Positioning precision control method for installation of ship fair lead

Abstract

The invention relates to the technical field of fair lead installation, in particular to a positioning precision control method for ship fair lead installation, which comprises a jig frame, an upper base and a lower base are installed on the jig frame, a structure reinforcing pipe is detachably installed between the upper base and the lower base, and a temporary pipe is fixedly installed at the top of the lower base. An additional supporting pipe is fixedly installed on one side of the lower base, temporary fasteners are arranged on one side of the temporary pipe and one side of the upper base, a temporary supporting beam is installed on the jig frame, a supporting column is arranged on one side of the jig frame, and jacks are arranged on the supporting column and the temporary supporting beam. The whole assembled fair-lead is subjected to tire release and then transported to the dock side to be integrally turned over, carried and hoisted, sealing, welding and debugging are carried out, in the fair-lead hoisting process, hoisting is carried out according to temporary fasteners, the additional supporting pipes and the chain rods are kept to be fixed, and then the combined fair-lead and the ship outer plate are integrally welded; and finally, dismantling the temporary fastener and the temporary pipe of the temporary structure in the fair lead.

Description

Technical Field

[0001] The invention relates to the technical field of fairlead installation, and in particular to a positioning accuracy control method for installing a hull fairlead. Background Art

[0002] There are a total of multiple sets of fairleads that need to be installed in the hull, which are distributed on the outside of the bow, starboard and stern. The fairleads are upper and lower bases and chain connectors. After the sections are completed, the fairleads are installed in the workshop, and then the multiple sets of fairleads are combined into an integral section. After completion, they are hoisted together with the hull as a whole in the dock. The installation of the fairleads needs to ensure the positioning accuracy requirements during the assembly and installation stages.

[0003] In the prior art, for example, a patent with publication number CN109094737A discloses an underwater chain guide for an R6-class mooring chain, comprising: a guide sprocket, a sprocket shaft, a bearing, a bushing, an upper base, a lower base, a through-length shaft, a guide sprocket mounting bracket, and a reinforced folded edge; the sprocket shaft is the central axis of the guide sprocket, a sprocket bearing and a sprocket bushing are provided between the sprocket shaft and the guide sprocket, the upper base and the lower base are connected by a through-length shaft, bearings and bushings are provided at the connection between the through-length shaft and the upper base and the lower base, the through-length shaft is connected to a guide sprocket mounting bracket, the guide sprocket is connected to both ends of the guide sprocket mounting bracket through the sprocket shaft, and the reinforced folded edge is provided at the junction of the guide sprocket mounting bracket and the through-length shaft.

[0004] The above structure utilizes the sprocket shaft and the guide sprocket mounting bracket to increase the overall stability of the guide sprocket mounting bracket, but its installation accuracy cannot be guaranteed during the fairlead assembly process, and it is easy to deviate from the main hull during the installation stage, affecting the overall installation accuracy. Summary of the invention

[0005] In view of this, the purpose of the present invention is to propose a positioning accuracy control method for hull fairlead installation to solve the problem that the installation accuracy of the fairlead cannot be guaranteed during the fairlead assembly process and it is easy to deviate from the main hull installation stage, affecting the overall installation accuracy.

[0006] Based on the above purpose, the present invention provides a positioning accuracy control method for installing a hull fairlead, which is applied to a hull installation device, wherein the hull installation device includes a tire frame, an upper base and a lower base are installed on the tire frame, and multiple groups of shaft holes matching the chain connector are opened in the upper base and the lower base; A structural reinforcement tube is detachably installed between the upper base and the lower base, a temporary tube is fixedly installed on the top of the lower base, and an additional support tube is fixedly installed on one side of the lower base, and temporary fasteners are provided on one side of the temporary tube and the upper base, and the temporary fasteners are used to connect with the sling; The chain connector comprises a CC wheel axle and a chain rod, the bottom end of the CC wheel axle is rotatably connected to the chain rod, the CC wheel axle and the chain rod are both provided with hanging points, and a roller shaft penetrates between the CC wheel axle and the shaft hole; A temporary support beam is installed on the tire frame, and the temporary support beam is located on the structural reinforcement tube and between the upper base and the lower base. A support column is arranged on one side of the tire frame, and jacks are arranged on the support column and the temporary support beam. A roller conveyor is fixedly installed at the center of the temporary support beam, and the roller conveyor is in contact with the roller shaft. The following steps are also included: In the workshop of the section work area, the upper base and the lower base are hoisted to the designated position of the tire frame by an overhead crane, and the center position is marked according to the 12 circle center data of the upper and lower openings of the upper base and the lower base. The data must be measured before hoisting, before welding, during welding, and after welding to monitor the data changes; At the same time, a temporary support beam is arranged on the structural reinforcement tube, and then the CC wheel shaft in the chain connector is rotated perpendicular to the chain rod and locked, and the lifting points on the chain connector are connected respectively by an overhead crane and a sling, and the chain connector is lifted to the top of the tire frame until the chain connector is vertically placed between the upper base and the lower base and located on the top of the temporary support beam; Arrange jacks on temporary support beams in advance to support the CC wheel axle in the chain connector, and place the chain rod in the chain connector on the jacks on the bracket to ensure that the CC wheel axle is aligned with the axle hole; The top, middle and bottom of the roller shaft are connected through the gantry and the sling. A threaded rod is connected to one end of the roller shaft. The threaded rod passes through the shaft hole and moves toward the tire frame. At the same time, a hydraulic cylinder is used to pull the threaded rod in one end of the lower base, and it moves synchronously with the roller conveyor until the roller shaft completely passes through the upper base, the lower base and the CC wheel axle. The threaded rod is disassembled and the temporary support beam, the top jack and the roller conveyor are removed. The chain connector is turned parallel to the angle of the upper base (1) and the lower base (2). Repeat the steps for multiple chain connectors. After the fairlead is assembled and the main hull is docked, use an elevated vehicle to fully affix patches to the hard stop position and reference line position of the fairlead and the side outer plate extension joint, and conduct overall three-dimensional data measurement, check the accuracy of the outer plate marking, analyze the overall flatness of the joint and determine the reference line position, record the original height value between the upper base and the lower base, and paint the measurement position; After the production is completed, the entire assembled fairlead will be removed from the mold, transported to the dock side, turned over as a whole, hoisted, and sealed, welded and debugged. During the installation of the fairlead, it is hoisted according to the temporary fasteners and installed after being painted and marked, keeping the additional support tube and the chain rod fixed, and then the combined fairlead is integrated and welded with the outer plate to complete the assembly and installation of the fairlead, and finally the temporary fasteners and temporary tubes of the temporary structure in the fairlead are removed.

[0007] Preferably, the positions of the upper, middle and lower reference lines of the combined fairlead as a whole and the spacing deviation from the longitudinal reference line in the middle of the ship are used to determine the cutting margin required for the joint position, and to detect whether the corresponding measurement positioning lines on the main hull and the fairlead correspond.

[0008] Preferably, the stroke of the hydraulic cylinder pulling the rod each time is controlled within 30 cm. If a problem occurs, emergency measures are formulated to pull back the roller shaft.

[0009] Preferably, the measurement positioning lines include a height reference line, a lateral reference line, and the levels of the upper and lower openings of the upper base and the lower base for positioning.

[0010] Preferably, a threaded column is rotatably mounted on the jack, a contact pad is provided on the top of the threaded column, and a nut is connected to the outside of the threaded column.

[0011] Preferably, a vertical column is mounted on the lower base via a flange, and the vertical column passes through the chain connector.

[0012] Preferably, the outside of the roller is provided with multiple sections of polytetrafluoroethylene layers, and the thickness of the polytetrafluoroethylene layer is 10 mm to balance the diameter of the roller for sliding into the shaft hole and the roller conveyor.

[0013] The beneficial effects of the present invention are as follows: first, the upper base and the lower base are hoisted to the designated position of the tire frame by means of temporary fastener slings, the CC wheel axle in the chain connector is rotated to be perpendicular to the chain rod and locked, the hanging points on the chain connector are respectively connected by means of an overhead crane and a sling, the chain connector is hoisted between the upper base and the lower base, and then the CC wheel axle in the chain connector is supported by arranging a jack on a temporary support beam, and the chain rod in the chain connector is placed on the jack on the bracket to ensure that the CC wheel axle is aligned with the shaft hole; The top, middle and bottom of the roller shaft are connected through the gantry and the sling. One end of the roller shaft is connected to a threaded column, which passes through the shaft hole and moves toward the tire frame. At the same time, a hydraulic cylinder is used to pull the threaded column in one end of the lower base, and it moves synchronously with the roller conveyor until the roller shaft completely passes through the upper base, the lower base and the CC wheel axle. The threaded column is disassembled and the temporary support beam, the top jack and the roller conveyor are removed. The steering angle of the chain connector is parallel to the angle of the upper base and the lower base. Repeat the steps for multiple chain connectors to complete the assembly of the fairlead, thereby improving the assembly accuracy of the fairlead as a whole and reducing the deviation between stages. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the present invention or 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 in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 It is a schematic diagram of the installation structure of the fairlead of the present invention; Figure 2 It is a structural schematic diagram of the upper base and the lower base of the present invention; Figure 3 It is a schematic diagram of the installation structure of the roller shaft of the present invention; Figure 4 It is a structural schematic diagram of the jack of the present invention.

[0016] The markings in the figure are: 1. Upper base; 2. Lower base; 3. Chain connector; 4. Structural reinforcement tube; 5. Temporary tube; 6. Tire frame; 7. Temporary support beam; 8. Jack; 9. Threaded column; 10. Nut; 11. Contact pad; 12. Roller conveyor; 13. Pillar; 14. Vertical column; 15. Temporary fastener; 16. Additional support tube; 17. CC wheel axle; 18. Chain rod; 19. Roller shaft; 20. Shaft hole; 21. Lifting point; 22. Hydraulic cylinder. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0018] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, a positioning accuracy control method for installing a hull fairlead is applied to a hull installation device, the hull installation device includes a tire frame 6, an upper base 1 and a lower base 2 are installed on the tire frame 6, and multiple groups of shaft holes 20 matching the chain connector 3 are opened in the upper base 1 and the lower base 2; A structural reinforcement tube 4 is detachably installed between the upper base 1 and the lower base 2, a temporary tube 5 is fixedly installed on the top of the lower base 2, and an additional support tube 16 is fixedly installed on one side of the lower base 2. A temporary fastener 15 is provided on one side of the temporary tube 5 and the upper base 1, and the temporary fastener 15 is used to connect with the sling; The chain connector 3 includes a CC wheel axle 17 and a chain rod 18. The bottom end of the CC wheel axle 17 is rotatably connected to the chain rod 18. Both the CC wheel axle 17 and the chain rod 18 are provided with a suspension point 21. A roller 19 passes through between the CC wheel axle 17 and the shaft hole 20. A temporary support beam 7 is installed on the tire frame 6, and the temporary support beam 7 is located on the structural reinforcement tube 4 and between the upper base 1 and the lower base 2. A support column 13 is provided on one side of the tire frame 6, and a jack 8 is provided on the support column 13 and the temporary support beam 7. A roller conveyor 12 is fixedly installed at the center of the temporary support beam 7, and the roller conveyor 12 is in contact with a roller shaft 19; The following steps are also included: In the workshop of the segmented work area, the upper base 1 and the lower base 2 are hoisted to the designated position of the tire frame 6 by an overhead crane, and the center position is marked according to the 12 center data of the upper and lower openings of the upper base 1 and the lower base 2. The data must be measured before hoisting, before welding, during welding, and after welding to monitor the data changes; At the same time, a temporary support beam 7 is arranged on the structural reinforcement pipe 4, and then the CC wheel shaft 17 in the chain connector 3 is rotated to be perpendicular to the chain rod 18 and locked, and the hanging points 21 on the chain connector 3 are respectively connected by an overhead crane and a sling, and the chain connector 3 is hoisted to the top of the tire frame 6 until the chain connector 3 is vertically placed between the upper base 1 and the lower base 2 and is located on the top of the temporary support beam 7; Arrange the jack 8 on the temporary support beam 7 in advance to support the CC wheel axle 17 in the chain connector 3, and place the chain rod 18 in the chain connector 3 on the jack 8 on the support 13 to ensure that the CC wheel axle 17 is aligned with the shaft hole 20; The top, middle and bottom of the roller shaft 19 are connected through the gantry and the sling. One end of the roller shaft 19 is connected to a threaded rod, which passes through the shaft hole 20 and moves toward the tire frame 6. At the same time, the hydraulic cylinder 22 is used in one end of the lower base 2 to pull the threaded rod, and it moves synchronously with the roller conveyor 12 until the roller shaft 19 completely passes through the upper base 1, the lower base 2 and the CC wheel axle 17. The threaded rod is disassembled and the temporary support beam 7, the top jack 8 and the roller conveyor 12 are removed. The chain connector 3 is turned 20 degrees to be parallel to the angle of the upper base 1 and the lower base 2. The steps are repeated for multiple chain connectors 3; After the fairlead is assembled and the main hull is docked, use an elevated vehicle to fully affix patches to the hard stop position and reference line position of the fairlead and the side outer plate extension joint, and conduct overall three-dimensional data measurement, check the accuracy of the outer plate marking, analyze the overall flatness of the joint and determine the reference line position, record the original height value between the upper base 1 and the lower base 2, and paint the measurement position; After the production is completed, the entire assembled fairlead will be demolded, transported to the dockside, turned over as a whole, hoisted, and sealed, welded, and debugged. During the installation of the fairlead, it is hoisted according to the temporary fasteners 15 and installed after being painted and marked, keeping the additional support tube 16 and the chain rod 18 fixed, and then the combined fairlead is integrated and welded with the outer plate to complete the assembly and installation of the fairlead, and finally the temporary fasteners 15 and the temporary tube 5 of the temporary structure in the fairlead are removed.

[0019] In this embodiment, the upper base 1 and the lower base 2 are first hoisted to the specified position of the tire frame 6 by means of the temporary fastener 15 sling, the CC wheel axle 17 in the chain connector 3 is rotated to be perpendicular to the chain rod 18 and locked, the hanging points 21 on the chain connector 3 are respectively connected by the overhead crane and the sling, the chain connector 3 is hoisted to between the upper base 1 and the lower base 2, and then the jack 8 is arranged on the temporary support beam 7 to support the CC wheel axle 17 in the chain connector 3, and the chain rod 18 in the chain connector 3 is placed on the jack 8 on the pillar 13 to ensure that the CC wheel axle 17 is aligned with the shaft hole 20; The top, middle and bottom of the roller shaft 19 are connected through the gantry and the sling, one end of the roller shaft 19 is connected to a threaded rod, the threaded rod passes through the axial hole 20 and moves toward the tire frame 6, and at the same time, the hydraulic cylinder 22 is used to pull the threaded rod in one end of the lower base 2, and it moves synchronously with the roller conveyor 12 until the roller shaft 19 completely passes through the upper base 1, the lower base 2 and the CC wheel axle 17, the threaded rod is disassembled and the temporary support beam 7, the top jack 8 and the roller conveyor 12 are removed, the chain connector 3 is turned 20 degrees to be parallel to the angle of the upper base 1 and the lower base 2, and multiple chain connectors 3 repeat the steps to complete the assembly of the fairlead, thereby improving the assembly accuracy of the fairlead as a whole and reducing the deviation between each stage.

[0020] As an implementation method, Figure 1 , Figure 2 As shown, the positions of the upper, middle and lower three-layer reference lines of the combined fairlead as a whole and the spacing deviation from the longitudinal reference line in the middle of the ship are used to determine the cutting margin required for the joint position and to detect whether the corresponding measurement positioning lines on the main hull and the fairlead correspond to each other; The measurement positioning lines include a height reference line, a lateral reference line, and the levels of the upper and lower openings of the upper base 1 and the lower base 2 for positioning.

[0021] In this embodiment, according to the measurement positioning line, the installation personnel must promptly measure the net opening dimensions of the upper and lower openings of the fairlead during positioning, assembly, before welding, welding, and after welding, and compare them with the original data before lifting. At the same time, the construction personnel must also measure the measuring points on the fairlead during this process and compare them with the original data to prevent the upper and lower pieces of the fairlead from shrinking during welding and affecting the rotation, thereby improving the installation accuracy of the fairlead and the main hull.

[0022] As an implementation method, Figure 3 As shown, the stroke of the hydraulic cylinder 22 pulling the rod each time is controlled within 30 cm. If a problem occurs, emergency measures are formulated to pull back the roller shaft 19.

[0023] In this embodiment, when one end of the roller 19 is connected to the threaded rod, the threaded rod passes through the axial hole 20 and moves toward the tire frame 6. At the same time, the hydraulic cylinder 22 is used to pull the threaded rod in one end of the lower base 2, and it moves synchronously with the roller conveyor 12 until the roller 19 completely passes through the upper base 1, the lower base 2 and the CC wheel axle 17. The threaded rod is disassembled and the temporary support beam 7, the top jack 8 and the roller conveyor 12 are removed. The stroke of the hydraulic cylinder 22 pulling the rod each time is controlled within 30 cm. If a problem occurs, emergency measures are formulated to pull back the roller 19 to prevent excessive deviations during the installation process that affect component assembly.

[0024] As an implementation method, Figure 4 As shown, a threaded column 9 is rotatably mounted on the jack 8 , a contact pad 11 is provided at the top of the threaded column 9 , and a nut 10 is connected to the outside of the threaded column 9 .

[0025] In this embodiment, the adjustable part composed of the threaded column 9 and the nut 10 is used, and the contact pad 11 is in contact with the CC wheel shaft 17, so as to maintain the chain connector 3 between the upper base 1 and the lower base 2, so as to avoid shrinkage during welding and movement of the chain connector 3 affecting the overall assembly accuracy; And the shaft hole 20 is kept corresponding to the CC wheel shaft 17 to facilitate the insertion of the roller shaft 19.

[0026] As an implementation method, Figure 1 , Figure 3 As shown, a vertical column 14 is mounted on the lower base 2 via a flange, and the vertical column 14 passes through the chain connector 3 .

[0027] In this embodiment, through the flange connection between the vertical column 14 and the lower base 2, when the overhead crane and the sling are respectively connected to the lifting points 21 on the chain connector 3, the chain connector 3 is lifted to the top of the tire frame 6 until the chain connector 3 is vertically placed between the upper base 1 and the lower base 2 and is located on the top of the temporary support beam 7, the vertical column 14 restricts the chain connector 3 to prevent movement during the assembly process.

[0028] As an implementation method, Figure 3 As shown, the outside of the roller shaft 19 is provided with multiple sections of polytetrafluoroethylene layers, and the thickness of the polytetrafluoroethylene layer is 10 mm to balance the diameter of the roller shaft 19 for sliding into the shaft hole 20 and the roller conveyor 12.

[0029] In this embodiment, a polytetrafluoroethylene layer is provided on the outside of the roller 19 to balance the diameter of the roller 19 so as to slide into the shaft hole 20 and the roller conveyor 12, thereby facilitating installation between the roller 19 and the chain connector 3, the upper base 1, and the lower base 2.

[0030] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0031] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for controlling the positioning accuracy of a hull fairlead installation, applied to a hull installation device, the hull installation device comprising a tire frame (6), an upper base (1) and a lower base (2) being installed on the tire frame (6), and a plurality of groups of shaft holes (20) matching with a chain connector (3) being provided in the upper base (1) and the lower base (2), It is characterized by: A structural reinforcement tube (4) is detachably mounted between the upper base (1) and the lower base (2), a temporary tube (5) is fixedly mounted on the top of the lower base (2), and an additional support tube (16) is fixedly mounted on one side of the lower base (2), and temporary fasteners (15) are provided on one side of the temporary tube (5) and the upper base (1), and the temporary fasteners (15) are used to connect with the slings; The chain connector (3) comprises a CC wheel axle (17) and a chain rod (18); the bottom end of the CC wheel axle (17) is rotatably connected to the chain rod (18); the CC wheel axle (17) and the chain rod (18) are both provided with hanging points (21); and a roller (19) passes through between the CC wheel axle (17) and the shaft hole (20); A temporary support beam (7) is installed on the tire frame (6), and the temporary support beam (7) is located on the structural reinforcement tube (4) and between the upper base (1) and the lower base (2). A support column (13) is provided on one side of the tire frame (6), and jacks (8) are provided on the support column (13) and the temporary support beam (7). A roller conveyor (12) is fixedly installed at the center of the temporary support beam (7), and the roller conveyor (12) is in contact with a roller shaft (19); The following steps are also included: In the workshop of the segmented work area, the upper base (1) and the lower base (2) are hoisted to the designated position of the tire frame (6) by an overhead crane, and the center position is marked according to the 12 center data of the upper and lower openings of the upper base (1) and the lower base (2). The data are measured before hoisting, before welding, during welding, and after welding, and the data changes are monitored; At the same time, a temporary support beam (7) is arranged on the structural reinforcement pipe (4), and then the CC wheel shaft (17) in the chain connector (3) is rotated vertically with the chain rod (18) and locked, and the lifting points (21) on the chain connector (3) are respectively connected by an overhead crane and a sling, and the chain connector (3) is lifted to the top of the tire frame (6) until the chain connector (3) is vertically placed between the upper base (1) and the lower base (2) and is located on the top of the temporary support beam (7); Arrange a jack (8) on the temporary support beam (7) in advance to support the CC wheel shaft (17) in the chain connector (3), and place the chain rod (18) in the chain connector (3) on the jack (8) on the bracket (13) to ensure that the CC wheel shaft (17) is aligned with the shaft hole (20); The top, middle and bottom of the roller shaft (19) are connected through the gantry and the sling. One end of the roller shaft (19) is connected to a threaded rod, which passes through the shaft hole (20) and moves toward the tire frame (6). At the same time, a hydraulic cylinder (22) is used in one end of the lower base (2) to pull the threaded rod and move synchronously with the roller conveyor (12) until the roller shaft (19) completely passes through the upper base (1), the lower base (2) and the CC wheel axle (17). The threaded rod is disassembled and the temporary support beam (7) and the top jack (8) and the roller conveyor (12) are removed. The chain connector (3) is turned 20 degrees to be parallel to the angle of the upper base (1) and the lower base (2). The steps are repeated for multiple chain connectors (3); After the fairlead is assembled and the main hull is docked, use an elevated vehicle to fully affix patches to the hard stop position and reference line position of the fairlead and the side outer plate extension joint, and conduct overall three-dimensional data measurement, check the accuracy of the outer plate marking, analyze the overall flatness of the joint and determine the reference line position, record the original height value between the upper base and the lower base, and paint the measurement position; After the production is completed, the entire assembled fairlead is removed from the mold and transported to the dockside, turned over as a whole, hoisted, and sealed, welded, and debugged. During the process of hoisting the fairlead, it is hoisted according to the temporary fasteners (15) and installed after being painted and marked, and the additional support pipe (16) and the chain rod (18) are kept fixed. Then, the assembled fairlead is integrated and welded with the outer plate to complete the assembly and installation of the fairlead. Finally, the temporary fasteners (15) and the temporary pipe (5) of the temporary structure in the fairlead are removed.

2. A method for controlling the positioning accuracy of a hull fairlead installation according to claim 1, characterized in that: The positions of the upper, middle and lower reference lines of the combined fairlead as a whole and the deviation of the spacing from the longitudinal reference line in the middle of the ship are used to determine the cutting allowance required for the joint position and to detect whether the corresponding measurement positioning lines on the main hull and the fairlead correspond.

3. A method for controlling the positioning accuracy of a hull fairlead installation according to claim 1, characterized in that: The stroke of the hydraulic cylinder (22) pulling the rod each time is controlled within 30 cm. If a problem occurs, emergency measures are formulated to pull back the roller shaft (19).

4. A method for controlling positioning accuracy for installation of a hull fairlead according to claim 2, characterized in that: The measurement positioning lines include a height reference line, a lateral reference line, and the levels of the upper and lower openings of the upper base (1) and the lower base (2) for positioning.

5. A method for controlling positioning accuracy for installation of a hull fairlead according to claim 1, characterized in that: A threaded column (9) is rotatably mounted on the jack (8), a contact pad (11) is provided at the top of the threaded column (9), and a nut (10) is connected to the outside of the threaded column (9).

6. A method for controlling positioning accuracy for installation of a hull fairlead according to claim 1, characterized in that: A vertical column (14) is mounted on the lower base (2) via a flange, and the vertical column (14) passes through the chain connector (3).

7. A method for controlling positioning accuracy for installation of a hull fairlead according to claim 1, characterized in that: The roller shaft (19) is provided with multiple sections of polytetrafluoroethylene layers on the outside. The thickness of the polytetrafluoroethylene layers is 10 mm, so as to balance the diameter of the roller shaft (19) and to be used for sliding into the shaft hole (20) and the roller conveyor (12).

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