JP2023531712A - Mooring equipment for in-line tensioning - Google Patents

Abstract

Systems and methods for tensioning mooring lines are provided. The system includes an in-line tensioner comprising a removable chain wheel, a tail chain disconnect table configured to enable tail chain disconnect and ROV docking, an in-line tensioner and a mooring A chain guide with low friction pads to reduce frictional engagement forces with the chain and a target link stop, the target link stop configured to stop movement of the mooring line at a predetermined location. As a result, the mooring line has a predetermined length and a predetermined link of the mooring line is positioned within the gripping zone of the latch of the in-line tensioner.

Description

The present disclosure (the present invention) relates to systems and methods for mooring ships and systems and methods for tensioning mooring lines. In particular, the present disclosure relates to systems and methods for tensioning mooring lines using in-line tensioners.

[Reference to related applications]
This application claims the benefit of U.S. Provisional Patent Application No. 63/043,403 (pending) (Title: Mooring Equipment for Use in In-Line Tensioning), filed June 24, 2020, which is incorporated by reference in its entirety.

In many applications, floating vessels require mooring, for example in offshore drilling platform applications. Mooring lines typically require at least some degree of tensioning to securely moor the vessel. One technique for mooring and tensioning uses a so-called "in-line tensioner (ILT)" to tension the mooring lines.

Some embodiments of the invention include an in-line tensioner for applying tension to mooring lines.

In some embodiments, the in-line tensioner has a frame configured to couple to the bottom chain of the mooring line, a latch coupled to the frame and positioned to grip the top chain of the mooring line, and a chain wheel. Chainwheels have at least two forms. At least two configurations include a first configuration in which the chainwheel is coupled to the frame and positioned to guide the top chain of the mooring line, and a second configuration in which the chainwheel is uncoupled from the frame.

In some embodiments, the in-line tensioner includes a frame configured to couple to the bottom chain of the mooring line, a latch coupled to the frame and positioned to grip the top chain of the mooring line, a chain wheel coupled to the frame and positioned to guide the top chain of the mooring line, and a chain guide coupled to the frame and positioned to guide the top chain of the mooring line. A latch is positioned between the chainwheel and the chain guide. Pads are provided on the chain guide and are positioned for sliding engagement with the top chain of the mooring line as the mooring line passes through the in-line tensioner. The chain guide is made of a first material and the pad is made of a second material. The first material and the second material are different. The second material exhibits a coefficient of friction with respect to a top chain sliding along the second material that is lower than the coefficient of friction exhibited by the first material with respect to a top chain sliding along the first material.

In some embodiments, the in-line tensioner has a frame configured to couple to the bottom chain of the mooring line, a latch coupled to the frame and positioned to grip the top chain of the mooring line, a chain wheel coupled to the frame and positioned to guide the top chain of the mooring line, and a tail chain disconnect table integral with or coupled to the frame. The tail chain disconnect table is configured to receive and secure the tail chain of the mooring line.

Some embodiments of the invention include a mooring system with a mooring line having a bottom chain and a top chain. The mooring system includes an in-line tensioner having a frame and a latch coupled to the frame. A bottom chain is coupled to the frame. A latch is positioned to selectively grip the top chain such that the length of the top chain portion of the mooring line is adjustable. The mooring system includes target link stops coupled to the top chain. A target link stop is positioned along the top chain such that the mooring line has a target length when the target link stop engages the in-line tensioner.

Some embodiments of the invention include a method of mooring a floating vessel.

In some embodiments, the method includes providing an in-line tensioner having a frame, a chain wheel coupled to the frame, and a latch coupled to the frame. The method includes providing a mooring line including a bottom chain and a top chain, coupling the bottom chain between the frame and the anchor, and coupling the top chain to the chainwheel. The method includes coupling a first end of the topchain to the floating vessel. The method includes adjusting the length of the top chain between the floating vessel and the in-line tensioner until the mooring line has a target length. A chain wheel guides the movement of the top chain during adjustment. The method includes latching the top chain when the mooring line has a target length. The method includes removing the chain wheel from the in-line tensioner with the mooring line having the target length.

In some embodiments, the method includes providing an in-line tensioner having a frame, a chain wheel coupled to the frame, a latch coupled to the frame, and a chain guide coupled to the frame. A pad is positioned on the chain guide. The method includes providing a mooring line including a bottom chain and a top chain, coupling the bottom chain between the frame and the anchor, and coupling the top chain to the chainwheel. The method includes coupling a first end of the topchain to the floating vessel. The method includes adjusting the length of the top chain between the floating vessel and the in-line tensioner until the mooring line has a target length. The chainwheel guides the movement of the top chain during adjustment. The method includes latching the top chain when the mooring line has a target length. A latch is positioned along the top chain between the chainwheel and the chain guide. During adjustment of the length of the top chain, the top chain slides along the pads. The chain guide includes a first material and the pad includes a second material. The first material and the second material are different. The second material exhibits a lower coefficient of friction with respect to the top chain sliding along the second material than that exhibited by the first material.

In some embodiments, the method includes providing an in-line tensioner having a frame, a chain wheel coupled to the frame, a latch coupled to the frame, and a tail chain disconnect table integral with or coupled to the frame. The method includes providing a mooring line including a bottom chain and a top chain, coupling the bottom chain between the frame and the anchor, and coupling the top chain to the chainwheel. The method includes coupling a first end of the topchain to the floating vessel. The method includes adjusting the length of the top chain between the floating vessel and the in-line tensioner until the mooring line has a target length. The chainwheel guides the movement of the top chain during adjustment. The method includes latching the top chain when the mooring line has a target length. The method includes securing a tail chain of a top chain to a tail chain disconnect table and removing at least some of the tail chain from the top chain.

In some embodiments, the method includes providing an in-line tensioner having a frame, a chain wheel coupled to the frame, and a latch coupled to the frame. The method includes providing a mooring line including a bottom chain and a top chain, coupling the bottom chain between the frame and the anchor, and coupling the top chain to the chainwheel. The method includes coupling a first end of the topchain to the floating vessel. The method includes coupling a target link stop to the top chain. A target link stop is positioned along the top chain such that the mooring line has a target length when the target link stop engages the in-line tensioner. The method includes adjusting the length of the top chain between the floating vessel and the in-line tensioner until the target link stop engages the in-line tensioner. The method includes latching the top chain when the target link stop engages the in-line tensioner.

So that the features and advantages of the systems, devices, products, and/or methods of the present invention may be understood in detail, the specific description outlined above may be directed to embodiments of the invention, which are illustrated in the accompanying drawings, which form a part hereof. It should be noted, however, that the drawings merely describe various exemplary embodiments and should therefore not be considered as limiting the disclosed technical idea, as the invention can also include other effective embodiments.

It is a figure which shows the whole mooring installation. Fig. 3 shows another mooring system or overall installation; 2B is an enlarged partial view of the mooring system of FIG. 2A; FIG. 1 is a perspective view of an in-line tensioner; FIG. 1 is a plan view of an in-line tensioner; FIG. 1 is a side view of an in-line tensioner; FIG. FIG. 4 is an end view of an in-line tensioner; FIG. 4 is a perspective view of an in-line tensioner showing a chain engaging the in-line tensioner; FIG. FIG. 4 shows the in-line tensioner with the chainwheel removed; FIG. 10 is a perspective view of a target link stop; FIG. 11 is an end view of the target link stop; FIG. 11 is a side view of a target link stop; FIG. 9B is a cross-sectional view of the target link stopper of FIG. 9B taken along line AA. FIG. 11 is another perspective view of the target link stop; FIG. 4 is a perspective view of a target link stop engaged with a chain guide; FIG. 4 is a side view of a target link stop engaged with a chain guide; FIG. 4 shows an in-line tensioner with a chain wheel attached; FIG. 11 shows a tail chain fixed on a tail chain disconnect table including a disconnect link in a lateral orientation; FIG. 10 shows a tail chain fixed on a tail chain disconnect table including a disconnect link in a vertical orientation; FIG. 12 shows a tail chain fixed on a tail chain disconnect table including a disconnect link in a hanging orientation; FIG. 11 shows an in-line tensioner with the tail chain fixed to the tail chain disconnect table; Figure 13B shows the in-line tensioner of Figure 13A with the chain wheel being lifted from the in-line tensioner; FIG. 12 shows the ROV docked at the tail chain disconnect table, with the links removed from the tail chain disconnect table; Fig. 2 shows an in-line tensioner coupled to a mooring line and without a chain wheel attached;

Certain aspects of the present invention include systems and methods for mooring ships and tensioning mooring lines. The present invention includes systems and methods for mooring ships and applying tension to mooring lines using or incorporating in-line tensioning technology. Embodiments of the present invention include an in-line tensioner that can be positioned within or along a mooring line and used to tighten the mooring line. As described in detail below, embodiments of the in-line tensioner disclosed herein include (1) a removable chain wheel, (2) a chain guide with low-friction pads to reduce the force of frictional engagement with the chain, (3) a target link stop to stop mooring line motion at a predetermined location, (4) a disconnect table that allows the tail chain to disconnect from the mooring line, (5), or a combination thereof.

Entire mooring facility

FIG. 1 is a diagram illustrating an exemplary overall mooring system or installation that can utilize the in-line tensioner systems and methods disclosed herein. Although FIG. 1 shows a tethered wind turbine 12, the in-line tensioner systems and methods disclosed herein are not limited to use with tethered wind turbines and can be used to moor other structures, such as oil and gas drilling and production platforms, ships, or other floating structures.

As shown, the overall mooring arrangement 10 includes a wind turbine 12 moored to the seabed 14 via mooring lines 16 . The mooring lines 16 include chains 18 (bottom chains) anchored to the seabed 14 . Chain 18 is coupled to an in-line tensioner 20 . The mooring line 16 includes a wire 22 (top chain) that is coupled to an in-line tensioner 20 on the side opposite the chain 18 . Mooring line 16 includes H-links 24 coupled to wires 22 and tri-plates 28 coupled to H-links 24 via chains 26 . A chain, rope or wire 30 (eg, a minimum breaking load chain) is coupled between the triplate 28 and a replaceable strengthening point 32 of the wind turbine 12 .

Figures 2A and 2B show another mooring system demonstrating the use of an anchor handling vessel during mooring line tensioning. Mooring system 34 includes mooring lines 42 positioned to moor wind turbines 48 . The mooring line 42 includes an anchor chain 44 (bottom chain) coupled via an in-line tensioner 40 to a chain chain 46 (top chain). Anchor handling vessel 36 is positioned to pull a wire or chain 38 which is coupled to in-line tensioner 40 and coupled to or integral with chain 46 . Pulling on the wire or chain 38 results in tensioning of the chain 46 and thereby tensioning of the mooring line 42 .

The mooring systems illustrated in FIGS. 1-2B are examples of mooring systems in which the systems and methods disclosed herein can be used in mooring operations. As will be appreciated by those skilled in the art, the in-line tensioner systems and methods disclosed herein can be used in other mooring systems and configurations.

in-line tensioner

Certain embodiments of the invention include an in-line tensioner. 3-8, in-line tensioners are illustrated in accordance with at least some embodiments of the present invention. An in-line tensioner 101 (also referred to as an ILT 101) is configured to receive and couple to a mooring line and to provide a desired tension and length to the mooring line without moving the position of the mooring line. In-line tensioner 101 has a frame 103 . The frame 103 provides a latch housing for the latch of the inline tensioner 101 and a mount for attaching the chainwheel of the inline tensioner 101 . Frame 103 may be the main body of in-line tensioner 101 .

The frame 103 is attached to a mud mat 107 (eg skid). The mud mat 107 provides the ability for the in-line tensioner 101 to move around the deck of an anchor handling vessel (AHV), for example by means of tugger winches, and provides a structure to withstand the loads created when the in-line tensioner 101 is deployed under tension (which may be up to 1000 kN) on the stern rollers of the anchor handling vessel. Mud mat 107 also provides a surface for ILT 101 that can be placed on the ocean floor. For example, the mud mat 107 may be placed on the seabed upon attachment to pre-laid mooring lines, or the mud mat 107 may be placed on the seabed while the mooring lines are being replaced.

ILT 101 is coupled to chain 135 (also called anchor chain or bottom chain). For example, chain 135 may be fixedly coupled to frame 103 of ILT 101 , such as by chain connector 141 . Chain connector 141 is coupled to chain 135 and frame 103 (at 103a) via bushing 143 (eg, pinned thereto by pin connections). Bushing 143 may be a composite bushing to provide galvanic isolation. Bushing 143 may comprise a material capable of withstanding the full design mooring load (MBL of the mooring line). In some embodiments, bushing 143 comprises a low friction support material. In some embodiments, chain 135 is a "passive chain link", thus the length of chain 135 is not adjustable (ie, passive). That is, with one end of the chain 135 attached to the anchor and the other end attached to the ILT 101, the length of the chain 135 between the anchor and the ILT 101 does not change.

ILT 101 is coupled to chain 131 (also called top chain or work chain). The connection between ILT 101 and chain 131 is an "active chain connection", so the length of chain 131 is adjustable. That is, using the AHV in conjunction with the chain wheels and latches of the ILT 101 allows the length and tension of the chain 131 to be adjusted, thereby permitting anchoring of structures coupled to the chain. For example, the AHV can haul in or out the chain 131 , thereby increasing or decreasing the tension applied to the chain 131 .

As shown in FIG. 7, the passive chain link is located at the bottom end of the ILT 101, the active chain link is located at the top end of the ILT 101, and the chain wheel 115 is positioned between the passive chain link and the active chain link. In some embodiments, the passive chain link includes an ROV-actuated pin link (not shown) that decouples frame 103 from chain 135 . Removing the tension on the mooring line allows the ROV actuated pin connection to be safely and reliably released when desired.

removable chainwheel

ILT 101 includes removable chainwheel 115 . Although the embodiment of chainwheel 115 shown in FIGS. 3-7 is a dual chainwheel, the systems and methods disclosed herein are not limited to use with dual chainwheels. Chain wheel 115 is attached (eg, pinned) to frame 103 at location 103b. Specifically, the chainwheel 115 has a chainwheel mounting frame 153 that is pinned to the frame 103 . Chainwheel 115 is rotatably mounted to chainwheel mounting frame 153 via chainwheel axle 152 so that chainwheel 115 can rotate relative to chainwheel mounting frame 153 .

The frame 103 may have a chainwheel dock, such as a funnel 159 and a pin 157 configured to receive and secure the chainwheel 115 . The chainwheel mounting frame 153 has a piercing pin 161 . Piercing pin 161 is positioned to fit within a mating funnel 159 of frame 103 . Thus, the stabbing pin 161 and mating funnel 159 permit engagement and disengagement of the chain wheel mounting frame 153 and frame 103 . In some embodiments, the chainwheel mounting frame 153 has a counterweight to facilitate maintaining the stabbing pin 161 in a desired orientation (e.g., vertical) when the chainwheel 115 is lowered into position on the frame 103 during installation of the chainwheel 115 on the ILT 101. Chainwheel mounting frame 153 is pinned to frame 103 by pins 157 . The chainwheel and chainwheel frame are not limited to the particular structures shown and can have other structures that can be selectively attached to and removed from the ILT to provide a removable chainwheel. Thus, the removable chainwheel 115 disclosed herein has at least two forms. At least two configurations include a first configuration in which the chainwheel 115 is coupled to the frame 103 and positioned to guide the top chain 131, and a second configuration in which the chainwheel 115 is uncoupled from the frame 103 and removed from the ILT 101.

In operation, the chain wheel 115 rotates and guides the chain 131 as it is being hauled in or out (eg, through an AHV). In some embodiments, the chain wheel 115 has one or more (e.g., two) chain wheel contours with surface contours designed to engage the chain and has chain contact areas shaped to follow (match) the shape of the chain links, thereby minimizing localized stress. In some embodiments, chainwheel 115 is a dual chainwheel capable of engaging and guiding at least two different sized chains. In other embodiments, chainwheel 115 is a single chainwheel designed for use with only one size chain. In embodiments where the chainwheel 115 is a dual chainwheel, the dual chainwheel is configured to provide a seamless transition from engagement with the small size adjustment chain to engagement with the mooring chain. For example, a connector (link coupler) can connect two different size chains and engage dual chain wheels, thereby facilitating transitions between chain sizes. For example, the chainwheel 115 may be the same as or similar to (but not limited to) the chainwheel disclosed in U.S. Patent Application Publication No. 2019/0092599 (hereinafter "the '599 Application Publication"), which is incorporated herein by reference in its entirety. Also, both of the link couplers disclosed in the '599 published application can be used to connect a smaller size adjustment chain to a larger size tether chain. The use of link couplers and dual chainwheels allows the two different size chains to remain "clocked" on the chainwheel 115 and drop into appropriate pockets in the chainwheel 115 for chain support, thereby reducing bending applied to at least the chain links.

In some embodiments, chainwheel 115 includes two self-lubricating bushings that minimize rotational resistance to mounting frame 153 without requiring the use of external grease lubrication.

A handle 173 is coupled to the chain wheel mounting frame 153 . In operation, handle 173 may be used to manipulate (e.g., move) chainwheel 115 and chainwheel mounting frame 153, e.g., for installation into and removal from frame 103. For example, a wire, rope or chain of a winch or crane (e.g. mounted on an AHV) may engage handle 173 to lift chainwheel 115 and chainwheel mounting frame 153 from frame 103 or lower chainwheel 115 and chainwheel mounting frame 153 onto frame 103. By allowing the chainwheel 115 to be easily removed and reinstalled, when the chainwheel 115 is not in use, the chainwheel 115 can be removed to reduce the weight of the ILT 101, and can be reinstalled to provide access to, for example, retrieving or unwinding the chain. Reducing the weight of the ILT 101 results in better long-term performance of the ILT 101, reduces the number of moving parts left in the water column, thereby reducing marine biofouling and corrosion concerns, shifts the center of gravity of the ILT 101 to a position below the chainline such that less twisting of the mooring line occurs after tensioning, better maintainability of the moving parts (e.g., chain wheel bearings), or a combination thereof. A "chainline" as used herein is an imaginary line that coincides with the extension of a mooring line. Thus, with the center of gravity of the ILT 101 located below the chainline, the center of gravity of the ILT 101 will be closer to the seabed than the chainline.

Also, the ability to remove the chainwheel 115 allows it to be used and reused with a number of different in-line tensioners, thereby reducing the total number of chainwheels 115 required for a mooring operation, thus reducing the overall cost of the mooring operation. The funnel 159 and pin 161 allow for easy docking of the chain wheel 115 onto the frame 103, as the pin 161 is aligned with the funnel 159 and inserted into the funnel such that the chain wheel 115 is docked in the correct location and orientation. Additionally, the pin 157 that secures the docked chainwheel 115 to the frame 103 may be ROV operable, thereby allowing easy securing of the chainwheel 115 to the frame 103 . Reversing pin 157, pin 161 and funnel 159 facilitates removal of chain wheel 115 from the frame.

Chain guide with low friction pads

ILT 101 has a chain guide 117 . Chain guide 117 is positioned and configured to guide chain 131 into ILT 101 toward its latch. Chain guide 117 may be a tapered funnel that guides the chain. Guide 117 may be useful, for example, if the chain is laterally offset from ILT 101 and is being turned at the same time (eg, up to about 20°). The chain guide 117 and frame 103 are provided with anodes 119 which enable cathodic protection. A chain guide 117 (chain guide shoe) is positioned at the outboard end of the frame 103 . In the illustrated embodiment, the chain guide 117 is a double “V” funnel that contacts the chain links to help guide the chain properly through the chain wheel 115 and latch 145 during chain hauling. However, the chain guide disclosed herein is not limited to this particular embodiment.

A low-friction pad 118 is provided on the chain guide 117 . A low friction pad 118 is positioned to engage chain 131 as it passes through chain guide 117 . The low-friction pad 118 exhibits a reduced frictional force as the chain 131 slides along the surface of the low-friction pad 118 during hauling or unwinding, compared to the degree of friction exhibited by the chain 131 sliding along the surface of the underlying chain guide 117 (in the absence of the low-friction pad 118). For example, the low friction pad 118 may comprise a different material than the underlying chain guide 117 material. In some embodiments, low-friction pad 118 comprises a material different than that of chain 131 . The material of the low-friction pad 118 may be a material that exhibits a low coefficient of friction against the mooring chain 131 when the chain 131 slides along the low-friction pad 118 as compared to the coefficient of friction exhibited by the material of the underlying chain guide 117 when the mooring chain 131 slides along the underlying material of the chain guide 117. In some embodiments, both chain guide 117 and mooring chain 131 comprise the same material, eg steel. Without wishing to be bound by theory, a steel mooring chain sliding along a chain guide flat steel plate in seawater typically exhibits a CoF of about 0.25-0.5. Thus, the CoF of a steel mooring chain sliding along a low friction pad 118 in seawater can be less than 0.5, less than 0.25, or less than 0.2. By reducing the engagement friction force between chain 131 and chain guide 117, low friction pad 118 reduces the tendency of ILT 101 and chain catenaries to cycle up and down when chain 131 is lifted from the AHV. That is, the low-friction pad 118 reduces frictional forces during tensioning of the mooring line, thus reducing the tendency of the ILT 101 to repeatedly lift and drop due to static frictional forces of the chain rubbing against the chain guide 117. The reduced frictional force provided by the low-friction pad 118 at the interface of the chain guide 117 with the chain 131 facilitates better control of the mooring operation compared to an otherwise identical ILT without the low-friction pad 118.

latch

Chain guide 117 guides chain 131 to latch 145 of ILT 101 . Latch 145 is or forms part of the chain stop for ILT 101 . Latch 145 is positioned to engage chain 131 coupled to frame 103 and passing through ILT 101 . Latches 145 are operable to open so that they do not interfere with chain links passing through ILT 101 . Latch 145 is also operable to close so that latch 145 engages (latches to) chain links passing through ILT 101 . In some embodiments, the latch 145 is rotatable to change the orientation of the latch 145 with respect to the direction of chain extension, such that the latch 145 can be rotated to engage both the longitudinal and transverse links. As used herein, the terms "flat link" and "vertical link" refer to adjacent links on a chain that are oriented at a 90° or substantially 90° angle to each other, as is well understood by those skilled in the art. For example, U.S. Pat. No. 10,272,973 (the '973 patent) discloses a rotatable chain stop in which the latch can be rotated to engage both horizontal and vertical links. In some embodiments, the latches disclosed herein are the same as or similar to the rotatable latches disclosed in the '973 patent, which is hereby incorporated by reference in its entirety. In some embodiments, latches 145 include latch pawls with machined profiled pockets configured and shaped to hug chain links, thus maximizing chain contact area and reducing chain wear. In some embodiments, latch 145 is a rotatable latch that allows for various orientations of the chain, thereby reducing misalignment forces on latch 145 and the chain. In some embodiments, the latch 145 comprises a material that is less stiff than the material of the chain such that the chain fits into the latch 145 and local deflections that may occur are applied to the latch 145 and not to the chain.

Latch 145 may be mechanically opened by the chain when the chain is hauled. The illustrated embodiment includes two latches 145 that are mechanically linked together by a synchronizing linkage 127 to synchronize their movements. The closing force of the latches 145 may be provided by mechanical springs 125 (latch closing springs) that couple with the latches 145 to bias the latches 145 into the closed state. Other methods of providing a closing force for latch 145 include the use of counterweights, pneumatic or hydraulic springs, or a combination of these methods, depending on the particular application. In some embodiments, the ROV may be used for remote operation of the latch 145, a diver may operate the latch 145, or a mechanical wire routed to the AHV described above may operate the latch 145. For example, the latch 145 may be pinned in an open position (out of the way of the chain) by the ROV or diver during chain payout if desired.

ILT 101 has a latch lock 121 that fixes the position of latch 145 and a latch open handle 123 that opens latch 145 . In one exemplary embodiment, the ROV is manipulated to twist the latch lock pin 121 to pin the latch 145 in the open position, thereby activating the lock opening mechanism. When the latch 145 is opened, the latch 145 can automatically lock in the open position. The latch 145 may be opened by the ROV after tension on the chain is removed or by retrieving the chain a short distance (e.g., less than one chain pitch or about 1.5 chain links) until the first link contacts the bottom of the latch 145 and pushes the latch 145 to the open position, at which point the lock opening mechanism holds the latch 145 open to allow chain retraction. When chain payout is complete, the ROV is operated to pull the handle of latch lock 121, thereby releasing latch lock 121, and latch 145 will automatically close. In some embodiments of the in-line tensioner 101, remote operation of the latch 145 is controlled by hydraulic cylinders attached to the frame 103 and may be controlled by hoses and/or tubing routed to the deck described above, or may be controlled by acoustic and/or wireless remote devices (e.g., the deck of an AHV).

In some embodiments, latch 145 is designed to stop the mooring chain in a manner that reduces chain stress by supporting the chain on two profiled latches. The in-line tensioner 101 disclosed herein has a holding capacity equal to the minimum breaking load (MBL) of the mooring line.

chain cutting table

ILT 101 has a tail chain disconnect table 109 . The tail chain detachment table 109 is a structure configured to receive and fix the tail chain portion of the chain 131, and this tail chain detachment table serves as a structure for detaching or cutting the tail chain portion of the chain 131. In some embodiments, the tail chain disconnect table 109 has a docking station configured to receive and secure the ROV used for chain disconnect. For example, the tail chain disconnect table 109 can have a funnel or tube 111 configured to receive an ROV docking or piercing pin so that the ROV can be docked onto the ILT 101 for chain disconnect operations. As will be appreciated by those skilled in the art, a funnel or tube may be provided on the ROV and the stabbing pin on the tail chain disconnect table 109 . Also, as will be appreciated by those skilled in the art, the tail chain disconnect table may have other structures capable of receiving and securing the ROV, and such tail chain disconnect table is not limited to including pins and funnels.

A tail chain disconnect table 109 may be used to disconnect the tail chain from the mooring lines. In some embodiments, after tensioning the mooring line, the remaining tail chain (adjustment chain or work chain) is severed to reduce weight in the catenary, minimize mooring line twisting, and eliminate cumbersome future reconnections due to long tail chains hanging in the water column. Prior to disconnecting the tail chain, the tail chain is laid on the tail chain disconnect table 109 of the ILT 101 and secured thereto, for example, by ROV operating pins. For example, when positioned on tail chain disconnect table 109 , chain 131 may be pinned by chain locking pin 129 . Once the tail chain is pinned or otherwise secured to the tail chain detach table 109, the ROV docked on the tail chain detach table 109 can be operated to detach at least a portion of the tail chain. Removal of at least a portion of the tail chain may involve cutting a link of the tail chain or removing a D-link (or other removable link) of the tail chain.

In some embodiments, the tail chain disconnect table 109 is positioned outside the chain line so that operations to remove the tail chain can be performed outside the chain line. For example, as shown in FIG. 7, tail chain disconnect table 109 bows upward from the chain line (an imaginary line coaxial with chains 131, 135).

target link stopper

Some embodiments disclosed herein include target link stoppers (TLS). 9A-9E, one embodiment of target link stop 113 (TLS 113) is illustrated. The TLS 113 is attached to the topwork chain of the mooring line at a predetermined location along the chain and is configured to stop chain travel at a desired length and tension during mooring line tensioning. For example, the TLS 113 may be positioned to stop the tensioning of the mooring line so that a given chain link of the mooring line is positioned to be gripped by the latch 145 of the ILT 101 . The TLS 113 may be positioned to stop the tensioning of the mooring line so that a given chain link of the mooring line is positioned on the tail chain disconnect table 109 for cutting or removal. In operation, if the ILT 101 overshoots the target link, the ILT 101 may be required to pay out additional chain to return to the target mooring line length. Thus, TLS 113 can prevent or reduce chain overshoot.

TLS 113 has a first body end 122 coupled (eg, pinned) to a second body end 124 . TLS 113 may include two parts pinned together. For example, body portion 133a may be pinned to body portion 133b by pin 126 and hinged by hinge 137, such that body portions 133a, 133b may be opened (partially separated) by pivoting body portions 133a, 133b about hinge 137, secured about a mooring line, and then closed about and pinned to the mooring line by pin 126. The TLS 113 has a spring-loaded mechanism including a spring 165 positioned within mating chambers 132,134. Each spring 165 is configured to absorb shock loads applied to TLS 113 such that upon collision of TLS 113 and ILT 101 each spring 165 compresses and second body end 124 moves toward first body end 122 . Each spring 165 is housed within a mating chamber 132, 134 of the first and second body ends 122, 124, respectively. TLS 113 has a crush pad 167 positioned thereon to interface engagement between TLS 113 and ILT 101 . Collapse pad 167 helps absorb shock loads on TLS 113 .

In some embodiments, the TLS 113 is ROV compatible, such that the TLS 113 can be attached using the ROV, removed, and reattached before and after deployment.

10A and 10B, spring-loaded TLS 113 is shown engaged with chain 131 and ILT 101 . TLS 113 is positioned on chain 131 prior to deployment and tensioning operations. By removing pin 126, TLS 113 can be removed after work is completed (eg, using an ROV). With TLS 113 mounted at a desired location on chain 131, TLS 113 acts as a stop on chain 131 by engaging ILT 101 (eg, chain guide 117). Chain guide 117 interfaces with TLS 113 to receive and mitigate impact loads. When TLS 113 engages ILT 101, at least some compression of TLS 113 may occur as a result of compression of the spring of TLS 113 (spring 165). Engagement of TLS 113 and ILT 101 stops further movement of chain 131 so that the desired links of chain 131 are positioned within and latched into ILT 101 (by latches 145) and the mooring line has the desired length and/or desired tension. That is, TLS 113 may be positioned along chain 131 to stop movement of chain 131 when a given link of chain 131 is positioned within the gripping zone of latch 145 . A "gripping zone" is a position where a chain link located within the gripping zone is gripped and latched by latch 145 when latch 145 is in the closed position.

In some embodiments, TLS 113 has a mating geometry that matches that of ILT 101 so that the surface contact faces of TLS 113 and ILT 101 conform to each other to spread the load over a large surface area. In some embodiments, TLS 113 is shaped and/or dimensioned such that TLS 113 cannot pass through chain guide 117, thereby preventing further tensioning of the mooring line upon engagement of TLS 113 and chain guide 117.

As will be appreciated by those of ordinary skill in the art, the target link stoppers disclosed herein are not limited to the particular structures shown in FIGS. 9A-10B, but can include other structures that can couple with the mooring line and that can stop the tensioning of the mooring line upon engagement of the target link stopper with the in-line tensioner.

action

Next, the action of ILT 101 during tensioning of mooring lines will be described. Referring to FIG. 11, ILT 101 is shown coupled with chain 135 . Chain 135 extends to an anchor (not shown) at the seabed (not shown). ILT 101 is also coupled to chain 131 including upper portion 131a and lower portion 131b. Upper portion 131a extends from ILT 101 to a moored structure (not shown) (eg, a wind turbine tower). Lower portion 131b extends from ILT 101 to an anchor handling vessel (not shown). In operation, the anchor handling vessel hauls in or pays out the chain 131 by reeling it in or unwinding it. Once the desired length of chain 131 and/or tension on chain 131 is achieved, the latch of ILT 101 is used to latch chain 131 to fix the position of chain 131 relative to ILT 101 . In some embodiments, the desired length of chain 131 and/or the tension applied to chain 131 is determined to occur when the target link stop engages ILT 101, as shown in FIGS. 10A and 10B.

While the mooring line is under tension during the chainwheel 115 tensioning operation, the reaction to the mooring load is provided by the latch 145 . During mooring operations, the chain wheels 115 may be configured to pass LLC® connecting links and messenger chains, thus meeting the needs of a variety of mooring, tensioning and re-tensioning operations. The pre-tension load from which the chain wheel 115 reacts is typically relatively small compared to the MBL of the mooring line that the latch 145 supports (or is designed to support). Chain tension on chain wheel 115 is removed when latch 145 engages (ie, latches onto) the chain in the closed position.

12A-12C, after chain 131 is latched by the latches of ILT 101, the lower portion (tail chain) of chain 131b is laid on tail chain disconnect table 109 and pinned by pins 129. Referring to FIGS. In some embodiments, pinning chain 131 b to table 109 is performed with an ROV docked to table 109 . The lower portion of chain 131b has removable links 130a-130c. Removable links 130 a - 130 c are chain links that can be opened and closed so that they can be selectively attached to and removed from the remainder of chain 131 . For example, removable links 130a-130c may be D-links or the like. Removable link 130 a is shown in a horizontal orientation on table 109 in FIG. 12A with link 130 a positioned on track 114 . Removable link 130b is shown in a vertical orientation on table 109 in FIG. 12B with link 130b positioned within slot 112. FIG. Removable link 130c is shown in a hanging orientation above table 109 in FIG. The removable links may be threaded through the ILT 101 to the chain wheels 115 in either a vertical or horizontal orientation, giving the mooring installer the ability to choose which orientation is preferred for removal after tensioning.

13A and 13B, once the end of chain 131b has been pinned in place on tail chain disconnect table 109, chainwheel 115 can be removed from ILT 101 by, for example, removing two ROV compatible pins on each side of chainwheel 115 and then reeling chainwheel 115 upward using an AHV. The chainwheel 115 is disconnected from the frame 103 of the ILT 101 and lifted therefrom. For example, wire 175 may be lowered from a winch or crane installed on the AHV. Wire 175 may have a hook 176 that engages handle 173 to lift chain wheel 115 .

The tail chain disconnect table 109 provides a structure that can position and fix the chain 131b and a dock for the ROV to engage the tail chain disconnect table 109 to disconnect the chain 131b. To facilitate the operation and stabilize the ROV during chain disconnection, the dock of the tail chain disconnect table 109 includes an interface funnel 111 which may include locking features for engaging the ROV into locking relationship therewith. An interface funnel 111 allows the ROV to be docked onto the tail chain disconnect table 109 . ROV docking interface funnels 111 are positioned on both sides of the detach table 109 to provide the ROV operator with the option of approaching the ILT 101 from either side. Since the ROV manipulators are not needed to hold the ROV on the table 109, not all of the docked ROV manipulators are used to detach the tail chain (rather than using one of the ROV manipulators for retention on the detach table 109). Docking the ROV allows the ROV to be easily controlled so as not to drop the chain lock pin 129 when it is being removed. A chain lock pin 129 on the disconnection table 109 is used to facilitate the disconnection operation. Chain lock pin 129 may be guided and captured by the ROV, thus reducing the risk of dropping chain lock pin 129 . A chain lock pin 129 is positioned outside the mooring load path and may be configured to meet corrosion requirements for mooring line life. The chain locking pin 129 fixes the position of the chain 131 on the disconnect table 109 by being pinned onto the links of the chain 131 .

Referring to FIG. 14, the chainwheel 115 has been removed from the ILT 101 and the ROV 201 is docked on the table 109 for work to disconnect the removable links of the chain 131 from the rest of the chain 131. A stab pin 203 of the ROV 201 fits within the funnel 111 . Removable link 130 allows disconnection of work chain 131 from the mooring chain after tensioning is complete. Because the final mooring length can be accurately calculated (e.g., using target link stops 113), the location of links 130 of chain 131 can also be accurately calculated so that links 130 can be installed at precise locations along chain 131. The link 130 is removable by removing a pin 171 threaded into the link 130 (e.g., threaded with an ACME screw that provides high strength and is detented so that the pin does not tend to loosen and pull itself out). This removal of pin 171 can be accomplished using ROV 201 . For added safety, a safety wire (not shown) may be used to keep pin 171 fully screwed in during operation. In such embodiments, ROV 201 can be used to cut the safety wire before pin 171 is removed. In one embodiment, the end of pin 171 has an internal hexagonal cavity that mates with a male drive bit attached to an ROV torque tool. By allowing ROV 201 to be rigidly attached to table 109 via funnel 111 and pin 203, ROV 201 can be safely used with torque tools. That is, by allowing ROV 201 to be rigidly attached to table 109 by funnel 111 and pin 203 (or other docking structure), "swimming" by ROV 201 is prevented or reduced during the task of uncoupling, so that ROV 201 is static or substantially static with respect to ILT 101 during uncoupling of link 130. In some embodiments, when one manipulator 205a of the ROV 201 is used to remove the pin 171 using a torque tool, another manipulator 205b of the ROV 201 can be used to capture the pin 171, thereby reducing the risk of the pin 171 falling to the ocean floor. Although decoupling the tail chain has been described as including removal of removable links, in other embodiments the links may be cut from the work chain. For example, the ROV may activate a cutting tool to cut the links of the work chain.

If the work chain 131 is installed in the AHV-mounted ILT 101 prior to deployment, the orientation of the chain links can be pre-selected. The ILT 101 of the present invention can accommodate any orientation of the chain links. Thus, the ILT 101 of the present invention allows the mooring installer to determine which chain link orientation is most favorable for use in a particular application and situation, and such chain link orientation is not limited to having the chain line have a particular orientation. Thus, the ILT 101 of the present invention has design flexibility for multiple locations for tail chain disconnection.

FIG. 15 shows ILT 101 incorporated into a mooring line and connecting chain 131 a to chain 135 , chain portion 131 b being pinned to ILT 101 by pin 129 .

After completion of mooring line tensioning, if additional chain payout is required, the ROV connecting link may be connected back to the last exposed link of the work chain left on the chain disconnect table 109. The uncoupling table 109 is configured so that the last link of the chain can be rejoined in either orientation (i.e., longitudinal or transverse orientation) in a manner that is available and accessible for rejoining. Three different options for the orientation and position of the connecting links are shown in Figures 12A-12C, as described above. With chain 131 and chain 135 coupled to the AHV prior to deployment, a determination can be made prior to deployment as to which orientation is best and easiest for future re-coupling. As shown, the uncoupling table 109 has slots 112 for receiving vertical links and tracks 114 for receiving lateral links. However, the detach table 109 is not limited to these particular configurations, and such detach table may include other structures for receiving and securing chain links in longitudinal or transverse orientation.

Another feature of the flexibility in the configuration of the uncoupling table 109 is that if additional lengths of chain need to be cut (e.g., more chain is required for hauling), an underwater diamond saw type chain cutter may be used, optionally modified. For example, a bayonet pin or other docking structure may be provided on the cutter to dock with (interface with) a receiving funnel 111 or other docking structure provided on the detach table 109 . Thus, the uncoupling table 109 is a structure capable of securing the work chain 131 and serving as a docking station for either an ROV or a chain cutter using a diamond wire saw to perform the severing.

floating boat

In some embodiments, the mooring methods and equipment disclosed herein are used on many vessels of various types, such as oilfield drilling or production platforms, floating production, storage and offloading (FPSO) vessels, offshore floating wind farm foundations, floating fish farms, or any other offshore floating structure. The AHV disclosed herein may be a watercraft that includes one or more winches, cranes, shark jaws, stern rollers, ROVs, and other equipment that can be used to moor the watercraft.

Mooring rope

The mooring lines disclosed herein may include one or more sections of line, each of which may be constructed of homogeneous or dissimilar materials. The various segments of mooring line may be joined together by shackles, H-links, or other connectors. Bottom chain 135 may be a pile forerunner attached to an anchor on the seabed. The anchors may be suction piles, driven piles, drag-embedded anchors, gravity anchors, torpedo anchors, or other types of anchors positioned on the revision. The bottom chain 135 may be pre-laid on the seabed at the site and stored subsea before the ship is towed to the site, or it may be laid on the seabed after the ship is towed to the site.

In some embodiments, the in-line tensioners disclosed herein are configured to use work chains that are smaller than the mooring line chains to tighten the mooring lines with reduced weight and cost.

Although specific embodiments and devices have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that the methods, systems, and apparatus disclosed herein are not limited to those specific embodiments described.

While embodiments and advantages of the present invention have been described in detail, it should be understood that various modifications, substitutions, and variations of such embodiments may be made without departing from the spirit and scope of the invention. Moreover, the scope of the invention is not limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art from this disclosure will readily appreciate, any process, machine, manufacture, composition of matter, means, method, or step now existing or later developed to perform substantially the same function or yield substantially the same results as the corresponding embodiments described herein can be utilized in accordance with the present disclosure. Accordingly, the appended claims are intended to include such processes, machines, manufacture, compositions of matter, means, methods, or steps within the scope of the invention as recited in such claims.

Claims (48)

An in-line tensioner for applying tension to a mooring line, the in-line tensioner comprising:
a frame configured to couple to the bottom chain of the mooring line;
a latch coupled to said frame, said latch positioned to grip a top chain of a mooring line;
An in-line tensioner having a chain wheel, said chain wheel having at least two configurations, said at least two configurations including a first configuration in which said chain wheel is coupled to said frame and positioned to guide a top chain of a mooring line, and a second configuration in which said chain wheel is uncoupled from said frame. 2. The in-line tensioner of claim 1, wherein the frame has a chainwheel dock, the chainwheel dock configured to receive the chainwheel in the first configuration. 3. The in-line tensioner of claim 2, wherein the chainwheel is attached to a chainwheel frame. 4. The in-line tensioner of claim 3, wherein in the first configuration, the chainwheel frame is pinned to the frame. 4. The in-line tensioner of claim 3, wherein the chainwheel frame includes a pin and the chainwheel dock includes a funnel, wherein in the first configuration the pin fits within the funnel and in the second configuration the pin disengages from the funnel. 4. The in-line tensioner of claim 3, further comprising a chainwheel handle coupled to the chainwheel frame, the chainwheel handle configured to couple to a line for lifting and removing the chainwheel from the frame. 4. The in-line tensioner of claim 3, wherein the chain wheel frame includes a counterweight configured to maintain the orientation of the pin. 2. The in-line tensioner of claim 1, wherein in the second configuration the center of gravity of the in-line tensioner is located below the chainline of the mooring lines. An in-line tensioner for applying tension to a mooring line, the in-line tensioner comprising:
a frame configured to couple to the bottom chain of the mooring line;
a latch coupled to said frame, said latch positioned to grip a top chain of a mooring line;
a chain wheel coupled to said frame and positioned to guide a top chain of a mooring line;
a chain guide coupled to the frame, the chain guide positioned to guide a top chain of a mooring line, the latch positioned between the chain wheel and the chain guide;
An in-line tensioner having a pad on said chain guide and positioned for sliding engagement with a top chain of a mooring line, said chain guide being made of a first material, said pad being made of a second material, said first material and said second material being different, said second material exhibiting a lower coefficient of friction with a top chain sliding along said second material than said first material exhibits. 10. The in-line tensioner of claim 9, wherein said first material comprises steel. 10. The in-line tensioner of claim 9, wherein said second material comprises bronze. 10. The in-line tensioner of claim 9, wherein said second material comprises a dry lubricious sintered material. 10. The in-line tensioner of claim 9, wherein the chain guide includes a tapered funnel, and the pad is positioned on an inner surface of the tapered funnel. An in-line tensioner for applying tension to a mooring line, the in-line tensioner comprising:
a frame configured to couple to the bottom chain of the mooring line;
a latch coupled to said frame, said latch positioned to grip a top chain of a mooring line;
a chain wheel coupled to said frame and positioned to guide a top chain of a mooring line;
An in-line tensioner comprising a tail chain disconnect table integral with or coupled to said frame, said tail chain disconnect table configured to receive and secure a tail chain of a mooring line. 15. The in-line tensioner of claim 14, wherein the tail chain disconnect table has a tail chain locking pin that secures the tail chain to the tail chain disconnect table. 15. The in-line tensioner of claim 14, wherein the tail chain disconnect table is configured to receive and secure the tail chain in a vertical orientation, a horizontal orientation, or a hanging orientation. 17. The in-line tensioner of claim 16, wherein the tail chain disconnect table has a track configured to receive the tail chain in a transverse orientation and a slot configured to receive the tail chain in a longitudinal orientation. 15. The in-line tensioner of claim 14, wherein the tail chain disconnect table comprises a tethered underwater vehicle (ROV) dock, the tethered underwater vehicle (ROV) dock configured to receive and secure a tethered underwater vehicle. 19. The in-line tensioner of claim 18, wherein the tethered underwater vehicle dock has a funnel configured to engage a pin of a tethered underwater vehicle. A mooring system, the mooring system comprising:
including a mooring line with a bottom chain and a top chain;
an in-line tensioner having a frame and a latch coupled to the frame, the bottom chain coupled to the frame, the latch positioned to selectively grip the top chain such that the length of the top chain portion of the mooring line is adjustable;
A mooring system comprising a target link stop coupled to the top chain, the target link stop positioned along the top chain such that the mooring line has a target length when the target link stop engages the in-line tensioner. 21. The mooring system of claim 20, wherein in the target length condition, the target link stop is positioned outboard of the latch and a removable link of the top chain is positioned opposite the latch, the removable link being a link selectively removable from the top chain. 22. The mooring system of claim 21, wherein said removable link is a D-link. 21. The mooring system of claim 20, wherein in the target length condition, a given link of the top chain is positioned to be gripped by the latch. 21. The mooring system of claim 20, wherein in the target target length condition, the top chain has a predetermined tension. 21. The mooring system of claim 20, wherein with the top chain moving in the first direction through the in-line tensioner, engagement of the target link stop with the in-line tensioner prevents further movement of the top chain in the first direction. 21. The mooring system of claim 20, wherein the target link stop has a first body and a second body, the first body and the second body coupled together about a portion of the top chain, and a spring coupled between the first body and the second body. 21. The mooring system of claim 20, wherein the in-line tensioner includes a chain guide, and the target link stop engages the chain guide when at the target length. A method of mooring a floating vessel, said method comprising:
providing an in-line tensioner having a frame, a chain wheel coupled to said frame, and a latch coupled to said frame;
providing a mooring line including a bottom chain and a top chain;
coupling the bottom chain between the frame and an anchor;
coupling the top chain to the chain wheel and coupling a first end of the top chain to the floating boat;
adjusting the length of the top chain between the floating vessel and the in-line tensioner until the mooring line has a target length, wherein the chain wheel guides movement of the top chain during the adjustment;
grasping the top chain with the latch when the mooring line has the target length;
and removing the chain wheel from the in-line tensioner with the mooring line having the target length. 29. The method of claim 28, wherein the step of removing the chainwheel comprises unpinning a chainwheel frame of the chainwheel from the frame of the in-line tensioner and lifting the chainwheel from the in-line tensioner. 30. The method of claim 29, wherein the step of lifting the chainwheel from the in-line tensioner is performed using an anchor handling vessel. A method of mooring a floating vessel, said method comprising:
providing an in-line tensioner having a frame, a chain wheel coupled to said frame, a latch coupled to said frame, and a chain guide coupled to said frame, wherein a pad is positioned on said chain guide;
providing a mooring line including a bottom chain and a top chain;
coupling the bottom chain between the frame and an anchor;
coupling the top chain to the chain wheel and coupling a first end of the top chain to the floating boat;
adjusting the length of the top chain between the floating vessel and the in-line tensioner until the mooring line has a target length, wherein the chain wheel guides movement of the top chain during the adjustment;
grasping the top chain with the latch when the mooring line has the target length, the latch being positioned along the top chain between the chain wheel and the chain guide;
wherein, during said adjustment of said length of said top chain, said top chain slides along said pad, said chain guide is made of a first material, said pad is made of a second material, said first material and said second material are different, said second material exhibiting a lower coefficient of friction for a top chain sliding along said second material than that exhibited by said first material. 32. The method of claim 31, wherein said first material comprises steel. 32. The method of claim 31, wherein said second material comprises bronze. 32. The method of claim 31, wherein said second material comprises a dry lubricious sintered material. A method of mooring a floating vessel, said method comprising:
providing an in-line tensioner having a frame, a chain wheel coupled to said frame, a latch coupled to said frame, and a tail chain disconnect table integral with said frame or coupled to said frame;
providing a mooring line including a bottom chain and a top chain;
coupling the bottom chain between the frame and an anchor;
coupling the top chain to the chain wheel and coupling a first end of the top chain to the floating boat;
adjusting the length of the top chain between the floating vessel and the in-line tensioner until the mooring line has a target length, wherein the chain wheel guides movement of the top chain during the adjustment;
grasping the top chain with the latch when the mooring line has the target length;
fixing the tail chain of the top chain to the tail chain disconnect table;
A method comprising detaching at least some of said tail chain from said top chain. 36. The method of claim 35, wherein securing the tail chain comprises pinning the tail chain to the tail chain disconnect table. 36. The method of claim 35, wherein detaching at least some of the tail chain from the top chain includes detaching a removable link from the tail chain. 38. The method of claim 37, wherein said removable link is a D-link. 38. The method of claim 37, wherein the removable link is in a vertical orientation, a horizontal orientation, or a hanging orientation on the tail chain disconnect table. 38. The method of claim 37, wherein the removable link is disconnected using a tethered underwater vehicle. 41. The method of claim 40, further comprising docking the tethered underwater vehicle onto the tailchain disconnect table and fixing a position of the tethered underwater vehicle on the tailchain disconnect table prior to the step of removing at least some of the tail chain from the top chain. 42. The method of claim 41, wherein the step of docking the tethered vehicle includes fitting a pin on the tethered vehicle into a funnel on the tail chain disconnect table. 36. The method of claim 35, wherein the step of removing at least some of the tail chain from the top chain comprises cutting links of the tail chain. A method of mooring a floating vessel, said method comprising:
providing an in-line tensioner having a frame, a chain wheel coupled to said frame, and a latch coupled to said frame;
providing a mooring line including a bottom chain and a top chain;
coupling the bottom chain between the frame and an anchor;
coupling the top chain to the chain wheel and coupling a first end of the top chain to the floating boat;
coupling a target link stop to the top chain, the target link stop positioned along the top chain such that the tether line has a target length when the target link stop engages the in-line tensioner;
adjusting the length of the top chain between the floating vessel and the in-line tensioner until the target link stop engages the in-line tensioner;
catching the top chain with the latch when the target link stop engages the in-line tensioner. 45. The method of claim 44, wherein engagement of the target link stop and the in-line tensioner prevents further tensioning of the top chain. 45. The method of claim 44, wherein the target link stop has a first body and a second body, the first body and the second body coupled together about a portion of the top chain, and a spring coupled between the first body and the second body. 47. The method of claim 46, wherein the spring compresses upon engagement of the target link stop and the in-line tensioner. 45. The method of claim 44, wherein the in-line tensioner has a chain guide and the target link stop engages the chain guide.

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