Single-point mooring method for offshore floating structure

Abstract

The invention relates to a single-point mooring method for a floating structure on the sea, a first ring body is fixedly arranged at the bottom of a mooring point of the floating structure, and the method comprises the following steps that a three-degree-of-freedom rotating tower is connected to the first ring body and comprises a second ring body, a rotating disc and a rotating supporting component for rotationally connecting the second ring body and the rotating disc; the first ring body and the second ring body are buckled, so that the three-degree-of-freedom rotating tower crane is hung below a mooring point, and the first ring body can swing relative to the second ring body around two mutually perpendicular axes respectively; laying a floating structure and laying an anchoring foundation; when one end of the mooring rope is connected with an anchoring foundation located at the target seabed and the other end of the mooring rope is connected with the rotating disc, the floating structure is moored in the target sea area in a single-point mooring mode, the floating structure has freedom degrees in the three directions of rolling, pitching and yawing, the cost is low, the structure is simple, the mooring stress is dispersed in the movement directions of the multiple freedom degrees, and the floating structure can be moored in the target sea area in a single-point mooring mode. And the fatigue damage rate of the mooring cable is reduced.

Description

Technical Field

[0001] The present invention relates to the field of marine engineering technology, in particular to a single-point mooring method for an offshore floating structure. Background Art

[0002] The development of marine resources is evolving from shallow waters to deep seas. However, the harsh and volatile deep sea environment and the higher safety and reliability requirements of floating offshore platforms present new challenges in the research, development, design, and manufacture of mooring systems for offshore structures. Single-point mooring is a widely used mooring method for floating structures. By allowing the float to adaptively yaw 360° around the mooring point, creating a weathervane effect, the floating structure always faces the direction of the combined force of wind, waves, and currents. This effectively reduces environmental loads and enhances typhoon resistance, making it widely used in waters with harsh environmental conditions.

[0003] However, currently, a turret device is usually installed on the floating structure. The turret device is built into the main structure of the floating structure, and the structure is complex and the cost is high. There is also a buoy device that assists in achieving the weather vane effect. The mooring cable is fixedly connected to the buoy, and the buoy is movably connected to the floating structure, such as a rigid yoke arm and a cable, which increases the number of structures and the cost of the entire system.

[0004] Although the above two single-point mooring methods can realize the weather vane effect of single-point mooring adaptive yaw, for deep sea areas with harsh sea conditions, during the service period of the floating structure, due to the impact of wind, waves and currents on the floating structure, the movement and floating frequency of the floating structure is relatively high, the torsion and shear conditions on the mooring cable are complex, and fatigue damage is prone to occur, which poses a greater safety risk. Summary of the Invention

[0005] In response to the shortcomings of the above-mentioned existing production technologies, the applicant provides a single-point mooring method for offshore floating structures, thereby connecting the mooring system to the floating structure with a low-cost and simple structure, dispersing the mooring stress in multiple degrees of freedom movement directions, reducing the shear force, torsional force and fatigue damage rate of the mooring cable, and improving the safety of the single-point mooring system.

[0006] The technical solutions adopted in the present invention are as follows:

[0007] A single-point mooring method for an offshore floating structure, wherein a first ring is fixedly provided at the bottom of the mooring point of the floating structure, and the method comprises the following steps:

[0008] A three-degree-of-freedom turret is connected to the first ring body. The three-degree-of-freedom turret includes a second ring body and a turntable, and a rotating support component that rotatably connects the second ring body and the turntable. The first ring body and the second ring body are fastened together so that the three-degree-of-freedom turret is suspended below the mooring point, and the first ring body can swing relative to the second ring body about two mutually perpendicular axes.

[0009] Deploy floating structures in the target sea area;

[0010] Deploy the anchor foundation on the target seabed, and connect the anchor foundation to one end of the mooring cable;

[0011] When one end of the mooring cable is connected to the anchor foundation located on the target seabed and the other end is connected to the turntable, the floating structure is moored in the target sea area in a single-point mooring manner, and the floating structure is released with the degrees of freedom in the three directions of roll, pitch and yaw.

[0012] As a further improvement of the above technical solution:

[0013] The rotating support component includes a first rotating part and a second rotating part that are coaxial and rotatably connected. The first rotating part is located outside the second rotating part. The first rotating part is coaxial and fixedly connected to the rotating shaft. The second ring body is fixed at the end of the rotating shaft. The turntable is fixedly arranged outside the second rotating part.

[0014] The rotation support component is a bearing, the first rotating part is an inner ring of the bearing, and the second rotating part is an outer ring of the bearing.

[0015] The inner hole of the first ring body is circular, and both ends of the inner hole are provided with guide arc surfaces. The inner hole of the second ring body is circular, and the annular cross section of the second ring body is circular.

[0016] The mooring cable is a carbon fiber composite cable, one end of the mooring cable is provided with a first conical anchor, and the other end of the mooring cable is provided with a second conical anchor;

[0017] Before the anchor foundation is deployed, the second conical anchor is connected to the anchor foundation via a bottom-lying cable, and a plug ear is fixedly connected to the second conical anchor;

[0018] During the process of deploying the anchor foundation on the target seabed, a lifting device is used to lower the anchor foundation to the seabed while releasing the mooring cable wound on the cable drum. When the anchor foundation is located on the target seabed, the lug is connected to the turntable located on the floating structure in the target sea area.

[0019] The bottom-lying section cable includes an anchor chain and a D-shaped shackle, one end of the anchor chain is fixedly connected to the anchoring foundation, and the other end of the anchor chain is buckled with the D-shaped shackle. The bending section of the shackle body of the D-shaped shackle is provided with a socket, and the end of the second conical anchor is fixedly connected to the adapter shaft. When the adapter shaft is rotatably connected to the socket, the end of the adapter shaft is located outside the socket to limit the shackle body on the adapter shaft.

[0020] The adapter shaft is embedded with an optical fiber sensor, and when the floating structure is moored in the target sea area, the optical fiber sensor monitors the mooring connection status.

[0021] The turntable is provided with an eye ring. When the plug ear is connected to the turntable, the plug ear and the eye ring are buckled together by a manual operation through a shackle.

[0022] The beneficial effects of the present invention are as follows:

[0023] The present invention has a compact and reasonable structure and is easy to operate. When mooring at a single point, the second ring body of the three-degree-of-freedom turret is connected to the first ring body at the bottom of the floating structure, and the mooring cable is then connected through the turntable of the three-degree-of-freedom turret. The degrees of freedom of the floating structure in the roll, pitch and bow directions are released through the relative swing between the first ring body and the second ring body, and the relative rotation between the second ring body and the turntable. The floating structure is deployed together with the three-degree-of-freedom turret after being connected, which simplifies the connection structure between the floating structure and the mooring cable. After the floating structure is moored, when the floating structure has a large movement and floating frequency in severe sea conditions, the torsion and shear force on the mooring cable are released, thereby reducing the fatigue damage rate of the mooring cable and improving the safety of single-point mooring.

[0024] At the same time, the present invention also has the following advantages:

[0025] (1) The first ring and the three-degree-of-freedom turret on the floating structure are used to connect the mooring cable to the floating structure. The three-degree-of-freedom turret effectively releases the torsion and shear of the mooring cable caused by the three-degree-of-freedom motion of the floating structure, namely, pitch, pitch and pitch. The carbon fiber composite cable is used for single-point mooring, which improves the service life and fatigue resistance of the mooring system and reduces the maintenance cost of the mooring system. The floating structure and the laying anchor foundation can be laid synchronously, which improves the efficiency of the mooring process and the convenience of laying the mooring cable.

[0026] (2) By fixing the adapter shaft at the end of the second conical anchor, the adapter shaft is rotatably connected to the D-type shackle, the anchor chain is buckled with the D-type shackle, one end of the carbon fiber mooring cable is connected to the anchor foundation through the bottom section cable of the three-section connection structure, and the other end of the carbon fiber mooring cable is connected to the mooring point through the three-degree-of-freedom turret, so that the torsion and shear force that the mooring cable may be subjected to are completely released from both ends of the mooring cable, so that the reliability of the carbon fiber composite cable as a mooring cable is significantly improved, and it is suitable for the high-standard requirements of deep-sea engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 It is a schematic diagram of the three-degree-of-freedom turret structure of the present invention.

[0029] Figure 3 It is a three-dimensional diagram of the first ring body and the second ring body of the present invention.

[0030] Figure 4 It is a schematic structural diagram of the bottom-lying cable of the present invention.

[0031] Figure 5 Schematic diagram of the connection structure between the D-type shackle and the second conical anchor of the present invention.

[0032] Figure 6 It is a schematic diagram of the connection structure between the bottom-lying cable and the anchor foundation of the present invention.

[0033] in:

[0034] 1. Floating structure; 2. Anchor foundation;

[0035] 3. Bottom-laying cable; 31. Adapter shaft; 32. D-type shackle; 33. Anchor chain;

[0036] 4. Mooring line; 41. First conical anchor; 42. Lug; 43. Second conical anchor;

[0037] 5. First ring body; 51. Guide arc surface;

[0038] 6. Three-degree-of-freedom turret; 61. Second ring; 62. Rotation support component; 621. First rotating part; 622. Second rotating part; 63. Turntable; 631. Eye ring; 64. Rotation shaft;

[0039] 7. Shackle. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention will be described below with reference to the accompanying drawings.

[0041] Example 1:

[0042] like Figure 1 、 Figure 2 As shown, in the single-point mooring method for an offshore floating structure of this embodiment, a first ring body 5 is fixedly installed at the bottom of the mooring point of the floating structure 1. The method includes the following steps:

[0043] A three-degree-of-freedom turret 6 is connected to the first ring body 5 of the floating structure 1. The three-degree-of-freedom turret 6 includes a second ring body 61, a turntable 63, and a rotating support member 62 that rotatably connects the second ring body 61 and the turntable 63. The first ring body 5 is fastened to the second ring body 61 so that the three-degree-of-freedom turret 6 is suspended below the mooring point, and the first ring body 5 can swing relative to the second ring body 61 about two mutually perpendicular axes.

[0044] Deploying a floating structure 1 in a target sea area;

[0045] Deploy an anchor foundation 2 on the target seabed, and connect the anchor foundation 2 to one end of a mooring cable 4;

[0046] When one end of the mooring cable 4 is connected to the anchor foundation 2 located on the target seabed and the other end is connected to the turntable 63, the floating structure 1 is moored in the target sea area in a single-point mooring manner, and the floating structure 1 is released to have three degrees of freedom in roll, pitch and yaw.

[0047] In a specific embodiment, the anchoring base 2 can be a gravity anchor, the number of mooring cables 4 is three, and the connection points between the mooring cables 4 and the turntable 63 are all distributed on the periphery of the turntable 63, such as Figure 1 shown.

[0048] The second ring body 61 rotates 360 degrees relative to the turntable 63, and releases the freedom of the bow rolling direction of the floating structure 1 after the floating structure 1 is moored;

[0049] When the three-degree-of-freedom turret 6 is not connected to the mooring line 4, the first ring body 5 swings with an amplitude of greater than or equal to 180° about its own axis relative to the second ring body 61. The first ring body 5 swings with an amplitude of greater than or equal to 180° about the axis of the second ring body 61. After the floating structure 1 is moored, the floating structure 1 can be released in both roll and pitch directions. The amplitude of the swing depends on the sea conditions. The two mutually perpendicular axes can be the axis of the first ring body 5 and the axis of the second ring body 61, and the specific angle depends on the coupling state of the first ring body 5 and the second ring body 61 and the angle between the planes in which the ring bodies are located.

[0050] In the prior art, when a buoy device is used to assist in achieving a weather vane effect, a mooring cable 4 is usually directly connected to the bottom or side of the buoy. The buoy moves with the roll, pitch and bow of the floating structure 1, causing the mooring cable 4 to be subjected to constantly changing torsion and shear forces.

[0051] In the single-point mooring method for offshore floating structures of this embodiment, the structural design connecting mooring cable 4 to the mooring point—the first ring 5 and the three-degree-of-freedom turret 6—endows the floating structure 1 with the ability to move in three directions of freedom: roll, pitch, and yaw relative to the mooring cable 4. This significantly reduces the impact of multi-directional environmental loads on the system, frees the rolling and pitching degrees of freedom of the floating structure 1 relative to the mooring system, and decouples it from the mooring system, thereby eliminating the torsional and shear forces on the mooring cable 4 generated by the movement of the floating structure 1. Furthermore, the single-point mooring method for offshore floating structures of this embodiment requires only a simple connection structure to connect the three-degree-of-freedom turret 6 to the floating structure 1, effectively reducing construction and installation costs.

[0052] During single-point mooring, the first ring body 5 at the bottom of the floating structure 1 is connected to the second ring body 61 of the three-degree-of-freedom turret 6, and then the mooring cable 4 is connected through the turntable 63 of the three-degree-of-freedom turret 6. The degrees of freedom of the floating structure 1 in the roll, pitch and yaw directions are released through the relative swing between the first ring body 5 and the second ring body 61, and the relative rotation between the second ring body 61 and the turntable 63. After the floating structure 1 is connected to the three-degree-of-freedom turret 6, they are deployed together, simplifying the connection structure between the floating structure 1 and the mooring cable 4. After the floating structure 1 is moored, when the floating structure 1 has a high floating frequency in severe sea conditions, the torsion and shear forces on the mooring cable 4 are released, thereby reducing the fatigue damage rate of the mooring cable 4 and improving the safety of single-point mooring.

[0053] The single-point mooring method for offshore floating structures of this embodiment is suitable for a variety of mooring scenarios, such as floating wind power and deep-sea aquaculture, etc. It fully releases the degrees of freedom of the floating structure 1, improves the safety of the platform, and is suitable for the high-standard requirements of deep-sea projects.

[0054] For example, Figure 2 As shown, the rotating support component 62 includes a first rotating part 621 and a second rotating part 622 that are coaxial and rotatably connected. The first rotating part 621 is located outside the second rotating part 622. The first rotating part 621 is coaxial and fixedly connected to the rotating shaft 64. The second ring body 61 is fixed to the end of the rotating shaft 64, and a turntable 63 is fixed outside the second rotating part 622.

[0055] The rotation support component 62 is a bearing, the first rotation portion 621 is an inner ring of the bearing, and the second rotation portion 622 is an outer ring of the bearing.

[0056] Specifically, bearings with sealing structures (such as dust covers and sealing rings) are selected. Crossed roller bearings can be used to integrate axial and radial load-bearing capacity. Rotating support component 62 supports floating structure 1 to rotate 360 degrees around the center of rotation axis 64, creating a weather vane effect, ensuring that floating structure 1 always faces the direction of the combined force of wind and waves, reducing environmental loads.

[0057] For example, Figure 2 、 Figure 3 As shown, the inner hole of the first ring body 5 is circular, and both ends of the inner hole are provided with guide arc surfaces 51. The inner hole of the second ring body 61 is circular and the circumferential cross section of the second ring body 61 is circular.

[0058] Specifically, the first ring body 5 is formed on a base at the bottom of the floating structure 1, and the inner diameter of the first ring body 5 is greater than or equal to the diameter of the annular cross-section of the second ring body 61. The inner diameter of the first ring body 5 is greater than the diameter of the annular cross-section of the second ring body 61 to increase the relative swing space between the first ring body 5 and the second ring body 61.

[0059] Example 2:

[0060] The reliability of the mooring cable 4 in the single-point mooring system plays a vital role in the stable operation of the floating platform in a complex marine environment. Traditional steel chains and steel cables are usually used for mooring, but their susceptibility to corrosion, heavy weight and short fatigue life often lead to insufficient buoyancy of floating marine structures and high maintenance costs. Therefore, simple steel chains and steel cables are not suitable for deep-sea mooring systems; although the new synthetic fiber cables are lighter and relatively more economical, they have disadvantages such as large creep, easy relaxation and poor wear resistance.

[0061] Currently, lightweight, high-strength, fatigue-resistant, and corrosion-resistant carbon fiber composite cables are considered to meet the long-life, fatigue-resistant, and low-maintenance mooring system requirements of major marine engineering structures. In the marine environment, cyclical loads caused by waves and currents can cause carbon fiber composite cables to repeatedly bend and twist. Although carbon fiber has excellent tensile properties, it has low interlaminar shear strength and insufficient torsional stiffness. Under torsional stress, it is prone to delamination, fiber breakage, or interfacial debonding, leading to cable failure. Existing technologies do not yet have a single-point mooring method suitable for carbon fiber composite mooring cables.

[0062] The single-point mooring method for offshore floating structures of Example 1 has a simple structure and high safety. It only requires a single connecting structure (first ring body 5) and a single three-degree-of-freedom turret 6 to achieve the connection between the mooring cable 4 and the floating structure 1. The three-degree-of-freedom turret 6 effectively releases the torsion and shear of the mooring cable 4 caused by the three-degree-of-freedom motion of the bow, roll and pitch of the floating structure 1. At the same time, the weather vane effect of the single-point mooring reduces the environmental load of the floating structure 1, thereby reducing its motion response and the load of the mooring system. In addition, the installation and operation and maintenance costs are low, providing a new and effective mooring method for the application of carbon fiber composite mooring cables in floating platform mooring systems.

[0063] The single-point mooring method for an offshore floating structure of this embodiment is based on the first embodiment. Carbon fiber composite cables are used for single-point mooring, thereby improving the service life and fatigue resistance of the mooring system and reducing the maintenance cost of the mooring system.

[0064] The mooring cable 4 is a carbon fiber composite cable, one end of the mooring cable 4 is provided with a first conical anchor 41, and the other end of the mooring cable 4 is provided with a second conical anchor 43;

[0065] Before laying the anchor foundation 2, the second conical anchor 43 is connected to the anchor foundation 2 via the bottom-lying cable 3, and the second conical anchor 43 is fixedly connected with the plug ear 42;

[0066] During the process of deploying the anchoring foundation 2 on the target seabed, a lifting device is used to lower the anchoring foundation 2 to the seabed while releasing the mooring cable 4 wound on the cable drum. When the anchoring foundation 2 is located on the target seabed, the plug ear 42 is connected to the turntable 63 located on the floating structure 1 in the target sea area.

[0067] Carbon fiber composite cables have been successfully used in large bridges such as cable-stayed bridges and suspension bridges. The conical anchor at the end of the cable is equipped with a continuous curved conical anchor cup. The end of the carbon fiber composite cable is scattered and placed in the conical anchor cup, and nano-modified epoxy resin is injected. After curing, a mechanical-chemical composite anchor is formed. This technology transfers the tensile load from the cable cross section to the side wall of the connector, realizing the load transfer from the cable to the connecting structure. There is an existing technology for processing the end of the carbon fiber composite cable, which will not be repeated here.

[0068] Carbon fiber composite cables are generally transported in reels. During the laying process, the carbon fiber composite cables are released by rotating the original cable reels used during transportation. Through manual operation, the carbon fiber composite cables can be synchronously stretched and released as the anchor foundation 2 is lowered, which improves the convenience of laying the mooring cable 4 and the anchor foundation 2.

[0069] The mooring cable 4 is connected to the floating structure 1 by using the first ring 5 and the three-degree-of-freedom turret 6 on the floating structure 1. The torsion and shearing of the mooring cable 4 caused by the three-degree-of-freedom motion of the floating structure 1, namely, pitch, pitch and pitch, are effectively released through the three-degree-of-freedom turret 6. The carbon fiber composite cable is used for single-point mooring, which improves the service life and fatigue resistance of the mooring system and reduces the maintenance cost of the mooring system. The floating structure 1 and the deployment anchor foundation 2 can be deployed synchronously, which improves the efficiency of the mooring process and the convenience of deploying the mooring cable 4.

[0070] In this embodiment, Figure 4-Figure 6 As shown, the bottom section cable 3 includes an anchor chain 33 and a D-type shackle 32. One end of the anchor chain 33 is fixedly connected to the anchor foundation 2, and the other end of the anchor chain 33 is buckled with the D-type shackle 32. The bending section of the shackle body of the D-type shackle 32 is provided with a socket. The end of the second conical anchor 43 is fixedly connected to the adapter shaft 31. When the adapter shaft 31 is rotatably connected to the socket, the end of the adapter shaft 31 is located outside the socket to limit the shackle body on the adapter shaft 31.

[0071] Specifically, the D-shaped shackle 32 is made of a lightweight alloy material (such as titanium alloy or high-strength aluminum alloy) to meet the requirements of high strength and lightness while avoiding galvanic corrosion. The adapter shaft 31 is also made of titanium alloy.

[0072] The anchor base 2 and the mooring cable 4 are connected by the D-shaped shackle 32, the anchor chain 33 and the adapter shaft 31. The torque of the mooring cable 4 is released so that the relative angle between the mooring cable 4 and the anchor base 2 and its own posture change along with the extension direction.

[0073] By fixing the adapter shaft 31 at the end of the second conical anchor 43, the adapter shaft 31 is rotatably connected to the D-type shackle 32, and the anchor chain 33 is buckled with the D-type shackle 32. One end of the carbon fiber mooring cable 4 is connected to the anchor foundation 2 through the bottom section cable 3 of the three-section connection structure, and the other end of the carbon fiber mooring cable 4 is connected to the mooring point through the three-degree-of-freedom turret 6. The torsional and shear forces that the mooring cable 4 may be subjected to are completely released from both ends of the mooring cable 4, so that the reliability of the carbon fiber composite cable as a mooring cable 4 is significantly improved, which is suitable for the high-standard requirements of deep-sea engineering.

[0074] The bottom-lying cable 3 of this embodiment is connected to the conical anchor using standardized components. It has a simple structure and is easy to implement. It effectively ensures the safety of the carbon fiber composite mooring cable 4 during its deployment and mooring along the anchoring foundation 2, and ensures the strength and fatigue life of the carbon fiber composite cable.

[0075] In this embodiment, the adapter shaft 31 is embedded with an optical fiber sensor, and when the floating structure 1 is moored in the target sea area, the optical fiber sensor monitors the mooring connection status.

[0076] Specifically, the embedded optical fiber sensor is used to sense the force applied to the adapter shaft 31 and transmit the signal to the control system on the floating structure 1 to detect the mooring connection status.

[0077] For example, Figure 2 As shown, an eye ring 631 is provided on the turntable 63 . When connecting the ear 42 to the turntable 63 , the ear 42 and the eye ring 631 are manually fastened together through the shackle 7 .

[0078] Standardized components are used to connect the plug ear 42 and the turntable 63, thereby ensuring connection strength while reducing customization costs.

[0079] During the application of the single-point mooring method for offshore floating structures of this embodiment, a specific mooring operation process is as follows:

[0080] Step 1: Install a three-degree-of-freedom turret 6 on the floating structure 1 on land, and connect the anchor foundation 2 to the second conical anchor 43 at the tail end of the coiled mooring cable 4 through the bottom-lying cable 3 on land. The first conical anchor 41 at the head end of the coiled mooring cable 4 is fixed with an ear 42.

[0081] Step 2: deploying the floating structure 1 equipped with the three-degree-of-freedom turret 6 in the target sea area;

[0082] Step 3: Use a lifting device to lower the anchor foundation 2 to the seabed. At the same time, the operator can release the mooring cable 4 wound on the cable drum from a small boat on the water surface. Steps 2 and 3 can be performed simultaneously without interference from the equipment.

[0083] Step 4: After the anchor foundation 2 is located on the target seabed, the lug 42 is manually connected to the eye 631 provided on the turntable 63 through the shackle 7 to complete the connection between the floating structure 1 and the mooring system. The floating structure 1 is moored to the target sea area in a single-point mooring manner, and the floating structure 1 has three degrees of freedom in the roll, pitch and yaw directions.

[0084] The above description is an explanation of the present invention, not a limitation of the present invention. The scope of the present invention is defined in the claims. Any modifications may be made within the scope of protection of the present invention.

Claims

1. A single-point mooring method for an offshore floating structure, characterized by: A first ring body (5) is fixedly arranged at the bottom of the mooring point of the floating structure (1), and the method comprises the following steps: A three-degree-of-freedom turret (6) is connected to the first ring body (5), the three-degree-of-freedom turret (6) comprising a second ring body (61) and a turntable (63), and a rotating support component (62) for rotatably connecting the second ring body (61) and the turntable (63); the first ring body (5) and the second ring body (61) are buckled so that the three-degree-of-freedom turret (6) is suspended below a mooring point, and the first ring body (5) can swing relative to the second ring body (61) around two mutually perpendicular axes; deploying a floating structure (1) in a target sea area; An anchoring foundation (2) is deployed on the target seabed, and the anchoring foundation (2) is connected to one end of a mooring cable (4); When one end of the mooring cable (4) is connected to the anchor foundation (2) located on the target seabed and the other end is connected to the turntable (63), the floating structure (1) is moored in the target sea area in a single-point mooring manner, and the floating structure (1) is released in the three degrees of freedom of roll, pitch and bow.

2. The single-point mooring method for an offshore floating structure according to claim 1, wherein: The rotating support component (62) includes a first rotating part (621) and a second rotating part (622) that are coaxial and rotatably connected. The first rotating part (621) is located outside the second rotating part (622). The first rotating part (621) is coaxially and fixedly connected to a rotating shaft (64). The second ring body (61) is fixedly provided at the end of the rotating shaft (64). The turntable (63) is fixedly provided outside the second rotating part (622).

3. The single-point mooring method for an offshore floating structure according to claim 2, wherein: The rotating support component (62) is a bearing, the first rotating part (621) is an inner ring of the bearing, and the second rotating part (622) is an outer ring of the bearing.

4. The single-point mooring method for an offshore floating structure according to claim 1, wherein: The inner hole of the first ring body (5) is circular, and both ends of the inner hole are provided with guide arc surfaces (51); the inner hole of the second ring body (61) is circular, and the annular cross section of the second ring body (61) is circular.

5. The single-point mooring method for an offshore floating structure according to claim 1, wherein: The mooring cable (4) is a carbon fiber composite cable, one end of the mooring cable (4) is provided with a first conical anchor (41), and the other end of the mooring cable (4) is provided with a second conical anchor (43); Before laying the anchor foundation (2), the second conical anchor (43) is connected to the anchor foundation (2) via the bottom-lying cable (3), and the second conical anchor (43) is fixedly connected with an ear (42); During the process of deploying the anchoring foundation (2) on the target seabed, a lifting device is used to lower the anchoring foundation (2) to the seabed while releasing the mooring cable (4) wound on the cable drum. When the anchoring foundation (2) is located on the target seabed, the plug ear (42) is connected to the turntable (63) located on the floating structure (1) in the target sea area.

6. The single-point mooring method for an offshore floating structure according to claim 5, wherein: The bottom-lying section cable (3) includes an anchor chain (33) and a D-type shackle (32), one end of the anchor chain (33) is fixedly connected to the anchor foundation (2), and the other end of the anchor chain (33) is buckled with the D-type shackle (32), and the bending section of the shackle body of the D-type shackle (32) is provided with a socket, and the end of the second conical anchor (43) is fixedly connected to the adapter shaft (31), and when the adapter shaft (31) is rotatably connected to the socket, the end of the adapter shaft (31) is located outside the socket to limit the shackle body on the adapter shaft (31).

7. The single-point mooring method for an offshore floating structure according to claim 6, wherein: The adapter shaft (31) is embedded with an optical fiber sensor, and when the floating structure (1) is moored in the target sea area, the optical fiber sensor monitors the mooring connection status.

8. The single-point mooring method for an offshore floating structure according to claim 5, wherein: The rotating disk (63) is provided with an eye ring (631). When the plug ear (42) is connected to the rotating disk (63), the plug ear (42) is buckled with the eye ring (631) by manually operating a shackle (7).

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