 10 to the fixture 6 of the vessel 1.

The tether 10 may include or consist of a single, flexible line of natural or plastics fibres, e.g. UHMWPE, which preferably is pliable enough to be pre-tensioned and then secured by hand to the clamp. The line 10 has a mid-portion between opposite end portions 10), 10".

The novel clamp may be supplied with the tether 10, or the user may obtain the tether, e.g. as a length cut from a reel of suitable line, and then fit the tether 10 to the clamp. In either case, the tether 10 is connected or connectable to the at least one tether connector 25, 26 to transfer the tension force from the mooring line 8, in the clamping position of the first and second parts 21, 22, via the clamp 20 to the fixture 6 of the vessel 1.

The at least one tether connector may include at least one projection 27 that is configured to receive multiple turns of the tether 10 (e.g. multiple turns of said single, flexible line). This makes it possible to secure a first end of the tether 10 to the first tether connector 25 without passing an end of the tether 10 through the first tether connector 25.

Preferably, as illustrated, the at least one tether connector includes first and second tether connectors 25, 26, wherein in use, the tether 10 is connected or connectable to each of the first and second tether connectors 25, 26, with the at least one projection formed on the first tether connector 25. The second tether connector 26 may be configured as a ring to receive a second end of the tether 10. The second end of the tether can be connected to transfer the tension force to the second tether connector 26, for example, by tying a stopper knot 12 as illustrated.

As illustrated, the at least one projection may include a pair of horns 27 which preferably are oppositely directed, forming a cleat to which the tether 10 can be secured by multiple turns in a figure-of-eight pattern as shown in Fig. 15.

Fig. 16 illustrates how a mid-portion of the tether 10 (e.g. of said single, flexible line), in-between its opposite, first and second end portions, may be secured in use to the fixture 6 of the vessel, e.g. by taking a half-turn or a full turn around the fixture 6. The first and second end portions 10, 10" of the tether 10 are connected, respectively to the first and second tether connector 25, 26. This arrangement can provide some mechanical advantage that helps in pre-tensioning the tether, and also ensures that the tension force is balanced between the two legs of the tether 10.

As illustrated, the pair of horns 27 may extend respectively in opposite directions of the mooring line axis X1 in the clamping position of the first and second parts 21, 22. This provides a convenient way to strain the free end of the tether 10, by pulling it over one of the horns pointing away from the fixture 6, so as to pre-tension the tether 10 against the fixture 6 as shown in Fig. 16. The user may also pull sideways on the mid-point of the tensioned part of the tether 10 leading to the horns 27, so as to generate further pre-tension using the mechanical advantage provided by the turn around the fixture 6, before securing the first end portion 10' of the tether 10 under tension with multiple turns around the horns 27.

As best seen in Fig. 12, the first and second tether connectors 25, 26 may be spaced apart angularly about the mooring line axis X1 in the clamping position of the first and second parts 21, 22. Optionally, the clamp may be configured so that the first and second tether connectors are arranged on opposite sides of the mooring line axis X1 in the clamping position of the first and second parts.

Further as illustrated, the first and second tether connectors 25, 26 may be arranged respectively on the first and second parts 21, 22 of the clamp.

These arrangements of the first and second tether connectors 25, 26 help to ensure that, when the tether 10 is carring the tension force from the mooring line 8, the central axis of the tensioned leg 8' of the mooring line will extend in a plane (P2, Fig. 18) that passes (at least proximate the clamp) between the two legs 10', 10" of the tether 10.

As illustrated, the first part 21 may be pivotably connected to the second part 22 at a pivot axis X2, so that the first and second parts 21, 22 are pivotably openable and closeable about the pivot axis X2 between the open position and the clamping position. The pivot axis X2 may be defined by a pin 28 that connects the first and second parts 21, 22 together.

As illustrated, the pivot axis X2 may be parallel with the mooring line axis X1 in the clamping position of the first and second parts 21, 22. The parallel orientation of the pivot axis X2 ensures that the tension force in the mooring line 8 will not cause the clamp 20 to become permanently jammed on the mooring line 8, so that it can be removed easily once the tether 10 is released.

As illustrated, at least one, and preferably each of the first and second parts 21, 22 may include an array of projections 29 which project inwardly into the mooring line receiving space 23 to grip the mooring line 8 in the clamping position of the first and second parts 21, 22. The projections 29 may be pointed, for example, in the form of tapering spikes, so that they engage easily between the strands of the mooring line 8.

Each of the first and second parts 21,22 may be made from a metal, e.g. aluminium or aluminium alloy, which may be hard anodized, or stainless steel, optionally as a unitary moulding (i.e. casting). The projections may be formed integrally with the respective part or as separate inserts, e.g. threaded stainless steel inserts, each of which may be screwed into a threaded hole in the respective part 21 or 22.

In Mediterranean mooring using a ground line, the ground line 8 lies slack on the bottom when not in use, and so, when it is brought onto the deck, it will be saturated with water and usually also slimy with mud. In these conditions the projections 29 will engage readily between the strands which tend to open up when wet. Advantageously, the novel clamp is operable to clamp mooring lines made from relatively slippery fibres which can be difficult to secure using the conventional method.

The clamping position is variable depending on the diameter of the mooring line 8. The clamp 20 may be configured to clamp a mooring line 8 having a maximum diameter of at least 45mm in the mooring line receiving space 23. Each of the first and second parts 21, 22 may extend with a length of at least 135mm along the mooring line axis X1, so that the mooring line receiving space 23 contains at least about three times the maximum diameter of the mooring line 8. This distributes the applied force so as to ensure a secure connection without damaging the mooring line.

Preferably, the clamp 20 is configured to clamp a mooring line 8 having any diameter in a range from 14mm to 45mm in the mooring line receiving space 23.

In tests, the illustrated clamp is found to clamp any mooring line with a diameter from as little as 8mm up to as much as 50mm in the mooring line receiving space 23.

The tether 10 may be arranged to engage (e.g. by direct contact with, or via a clamping mechanism) each of the first and second parts 21, 22, to transfer the tension force to each of the first and second parts 21, 22, to urge the first and second parts 21, 22 to the clamping position.

For this purpose, the first and second parts 21, 22 may be configured, when the tether 10 is connected to the clamp 20, to constrain the tether 10 to follow a sinuous path S. The first and second parts 21, 22 are moveable to the clamping position by the tether 10, by straightening of the sinuous paths responsive to the tension force acting through the tether 10.

For this purpose, the second part 22 may be provided with a second guide 30, which may be configured as a ring, and the first part 21 with a first guide 31, which may be configured as a hook.

As illustrated, the second guide 30 may be axially aligned with the second tether connector 26 along an alignment axis X3 parallel with the mooring line axis Xl. The first guide or hook 31 may be arranged, in the clamping position, axially in-between (and preferably axially equidistant from) the second tether connector 26 and the second guide 30, but spaced apart angularly about the mooring line axis X1 from the alignment axis X3 in the clamping position. (By "axially in-between" is meant that the position of the first guide 31, when considered along the alignment axis X3, is in-between the second tether connector 26 and the second guide 30, although the first guide 31 is acollinear with, i.e. offset laterally from, the alignment axis X3.) The sinuous path S extends between the second tether connector 26 and the second guide 30 via the first guide 31.

In use, the second end portion 10" of the tether is passed through the second guide 30 and then connected to the second tether connector 26. When the clamp 20 is closed, the part of the second end portion 10" of the tether between the second tether connector 26 and the second guide 30 is pulled laterally away from the alignment axis X3 and engaged around the first guide or hook 31 to define the sinuous paths. Then, when the tension force is transferred from the mooring line 8 to the tether 10, the tether 10 slips through the second guide 30 and straightens, pulling the first guide or hook 31 back towards the alignment axis X3 and so urging the first and second parts 21, 22 together to the clamping position.

As illustrated, a recess 32 may be formed in the second part 22, wherein the first guide or hook 31 is receivable in the recess 32 in the clamping position.

The recess 32 makes it possible to move the first and second parts 21, 22 very close together so as to clamp mooring lines of very small diameter.

Embodiments of the novel method will now be described with reference to Figs. 3, 7, and 16 -20.

The floating vessel 1 is moored to a mooring line by providing a portable clamp as previously described (e.g. clamp 20 as illustrated), and connecting a tether 10 between the clamp 20 and a fixture 6 of the vessel 1. Optionally, as described above, a second end portion 10" of the tether may be connected to the clamp 20 before passing the tether 10 around the fixture 6 and then hauling the first end portion 10' tight.

The mooring operation begins in the conventional way by passing an inboard portion of the mooring line 8 around the drum 4 of a winch 4,5 on board the vessel 1, and operating the winch 4, 5 to generate a tension force in a tensioned mid-portion 8 of the mooring line (Fig. 3).

The mooring line will pass onboard the vessel 1 via a mooring chock 3 or fairlead, and on some vessels may pass around further fairleads (not shown) on its path to the winch 4,5.

Then, in the open position of the first and second parts 21, 22 (Fig. 10, Fig. 11), the clamp 20 is arranged around the tensioned mid-portions' of the mooring line by introducing the tensioned mid-portion 8' of the mooring line via the opening 24, into the mooring line receiving space 23 between the first and second parts 21, 22 without passing an end of the mooring line 8 through the clamp 20.

Then, the first and second parts 21, 22 are moved from the open position to the clamping position to clamp the tensioned mid-portion 8' of the mooring line to extend through the mooring line receiving space 23 between the first and second parts 21, 22.

Optionally, connecting the tether 10 between the clamp 20 and the fixture 6 of the vessel may include pre-tensioning the tether, e.g. by hauling on the first end portion 10' as previously described (Fig. 16).

Optionally, before pre-tensioning the tether, the second end portion 10" of the tether may be connected to the second tether connector 26, and the mid-portion of the tether may be secured to the fixture 6 of the vessel.

Optionally, before pre-tensioning the tether, the tether may be arranged in a sinuous path between the second tether connector 26 and the first and second guides 31, 30 formed respectively on the first and second parts 21, 22, before straightening the sinuous path 5, by said pre-tensioning the tether 10, to move the first and second parts 21, 22 from the open position to the clamping position.

After pre-tensioning the tether, the first end portion 10' of the tether may be connected to the first tether connector 25 by wrapping multiple turns of the first end portion 10' of the tether about the first tether connector 25 without passing an end of the tether 10 through the first tether connector 25 (Fig. 17, Fig. 15).

Then, after clamping the mooring lines in the clamp 20 and optionally also pre-tensioning the tether 10, the inboard portion 8" of the mooring line is released from the winch 4, 5 to transfer the tension force from the tensioned mid-portion 8' of the mooring line, via the clamp 20 and the tether 10, to the fixture 6 of the vessel (Fig. 18). The mooring line 8 is now restrained under tension by the clamp 20 and the tether 10 arranged in series between the mooring line 8 and the fixture 6.

Then, the inboard portion 8" of the mooring line is connected to the fixture 6 of the vessel, e.g. by taking multiple turns in a figure-of-eight pattern around the bitts 6 as shown in Fig. 19.

Then, the tether 10 is released to transfer the tension force from the tensioned mid-portion 8' of the mooring line to the fixture 6 of the vessel via the previously slack, inboard portion 8" of the mooring line, which straightens as it takes up the load. As illustrated, the tether may be released by loosening the turns of its first end portion 10' so that it slips controllably from the first tether connector 25 (Fig. 20).

Finally, the first and second parts 21,22 of the clamp are moved to the open position and the clamp 20 is removed from the mooring line 8, leaving the mooring line 8 under tension between the fixture 6 and the anchor point as shown in Fig. 7.

In order to preserve the tension force in the mooring line 8 while it is transferred from the winch drum 4 to the deck fixture 6, it is desirable to arrange the deck fixture 6 as far as possible in line with the axis of the tensioned leg 8' of the mooring line between the winch drum 4 and the first mooring chock 3 or fairlead which guides the mooring line 8 immediately outboard of the winch, and to minimise lateral displacement of the mooring line 8 during the mooring operation.

Advantageously, arranging for the central axis of the tensioned leg 8' of the mooring line to extend in a plane P2 (Fig. 18) that passes (at least proximate the clamp 20) between the two legs 10, 10" of the tether 10 provides that the clamp 20 will remain in axial alignment with the tensioned leg 8' of the mooring line, so that the forces reacted by the clamp 20 are balanced across the mooring line.

This ensures that the clamp 20 does not apply torque or moment to the mooring line 8 which could upset its stranded structure. It also ensures that the tensioned leg 8' of the mooring line will move as little as possible off its axis (depending on the relative positions of the winch drum 4, the fixture 6, and the mooring chock 3 or fairlead) as the tether 10 is released, so that relaxation of the tension force is minimised.

Securing both end portions of the tether 10 to the clamp 20 allows the tether to be secured to the deck fixture 6 by a half turn, so it can be easily released by pulling it out from beneath the multiple turns of the mooring lines after tying off the mooring line 8 to the deck fixture 6.

Advantageously, by arranging for the tether 10 to apply a clamping force to close the first and second parts together -e.g. by arranging it as shown in a sinuous path S -and by also configuring the first tether connector 25 with one or more projections, preferably as a horned cleat, it is possible to apply the clamping force by hauling the tether 10 around the deck fixture 6 and the first tether connector 25 to pre-tension it before securing it with multiple turns around the horns.

The configuration of the first tether connector 25 also allows the tether 10 to be released quickly and controllably from a safe distance in case of an emergency while mooring. Once the mooring line 8 has been secured to the fixture 6, the user can hold the free end 10 of the tether while removing most of its turns from the first tether connector 25. Then, standing clear of the clamp 20 and the mooring lines, the user can allow that the final turn or turns of the tether 10 to slip around the first tether connector 25, to quickly but controllably relieve the tension in the tether 10.

Further advantageously, the arrangement of the pivot axis X2 in parallel with the mooring line axis Xl, in combination with the arrangement (e.g. the sinuous paths) whereby the tether 10 applies a clamping force to close the first and second parts 21,22 together, allows the clamp 20 to open to release its grip on the mooring line 8 when the tension is relieved from the tether 10. This provides for safe operation, since the mooring line Scan then slip freely through the clamp 20 once the tension is relieved from the tether 10. So, if the mooring line 8 should snap or the deck fixture 6 should fail, the user can stand clear of the clamp 20, safely out of the snap-back zone, while the tensioned mooring line 8 runs out through the opened clamp 20 and the mooring chock 3 or fairlead until the force is dissipated.

The novel clamp is portable in the sense of hand-portable, so that the novel clamp may be carried on and off the vessel, stored away in any convenient place on the vessel, and then brought out and carried to where it is to be used, e.g. on a work deck at the bow 2 or the stern of the vessel 1.

Since the novel clamp is portable and not fixed to the vessel 1, it can be moved and applied in any selected position on the tensioned leg 8' of the mooring line while the mooring line is under tension, and then will move with the mooring line as the tension transfers from the winch drum 4 to the tether 10. This allows the tether 10 to align with the axis of the tensioned leg 8' of the mooring line as the tension force is reacted through the tether 10 and the tensioned leg 8' of the mooring line, ensuring minimal relaxation of the tension force when the tether 10 is released.

Of course, portability also allows the clamp to be used on any vessel.

In summary, a mooring line is transferred from a winch to a deck fixture by applying a portable clamp to the tensioned mooring line and connecting the clamp to the deck fixture via a tether. Then, the mooring line is released from the winch so that the tension force is restrained by the clamp and tether. Then, the inboard end of the mooring line is connected to the deck fixture before releasing the tether and removing the clamp. The clamp includes first and second parts that are moveable from a clamping position to an open position to receive the mooring line without passing an end of the mooring line through the clamp.

The clamp may be used for mooring to any tensioned mooring line, whether anchored on the seabed or fixed to any other anchor point.

In alternative embodiments, the clamp 20 may include a clasp or other closure element for urging the first and second parts 21, 22 to the clamping position and releasably securing them in that position. The closure element could have for example a screw connection or an over-centre mechanism. For example, the closure element could be mounted on one of the first and second parts and operable to releasably engage the other one of the first and second parts, e.g. by means of a hook or abutment, before tightening the closure element to draw the first and second parts 21, 22 together.

In the illustrated embodiment, the clamp 20 is configured as an elongate sleeve having a generally cylindrical form factor, divided axially into two cooperating parts 21, 22 which are hinged together at a pivot axis X2 parallel with the mooring line axis X1. The parts are moveable together to the clamping position, which is variable to accommodate mooring lines of different diameters. The two parts 21, 22 have concave, cylindrically radiused, inwardly facing surfaces on which the projections 29 are formed, defining between them the mooring line receiving space 23, each of the internal surfaces being radiused about a line that extends in parallel with the mooring line axis X1. As illustrated, the clamp may be symmetric about the plane P1 when defined mid-way between its axial ends, so that the functions of the second tether connector 26 and the second guide 30 may be interchangeable depending on which way round the clamp 20 is applied to the mooring line 8.

In alternative embodiments, instead of arranging the first tether connector 25 on the first part 21, the first tether connector 25 might be arranged together with the second tether connector 26 and the second guide 30 on the second part 22, with the first guide 31 being formed on the first part 21 as illustrated.

In less preferred embodiments, the sinuous path S could be provided as described above, but without providing a first tether connector 25, or with a first tether connector formed without a projection or projections, i.e. other than as a horned cleat.

In yet further embodiments, the or each tether connector could include a clamping mechanism (e.g. a pivoted linkage) for applying a clamping force to urge the first and second parts to the clamping position responsive to tension in the tether 10.

In yet further embodiments, the clamp may be configured generally other than as illustrated.

For example, in further alternative embodiments, the clamp may include a frame on which the first and second parts are moveably mounted, e.g. slidably or pivotably mounted, for movement between the open and clamping positions. In such arrangements the at least one tether connector may be arranged on the frame, or first and second tether connectors may be arranged respectively on the first and second parts. The first and second tether connectors may be configured to apply the tension force from the tether (e.g. from the single, flexible line) when it is connected to each of the first and second tether connectors, to each of the first and second parts of the clamp, to urge the first and second parts to the clamping position.

The first and second parts may be formed as sliding or rotating parts, e.g. wedges or cams. Rotating parts may have a curved face (e.g. with a logarithmic curve or any other suitable shape as known in the art) for engaging the mooring line, the face extending progressively further from the pivot axis as the cam rotates responsive to the tension force to accommodate mooring lines of different diameters, so that the tension force acts on the first and second parts to urge them towards the clamping position.

The curved faces of the first and second parts (optionally also the entirety of the first and second parts) may be mirror-symmetric about a plane containing the mooring line axis in the clamping position.

Alternatively, the first part may have a recess which receives a portion of the second part in the clamping position, the mooring line receiving space being defined within the recess so that the first and second parts enclose, together, the mooring line receiving space in the clamping position, when considered in a plane normal to the mooring line axis.

Alternatively, a third part may cooperate with the first and second parts to enclose, together, the mooring line receiving space in the clamping position. The first and second parts may be slidably or pivotably mounted on the third part.

In these and other alternative embodiments, the first and second parts may be moveable between the open and clamping positions about a pivot axis or axes that is or are non-parallel with the mooring line axis in the clamping position. For example, the or each pivot axis may be normal to a plane containing the mooring line axis, wherein the pivot axis either intersects the mooring line axis or is offset from (i.e. does not intersect) the mooring line axis.

Many further adaptations are possible.

In the claims, reference numerals and characters are provided in parentheses, purely for ease of reference, and are not to be construed as limiting features.

Claims

CLAIMS1. A method of mooring a floating vessel (1) to a mooring line (8), including: providing a portable clamp (20) and a tether (10), and connecting the tether (10) between the clamp (20) and a fixture (6) of the vessel; the clamp (20) having first and second parts (21, 22) moveable between an open position and a clamping position, wherein a mooring line receiving space (23) is defined between the first and second parts (21, 22); the method further including: passing an inboard portion (8") of the mooring line around a winch (4, 5) on board the vessel and operating the winch (4,5) to generate a tension force in a tensioned mid-portion of the mooring line; and then, in the open position of the first and second parts (21, 22), arranging the clamp (20) around the tensioned mid-portion (8') of the mooring line (8) by introducing the tensioned mid-portion (8') of the mooring line into the mooring line receiving space (23) between the first and second parts (21, 22) without passing an end of the mooring line through the clamp (20); and then moving the first and second parts (21, 22) from the open position to the clamping position to clamp said tensioned mid-portion (8') to extend through the mooring line receiving space (23) between the first and second parts (21, 22); and then releasing the inboard portion (8") of the mooring line from the winch (4, 5) to transfer the tension force from the tensioned mid-portion (8') of the mooring line, via the clamp (20) and the tether (10), to the fixture (6) of the vessel; and then connecting the inboard portion (8") of the mooring line to the fixture (6) of the vessel; and then releasing the tether (10) to transfer the tension force from the tensioned mid-portion (8') of the mooring line, via the inboard portion (8") of the mooring line, to the fixture (6) of the vessel; and then moving the first and second parts (21, 22) of the clamp (20) to the open position and removing the clamp (20) from the mooring line (8).
2. A method according to claim 1, wherein the clamp (20) includes a first tether connector (25), and connecting the tether (10) between the clamp (20) and a fixture (6) of the vessel includes: pre-tensioning the tether (10), and then connecting a first end portion (10') of the tether to the first tether connector (25) by wrapping multiple turns of the first end portion (10') of the tether about the first tether connector (25) without passing an end of the tether (10) through the first tether connector (25).
3. A method according to claim 1, wherein the clamp (20) includes first and second said tether connectors (26, 26), and the tether (10) has a mid-portion between opposite, first and second end portions (10', 10"); and connecting the tether (10) between the clamp (20) and a fixture (6) of the vessel includes: connecting the second end portion (10") of the tether to the second tether connector (26), and securing the mid-portion of the tether (10) to the fixture (6) of the vessel; and then pre-tensioning the tether (10); and then connecting the first end portion (10') of the tether to the first tether connector (25) by wrapping multiple turns of the first end portion (10') of the tether about the first tether connector (25) without passing an end of the tether (10) through the first tether connector (25).
4. A method according to claim 3, including: arranging the tether (10) in a sinuous path (5) between the second tether connector (26) and first and second guides (31, 30) formed respectively on the first and second parts (21, 22); and then straightening the sinuous path (5), by said pre-tensioning the tether (10), to move the first and second parts (21, 22) from the open position to the clamping position.
5. An apparatus for use in the method of claim 1, including: a portable clamp (20) having first and second parts (21, 22) moveable between an open position and a clamping position, wherein a mooring line receiving space (23) is defined between the first and second parts (21, 22), wherein in the clamping position the mooring line receiving space (23) extends along a mooring line axis (X1); wherein, in the open position, the mooring line receiving space (23) is partially unbounded when considered in a plane (P1) normal to the mooring line axis (X1), so that a tensioned mid-portion (8') of a mooring line (8) may be introduced into the mooring line receiving space (23) between the first and second parts (21, 22) without passing an end of the mooring line (8) through the clamp (20); the first and second parts (21, 22) being moveable from the open position to the clamping position to clamp said tensioned mid-portion (8') to extend along the mooring line axis (X1) through the mooring line receiving space (23) between the first and second parts (21, 22); the clamp (20) further including at least one tether connector (25, 26), the at least one tether connector (25, 26) being configured to connect a tether (10) to the clamp (20), in the clamping position of the first and second parts (21, 22), to transfer a tension force from the mooring line (8) via the clamp (20) and the tether (10) to a fixture (6) of the vessel.
6. An apparatus according to claim 5, wherein the at least one tether connector includes a first tether connector (25), the first tether connector (25) including at least one projection (27) configured to receive multiple turns of the tether (10), to secure the tether (10) to the first tether connector (25), without passing an end of the tether (10) through the first tether connector (25).
7. An apparatus according to claim 6, wherein the at least one projection includes a pair of horns (27).
8. An apparatus according to claim 7, wherein the pair of horns (27) extend respectively in opposite directions of the mooring line axis (X1) in the clamping position of the first and second parts (21, 22).
9. An apparatus according to claim 5 or claim 6, wherein the at least one tether connector includes first and second said tether connectors (25, 26), wherein in use, said tether (10) is connected or connectable to each of the first and second tether connectors (25, 26).
10. An apparatus according to claim 9, wherein the first and second tether connectors (25, 26) are spaced apart angularly about the mooring line axis (X1) in the clamping position of the first and second parts (21, 22).
11. An apparatus according to claim 5 or claim 6, wherein the first part (21) is pivotably connected to the second part (22) at a pivot axis (X2), the first and second parts (21, 22) being pivotably openable and closeable about the pivot axis (X2) between the open position and the clamping position.
12. An apparatus according to claim 11, wherein the pivot axis (X2) is parallel with the mooring line axis (X1) in the clamping position of the first and second parts (21, 22).
13. An apparatus according to claim 12, wherein the first and second parts (21, 22) are configured, when the tether (10) is connected to the clamp (20), to constrain the tether (10) to follow a sinuous path (5), wherein the first and second parts (21, 22) are moveable to the clamping position by the tether (10), by straightening of the sinuous path (S) responsive to the tension force acting through the tether (10).
14. An apparatus according to claim 13, wherein the at least one tether connector includes a second said tether connector (26) formed on the second part (22); the second part (22) further including a second guide (30); the first part (21) including a first guide (31); the second guide (30) being axially aligned with the second tether connector (26) along an alignment axis (X3) parallel with the mooring line axis (X1); the first guide (31) being arranged, in the clamping position, axially in-between the second tether connector (26) and the second guide (30) and spaced apart angularly about the mooring line axis (X1) from the alignment axis (X3); wherein the sinuous path (5) extends between the second tether connector (26) and the second guide (30) via the first guide (31).
15. An apparatus according to claim 14, wherein the first guide (31) is configured as a hook.
16. An apparatus according to claim 14, wherein a recess (32) is formed in the second part (22), wherein the first guide (31) is receivable in the recess (32) in the clamping position.
17. An apparatus according to any preceding claim, wherein at least one of the first and second parts (21, 22) includes an array of projections (29) projecting inwardly into the mooring line receiving space (23) to grip the mooring line (8) in the clamping position of the first and second parts (21, 22).
18. An apparatus according to any preceding claim, wherein the clamp (20) is configured to clamp a mooring line (8) having a maximum diameter of at least 45rnm in the mooring line receiving space (23).
19. An apparatus according to claim 18, wherein each of the first and second parts (21, 22) extends with a length of at least 135mm along the mooring line axis (X1).
20. An apparatus according to any preceding claim, wherein the clamp (20) is configured to clamp a mooring line (8) having any diameter in a range from 14mm to 45mm in the mooring line receiving space (23).
21. An apparatus according to any preceding claim, further including said tether (10), the tether being connected or connectable to the at least one tether connector (25, 26) to transfer said tension force from the mooring line (8), in the clamping position of the first and second parts (21, 22), via the clamp (20) to a fixture (6) of the vessel.
22. An apparatus according to claim 21, wherein the tether (10) includes or consists of a single, flexible line of natural or plastics fibres.