Accurate laying and tensioning method for high holding power anchor and large-diameter anchor chain

Abstract

The invention provides a precise laying and tensioning method for a high holding power anchor and a large-diameter anchor chain. The precise laying and tensioning method specifically comprises the steps that S1, the anchor chain is pre-laid; s2, designing a laying anchor point around the center of the installation position of the aquaculture net cage; and S3, lowering the high holding power anchor at each laying anchor point and laying the corresponding anchor chain, specifically comprising the following steps of: (1) positioning the gunwale chain outlet point above the laying anchor point; (2) hoisting the high holding power anchor out of the outboard to a gunwale chain outlet point; (3) releasing the anchor chain through the winch to enable the high holding power anchor and the anchor chain to be lowered to the seabed, and releasing the anchor chain through the winch in a circulating releasing mode; (4) the engineering ship is made to advance along the anchor chain line, and the anchor chain is laid along the anchor chain line; (5) the anchor chain is tensioned, and the requirement is met when it is monitored that the tensioning force reaches 125 tons through a tension meter; and (6) positioning beacons are installed at the tail ends of the high holding power anchor and the anchor chain. The problems that deviation and bending exist in an existing anchor chain laying mode, and the anchoring precision is prone to being affected by external air flow are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of aquaculture cage installation, and in particular to a method for accurately laying and tensioning a large-grip anchor and a large-diameter anchor chain. Background Art

[0002] In the field of aquaculture cage installation, the laying of large-diameter anchor chains must not only meet the technical requirements of free lifting and lowering of the aquaculture cages, but also avoid entanglement between the cages and the underwater anchor chains. The laid anchor chains must also meet the specified tension requirements. The laying method of anchor chains used in the prior art is prone to deviation and bending, and the anchoring accuracy is easily affected by external wind currents, resulting in the inability to guarantee the catenary tension. In addition, an additional construction mother ship is required during the construction process to place the linear winch, affecting the construction efficiency. Summary of the invention

[0003] According to the above technical problems that the existing anchor chain laying method has deviation and bending, and the anchoring accuracy is easily affected by external wind flow, a method for accurately laying and tensioning a large-gripping anchor and a large-diameter anchor chain is provided.

[0004] The technical means adopted by the present invention are as follows:

[0005] A method for accurately laying and tensioning a large-holding anchor and a large-diameter anchor chain, specifically comprising the following steps:

[0006] S1. Anchor chain pre-laying: Complete the deck laying of four anchor chains and four large holding anchors on the engineering vessel and connect the four anchor chains with the four positioning anchors one-to-one;

[0007] S2. Design four anchor points with large holding power around the center of the aquaculture cage installation position, numbered as anchor points 1, 2, 3 and 4 in sequence. The line connecting each anchor point and the center of the aquaculture cage installation position is the anchor chain line for laying the anchor chain. The lengths of the four anchor chains are equal;

[0008] S3. After the tugboat arrives at the construction site with the engineering vessel, it lowers the high-holding anchor and lays the corresponding anchor chain at each anchoring point in a clockwise or counterclockwise order;

[0009] The process of lowering the high-holding anchor and laying the corresponding anchor chain at each anchoring point specifically includes:

[0010] (1) The tugboat tows the engineering vessel to the location of the anchoring point, and the tugboat assists the engineering vessel to drop anchor around the anchoring point. Then, the tugboat winds up the anchor wire of the engineering vessel so that the side chain exit point of the corresponding anchor chain of the high-holding anchor to be lowered on the engineering vessel is located above the anchoring point;

[0011] (2) The tugboat approaches the side chain exit point of the anchor chain of the large grab anchor to be lowered on the engineering vessel. The crane on the engineering vessel is connected to the anchor chain of the large grab anchor to be lowered through a steel cable. The large grab anchor is hoisted outboard and placed at the side chain exit point. The steel cable installed on the back plate of the anchor head of the large grab anchor is connected to the stern of the tugboat through a traction wire. The large grab anchor is affected by its own center of gravity and its posture is adjusted to have the anchor claw facing downward. Then the steel cable connecting the crane and the anchor chain is untied.

[0012] (3) The winch on the engineering vessel is used to release the anchor chain so that the high-holding anchor is lowered to the seabed together with the anchor chain. The winch releases the anchor chain in a cyclical manner, with 30 meters of anchor chain released in each cycle. The position of the tugboat is controlled so that the traction wire stabilizes the posture of the high-holding anchor during the lowering process and the anchor claw is always kept facing downward, thereby ensuring that the high-holding anchor can land positively at the anchor point and grab the seabed;

[0013] (4) Make the engineering ship move along the anchor chain line toward the center of the installation position of the aquaculture cage, and release the anchor chain through the winch on the engineering ship, so that the anchor chain is laid along the anchor chain line; when the total length of the anchor chain reaches 150m, the anchor chain is tensioned once, and the anchor chain is tensioned every time 50m of anchor chain is released, until the entire anchor chain is laid along the anchor chain line; the anchor chain is tensioned in the following way: the anchor chain is braked by the ratchet sprocket of the winch and continuously applied with force, and the anchor chain is tensioned as the engineering ship moves along the anchor chain line;

[0014] (5) Tensioning and tension test of the laid anchor chain: connect a dynamometer between the steel cable of the winch and the anchor chain at the end of the laid anchor chain. Before tensioning the anchor chain, stop the engineering vessel and brake the winch. Then, wind up the anchor wire on the engineering vessel on the different side of the anchor chain and loosen the anchor wire on the same side of the anchor chain to tension the anchor chain.

[0015] When the tension of the anchor chain reaches 125 tons through the tension meter, it means that the tension of the anchor chain meets the requirement. Then, the anchor wire on the same side as the anchor chain on the engineering ship is reeled in, and the anchor wire on the different side of the anchor chain is loosened to loosen the tensioned anchor chain.

[0016] (6) A positioning beacon is installed on the anchor eye plate of the high-holding anchor and at the end of the anchor chain, respectively, to detect the position of the high-holding anchor and the end of the anchor chain, and to determine whether there is a directional deviation or anchor chain stacking in the laying of the anchor chain based on the detected position of the high-holding anchor and the end of the anchor chain.

[0017] Furthermore, the high holding power anchor weighs 18T; the diameter of the anchor chain is 105mm, the weight of each meter of the anchor chain is 224kg, and the length of each anchor chain is 445m.

[0018] Furthermore, step S1 specifically includes: at the dock, using a crane on the engineering ship to first place four anchor chains and four large-holding anchors on the deck of the engineering ship, and laying each anchor chain in a serpentine shape along the width direction of the deck, placing the anchor claws of the large-holding anchor facing upward on the deck of the engineering ship, and then connecting the four anchor chains to the four positioning anchors one-to-one; and then connecting a steel cable to each of the two back plates of the anchor head of the large-holding anchor through a connecting shackle, so as to prepare for the subsequent laying of the anchor chain and ensure the positive landing of the large-holding anchor.

[0019] Furthermore, in step S3 (1), the error of the distance between the side chain point and the anchor point is (-25m, +10m), and the side closer to the installation position of the aquaculture cage when the side chain point is located on the straight line where the anchor line is located is a negative value.

[0020] Furthermore, in step S3 (6), shackles are installed on the anchor eye plate of the high-holding anchor and at the end of the anchor chain, and the nylon rope of the corresponding positioning beacon is passed through the shackle and fixed to the stern of the tugboat and the side of the engineering vessel respectively.

[0021] Further, in step S3 (3), when releasing the anchor chain by the winch, in each cycle: first, the winch's steel cable is connected to the anchor chain, and the winch is controlled to release the anchor chain. When the anchor chain is released by 30 meters, the connection between the winch's steel cable and the anchor chain reaches the cable guide pile on the side of the engineering vessel. Then, the connection between the anchor chain and the winch's steel cable is connected to the ground order on the deck of the engineering vessel through a steel wire, and the connection between the winch's steel cable and the anchor chain is released, and the next cycle of releasing the anchor chain is entered.

[0022] Furthermore, step S3 (3) also includes: marking the end of the anchor chain connected to the high-holding anchor at a specified length from the installation position of the steel cable on the back plate of the high-holding anchor head; and determining the length of the anchor chain that needs to be released to allow the high-holding anchor to fall to the seabed at the anchor point according to the water depth at the anchor point through the mark on the anchor chain.

[0023] Furthermore, in step S3 (4), after the high-holding anchor is gripped into the seabed, when the 30m-50m anchor chain is released, the engineering vessel uses a winch to pull the anchor chain to confirm whether the high-holding anchor has gripped into the seabed. After confirming that it has gripped into the seabed, the anchor chain laying continues.

[0024] Furthermore, a 2T float is connected to the end of the anchor chain after tensioning and tension testing through a short steel cable, and the float is dropped into the sea.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The method for accurately laying and tensioning a large-holding anchor and a large-diameter anchor chain provided by the present invention uses an engineering vessel to accurately lay and tension the large-holding anchor and the anchor chain, can smoothly achieve the positive landing of the large-holding anchor, and can meet the 125t tensile test requirement of the anchor chain connecting the aquaculture cage in the absence of a tightening device for the anchor chain. The construction process is stable and is relatively less affected by on-site wind, waves, and currents. It also avoids the need to travel back and forth between the site and the dock for loading and unloading due to the use of a tugboat, thereby saving operation time.

[0027] Based on the above reasons, the present invention can be widely promoted in the field of aquaculture cage installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0029] Figure 1 Schematic diagram of the engineering vessel in position.

[0030] Figure 2 Schematic diagram of the engineering vessel arriving at the anchor point.

[0031] Figure 3 This is a schematic diagram of the state of the traction wire connecting the high-holding power anchor and the tugboat.

[0032] Figure 4 (1)-(3) are schematic diagrams of the process of amplifying the grip anchor under the cyclic release anchor chain.

[0033] Figure 5 (1)-(3) are schematic diagrams of the anchor chain laying process.

[0034] Figure 6 This is a schematic diagram of the anchor chain tensioning operation. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, the present invention provides a method for accurately laying and tensioning a large-grip anchor and a large-diameter anchor chain. The aquaculture cage in this embodiment is a deep-sea aquaculture cage, which specifically includes the following steps:

[0038] S1. Anchor chain pre-laying: Complete the deck laying of four anchor chains and four large holding anchors on the engineering vessel and connect the four anchor chains with the four positioning anchors one-to-one;

[0039] S2. Design four anchor points with large holding power around the center of the aquaculture cage installation position, numbered as anchor points 1, 2, 3 and 4 in sequence. The line connecting each anchor point and the center of the aquaculture cage installation position is the anchor chain line for laying the anchor chain. The lengths of the four anchor chains are equal;

[0040] S3. After the tugboat tows the engineering vessel to the construction site, it lowers the high-holding anchor and lays the corresponding anchor chain at each anchoring point in a clockwise or counterclockwise order. The order of laying the high-holding anchor and anchor chain (clockwise or counterclockwise) can be determined according to the wind flow conditions of the on-site environment, and the characteristics of the assisting ship being easier to operate against the current and downstream than the cross current can be fully considered to avoid the dangerous interference between the two ships caused by the inappropriate angle between the tugboat and the engineering vessel when pulling the anchor;

[0041] The process of lowering the high-holding anchor and laying the corresponding anchor chain at each anchoring point specifically includes:

[0042] (1) The tugboat tows the engineering vessel to the anchoring point. The tugboat assists the engineering vessel in dropping anchors around the anchoring point. The engineering vessel drops at least 6 anchors. Then, by reeling in the anchor wire of the engineering vessel, the side chain exit point of the corresponding anchor chain of the high-holding anchor to be lowered on the engineering vessel is located above the anchoring point.

[0043] (2) The tugboat maneuvers to approach the side chain exit point of the anchor chain of the large holding anchor to be lowered on the engineering vessel. The crane on the engineering vessel is connected to the anchor chain of the large holding anchor to be lowered through a steel cable (the connecting steel cable is φ38mm and 80m long, connected to the anchor chain at a position about 25m away from the large holding anchor through a shackle 85T). The large holding anchor is hoisted outboard and placed at the side chain exit point. The steel cable (φ38mm, 20m long, two cables) installed on the back plate of the large holding anchor head is connected to the stern of the tugboat through a traction wire (φ60mm, 75m long) (the traction wire is connected to the stern of the tugboat through a shackle 55T). The large holding anchor is affected by its own center of gravity and its posture is adjusted to have the anchor claw facing downward. Then the steel cable connecting the crane and the anchor chain is untied.

[0044] (3) The anchor chain is released by the winch (80t) on the engineering vessel so that the large holding power anchor is lowered to the seabed together with the anchor chain. The winch releases the anchor chain in a cyclical manner, with 30 meters of anchor chain released in each cycle, so that the large holding power anchor and the anchor chain can be released slowly, improving the accuracy of anchoring and preventing the anchor chain from being piled up on the seabed due to the anchor chain being released too quickly. The position of the tugboat is controlled so that the traction wire stabilizes the posture of the large holding power anchor during the lowering process and the anchor claw is always kept facing downward, thereby ensuring that the large holding power anchor can land positively at the anchoring point and grab the seabed;

[0045] The present invention ensures that the chain exit point on the side of the engineering ship is as close to the anchor point as possible through step (2), and the large grip anchor can ensure that the error of the distance between the landing point of the large grip anchor and the anchor point is (-25m, +10m) in combination with the method of step (3), and the landing point of the large grip anchor is located on the straight line where the anchor chain line is located, and the side close to the installation position of the aquaculture cage is a negative value;

[0046] (4) The engineering ship moves along the anchor chain line toward the center of the installation position of the aquaculture cage, and at the same time, the anchor chain is released by the winch on the engineering ship, so that the anchor chain is laid along the anchor chain line; when the total length of the anchor chain reaches 150m, the anchor chain is tensioned once, and the anchor chain is tensioned every time 50m of anchor chain is released, until the entire anchor chain is laid along the anchor chain line, so as to ensure that the anchor chain is laid in a straight line, which indirectly solves the problem of deviation and bending of the anchor chain laying; the anchor chain is tensioned in the following way: the anchor chain is braked by the ratchet sprocket of the winch and continuously applied with force, and the anchor chain is tensioned as the engineering ship moves along the anchor chain line;

[0047] During the anchoring process, the engineering vessel needs to be precisely manipulated to ensure that it always moves along the anchor chain line without too much deviation, to avoid large lateral displacement of the anchor chain and to prevent the anchor chain from accumulating, so as to lay a good foundation for the subsequent tensioning of the anchor chain and the connection of the cage;

[0048] (5) Tensioning and tension test of the laid anchor chain: a dynamometer is connected between the steel cable of the winch used for laying the anchor chain and the anchor chain. Before tensioning the anchor chain, the engineering vessel stops moving and brakes the winch. Then, the anchor wire on the engineering vessel on the different side of the anchor chain is reeled in, and the anchor wire on the same side as the anchor chain is loosened to tension the anchor chain. The dynamometer is installed between the steel cable of the winch used for laying the anchor chain and the anchor chain through two 120T shackles, and a swivel is connected in the middle to prevent the steel cable from twisting during tensioning.

[0049] When the tension of the anchor chain reaches 125 tons through the tension meter, it means that the tension of the anchor chain meets the requirement. Then, the anchor wire on the same side as the anchor chain on the engineering ship is reeled in, and the anchor wire on the different side of the anchor chain is loosened to loosen the tensioned anchor chain.

[0050] (6) A positioning beacon is installed on the anchor eye plate of the high-holding anchor and at the end of the anchor chain (the end close to the installation position of the aquaculture cage after laying) to detect the position of the high-holding anchor and the end of the anchor chain, and determine whether there is a directional deviation or anchor chain stacking in the laying of the anchor chain based on the detected position of the high-holding anchor and the end of the anchor chain.

[0051] Furthermore, step S1 specifically includes: at the dock, using a crane on the engineering ship to first place four anchor chains and four large-holding power anchors on the deck of the engineering ship, and laying each anchor chain in a serpentine shape along the width direction of the deck, placing the anchor claws of the large-holding power anchor on the deck of the engineering ship with the anchor claws facing upwards, and then connecting the four anchor chains to the four positioning anchors one-to-one; and then connecting a φ38mm steel cable with a length of 20m on the two back plates of the anchor head of the large-holding power anchor through connecting buckles (35T) respectively, to prepare for the subsequent laying of anchor chains and to ensure the positive landing of the large-holding power anchor.

[0052] Furthermore, the large holding power anchor weighs 18T; the anchor chain diameter is 105mm, the weight of each meter of the anchor chain is 224kg, and the length of each anchor chain is 445m; in step S1, when using a crane, a crane short rope with sufficient safety load should be selected, and the two main hooks and four auxiliary hooks of a small forklift and a crane are required to cooperate with each other to lift the anchor chain and lay the anchor chain on the deck; the anchor chain cannot be stacked on the deck to avoid affecting the deck operation when anchoring.

[0053] Furthermore, step S1 may also be based on actual arrangement conditions. If the deck space of the engineering vessel is insufficient to complete the advance connection of the anchor chain and the high-holding anchor, then on-site connection of the anchor chain and the high-holding anchor may be considered.

[0054] Furthermore, in step S3 (1), the error of the distance between the side chain point and the anchor point is (-25m, +10m), with the side chain point being located on the straight line where the anchor line is located and close to the installation position of the aquaculture cage as a negative value. The error of the distance between the side chain point and the anchor point can be monitored by the positioning equipment on the engineering vessel.

[0055] Further, in step S3 (6), shackles are installed on the anchor eye plate of the large holding power anchor and at the end of the anchor chain (the end close to the installation position of the aquaculture cage after laying), and the nylon rope of the corresponding positioning beacon (φ30mm, length 200m) is passed through the shackle and fixed to the stern of the tugboat and the side of the engineering ship respectively; after the anchor chain is tensioned, the tugboat detects the position of the large holding power anchor through the positioning beacon on the large holding power anchor, and the engineering ship uses the φ38mm steel cable to lower the end of the anchor chain to the seabed, and then detects the position of the end of the anchor chain through the positioning beacon installed at the end of the anchor chain. The detected position of the large holding power anchor and the position of the end of the anchor chain can be used to determine whether there is a directional deviation or anchor chain stacking in the laying of the anchor chain: the position of the end of the anchor chain after laying can be predicted in combination with the actual length of the anchor chain and the position of the arranged anchor point, and the comparison result between the detected position of the end of the anchor chain and the predicted position can be used to determine whether there is a deviation in the laying of the anchor chain; the laying distance of the anchor chain can be obtained based on the distance between the detected large holding power anchor and the position of the end of the anchor chain, and compared with the actual length of the anchor chain, it can be determined whether there is anchor chain stacking in the laying of the anchor chain.

[0056] Further, in step S3 (3), when releasing the anchor chain by the winch, in each cycle: first, the winch's steel cable is connected to the anchor chain, and the winch is controlled to release the anchor chain. When the anchor chain is released by 30 meters, the connection between the winch's steel cable and the anchor chain reaches the cable guide pile on the side of the engineering vessel. Then, the connection between the anchor chain and the winch's steel cable is connected to the ground order on the deck of the engineering vessel through a steel wire, and the connection between the winch's steel cable and the anchor chain is released, and the next cycle of releasing the anchor chain is entered.

[0057] Furthermore, step S3 (3) further includes: marking the end of the anchor chain connected to the high-hold anchor at a specified length (10 meters) from the installation position of the steel cable on the back plate of the high-hold anchor head; according to the water depth at the anchoring point, the length of the anchor chain required to be released to make the high-hold anchor fall to the seabed at the anchoring point can be determined by the mark on the anchor chain, so that the anchor chain can be released by accurately controlling the operation of the winch, and the ship can be manipulated to make the chain exit point on the side of the engineering ship as close to the specified anchor point as possible, and the two ships can be coordinated and controlled to ensure that the error of the distance between the landing point of the high-hold anchor and the deployment anchor point is (-25m, +10m), and the side close to the installation position of the aquaculture cage when the landing point of the high-hold anchor is on the straight line where the anchor chain line is located is a negative value.

[0058] Furthermore, in step S3 (4), when the engineering vessel is laying the anchor chain, the anchor wire of the engineering vessel is reeled in to ensure that the engineering vessel moves along the anchor chain line and the side chain exit point remains above the anchor chain line.

[0059] Furthermore, in step S3 (4), after the high-holding anchor is gripped into the seabed, when 30m-50m of anchor chain is released (taking the water depth of 56m as an example, about 100m of anchor chain is released at this step), the anchor chain is pulled by a winch on the engineering ship to confirm whether the high-holding anchor has been gripped into the seabed. After confirming that it has been gripped into the seabed, the anchor chain laying is continued.

[0060] Further, in step S3, if it is found that the landing point of the high holding power anchor does not meet the requirements, or the laying of the anchor chain does not meet the requirements, the tugboat can assist in recovering the high holding power anchor, and the high holding power anchor can be lowered and the anchor chain can be laid again until the requirements are met.

[0061] Furthermore, after completing the tensioning and tension tests, the anchor chain is driven by the engineering vessel to deviate from the anchor chain line and pull back 50m to create a bend, providing a clear space for the entry and connection of the cages.

[0062] Furthermore, a 2T float was connected to the end of the anchor chain after tensioning and tension testing through a short steel cable (φ38mm, length 80m), and the float was dropped into the sea. The float was used to provide a position mark for the subsequent operation of connecting the anchor chain during the installation of the aquaculture cage.

[0063] Furthermore, after completing the lowering of each large holding power anchor and the laying and tensioning of the corresponding anchor chain, the engineering vessel rotates the bow 90° and lowers the large holding power anchor and lays and tensions the corresponding anchor chain at other anchoring points in the same manner.

[0064] Furthermore, the tensioning method of each anchor chain is as described in step S3 (5).

[0065] The present invention uses an engineering vessel for operation, which has the following advantages:

[0066] First, it has a large deck area, which can realize the orderly arrangement and pre-laying of all four anchor chains and high-holding anchors, and also provides a large space for personnel to operate on deck, avoiding the need to travel back and forth between the site and the dock for loading and unloading when using tugboats, greatly saving operation time;

[0067] Second, the laying and tensioning of the anchor chain is driven by cranes and winches, which makes the construction process relatively stable and less affected by wind, waves and currents on site. This improves the tensioning method of the tugboat using a motor vehicle and also saves the fuel consumption cost of the tugboat.

[0068] Thirdly, the deck can be equipped with cranes and numerous deck machinery for auxiliary support, which is extremely convenient for lowering large-diameter anchor chains.

[0069] The use of the large-holding power anchor and large-diameter anchor chain precise laying and tensioning method described in the present invention can smoothly meet the positive landing and 125T tensile test requirements of the large-holding power anchor, solve the difficult problems of laying deviation and bending of the anchor chain of the aquaculture cage, and solve the influence of external wind flow on the anchoring accuracy.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for accurately laying and tensioning a large-holding anchor and a large-diameter anchor chain, characterized in that: The specific steps include: S1. Anchor chain pre-laying: Complete the deck laying of four anchor chains and four large holding anchors on the engineering vessel and connect the four anchor chains with the four positioning anchors one-to-one; S2. Design four anchor points with large holding power around the center of the aquaculture cage installation position, numbered as anchor points 1, 2, 3 and 4 in sequence. The line connecting each anchor point and the center of the aquaculture cage installation position is the anchor chain line for laying the anchor chain. The lengths of the four anchor chains are equal; S3. After the tugboat arrives at the construction site with the engineering vessel, it lowers the high-holding anchor and lays the corresponding anchor chain at each anchoring point in a clockwise or counterclockwise order; The process of lowering the high-holding anchor and laying the corresponding anchor chain at each anchoring point specifically includes: (1) The tugboat tows the engineering vessel to the location of the anchoring point, and the tugboat assists the engineering vessel to drop anchor around the anchoring point. Then, the tugboat winds up the anchor wire of the engineering vessel so that the side chain exit point of the corresponding anchor chain of the high-holding anchor to be lowered on the engineering vessel is located above the anchoring point; (2) The tugboat approaches the side chain exit point of the anchor chain of the large grab anchor to be lowered on the engineering vessel. The crane on the engineering vessel is connected to the anchor chain of the large grab anchor to be lowered through a steel cable. The large grab anchor is hoisted outboard and placed at the side chain exit point. The steel cable installed on the back plate of the anchor head of the large grab anchor is connected to the stern of the tugboat through a traction wire. The large grab anchor is affected by its own center of gravity and its posture is adjusted to have the anchor claw facing downward. Then the steel cable connecting the crane and the anchor chain is untied. (3) The winch on the engineering vessel is used to release the anchor chain so that the high-holding anchor is lowered to the seabed together with the anchor chain. The winch releases the anchor chain in a cyclical manner, with 30 meters of anchor chain released in each cycle. The position of the tugboat is controlled so that the traction wire stabilizes the posture of the high-holding anchor during the lowering process and the anchor claw is always kept facing downward, thereby ensuring that the high-holding anchor can land positively at the anchor point and grab the seabed; (4) Make the engineering ship move along the anchor chain line toward the center of the installation position of the aquaculture cage, and release the anchor chain through the winch on the engineering ship, so that the anchor chain is laid along the anchor chain line; when the total length of the anchor chain reaches 150m, the anchor chain is tensioned once, and the anchor chain is tensioned every time 50m of anchor chain is released, until the entire anchor chain is laid along the anchor chain line; the anchor chain is tensioned in the following way: the anchor chain is braked by the ratchet sprocket of the winch and continuously applied with force, and the anchor chain is tensioned as the engineering ship moves along the anchor chain line; (5) Tensioning and tension test of the laid anchor chain: connect a dynamometer between the steel cable of the winch and the anchor chain at the end of the laid anchor chain. Before tensioning the anchor chain, stop the engineering vessel and brake the winch. Then, wind up the anchor wire on the engineering vessel on the different side of the anchor chain and loosen the anchor wire on the same side of the anchor chain to tension the anchor chain. When the tension of the anchor chain reaches 125 tons through the tension meter, it means that the tension of the anchor chain meets the requirement. Then, the anchor wire on the same side as the anchor chain on the engineering ship is reeled in, and the anchor wire on the different side of the anchor chain is loosened to loosen the tensioned anchor chain. (6) A positioning beacon is installed on the anchor eye plate of the high-holding anchor and at the end of the anchor chain, respectively, to detect the position of the high-holding anchor and the end of the anchor chain, and to determine whether there is a directional deviation or anchor chain stacking in the laying of the anchor chain based on the detected position of the high-holding anchor and the end of the anchor chain.

2. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: The large holding power anchor weighs 18T; the diameter of the anchor chain is 105mm, the weight of each meter of the anchor chain is 224kg, and the length of each anchor chain is 445m.

3. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: Step S1 specifically includes: at the dock, using a crane on an engineering ship to first place four anchor chains and four large-holding power anchors on the deck of the engineering ship, and laying each anchor chain in a serpentine shape along the width direction of the deck, placing the large-holding power anchor with its anchor claw facing upward on the deck of the engineering ship, and then connecting the four anchor chains to the four positioning anchors one-to-one; and then connecting a steel cable to each of the two back plates of the anchor head of the large-holding power anchor through a connecting shackle, so as to prepare for the subsequent laying of the anchor chain and ensure the positive landing of the large-holding power anchor.

4. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: In step S3 (1), the error of the distance between the side chain point and the anchor point is (-25m, +10m), and the side closer to the installation position of the aquaculture cage when the side chain point is on the straight line where the anchor line is located is a negative value.

5. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: In step S3 (6), shackles are installed on the anchor eye plate of the high-holding anchor and at the end of the anchor chain, and the nylon rope of the corresponding positioning beacon is passed through the shackle and fixed to the stern of the tugboat and the side of the engineering vessel respectively.

6. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: In step S3 (3), when releasing the anchor chain by the winch, in each cycle: first, the winch's steel cable is connected to the anchor chain, and the winch is controlled to release the anchor chain. When the anchor chain is released for 30 meters, the connection between the winch's steel cable and the anchor chain reaches the cable guide pile on the side of the engineering vessel. Then, the connection between the anchor chain and the winch's steel cable is connected to the ground order on the deck of the engineering vessel through a steel wire, and the connection between the winch's steel cable and the anchor chain is released, and the next cycle of releasing the anchor chain is entered.

7. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: Step S3 (3) also includes: marking the end of the anchor chain connected to the high-holding anchor at a specified length from the installation position of the steel cable on the back plate of the high-holding anchor head; and determining the length of the anchor chain that needs to be released to drop the high-holding anchor to the seabed at the deployment point based on the water depth at the deployment point through the mark on the anchor chain.

8. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: In step S3 (4), after the high-holding anchor is gripped into the seabed, when the 30m-50m anchor chain is released, the engineering vessel uses a winch to pull the anchor chain to confirm whether the high-holding anchor has gripped into the seabed. After confirming that it has gripped into the seabed, the anchor chain laying continues.

9. The method for accurately laying and tensioning a large holding power anchor and a large diameter anchor chain according to claim 1, characterized in that: At the end of the anchor chain that has been tensioned and tested for tension, a 2T buoy is connected through a short steel cable and the buoy is dropped into the sea.

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