Mooring system and method

Abstract

It is an object of the present invention to provide a method for mooring a floating vessel having a fairlead stopper attached thereto. The method includes retrieving a line that is pre-secured on a fairlead stopper, connecting the line to an upper end of a mooring line, retrieving a second end of the line, connecting the second end to a winch of the AHV, and pulling on the mooring line to apply tension to the mooring line. Also disclosed are mooring lines and systems including the line having a tension connector, such as a triplate connector, for stretching the line.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 312,728, entitled "Mooring Systems and Methods," filed February 22, 2022, which is incorporated by reference in its entirety and forms part of this disclosure.

[0002] The present disclosure relates to methods, systems and apparatus for mooring vessels and tensioning mooring lines. [Background technology]

[0003] In many applications, such as offshore drilling platform applications, there is a need to moor floating vessels or structures. Mooring typically involves transporting the vessel and mooring structure to the site, tensioning, securing, cutting and storing the mooring lines. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 5,845,893 [Patent Document 2] U.S. Pat. No. 8,915,205 [Patent Document 3] U.S. Pat. No. 9,126,659 [Patent Document 4] US Patent Application Publication No. 2018 / 0086421 Summary of the Invention [Means for solving the problem]

[0005] The present disclosure includes a fairlead stopper including a housing assembly, a latch movably coupled to the housing assembly, a chain wheel rotatably coupled to the housing assembly, and at least one chain retaining arm coupled to the housing assembly. The at least one chain retaining arm is movable between an open position and a closed position. In the closed position, the at least one chain retaining arm is positioned to secure a mooring line passing through the fairlead stopper.

[0006] The present disclosure includes a method of handling a mooring line coupled to a fairlead stopper. The method includes providing a fairlead stopper having a housing assembly, a latch coupled to the housing assembly, a chain wheel coupled to the housing assembly, and at least one chain retaining arm coupled to the housing assembly. The method includes locking the mooring line with the latch. The mooring line extends from the latch to the chain wheel and beyond the chain wheel. The method includes moving the at least one chain retaining arm to a closed position such that the mooring line is secured between the at least one chain retaining arm and another portion of the fairlead stopper.

[0007] The present disclosure includes a marine vessel including a hull and a marine anchorage brace coupled to the hull, a fairlead stop coupled to the marine anchorage brace, the marine anchorage brace extending from the hull to position the fairlead at an angle relative to the hull.

[0008] The present disclosure includes a method of positioning a fairlead stopper relative to a vessel, the method including coupling a marine fixed brace to the vessel and coupling the fairlead stopper to the marine fixed brace, the marine fixed brace extending from the vessel to position the fairlead at an angle relative to the vessel.

[0009] The present disclosure includes a marine vessel. The marine vessel includes a hull and a wave reaction bar coupled to the hull. A fairlead stop is coupled to the wave reaction bar. The wave reaction bar reacts to forces applied to the fairlead stop.

[0010] The present disclosure includes a method of attenuating forces applied to a marine vessel from a fairlead stopper. The method includes coupling a wave reaction bar to the marine vessel and coupling a fairlead stopper to the wave reaction bar. The method includes reacting with the wave reaction bar to forces applied to the fairlead stopper.

[0011] The present disclosure includes a method of mooring a floating vessel. The method includes threading a pre-messenger line through a fairlead stopper coupled to the vessel. The method includes retrieving the pre-installed mooring line from the ocean floor by an AHV and anchoring the pre-installed mooring line on a deck of the AHV. The method includes connecting a holdback line between a winch of the AHV and a tri-plate connector coupled to a top chain of the pre-installed mooring line. The method includes transferring two ends of the pre-messenger line from the vessel to the AHV. The two ends include an outboard end and an inboard end. The method includes connecting the outboard end to a first end of the messenger line on the AHV, overboarding the connected ends of the pre-messenger line and the messenger line, and anchoring the second end of the messenger line on the deck of the AHV. The method includes pulling the pre-messenger line and the messenger line by pulling an inboard end of the pre-messenger line through a fairlead stopper until the messenger line passes through the fairlead stopper and is pulled onto the deck of the AHV. The method includes decoupling the pre-messenger line from the messenger line. The method includes connecting a top chain of the mooring line to a second end of the messenger line that extends from the AHV to a chain guide of the fairlead. A winch on the AHV is connected to a first end of the messenger line that extends from a chain wheel of the fairlead stopper to the AHV. The method includes hauling the connected top chain and messenger line overboard and pulling the messenger line until the top chain of the mooring line enters the fairlead stopper and a first tension is applied to the mooring line. The method includes decoupling the messenger line from the top chain.

[0012] The present disclosure includes a method of mooring a floating vessel having a fairlead stopper associated therewith. The method includes securing a plurality of mooring lines to a plurality of fairlead stoppers on the floating vessel. The method includes severing lengths of tail chain from the plurality of mooring lines after securing the plurality of mooring lines. The method includes connecting at least one of the severed lengths of tail chain to one of the plurality of mooring lines and thereafter hauling the mooring lines.

[0013] So that the features and advantages of the disclosed systems, apparatus, products and / or methods can be more fully understood, the description briefly summarized above can be made in more detail by reference to the embodiments illustrated in the accompanying drawings, which form a part hereof. However, the drawings depict only various exemplary embodiments and therefore should not be considered as limiting the disclosed concepts, as the disclosed concepts may include other useful embodiments. [Brief description of the drawings]

[0014] [Figure 1A-1C] FIG. 1A is a side view of a work site with a floating vessel located prior to mooring using an AHV, FIG. 1B is a detailed view of a fairlead stopper of the floating vessel of FIG. 1A, and FIG. 1C is a detailed view of a tension coupler of the mooring line of FIG. 1A. [Figure 1D] FIG. 1B is a side view of the AHV of FIG. 1A retrieving a messenger line from a fairlead stopper on a vessel. [Figure 1E] FIG. 1E is a side view of the AHV of FIG. 1D with mooring and messenger lines secured to the AHV. [Figure 1F] FIG. 1 is a top view of a portion of an AHV with mooring and messenger lines secured to the AHV. [Figure 1G] FIG. 1 is a side view of an AHV with attached mooring and messenger lines lowered into the water. [Figure 1H] FIG. 13 is a side view of the AHV retrieving the other end of the messenger line. [Figure 1I]FIG. 1 is a side view of an AHV with hold lines lowered and secured to submerged mooring lines. [Figure 1J] FIG. 1 is a side view of an AHV pulling in mooring and hold lines. [Fig. 1K-1L] FIG. 1K is a side view showing the ROV monitoring the retraction of the mooring lines, and FIG. 1L is a detailed view of the fairlead stop of FIG. 1K during the retraction of the mooring lines. [Figure 1M] FIG. 13 is a side view of the vessel and AHV showing the ROV monitoring the provision of slack to the top chains of the mooring lines. [Figure 1N] FIG. 1C is a detailed view of the fairlead stopper of FIG. 1M. [Figure 1O] FIG. 1C is a top view of the AHV of FIG. 1N. [Fig. 1P-1Q] FIG. 1P is a side view showing the AHV releasing the mooring lines after completion of the pull, and FIG. 1Q is a detailed view of the fairlead stopper of FIG. 1P. [Figure 1R] FIG. 1 is a side view showing an AHV stretching a vessel's mooring lines. [Figure 2A] FIG. 1 is a detailed view of a fairlead stopper including a pre-fixed messenger line with both ends bonded to pad eyes on the floating structure. [Figure 2B] FIG. 2B shows the fairlead stopper of FIG. 2A with the first end of the messenger line disconnected from the pad eye on the floating structure. [Figure 2C] FIG. 2C shows the fairlead stopper of FIG. 2B with the second end of the messenger line disconnected from the pad eye on the floating structure. [Figure 2D] FIG. 2B is a detailed view of the fairlead stopper of FIG. 2A with the mooring lines retracted. [Figure 2E] FIG. 2E shows the fairlead stopper of FIG. 2D with the mooring line pulled in further compared to FIG. 2D so that the mooring line engages the latch of the fairlead stopper. [Figure 2F]FIG. 2F shows the fairlead stopper of FIG. 2E with the mooring line pulled in further compared to FIG. 2E so that the mooring line engages the fairlead stopper latch and chain wheel. [Figure 2G] FIG. 2F shows the fairlead stop of FIG. 2F after the mooring line has been fully hauled in, including a guide shoe and chain slack holder onto which the anchor end of the mooring line can be placed. [Figure 2H] FIG. 2F shows the fairlead stopper of FIG. 2F after the mooring lines have been fully hauled in, with the anchor chain ends of the mooring lines tied to pad eyes on the floating structure. [Figure 2I] FIG. 2C shows the fairlead stopper of FIG. 2F after the mooring lines have been fully hauled in, including a deflector plate on the fairlead stopper through which the anchor chain end can be cut. [Diagram 3] FIG. 13 shows a tension coupler that joins lengths of mooring lines together and provides a load point that applies tension to the mooring lines for stretching. [Figure 4] It is an at least partially moored floating structure. [Diagram 5] 1 is a graph of one exemplary mooring system pattern. [Figure 6A] FIG. 1 is a perspective view of a fairlead stopper including a chain and wheel lock pin. [Figure 6B] FIG. 6B is another perspective view of the fairlead stopper of FIG. 6A. [Figure 6C] FIG. 6B is a front view of the fairlead stopper of FIG. 6A. [Figure 6D] FIG. 6B is a side view of the fairlead stopper of FIG. 6A. [Figure 6E] FIG. 6B is a top view of the fairlead stopper of FIG. 6A. [Figure 7] FIG. 2 is a perspective view of a fairlead stopper having a chain retaining arm. [Figure 8] FIG. 8 is another perspective view of the fairlead stopper of FIG. 7. [Figure 9] FIG. 8 is a side view showing the movable range of the fairlead stopper of FIG. 7. [Figure 10A] FIG. 8 shows the fairlead stopper of FIG. 7 handing over the anchor chain end of the mooring line. [Figure 10B] FIG. 8 shows the fairlead stopper of FIG. 7 handing over the anchor chain end of the mooring line. [Figure 11] FIG. 8 shows the fairlead stopper of FIG. 7 fixed to a vessel. [Figure 12] FIG. 1 shows a number of fairleads in fixed positions at sea. [Figure 13] FIG. 1 shows multiple fairleads in a deployed position. [Figure 14] FIG. 13 shows a fairlead stopper with marine fixed brace and wave reactive bar. [Figure 15] FIG. 13 shows a fairlead stopper with marine fixed brace and wave reactive bar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The systems, apparatus and methods according to the present disclosure will now be described more fully with reference to the accompanying drawings, in which various exemplary embodiments are shown. However, the concepts according to the present disclosure may be embodied in many different forms and should not be construed as being limited by the exemplary embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the various concepts and the best preferred modes of implementation to those skilled in the art.

[0016] Some aspects of the present disclosure include methods and systems for mooring vessels and tensioning mooring lines, cutting and securing tail chains, and securing fairlead stoppers to floating vessels.

[0017] Mooring with fairlead stoppers Some aspects of the present disclosure include methods, systems, and apparatus for mooring vessels and tensioning mooring lines using fairlead chain stoppers (also referred to as fairleads or fairlead stoppers) and an anchor handling vessel (AHV), such as an anchor handling tug supply (AHTS) vessel. In some such aspects, the vessels are moored and the mooring lines tensioned without the use of chain jacks, such as chain jacks located on the deck of the vessel, and other dedicated on-vessel or off-vessel tensioning equipment. For example, but not by way of limitation, a fairlead stopper as used herein can be a fairlead according to those disclosed in U.S. Patent Nos. 5,845,893, 8,915,205, or 9,126,659, or a fairlead according to those disclosed in U.S. Patent Publication No. 2018 / 0086421, each of which is incorporated herein by reference in its entirety. One exemplary fairlead suitable for use herein is the BARLATCH™ fairlead stopper by Bardex Corporation.

[0018] Exemplary Mooring Line Hook Up, Tensioning and Stretching Procedures Some embodiments of the present disclosure include a mooring hook-up and tensioning procedure using a fairlead stopper. FIGS. 1A-1R show a floating structure moored according to some embodiments of the present disclosure, and FIGS. 2A-2I show detailed views of a fairlead stopper used during mooring of the floating structure. The steps of mooring a floating structure are described below with reference to FIGS. 1A-1R and 2A-2I. The order of steps presented is only one possible order and may therefore be determined depending on the particular mooring arrangement, conditions, and other variables. Throughout the figures provided herein, elements are not necessarily to scale but are representative thereof. Also, like reference numerals refer to like elements throughout the figures provided herein.

[0019] In general, some embodiments of the methods disclosed herein include: (1) coupling a pre-secured messenger line of an on-board fairlead stop to a pre-laid mooring line and a winch on the AHV; (2) pulling the mooring line to a first pre-tension value (e.g., 250 metric tons) while maintaining the position of the AHV using a hold-back line coupled between the AHV and the mooring line and ensuring that a polyester segment of the mooring line is raised off the seabed during the pulling step, if a polyester segment of the mooring line is used; (3) optionally proof loading the mooring line to, for example, 40% of the MBL of the extendable (e.g., polyester) segment of the mooring line by applying tension using a tensioning line coupled between the AHV and the mooring line; and (4) pulling the mooring line to a second pre-tension value (e.g., 300 metric tons).

[0020] Floating vessel 1A , the mooring method disclosed herein includes towing the vessel 200 to a desired site. The vessel 200 can be any of a variety of types of floating structures requiring mooring, such as an oil drilling or production platform, a floating production storage offloading (FPSO) vessel, an offshore floating wind power foundation, a floating fish farm, or other offshore floating structure. The site can be the location where the vessel 200 is to be moored, such as an offshore location where the vessel 200 is to be used in an oil drilling or production operation.

[0021] Anchor Handling Vessel Also located on site is an anchor handling vessel (AHV) 700. The AHV 700 can be a vessel that includes one or more winches, cranes, shark jaws, stern rollers, ROVs, and other equipment that can be used in the mooring of a vessel.

[0022] Fairlead stopper A fairlead stopper 100 is coupled to the vessel 200 (e.g., coupled to the hull). The vessel 200 may include multiple fairlead stoppers 100. The fairlead stoppers 100 may be located along each side of the vessel 200. The fairlead stoppers 100 may be located above a waterline 716 of the vessel 200, below the waterline 716, or a combination thereof.

[0023] Figure 2A shows the fairlead stopper 100 positioned and arranged in a manner suitable for transportation of the vessel 200. For example, the fairlead stopper 100 can be in the position and arrangement shown in Figure 2A from the time the vessel 200 is at dock, during transportation of the vessel 200 from the dock to the site, and while it is located at the site prior to the vessel 200 commencing mooring (e.g., as shown in Figure 1A).

[0024] The fairlead stopper 100 includes a fairlead housing 112 coupled to the vessel 200 via brackets 114 and 116. The fairlead housing 112 may be movably (e.g., pivotably) coupled to the brackets 114 and 116 via pins. The fairlead stopper 100 includes a latch housing 120 that may be movably (e.g., pivotably) coupled to the fairlead housing 112 via a pin 122 or the like. The latch housing 120 may include a guide member 124 for guiding a line (e.g., rope, chain, and other such line) in and out of the latch housing 120. A latch 130 may be positioned within the latch housing 120 and arranged to engage a chain or other line passing through the latch housing 120. The fairlead stopper 100 includes a chainwheel 110 that may be movably (e.g., pivotably) coupled to the fairlead housing 112 via an axle 126 or the like. The chain wheel 110 can be positioned to engage lines (e.g., ropes, chains, and other such lines) and move, guide, or otherwise facilitate movement of such lines through the fairlead housing 112 and latch housing 120. In some embodiments, the latch housing 120 or another portion of the fairlead stopper 100 can be temporarily secured to the vessel 200, such as to a bracket 117 on the vessel 200 (as shown in FIG. 2D), during transportation. The fairlead stoppers disclosed herein are not limited to the particular structures shown in FIGS. 2A-2I, but can be any of a variety of structures capable of moving or facilitating movement of mooring lines and fixing the position of the mooring lines for tensioning of the mooring lines and mooring of the floating vessel.

[0025] As shown in FIG. 2A, the fairlead stopper 100 may have a messenger line 300 pre-secured thereto. That is, the fairlead stopper 100 may have a messenger line 300 that at least partially engages the fairlead stopper 100. Pre-securing the messenger line 300 to the fairlead stopper 100 may be performed at port before the vessel 200 leaves port for the site. The lower end of the messenger line 300 is looped up from below the fairlead stopper 100 to a pad eye 202a on the hull of the vessel 200. As shown in FIG. 2A, the messenger line 300 passes through the fairlead housing 112 adjacent the chain wheel 110, through the latch housing 120, and between the latch 130 and the adjacent guide member 124. The messenger line 300 may be a chain, rope, polymer line, wire, or another type of line. The first and second ends 300a and 300b of the messenger line 300 may be coupled to the vessel 200 during transport. As shown, the first and second ends 300a and 300b include shackles 302a and 302b, respectively, that couple to the pad eyes 202a and 202b, respectively, via pins 201. The pad eyes 202a and 202b may be located on the vessel 200 (e.g., welded to the vessel 200). However, the messenger line 300 is not limited to being coupled to the vessel 200 via shackles and pad eyes, but may be coupled to the vessel 200 via other structures. Additionally, the messenger line 300 may not be coupled to the vessel 200, but instead may be coupled to a portion of the fairlead stopper 100 or another structure. Regardless of the particular structure to which the messenger line 300 is coupled, one or both ends of the messenger line 300 may be secured during transport of the vessel 200. Although the fairlead stopper 100 is shown as being located below the waterline 716 , in some embodiments the fairlead stopper 100 is located above the waterline 716 .The fairlead stopper 100 can be an underwater chain stopper fairlead (UCSF). In some such embodiments, the pad eyes 202a and 202b can be located below the fairlead stopper 100 to allow a remotely operated vehicle (ROV) or diver to access the messenger line 300 for coupling the messenger line 300 to a line and / or winch of the AHV 700. In other embodiments, one end of the messenger line 300 can be coupled to a counterweight that is secured to the hull of the vessel 200 or to the fairlead stopper 100.

[0026] 1A-1C, the method includes releasing the sea-fastening of the fairlead stopper 100, such as by disconnecting the fairlead stopper 100 from the bracket 117 (shown in FIG. 2D) so that the fairlead stopper 100 is positioned for operation. As shown in FIG. 1B, the messenger line 300 includes a first end 300a and a second end 300b, each of which may be at least partially comprised of a metal or polymer wire or rope, or another material. As described with reference to FIG. 2A, the first end 300a and the second end 300b may each be coupled to the hull of the vessel 200. The messenger line 300 also includes an intermediate segment 300c, which may be at least partially comprised of a chain (e.g., a steel chain). Once the first end 300a and the second end 300b are coupled to the hull 200, the intermediate segment 300c is threaded through the latch housing 120 and the adjacent chain wheel 110. The first and second ends (or segments) 300 a and 300 b of the messenger line 300 can be of a non-rotating structured wire that mitigates the introduction of twist into the top chain 310 .

[0027] The AHV 700 moves into position relative to the floating vessel 200 (e.g., by moving in direction 500a). As shown in FIG. 1A, the AHV 700 includes a work-line 311 coupled to a winch on the AHV 700. Once the AHV 700 is in position relative to the floating vessel 200, it pays out the work-line 311 as needed. The method includes paying out the work-line 311 to retrieve the mooring line 701 from the seabed 718. While paying out the work-line 311, the AHV 700 maintains station using minimal thrust and maintains correct rudder clearances from the vessel 200. The work-line 311 is then coupled to the top chain 310 via a shackle or the like. This operation may be assisted by a diver or an ROV. After the working line 311 is coupled to the top chain 310, the working line 311 can be pulled towards the AHV 700 such that the mooring line 701 is at least partially lifted from the ocean floor 718 towards the AHV 700. Although the working line 311 is shown and described as being used, in some embodiments, such as operations in shallow waters, a working line is not used. In some such embodiments, a winch wire is paid out to retrieve the mooring line 701.

[0028] Mooring lines The mooring line 701 may include one or more line sections, each of which may be constructed of the same or different materials. The various segments of the mooring line 701 may be coupled to one another via shackles, H-Links, or other connectors. The mooring line 701 includes a bottom chain 722, which may be a pile forerunner, coupled to an anchor 714 at the seabed 718. The anchor 714 may be a suction pile, driven pile, drag embedment anchor, gravity anchor, torpedo anchor, or another type of anchor that is disposed on the seabed 718. The mooring line 701 includes a midspan mooring line coupled to the bottom chain 722. In FIG. 1A, the midspan mooring line includes two individual segments 724a and 724b of polyester line. Mid span line 724a is coupled to bottom chain 722 via a shackle or the like. Mid span line 724b is coupled to mid span line 724a via tension coupler 712a. Mid span lines 724a and 724b can be ropes, chains, or polymer lines. Mooring lines 701 can be pre-installed and wet stored on the seabed 718 at the site before towing vessel 200 to the site, or installed on the seabed 718 after vessel 200 is towed to the site.

[0029] In some aspects, the mid-span lines 724a and 724b may at least partially comprise polyester, metal, composite, or another material. As described in more detail below, in some aspects, materials such as polyester or other polymers undergo a stretching step in the mooring process. The stretching step may be performed after the mooring line 701 is connected to the vessel 200 and pre-tensioned. The mooring lines disclosed herein are not limited to the particular example configuration shown in FIG. 1A and may include a different number of line segments and / or be constructed of different materials.

[0030] Tension Coupler As shown in FIG. 1C, tension coupler 712 includes a plate 713 coupled to a connecting chain 719 that simultaneously couples to both mid-span lines 724a and 724b. Also coupled to plate 713 is a shackle 717 that couples to a tension line (not shown). Mid-span line 724b is coupled to top chain 310 (e.g., a steel chain) via tension coupler 712b, which may be identical to tension coupler 712a. In operation, tension coupler 712b may be used to couple to a winch line of AHV 700 to hold the position of AHV 700 during tensioning of mooring line 701, and tension coupler 712a may be used to couple to a winch line of AHV 700 for stretching of mooring line 701.

[0031] Tension couplers 712a and 712b are coupled at locations along the length of mooring line 701. As shown in FIG. 1A, tension coupler 712b is coupled between mid span 724a and top chain 310, and tension coupler 712a is coupled between mid span lines 724a and 724b. However, tension couplers disclosed herein can also be coupled at other locations along mooring line 701, such as within bottom chain 722, within mid spans 724a and 724b, between bottom chain 722 and mid span 724a, between mid span 724b and top chain 310, or at another location along mooring line 701. Tension couplers 712a and 712b can be structures that can couple two, three, or more lines, ropes, wires, or chains together (as shown and described in more detail below) and provide points along the length of mooring line 701 where tension can be applied to mooring line 701. In some embodiments, if mid spans 724a and 724b are or include ropes, tension coupler 712a can be used to stretch the ropes as needed after pre-tensioning of mooring line 701 is complete by pulling tension coupler 712a upward in a manner similar to plucking a "bow string." In some embodiments, tension couplers 712a and 712b include steel plates with through holes disposed therein.

[0032] Connection of messenger line to mooring line 1D, after the AHV 700 has been moved into position relative to the vessel 200, the method includes retrieving the first end 300a of the messenger line from the vessel 200 and securing the first end 300a of the messenger line onto the AHV 700 (e.g., securing the first end 300a of the messenger line within a shark jaw of the AHV 700). For example, as can be seen with reference to FIG. 2B, the first end 300a can be removed from the pad eye 202a by removing the associated pin 201. This removal can be performed by a diver, an ROV, from the deck, or otherwise.

[0033] Once the first end 300a of the messenger line is secured on the AHV 700 (e.g., in the shark jaw), the method includes moving the AHV 700 away from the vessel 200 (e.g., along direction 500b) to a location suitable for connecting the first end 300a to the top chain 310. In some such embodiments, while the AHV 700 is moving away from the vessel 200, the method includes reeling in the mooring line 701 by reeling in the working line 311 (e.g., along direction 501a).

[0034] 1E and 1F, the method includes pulling the mooring line 701 through a stern roller 721 until the top chain 310 is secured such as in a shark jaw 727 on the deck of the AHV 700. The method also includes pulling the first end 300a through another stern roller 721 and securing the first end 300a such as in another shark jaw 727 on the deck of the AHV 700. Once the first end 300a of the messenger line and the top chain 310 are secured in the shark jaw 727, rigging 313 (e.g., A&R rigging) is coupled to the top chain 310 and the first end 300a for over-boarding the mooring line 701. The rigging 313 is coupled to the first end 300a and the top chain 310 through an ROV shackle 314. In some embodiments, the AHV 700 maintains its position with minimal thruster assistance during connection between the top chain 310 and the first end 300a.

[0035] 1G, the method includes lowering the first end 300a and the top chain 310, which are coupled together via the rigging 313, overboard into the water (e.g., along the direction 503a). After the first end 300a and the top chain 310 are lowered into the water, the rigging 313 is disconnected therefrom, such as by use of an ROV or by a diver. The rigging 313 can then be retrieved onto the deck of the AHV 700. Once the first end 300a, the top chain 310 and the rigging 313 are disconnected, the fairlead stopper 100 (via the latch of the fairlead stopper 100) carries the load of the mooring line 701.

[0036] Messenger Line and AHV integration Next, as can be seen with reference to FIG. 1H, once the fairlead stopper 100 is carrying the load of the mooring line 701, the method includes moving the AHV 700 into a position to receive the second end 300b of the messenger line, such as by moving the AHV 700 along direction 500a towards the vessel 200. Once the AHV 700 is in position, the method includes delivering the second end 300b to the AHV 700 and securing the second end 300b to a winch on the AHV 700. For example, as shown in FIG. 2C, the second end 300b can be removed from the pad eye 202b by removing the associated pin 201. The second end 300b of the messenger wire 300 can then be coupled to a winch on the AHV 700.

[0037] Attaching the AHV to the mooring line 1I, once the second end 300b is secured to a winch on the AHV 700 and / or within a shark jaw on the AHV 700 via a winch line 729, the method includes moving the AHV 700 (e.g., along direction 500b) to a position above the tension coupler 712b while paying out (e.g., along direction 503a) a tension line 720 (also referred to as a hold line or holdback line) which is a winch line from a winch on the AHV 700. The method includes lowering the tension line 720 towards the tension coupler 712b. The tension line 720 may include a hook or other coupler for connecting to a shack 717 of the tension coupler 712b. The ROV 800 may be deployed from the AHV 700 to observe and / or assist in coupling the tension line 720 to the tension coupler 712b.

[0038] 1J, once the tension line 720 is coupled to the tension coupler 712b, the method includes using a winch on the AHV 700 to pull the tension line 720 to a desired degree of payout. The second end 300b is also pulled via another winch on the AHV 700. Pulling the second end 300b also eventually pulls the top chain 310 through the fairlead stop 100 and engages its latch. Pulling the tension line 720 helps hold the AHV 700 in place while it pulls the mooring line 701. In some such embodiments, when tension line 720 is pulled, a significant horizontal load acts on the AHV 700 pulling it away from vessel 200, positioning tension coupler 712b far enough away from vessel 200 to counteract an opposing horizontal load acting on the AHV 700 due to the pulling of messenger line 300 and / or top chain 310. In some such embodiments, the tension on tension line 720 creates a force on the AHV 700 away from vessel 200 sufficient to counteract the force on the AHV 700 towards vessel 200 (resulting from the pulling of mooring line 701), thus balancing these forces on the AHV 700 so that the AHV 700 maintains its position with no or minimal use of its thrusters.

[0039] Mooring line tension 1K and 1L, the method includes continuing to pull the top chain 310 until the desired link of the top chain 310 is secured via the latch of the fairlead stopper 100. Securing the desired link of the top chain 310 with the latch of the fairlead stopper 100 can indicate that a desired pretension of the mooring line 701 has been achieved. In some such embodiments, the ROV 800 monitors the top chain 310 as it passes the fairlead stopper 100. In some embodiments, the desired link of the top chain 310 is marked (e.g., painted) so that the ROV 800 can visually observe when the desired link of the top chain 310 is secured via the latch of the fairlead stopper 100. Once the desired link of the top chain 310 is observed to be secured via the latch of the fairlead stopper 100, the method can include stopping the pulling of the mooring line 701.

[0040] The AHV 700 can maintain position with minimal thruster assistance during the pulling of the mooring lines 701. The AHV 700 maintains an equilibrium position where the horizontal load component from the tensioned top chain 310 is countered by the horizontal load component posed by the lines 720.

[0041] The messenger line 300 and top chain 310 are pulled through the fairlead stopper 100 by pulling the messenger line 300 using a winch on the AHV 700. As the top chain 310 approaches engagement with the fairlead stopper 100, the messenger line 300 travels through the fairlead stopper 100 until the links of the top chain 310 are pulled toward and pass through the fairlead stopper 100, as shown in FIG 2D. Once the top chain 310 passes the fairlead stopper 100, the links of the top chain ratchetedly engage the fairlead stopper latches 130, as shown in FIG 2E. In some aspects, a second winch on the AHV 700 is used to pull on the tension line 720 while using a winch to pull on the mooring line 701 to provide a restoring force, such that the AHV 700 does not need to use thrusters to provide a restoring force, or the thrusters are assisted by at least a horizontal force component that tends to pull the AHV 700 away from the vessel 200.

[0042] As shown in FIG. 2F, the AHV 700 continues to pull the top chain 310 via the chain wheel 110 through the fairlead stopper 100 until the appropriate desired pre-tension is achieved for the mooring line 701. In some aspects, the latch 130 on the fairlead stopper 100 can be configured for automatic locking, closing after every link or every other link so that there is no need to manually operate the latch 130. In some aspects, the latch 130 can be configured to remain open while the top chain 310 passes through the fairlead stopper 100 and close when the top chain 310 tensions to a desired level. Thus, the mooring method includes continuing to pull the top chain 310 until the mooring line 701 tensions to a desired level. The top chain-messenger line connection can be disconnected on the AHV 700 or on the deck of the vessel 200 depending on how much tail chain is present when the desired tension level is reached. When pulled, the latch 130 remains closed around at least one link of the top chain 310 (sometimes called the “golden link”), fixing and maintaining tension on the mooring line 701 .

[0043] In some embodiments, during tensioning by pulling on the messenger line 300, the method includes simultaneously pulling on the tension line 720, and thus the tension coupler 712b and the mooring line 701, to pull on the catenary weight to hold the AHV 700 away from the vessel 200 and reduce the load on the messenger line 300 being pulled by the winch. In some embodiments, pulling on the mooring line 701 with the line 720 simultaneously equalizes or substantially equalizes the horizontal forces on the AHV 700, allowing the AHV 700 to remain stationed. In some such embodiments, propulsion using the thrusters of the AHV 700 is used to keep the AHV 700 stationed.

[0044] 1M-1O, the method includes providing slack to the top chain 310 by releasing tension on the top chain 310 from the AHV 700, allowing the fairlead stopper 100 to bear the load of the mooring line 701 with the desired link of the top chain 310 secured via the latch of the fairlead stopper 100. The ROV 800 can be used to monitor the slack of the top chain 310. The method then includes moving the first end 300a (platform hang-off rigging) to the vessel 200 and securing it thereto, as shown in FIG. 2H.

[0045] 1P and 1Q, the method includes decoupling the top chain 310 from the AHV 700, then moving the AHV 700 away from the vessel 200 to a position above the tension coupler 712b and decoupling the tension line 720 from the tension coupler 712b, which may be facilitated via the ROV 800. The AHV 700 may then retrieve all lines and the ROV 800 in preparation for the next mooring hookup and pulling procedure. In some embodiments, the end of the top chain 310 is cut to remove excess chain. The remaining excess slack top chain 310 length may be sufficient to connect the top chain 310 to the hull of the vessel 200 and / or to connect additional chains or wires for slackening operations for replacement or repair operations.

[0046] Stretching the mooring lines Once pre-tensioning is complete, the AHV 700 can release the load on the bitter end of the top chain 310 and use a winch to pull on the tension line 720 to pull on the tension coupler 712b to stretch any stretchable portions of the mooring line 701 (e.g., the mooring line rope at mid-spans 724a and 724b) if necessary or desired. For example, a polyester rope or the like may stretch from its initial purchased length and become stiffer, and therefore require stretching to achieve 40-60% of its minimum break load (MBL). The AHV 700 can then move to reposition itself vertically further above the tension coupler 712b before pulling on the tension line 720 to stretch the mooring line 701. An exemplary polyester line with an initial MBL of 1,750 metric tons has an MBL of 700 metric tons at a proof load of 40% MBL. In some embodiments, stretching a polyester segment of a mooring line can increase the stiffness of that segment by 11 times MBL to 15 times MBL, etc. In some embodiments, stretching is accomplished by pulling on the same tension coupler to which the tension line was coupled during tensioning of the mooring line. In other embodiments, stretching is accomplished by pulling on a different tension coupler to which the tension line was coupled during tensioning of the mooring line.

[0047] 1R, the method includes stretching at least a portion of the mooring line 701 after tensioning and releasing the mooring line 701. The method may include positioning the AHV 700 above a tension coupler 712a, lowering a line 720 to the tension coupler 712a, and coupling the line 720 to a shackle 717 of the tension coupler 712a. Once the line 720 and tension coupler 712a are coupled, the method may include pulling the line 720 toward the AHV 700 along direction 505a to apply a force to the mooring line 701. The application of this force results in at least some portions of the mooring line 701, such as polyester midspan lines 724a and 724b, being stretched.

[0048] In some embodiments, each polyester segment (or other stretchable segment) of mooring line 701, such as mid-span lines 724a and 724b, is stretched to at least 40% of the MBL of that segment. Such stretching can be performed to remove construction stretch from the line and minimize the need for further re-tensioning of the line.

[0049] As an example, Table 1 shows ship and AHV load data associated with proof tensioning a vessel's first mooring line (i.e., the first of all the vessel's mooring lines to be stretched) to 40% MBL of polyester, and Table 2 shows line load data associated with proof tensioning the first mooring line to 40% MBL. Table 1 JPEG2025507635000002.jpg28154 Table 2 JPEG2025507635000003.jpg39153

[0050] Table 3 shows the vessel and AHV load data associated with the assurance tension of the vessel's last mooring line (i.e., the last of all the vessel's mooring lines to be stretched) to 40% MBL of polyester, and Table 4 shows the line load data associated with the assurance tension of the last mooring line to 40% MBL. Table 3 JPEG2025507635000004.jpg28153 Table 4 JPEG2025507635000005.jpg39155

[0051] In some embodiments, the length ratio of the polyester segments 724a and 724b is optimized for up to 40% proof load while reducing tension and bollard pull. Table 5 shows some example data for different length ratios between the polyester segments 724a and 724b. The bollard pull data in Table 5 does not take into account vessel motion or offset. Table 5 JPEG2025507635000006.jpg44154

[0052] In light of the data in Table 5, in at least some embodiments, the optimal polyester segment ratio is one in which the upper polyester segment (724b) constitutes 25% of the total midspan length (i.e., the combined length of 724a and 724b) and the lower polyester segment (724a) constitutes 75% of the total midspan length. Such asymmetric polyester segments increase utilization of line 720 by reducing the pulling force required for stretching.

[0053] In some embodiments, the mooring lines are tensioned again after the tensioning has occurred (e.g., according to FIG. 1K). For example, top chain 310 can be reconnected to the shark jaws of AHV 700, lines 720 can be reconnected to tension coupler 712b, and mooring lines 701 can be tensioned to a second tension. In some embodiments, each of the mooring lines of the vessel is tensioned to a first tension, then each of the mooring lines is stretched, after which each of the mooring lines is further tensioned to a second tension that is higher than the first tension.

[0054] Anchor chain end of mooring line The top chain 310 anchor end can be secured, stored, and / or cut. With reference to FIG. 2G, in some embodiments, after pretensioning is completed, the top chain 310 anchor end rests on a guide shoe 124 including a chain slack holder 125 on the side of the fairlead stopper 100. The chain slack holder 125 can be a structure configured to hold the top chain 310 on or of the fairlead coupler 100. In other embodiments, the top chain 310 anchor end is secured to the vessel's hull for permanent or long term mooring. For example, as can be seen with reference to FIG. 2H, the top chain 310 anchor end can be coupled to the pad eye 202a of the vessel 200 via a pin 201 and a shackle 302c. In another embodiment, as shown in FIG. 2I, the anchor chain end of the top chain 310 is routed over a deflector plate 119 disposed over the latch housing 120 where it is cut off.

[0055] 6A-6E show another embodiment of a fairlead stopper 100 illustrating one method of handling the mooring line's anchor chain end according to the present disclosure. The fairlead stopper 100 includes a chain and wheel locking pin 600. In operation, as the mooring line is pulled or unpulled along the pulling direction (as shown in FIG. 6D), the pin 600 is removed from the chain wheel 110 to allow the mooring line to enter the fairlead stopper 100 as shown by chain 310a and move over the chain wheel 110 as shown by 310b. After completion of the pulling, the mooring chain is pinned to the fairlead stopper 100 and the excess mooring chain is cut or cut off. 310a shows the position of the mooring chain during pulling, while 310c shows the position of the unpinned mooring chain after pulling. The mooring chain 310c engages around the chain wheel 110 and the pin 600 engages the fairlead stopper 100 to keep the chain 310c held on the chain wheel 110. As shown in FIGS. 6A-6E, the pin 600 engages through the chain guide 612 such that the pin 600 holds the chain 310c engaged with the chain wheel 110 and prevents the chain 310c from disengaging from the chain wheel 110. The fairlead stopper 100 can engage the upper bracket 114 via an upper retainer 616. The fairlead stopper 100 also includes a linear transducer 610 for actuating the latch, latch locker, cover 618 and linkage cover 614. Although not shown, the fairlead stopper 100 also includes within the latch housing 120 latches for operation of at least one embodiment of the fairlead stopper, synchronizing links between the latches, and latch tension springs.

[0056] In some embodiments, the mooring line includes a connecting link that can be disconnected from the mooring line after the tension is completed to remove excess tail chain.

[0057] After completion of the pulling and optionally stretching, the AHV 700 may be moved onto the next mooring line of the vessel 200 or another vessel for the pulling and / or stretching operation.

[0058] Tri-Plate Connector An exemplary tension coupler 712 is shown in FIG. 3. The tension coupler 712 shown in FIG. 3 is also referred to as a tri-plate connector and includes a body 713 with through holes 715 disposed therein. The body 713 is or can include steel. Each through hole 715 can be arranged and configured to connect to a rope, chain, wire, or other tension or mooring line via a shackle or the like. In some aspects, the tension coupler 712 is configured to couple to the segments of the mooring line 701 such that the segments of the mooring line 701 can be tensioned to extend in a substantially linear arrangement with respect to one another. For example, the mid spans 724a and 724b and the top chain 310 can be coupled to the through holes 715 such that when the mooring line 701 is tensioned, the top chain 310 and the mid spans 724a and 724b extend in a linear arrangement along (or at least parallel to) the direction. Additionally, the through holes 715 may be positioned to allow a tension line 720 to be coupled to apply tension or traction along another direction that is not perpendicular or at least not parallel to the direction of extension of the mooring line 701 .

[0059] Moored vessels Figure 4 shows a vessel 200 moored via multiple mooring lines 701, each including an anchor 714, a bottom chain 722, mid spans 724a and 724b, a top chain 310, and tension couplers 712a and 712b. For simplicity, only the details of one of the mooring lines 701 are shown. Also shown is an AHV 700 with two winches 710a and 710b. Figure 5 is a graph of one exemplary mooring system pattern with a vessel 200, multiple mooring lines 701, and multiple anchors 714.

[0060] Table 6 below shows the lengths of one exemplary mooring line component during different stages of the mooring and tensioning procedure of the present disclosure. The length of the polyester segment takes into account the estimated elongation due to the applied load. Table 6 JPEG2025507635000007.jpg78155

[0061] Installation and Maintenance As disclosed herein, the fairlead stopper used in the mooring method can be attached to the hull below or above the waterline. If below the waterline, the fairlead stopper can be located outside the splash zone. A fairlead stopper that can be installed at a port can be installed at a relatively high position on the hull above the waterline so that it can be accessed for inspection, installation, etc., quayside at a shipyard rather than in a dry dock. In this way, the fairlead stopper can be used for power washing and inspection before departure to the installation site, facilitating offshore ROV and diver operations and chain fastening, as well as reducing risk before arriving on site for mooring hookup.

[0062] The instrumentation on the fairlead stopper can be designed and constructed for a relatively long service life and, depending on the application, can go a significant period of time without needing replacement. In some aspects of the mooring method, the fairlead stopper does not require long term maintenance other than visual inspection. For example, cleaning and visual inspection once every five years may be sufficient for fairlead stopper maintenance. The fairlead stopper may also be subjected to bearing wear inspection and measurement. In the event that replacement or maintenance of the fairlead stopper is required, a diver or ROV may remove and replace the instrumentation on the fairlead stopper without disturbing the mooring load on the fairlead stopper. That is, in some aspects, such instrumentation on the fairlead stopper does not include a load cell located in the load path. The load may be determined by measuring strain within the housing of the fairlead stopper so that removal and replacement can be performed without requiring removal of the mooring load. In some such aspects, the method includes avoiding the use of an acoustic system to monitor the load on the fairlead stopper. Thus, in at least some embodiments, the fairlead stoppers are maintenance free or substantially maintenance free, thereby reducing or eliminating equipment maintenance. These methods can also be used to reduce installation time and costs for mooring lines.

[0063] Weight reduction In some embodiments, the method reduces weight on the moored vessel and / or mooring lines compared to methods using inline tensioners (ILTs). For example, in methods using ILTs, the ILT and tail chain (the mooring line adjustment chain) remain suspended mid span from the top chain. The weight of the ILT on the top chain has long term effects on the fatigue and life of the chain. Additionally, the weight of the ILT on the top chain affects the geometry of the top chain catenary, causing other risks and effects on mooring performance. Additionally, the weight of the ILT on the top chain increases buoyancy requirements or reduces the vessel's topsides weight capacity.

[0064] In some embodiments, the mooring methods disclosed herein allow for a reduction in the weight of deck equipment on the moored vessel by eliminating some or all of the tensioning devices on the moored vessel. Thus, the methods disclosed herein allow for freeing up space on the deck of the moored vessel for other uses by eliminating some or all of the tensioning devices and associated hydraulics, controls, and piping. The methods disclosed herein can also further reduce onboard weight by eliminating the need to store tail chains onboard in chain lockers. In some embodiments, mooring costs are reduced when utilizing the methods compared to methods using ILTs.

[0065] Motion Control In some embodiments, the method overcomes problems associated with controlling the movement of the ILT during a pulling operation. Since the ILT does not move freely on the mooring line when lifted, the AHV lifts the entire mooring line catenary upwards until a sufficient load is achieved to overcome friction, at which point the ILT moves downward on the chain and falls until friction is overcome again and stops the ILT movement. Thus, when using the ILT, it is difficult to control how much to pull the chain because the ILT typically moves past the "golden" link and must pay out the chain to return to the "golden" link. Paying out the chain can be difficult and may require the use of stops attached to the chain links to force a stop when the "golden" link reaches the latching device. The use of such stops creates an impact load on the chain and ILT when the ILT is moving down the chain and suddenly hits the stop.

[0066] In some aspects of the method, as the AHV pulls on the top chain, the top chain passes through the fairlead stop relatively smoothly because the method does not rely on the weight of a chain tensioner device to overcome resistance to movement in the fairlead stop. Thus, in some such aspects, the method disclosed herein avoids sudden and uncontrolled movement of the mooring lines, reduces the likelihood of damage to the mooring lines or tensioner assembly compared to in-line tensioners, provides increased safety compared to in-line tensioners, and reduces the occurrence of mooring line stretch and winch stall compared to in-line tensioners.

[0067] Paying out the mooring line In some embodiments, the present method does not exhibit at least some of the problems that methods using ILTs exhibit during payout of the mooring line. ILTs require the ROV to control the actuation of a latch to allow for payout of the chain. Locking the latch open can cause the locking mechanism to fail, making the operation risky. Also, ILTs may be located too deep for divers to repair. Furthermore, ILTs are suspended from a catenary of the mooring line and are not attached to a rigid structure such as a vessel hull. Failure to hold the ILT's latching mechanism open would prevent the chain from being extracted from the ILT for recovery and / or repair.

[0068] In some aspects of the method, the method includes paying out additional mooring lines. The top chain end of the anchor haul can be retrieved (e.g., by unpinning the end of the anchor haul from the vessel's hull). The top chain end of the anchor haul can then be coupled to one of the winches of the AHV, which can pull on the mooring lines to free the fairlead coupler latches to open. Stopper latches, which can also be operated by wire ropes from above the vessel's hull, can be opened by an ROV or diver to lock the latches in the open position. The AHV can then pay out the mooring lines until a desired tension is achieved, or all of the mooring lines if disconnection from the mooring lines is required.

[0069] Simplifying tail chain handling In some embodiments, the method simplifies handling of the tail chain compared to methods using ILTs. Handling the tail chain after tensioning with an ILT can be difficult, requiring cutting of the tail chain by an ROV or diver. When cut, the tail chain contains two loose half links and must be handled while holding the remainder of the tail chain. Also, special handling tools are required to ensure that the parts do not fall uncontrollably after the tail chain is cut. The tail chain resides on one side of the ILT, and depending on the weight of the tail chain, the tail chain remaining on one side may cause twisting of the mooring line. Torsional loads on the links in the ILT can have long-term effects on chain wear.

[0070] In some embodiments of the method, after the mooring lines are pre-tensioned through the fairlead stopper, the mooring line ends can be placed on the vessel's hull and pinned off into the eye using a standard shackle. In some such embodiments, this allows for easy access to the mooring lines for re-tensioning at a later time, if necessary. In some embodiments, the mooring lines are not twisted (e.g., 180 degrees) during the mooring operation, thus reducing interlink wear and increasing chain life compared to in-line tensioners. In some embodiments of the method, the tail chain does not need to be cut after the mooring lines are tensioned, thus saving time, money, improving safety, and increasing available deck space on the vessel compared to methods using in-line tensioners.

[0071] In some embodiments, operation of the hook-up and tensioning procedures disclosed herein can be facilitated through the use of simulation and analysis software such as OrcaFlex 10.0d.

[0072] Fairlead with chain retention arms Embodiments disclosed herein include methods and systems for cutting, storing, and securing the tail chain of a mooring line. A fairlead stopper 700 is shown in Figures 7-11. The fairlead stopper 700 includes a housing assembly including a fairlead housing 712, a chain wheel housing 711, and a latch housing 720. The fairlead housing 712 is movably coupled to brackets 714 and 716 such that the fairlead housing 712 is rotatable relative to the brackets 714 and 716 and pivotable about a pivot point 715. The brackets 714 and 716 can be attached to or can be part of a floating vessel 793 (shown in Figure 9).

[0073] The fairlead stopper 700 includes a chainwheel housing 711 coupled to a fairlead housing 712, and a chainwheel 710 coupled to the chainwheel housing 711. The chainwheel 710 is rotatably coupled to the chainwheel housing 711 at an axle 713 such that the chainwheel 710 is rotatable relative to the chainwheel housing 711.

[0074] The fairlead stopper 700 includes a latch housing 720 coupled to a chain wheel housing 711. The latch housing 720 is pivotally coupled to the chain wheel housing 711 such that the latch housing 720 is pivotable about a pin 721. Figure 9 illustrates the range of motion of the latch housing 720. A latch 730 (shown in Figure 9) is disposed within the latch housing 720 and configured to latch a chain link of a mooring line 790.

[0075] The fairlead stopper 700 includes a chain guide 724 positioned to guide the mooring line 790 as it passes through the fairlead stopper 700 .

[0076] The fairlead stopper 700 is configured to cut, store, and secure the tail chain of the mooring line. Components of the fairlead stopper 700 that facilitate cutting, storing, and securing the tail chain include, but are not limited to, a tail chain deflector 725, a tail chain retaining plate 726, a tail chain retaining arm 727, and a chain retaining arm 728. During mooring, a mooring line 790 passes through the fairlead stopper 700 and through the latch housing 720 over the chain wheel 710. A latch 730 is disposed within the latch housing 720 to latch a chain link of the mooring line 790 to ensure tension on the mooring line 790. Once the desired tension on the mooring line 790 is achieved and the latch 730 is latched to the mooring line 790, the anchor haul end 792 of the mooring line 790 is positioned to hang from the chain deflector 725 (as shown in FIGS. 10A and 10B). Once the desired tension on the mooring line 790 is achieved, the chain retaining arm 728 engages over the chain wheel 710 and the portion of the mooring line 790 that engages the chain wheel 710. Also, once the desired tension on the mooring line 790 is achieved, the anchor haul end 792 is positioned on the chain table 726 and extends over the chain deflector 725 which deflects the position of the anchor haul end 792 from the position of the mooring line 790 (as shown in FIG. 9). Once the anchor chain end 792 is positioned on the chain table 726, the tail chain retaining arm 727 engages over the anchor chain end 792 such that the anchor chain end 792 is secured between the tail chain retaining arm 727 and the chain table 726. The ROV or diver can swing the chain retaining arm 728 and the tail chain retaining arm 727 into a closed position. In some embodiments, the chain table 726 and the chain deflector 725 are different parts of the same component. In other embodiments, the chain table 726 and the chain deflector 725 are different components.

[0077] The chain table 726 includes two angled wings or plates 705a and 705b. The chain table 726 includes or defines a trough 795 where the plates 705a and 705b meet. The trough 795 is configured (e.g., shaped and positioned) to receive the mooring line 790.

[0078] If the length of the anchor chain end 792 extending from the chain guide 724 is longer than the maximum excess chain length, the portion of the anchor chain end 792 that is longer than the maximum excess chain length is cut off. For example, an ROV or a diver may cut off the anchor chain end 792. The maximum excess chain length may be based on, for example, the weight of the anchor chain end 792 and / or the length of the anchor chain end 792. Thus, cutting the anchor chain end 792 reduces the weight that the anchor chain end 792 exerts on the fairlead stopper 700. Cutting the anchor chain end 792 also reduces the length of the anchor chain end. Reducing the length of the anchor chain end 792 may reduce the risk and associated hazards of the anchor chain end 792 becoming entangled with other parts of the fairlead stopper 700 or other components of the floating vessel. When the anchor chain end 792 is cut, the loss of weight of the anchor chain end 792 puts tension on the mooring line, pulling the anchor chain end 792 towards the chain wheel 710, which rotates and pulls the anchor chain end 792 with it. The chain retaining arm 728 and the tail chain retaining arm 727 fix the position of the mooring line 790. Thus, the chain retaining arm 728 and the tail chain retaining arm 727 prevent or at least resist the pulling of the anchor chain end 792 towards the chain wheel 710 that would have occurred if the anchor chain end 792 had broken.

[0079] The chain retaining arm 728 and the tail chain retaining arm 727 can be bars that lock the position of the mooring lines when closed. Figure 7 shows the chain retaining arms 727 and 728 in a closed position, and Figure 11 shows the chain retaining arm 728 in an open position. Securing the anchor chain end 792 reduces movement (e.g., sway) of the anchor chain end 792, such as during heavy weather or sea conditions, thereby reducing the risk of damage to the fairlead stopper 700 and / or the floating vessel.

[0080] When the anchor chain end 792 is secured to the chain table 726, a portion of the anchor chain end 792 engages over the chain deflector 725. The chain deflector 725 provides a surface for the portion of the anchor chain end 792 to rest on without interfering with other components of the fairlead stopper 700, such as the latch 730. As shown in Figures 10A and 10B, the chain deflector 725 deflects the anchor chain end 792 so that it hangs to one side of the mooring line 790, rather than hanging from the fairlead stopper 700 in alignment with the mooring line 790. Thus, the chain deflector 725 protects a portion of the fairlead stopper 700 from the anchor chain end 792. The chain deflector 725 includes a baffle 799. The baffle 799 includes or defines a trough 797. The baffles 799 are positioned to deflect the mooring lines into either trough 797. The troughs 797 deflect the mooring lines to either side of the fairlead stopper 700.

[0081] As shown in FIG. 8, the tail chain retaining arm 727 and the chain retaining arm 728 include handles 729a and 729b, respectively. The fairlead stopper 700 also includes a third handle 729c. The handles 729a-729c can be configured to allow engagement by an ROV or a diver. For example, the ROV or diver can engage the handle 729c to fix the position of the ROV or diver relative to the fairlead stopper 700. Once the position of the ROV or diver is fixed, the ROV or diver can engage the handle 729a to open or close the chain retaining arm 728. Once the position of the ROV or diver is fixed, the ROV or diver can engage the handle 729b to open or close the tail chain retaining arm 727. Each handle 729an-729c can be locked in place. Chain retaining arm 728 is pivotally coupled to arm housing 703a (which is coupled to or part of chainwheel housing 711) such that an ROV or diver can swing chain retaining arm 728 between open and closed positions about pivot pin 731. In the closed position, chain retaining arm 728 can be locked onto arm housing 703b. Similarly, tail chain retaining arm 727 is pivotally coupled to chain plate 705a such that an ROV or diver can swing tail chain retaining arm 727 between open and closed positions about pivot pin 735 as shown. In the closed position, tail chain retaining arm can be locked onto chain plate 705b.

[0082] The fairlead stopper 700 also includes a latch actuation lever 740 that an ROV or diver can actuate to control opening and closing of the latch. Actuation of the latch 730 can be performed to pay out additional mooring line. In some embodiments, actuation of the latch 730 can be performed from above the fairlead and / or remotely by the ROV or diver. In some embodiments, the ROV or diver can connect the wires from the deck of the vessel at a point above the fairlead, rather than from a location on the latch housing between the fairleads.

[0083] The fairlead stopper 700 includes a sea-fastening clevis 780 and a sea-fastening bracket 782. The sea-fastening bracket 782 is configured to have a first end 784 coupled to the floating vessel and a second end 786 coupled to the sea-fastening clevis 780. The sea-fastening clevis 780 and the sea-fastening bracket 782 are used to secure the fairlead stopper 700 to the floating vessel, such as during transportation of the floating vessel.

[0084] In some embodiments, a tail chain retaining arm is used instead of one or more pins (e.g., three pins) that secure the anchor end of the chain to the chain table. In some embodiments, the use of a tail chain retaining arm has advantages over the use of pins that secure the anchor end to the chain table. For example, a pin would normally need to be installed during transport, removed before mooring, and reinstalled after mooring, each of these steps requiring the use of an ROV or diver, and suitable sea conditions for the use of the ROV or diver. The tail chain retaining arm can be placed in an open position during transport of the vessel and left in the open position until mooring is completed. Thus, the tail chain retaining arm can be used without the need for an ROV or diver to open and close the arm before mooring. Also, whereas a pin has a high risk of falling when installed or removed, the tail chain retaining arm in some embodiments remains pivotally connected to the fairlead stopper at all times before, during, and after mooring. Both the chain retaining arm and the tail chain retaining arm can be locked in an open position (e.g., during transport) and locked in a closed position (e.g., after mooring is completed). The ability to lock and unlock the position of the chain retaining arm and tail chain retaining arm allows the chain retaining arm to be positioned out of the way during mooring operations and then swung into a locked position by the ROV or diver after mooring is complete. For example, the chain retaining arm and tail chain retaining arm can be locked into a closed position after mooring tensioning and poly stretching are completed.

[0085] Once the chain deflector 725 has deflected the chain end 792 to a position below the fairlead stop 700, an ROV or diver can access the chain end 792 for cutting operations. The chain deflector 725 is shaped and sized to move the chain end 792 to a desired position through the action of gravity upon lowering (e.g., from an AHTS). By hanging the chain end 792 from the chain deflector 725 to a position below the fairlead 700, the chain end 792 is more accessible for cutting and for reconnecting additional chain to extend the length of the mooring line. In some embodiments, the chain deflector 725 has a relatively large bell mouth that does not include protruding features and is shaped and sized to deflect the chain end to one side or the other of the latch housing 720.

[0086] Eliminating the use of pins to cut the tail chain allows the fairlead to swing vertically through a greater range without the risk of the chain bunching up between the pins. In some embodiments, the pins can be inserted only when the fairlead has enough tension to achieve a sufficient vertical angle.

[0087] Marine Fixed Braces and Wave-Reaction Bars Some floating vessels are designed such that the fairlead hangs vertically below the keel (e.g., floating production storages with relatively small pontoons) if the fairlead can hang vertically. In such an embodiment, the fairlead can be marine fixed in a position where the fairlead latch housing hangs at an angle such as 45 degrees. A marine fixing brace can be used to assist in the attachment of the fairlead to such vessels. A fairlead stopper 800 is shown in Figures 14-15. The fairlead stopper 800 includes a marine fixing brace 889. The marine fixing brace 889 is coupled between the fairlead housing 812 and the latch housing 820 (or another portion of the fairlead stopper). The marine fixing brace 889 can be a rigid bar or other structure configured to position the fairlead stopper 800 at a desired angle relative to the vessel (not shown). The length of the marine fixed brace 889 may be adjusted (adjustable) to change the angle of the fairlead stopper 800 relative to the fairlead housing 812 and / or the vessel to which the fairlead stopper 800 is coupled.

[0088] The fairlead stopper 800 also includes a wave reactive bar 879. The wave reactive bar 879 is coupled between the vessel (not shown) and the latch housing 820. The wave reactive bar 879 can be, for example, a strut or other device (e.g., a spring) capable of reacting to a force. The wave reactive bar 879 is configured to react to and dampen a force applied to the fairlead stopper 800. The wave reactive bar 879 can reduce the amount of force transmitted from the fairlead stopper 800 to the vessel. Although the wave reactive bar 879 is referred to as a "wave reactive" bar, it can also react to forces not caused by waves. The wave reactive bar 879 can be coupled between the vessel and the fairlead stopper 800, for example, during transport.

[0089] Pre-Messenger Line Some embodiments include a pre-messenger line that is used during mooring operations. The pre-messenger line can be secured at sea to the fairlead stopper and / or vessel prior to sailing, such as in the same or similar manner as shown in FIG. 2A. The pre-messenger line can be used at sea to pass heavier messenger lines. Referring to FIG. 2A, the pre-messenger line 300 has two LLLC links 302a and 302b. In other embodiments, the pre-messenger line has only one link. In other embodiments, the pre-messenger line has no links. In some embodiments, the pre-messenger line and the messenger line do not have standard chain links.

[0090] The use of pre-messenger lines avoids the need to move heavier messenger lines to the AHV for connection to the winch and mooring lines. In some embodiments, a pre-messenger line is attached to each fairlead stopper on the vessel. The pre-messenger lines can be attached at the shipyard prior to transport of the vessel. When the vessel is at the offshore site for mooring operations, a relatively heavy and sturdy messenger line can be threaded through the fairlead stopper. During mooring operations, this heavy and sturdy messenger line can be reused with each fairlead stopper on the vessel. This method has the advantage that only one messenger line is needed during mooring operations, instead of one messenger line for each mooring line.

[0091] 1A-1R, in some embodiments, the outer messenger line (first end 300a) is connected to the top chain 310 on the AHV 700 (as shown in FIG. 1F) and then placed overboard (as shown in FIG. 1G) before picking up the inner messenger line (second end 300b) as shown in FIG. 1H. At this point, the catenary is held by the fairlead stopper 100 while the AHV 700 approaches the vessel 200 to retrieve the inner messenger (second end 300b) as shown in FIG. 1H. In this process scenario, the need to place both the inner and outer messenger lines (first and second ends 300a, 300b) as well as the top chain 310 and holdback line (tension line 720) all on the deck of the AHV 700 at the same time can be avoided. Also, in at least some embodiments of this process scenario, there does not need to be more than two chain links in the pre-messenger line so that it can be hung off in the fairlead stopper.

[0092] Reducing ROV or diver effort provides the ability to complete mooring operations more quickly and allows mooring operations to be performed in poor conditions where ROVs and divers cannot operate, such as strong currents or significant wave height (Hs). In some embodiments, all four lines (inner messenger line, outer messenger line, top chain, holdback line) are taken simultaneously on the deck of the AHV. The chain links in the messenger lines introduce additional weight that must be held up (e.g., from falling into or below the fairlead stop). Thus, pre-messenger lines that do not include chain links can be used to reduce the weight of the AHV.

[0093] The pre-messenger line can be a small line that is relatively easy to handle. Examples of such pre-messenger lines include rope (e.g., .about.25 mm Dyneema) or wire. In some such embodiments, steel wire is used as the pre-messenger line because it does not float in typical sea conditions, is generally less flexible than other ropes, and is therefore less likely to get snagged during hand over operations. Both the first and second ends of the pre-messenger line are relatively easily delivered to the AHV and connected to a thicker messenger line on the deck of the AHV and threaded through a fairlead in preparation for connection to the top chain. In such embodiments, operations can be performed away from the moored floating vessel, avoiding the need for the AHV to remain stationed near the floating vessel for extended periods of time.

[0094] Exemplary Pre-Messenger Line Method One exemplary method of using pre-messenger lines includes threading the pre-messenger lines through fairlead stoppers at a shipyard before the ship sails, with both ends of the pre-messenger lines secured at the column tops of the ship.

[0095] After the pre-installed mooring lines are threaded through the fairlead stoppers and secured to the vessel, the vessel is transported to the desired site. At the desired site, an AHV is used to retrieve the pre-installed mooring lines from the seabed. The pre-installed mooring lines are locked to the Shark Jaws on the deck of the AHV.

[0096] After the mooring lines are locked, a holdback line is connected between the AHV's winch and a triplate connector located on the top chain of the mooring lines (e.g., at the top chain-to-poly connection).

[0097] After connection to the Tri-Plate connector, the AHV is positioned close to the vessel's hull (e.g., within approximately 25 m of the vessel).

[0098] Once the AHV is positioned near the vessel's hull, both ends of the pre-messenger line are transferred from the vessel to the AHV. The outer ends of the pre-messenger line are connected to a messenger line (e.g., wire or rope) on the AHV. The connected pre-messenger line ends and messenger line are then routed overboard and the loose ends of the messenger lines are secured to the deck of the AHV.

[0099] The AHV then pulls the inner pre-messenger line, pulling the connected pre-messenger line and messenger line through the fairlead stopper until the messenger line passes the fairlead stopper, then back onto the AHV.

[0100] Once the messenger line connected to the pre-messenger has passed the fairlead stopper and been pulled back onto the AHV, the pre-messenger line can be disconnected and discarded. At this point, both ends of the messenger line are on the deck of the AHV.

[0101] The top chain of the mooring line is then connected to the end of the messenger line that runs from the AHV into the chain guide (eg, 724) of the fairlead, i.e., the outer messenger line end.

[0102] A winch on the AHV is connected to the end of the messenger line that extends from the fairlead stopper chain wheel to the AHV (i.e., the inner messenger line end).

[0103] The connected top chain and outer messenger line are then let overboard.

[0104] The AHV pulls the messenger line until the messenger line chain enters the fairlead stopper.

[0105] The AHV continues to pull on the mooring line until the top chain is pulled onto the golden link of the mooring line. The messenger line can be disconnected from the top chain at a convenient time during the process (e.g., when the messenger line attachment point reaches the deck of the AHV or when enough chain has been pulled through the fairlead and lowered to hang from the fairlead stop). In some embodiments, the messenger line is disconnected from the mooring line by an ROV or diver.

[0106] An exemplary pre-messenger line method is not limited to performing each of the steps above, nor is it limited to the order of steps described above. Some of the steps can be eliminated, some steps can be added, and some of the steps can be reordered. For example, the connection of the winch on the AHV to the tri-plate connector can be done after the messenger line is threaded through the fairlead stopper, if tension is low enough that the pre-messenger line can be pulled through the fairlead stopper, etc. Also, the messenger line can be pulled through the fairlead stopper before the top chain is overboard. The exact steps and their sequencing can be based on the length of the line, the load, the characteristics of the vessel, and the installation contractor's preferences.

[0107] Additional Features In conventional mooring systems using chain jacks, it is beneficial to limit the amount of chain that needs to be pulled, as pulling in chain results in an inefficient use of deck space and increases the weight of the chain locker without providing any benefit. If there is not enough excess chain to pull in, the AHV must be positioned in close proximity to the floating vessel to be moored, which requires additional energy and makes it difficult to maintain position. Typically, the initial mooring line can be relatively easily installed, since the tugs can move the floating vessel from a position close to the mooring line to facilitate the operation. Once the floating vessel is storm safe and the tugs are cut off, the floating vessel remains in place. Using the mooring method disclosed herein, remnants of the first cut LLLC connectorized chain length (e.g., the first four cut chain lengths) can be used to increase the amount of chain to thread through the fairleads on the ends of the mooring lines. This allows for a virtually infinite access to the chain that can be cut off after the pull ("infinite chain locker"). Adding an additional tail chain prior to the towing can reduce the towing power requirements of the AHV performing the towing task (e.g. allowing a smaller, lower cost AHV to be used).

[0108] Although specific embodiments and arrangements have been illustrated and described herein, those skilled in the art will understand that the methods, systems, and apparatus disclosed herein are not limited to the specific embodiments described.

[0109] Although the present embodiments and advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the present disclosure. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the processes, machines, products, compositions, means, methods and steps described herein. As will be readily apparent from the present disclosure to those skilled in the art, the present disclosure can be used to utilize existing or later developed processes, machines, products, compositions, means, methods or steps that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, products, compositions, means, methods or steps. [Explanation of symbols]

[0110] 100 Fairlead Stopper 110 Chainwheel 120 Latch housing 200 ships 300 Messenger Line 300a First end of messenger line 300b Second end of messenger line 300c messenger line mid-segment 310 Top Chain 311 Work Line 500a direction 700 Anchor Handling Vessel (AHV) 701 Mooring Line 712 Tension Coupler 712a Tension Coupler 712b Tension Coupler 713 Plate 714 Anchor 716 Waterline 717 Shackle 718 Undersea 719 Connection Chain 722 Bottom Chain 724a Midspan Line 724b Midspan Line

Claims

1. A fairlead stopper, a housing assembly; a latch movably coupled to the housing assembly; a chain wheel rotatably coupled to the housing assembly; at least one chain retention arm coupled to the housing assembly; the at least one chain retaining arm is movable between an open position and a closed position, the at least one chain retaining arm being positioned to secure a mooring line passing through the fairlead stopper in the closed position. A fairlead stopper characterized by the above.

2. a chain table coupled to the housing assembly; a chain deflector coupled to the housing assembly; the chain wheel is arranged to guide a mooring line to the chain table, the chain table is arranged to guide the mooring line to the chain deflector, and the chain deflector is configured to deflect the mooring line to one side of the fairlead stopper.

2. The fairlead stopper of claim 1.

3. the chain table includes a first chain plate coupled to a second chain plate, the first and second chain plates defining a trough positioned to receive a mooring line from the chain wheel; 3. The fairlead stopper according to claim 2.

4. the chain deflector includes a baffle defining at least one chain deflector trough, the at least one chain deflector trough positioned to deflect a mooring line to one side of the fairlead stop; 3. The fairlead stopper according to claim 2.

5. the at least one chain deflector trough includes a first chain deflector trough positioned to deflect a mooring line toward a first side of the fairlead stopper and a second chain deflector trough positioned to deflect a mooring line toward a second side of the fairlead stopper.

5. The fairlead stopper according to claim 4.

6. The at least one chain retaining arm comprises: a first chain retaining arm coupled to the housing assembly, movable between an open position and a closed position, the first chain retaining arm covering and engaging the chain wheel in the closed position to secure a mooring line passing through the chain wheel; a second chain retaining arm coupled to the chain table, movable between an open position and a closed position, the second chain retaining arm covering and engaging the chain table in the closed position to secure a mooring line disposed on the chain table; 3. The fairlead stopper of claim 2, comprising:

7. the at least one chain retention arm is pivotally coupled to the housing assembly and pivotally movable relative to the housing assembly between the open position and the closed position; 2. The fairlead stopper of claim 1.

8. and a marine fixation bracket, the marine fixation bracket being selectively coupleable to the housing assembly to secure the fairlead stopper to the vessel.

2. The fairlead stopper of claim 1.

9. 1. A method for handling mooring lines connected to a fairlead stopper, comprising: providing a fairlead stopper including a housing assembly, a latch coupled to the housing assembly, a chain wheel coupled to the housing assembly, and at least one chain retaining arm coupled to the housing assembly; Engaging a mooring line with the latch, the mooring line extending from the latch to the chain wheel and extending from the chain wheel beyond the chain wheel; moving the at least one chain retaining arm to a closed position such that the mooring line is secured between the at least one chain retaining arm and another portion of the fairlead stop; A method comprising:

10. directing the mooring line from the chain wheel to a chain table coupled to the housing assembly; directing the mooring line from the chain table to a chain deflector coupled to the housing assembly; deflecting the mooring line to one side of the fairlead stopper with the chain deflector; 10. The method of claim 9, further comprising:

11. further comprising locking the at least one chain retaining arm in the closed position.

10. The method of claim 9.

12. A vessel, The hull and a fairlead stopper coupled to the hull; a marine fixed brace coupled between the fairlead stopper and the hull or between a first portion of the fairlead stopper and a second portion of the fairlead stopper; wherein the marine fixed brace extends to position the fairlead stopper at a fixed angle relative to the hull. A vessel characterized by:

13. 1. A method of positioning a fairlead stopper relative to a vessel, comprising: coupling the fairlead stopper to the vessel; connecting a marine fixed brace between the fairlead stopper and the vessel or between a first portion of the fairlead stopper and a second portion of the fairlead stopper; wherein the marine fixed brace extends to position the fairlead at an angle relative to the vessel. A method characterized by:

14. A vessel, The hull and a wave reactive bar coupled to the hull; a fairlead stopper coupled to the wave reactive bar; wherein the wave reaction bar reacts to forces applied to the fairlead stopper. A vessel characterized by:

15. the wave reactive bar includes a strut; 15. The watercraft of claim 14.

16. 1. A method for damping forces applied to a vessel from a fairlead stopper, comprising: coupling a wave reactive bar to the vessel; coupling a fairlead stopper to the wave reactive bar; Responding to forces applied to the fairlead stopper with the wave reaction bar; A method comprising:

17. 1. A method of mooring a floating vessel, comprising: passing a pre-messenger line through a fairlead stopper coupled to the vessel; retrieving pre-installed mooring lines from the seabed by an AHV and securing the pre-installed mooring lines on a deck of the AHV; connecting a holdback line between a winch of the AHV and a tri-plate connector coupled to a top chain of the pre-installed mooring line; transferring two ends of the pre-messenger line, including an outer end and an inner end, from the vessel to the AHV; connecting the outer end to a first end of a messenger line on the AHV; extending the connected ends of the pre-messenger line and the messenger line overboard and securing a second end of the messenger line on the deck of the AHV; pulling the inboard end of the pre-messenger line through the fairlead stopper to pull the pre-messenger line and the messenger line until the messenger line passes through the fairlead stopper and is raised onto the deck of the AHV; disconnecting the pre-messenger line from the messenger line; connecting the top chain of the mooring line to the second end of the messenger line extending from the AHV to a chain guide of a fairlead, and connecting a winch on the AHV to the first end of the messenger line extending from a chain wheel of the fairlead stopper to the AHV; taking the connected top chain and messenger line outboard; pulling the messenger line until the top chain of the mooring line enters the fairlead stopper and a first tension is applied to the mooring line; disconnecting the messenger line from the top chain; A method comprising:

18. 1. A method of mooring a floating vessel having a fairlead stopper attached thereto, comprising: securing a plurality of mooring lines to a plurality of fairlead stoppers on the floating vessel; cutting a length of tail chain from the plurality of mooring lines after securing the plurality of mooring lines; connecting at least one of the cut lengths of the tail chain to one of the plurality of mooring lines and thereafter hauling in the mooring line; A method comprising:

19. 1. A method of mooring a floating vessel, comprising: passing a pre-messenger line through a fairlead stopper coupled to the vessel; connecting a first end of the pre-messenger line to a first end of a messenger line on an AHV; extending the connected ends of the pre-messenger line and the messenger line overboard and securing a second end of the messenger line on the deck of the AHV; pulling the connected pre-messenger line and messenger line by drawing the second end of the pre-messenger line through the fairlead stopper onto the AHV until the first end of the messenger line passes through the fairlead stopper and is raised onto the deck of the AHV; disconnecting the pre-messenger line from the messenger line; connecting a mooring line to the second end of the messenger line extending from the AHV into a chain guide of a fairlead, and connecting a winch on the AHV to the first end of the messenger line extending from a chain wheel of the fairlead stopper to the AHV; letting the connected mooring lines and messenger lines outboard; pulling the messenger line until the mooring line enters the fairlead stopper and a first tension is applied to the mooring line; disconnecting the messenger line from the mooring line; A method comprising:

20. 1. A method for connecting a messenger line to a fairlead stopper, comprising: passing a pre-messenger line through a fairlead stopper coupled to the vessel; connecting a first end of the pre-messenger line to a first end of a messenger line on an AHV; extending the connected ends of the pre-messenger line and the messenger line overboard and securing a second end of the messenger line on the deck of the AHV; pulling the connected pre-messenger line and messenger line by drawing the second end of the pre-messenger line through the fairlead stopper onto the AHV until the first end of the messenger line passes through the fairlead stopper and is raised onto the deck of the AHV; disconnecting the pre-messenger line from the messenger line; A method comprising:

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