Ship applied to offshore anchor system tension verification

Abstract

The invention discloses a ship applied to marine anchor system tension verification. The ship comprises a main ship body, and a head winch system capable of providing tension in the direction from a stern to a prow for the main ship body and a propelling system capable of providing thrust in the direction from the stern to the prow for the main ship body are arranged on the main ship body; the head winch system comprises a head winch, and the head winch is fixedly arranged at the head of the main ship body; the main ship body is further provided with a chain stopping system used for being connected with a to-be-verified anchor system. The chain stopping system comprises chain stopping equipment with a tension display function; and the chain stopping equipment is fixedly arranged at the tail of the main hull. The method is more convenient to use, lower in investment cost and better in economical efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of ships, and in particular to a ship used for verifying the tension of offshore anchoring. Background Art

[0002] Offshore wind turbines are divided into fixed offshore wind turbines and floating wind turbines. The difference between fixed offshore wind turbines and floating wind turbines lies in their different wind turbine foundations. Fixed offshore wind turbine foundations are mainly suitable for water depths of 0 to 50m near the coast, including single pile foundations, jacket foundations, tripod foundations and gravity foundations, etc. Floating wind turbine foundations are generally used in sea areas with a seawater depth of greater than or equal to 50m, such as column foundations, tension leg foundations and semi-submersible foundations. Generally speaking, unlike fixed shallow water offshore wind turbines, which are installed on the offshore foundation by a dedicated wind turbine installation platform or crane ship at sea, floating wind turbines are already installed on the foundation at the onshore base.

[0003] Compared with fixed wind turbines, floating wind turbines are free from the limitation of water depth to a certain extent, which makes it easier to find better wind farms in the wider sea. In terms of scale, offshore floating wind turbines are easier to increase the scale of wind farms and are more economical.

[0004] The installation and positioning of floating wind turbines refers to effectively fixing floating wind turbines in offshore wind farms so that they can safely carry out wind power generation operations. The mooring and positioning system is crucial to ensure the normal power generation and even self-sustaining of floating wind turbines. Currently, the common floating wind turbine mooring systems mainly include catenary mooring and vertical tension leg mooring.

[0005] For column-type, semi-submersible and barge-type offshore floating wind turbines, catenary mooring is often used, and the mooring line is usually a steel chain structure. Steel chain has become the most widely used mooring material due to its low manufacturing cost, simple process and high strength. The pre-tension of the mooring line mainly depends on the suspended section of the anchor chain, and the restoring force of the anchor chain is mainly achieved by the change of the suspended section of the anchor chain; however, this mooring method has a long seabed lying section, so it occupies a larger seabed space, and the weight increases sharply with the increase of water depth.

[0006] The catenary mooring system is to fix the floating wind turbine foundation by the weight and curved shape of the steel chain. The lower section of the steel chain is located on the seabed and fixed to the seabed by supporting anchors to limit the movement of the platform. The characteristics of the catenary system are low installation cost and good economy, but the anchor tension verification is required to ensure the grip reliability of the anchor system.

[0007] For tension-leg offshore floating wind turbines, vertical tension-leg mooring is often used, and synthetic materials are often used for this type of mooring line. The tension mooring system is a system in which the floating wind turbine foundation and the anchor are tightened and fixed by steel chains or high-strength fibers to ensure the stability of the floating platform. The tension-leg platform balances the excess buoyancy of the floating wind turbine foundation upward through the vertical mooring tension, which is similar to a "tightening up and down" mechanism, so it has better platform vertical motion performance, but its installation process is more complicated. The characteristics of the tension mooring system are that it does not require anchor tension verification, but the installation cost is huge and the economy is poor.

[0008] Take the "Haiyou Guanlan", my country's first deep-sea floating wind turbine, for example. It is installed in an offshore oil field 136 kilometers offshore and 120 meters deep. The "Haiyou Guanlan" uses a three-way anchor positioning system, with three sets of anchors in each direction, a total of 9 152mm non-stop anchor chains and 9 suction anchors.

[0009] In order to ensure the reliability of the high holding power anchor, it is necessary to verify the tension of the offshore anchor system. The conventional tension verification method relies on the towing system of the anchor handling towing supply vessel (AHTS).

[0010] AHTS is mainly used for anchoring, towing and supplying, so it is also called anchor tug supply ship. The three-purpose work ship has its own mooring machine and can provide towing, anchoring and supply services for drilling operations of drilling platforms. In addition to the transportation function, the most important feature of this type of ship is that it is equipped with an anchoring and towing system.

[0011] In the prior art, when a three-purpose workboat is used to perform anchor tension verification operations, the positioning anchor that needs to be tension verified is mainly connected through the towing winch on the main deck, and the tension of the positioning anchor is verified through the thrust of the rear thruster of the three-purpose workboat. The tension of the positioning anchor will be displayed on the towing winch with tension display.

[0012] Since the verification load of the large holding anchor of the floating wind turbine mooring system is very large, usually exceeding 600t, and with the increase of the power generation of offshore floating wind turbines and the water depth of wind farms in the future, the verification load of the large holding anchor of the floating wind turbine mooring system will further increase, even exceeding 1000t. At present, the AHTS with the largest bollard pull in the world is 477t (the bollard pull is the tension value measured when the main engine is running at rated power and towed away from the dock or fixed point with a 100-meter-long towline when the ship is fully loaded, also known as the dock pull, the unit is t.). Since AHTS needs to perform many types of operations, the anchoring operation is only part of all its uses. Limited by the economic considerations of a single AHTS (higher bollard pull means that a larger power main engine is required), the bollard pull of AHTS cannot be increased indefinitely. Therefore, for smaller floating wind turbines, two AHTSs are currently required in parallel to complete the test operation (by connecting to the same towing lock). However, using two AHTS to verify the anchor tension at sea will greatly increase the economic cost and have more complicated operation steps. At the same time, using the towing lock to verify the tension, according to the parallelogram law of force synthesis, the tension of the towing lock on the anchor is less than the sum of the bollard towing forces of the two AHTS, but adding more AHTS means higher economic costs and more complicated operation procedures. Therefore, the operation process of using two or more AHTS is more complicated and the economic cost is very high.

[0013] For other offshore platforms, their foundations are similar to those of offshore floating wind turbines. They also need to be anchored and positioned in deep-water operating areas, and they also need to perform tension verification operations on offshore anchor systems.

[0014] The existing technology has the following defects: For the current smaller floating wind turbines, two AHTSs are also needed in parallel to complete the test operation. However, two AHTSs for offshore anchor tension verification means higher economic costs and more complicated operation steps. Adding more AHTSs means higher economic costs and more complicated operation processes. For larger floating wind turbine foundations or offshore platform foundations, there is currently no good method for offshore anchor tension verification. Summary of the invention

[0015] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a ship used for verifying the tension of offshore anchoring.

[0016] The present invention solves the above technical problems through the following technical solutions:

[0017] A ship used for verifying the tension of offshore anchoring comprises a main hull, on which is provided a bow winch system capable of providing the main hull with a pulling force from the stern toward the bow and a propulsion system capable of providing the main hull with a thrust from the stern toward the bow; the bow winch system comprises a bow winch, which is fixedly arranged at the bow of the main hull; the main hull is also provided with a chain stopper system for connecting with the anchor to be verified; the chain stopper system comprises a chain stopper device with a tension display; the chain stopper device is fixedly arranged at the middle or middle rear of the main hull.

[0018] Furthermore, the bow winch system also includes a reaction force anchor and a reaction force anchor chain; the reaction force anchor is connected to the bow winch through the reaction force anchor chain.

[0019] Furthermore, a bow roller is provided at the bow of the main hull for providing rolling support for the reaction force anchor chain.

[0020] Furthermore, the number of the head winch is 1 or more.

[0021] Furthermore, the chain stopping device is a chain stopper, or a towing winch.

[0022] Furthermore, the propulsion system includes a tail thruster, which is arranged at the tail of the main hull.

[0023] Furthermore, the number of the tail thrusters is 1 or more.

[0024] Furthermore, the propulsion system also includes a bow thruster; the bow thruster is arranged at the bow of the main hull.

[0025] Furthermore, the propulsion system also includes a telescopic propeller; the telescopic propeller is arranged at the bow of the main hull.

[0026] Furthermore, a tail roller is provided at the tail of the main hull for providing rolling support for the anchor chain between the chain-stopping device and the anchor system to be verified.

[0027] The beneficial effect of the present invention is that the present invention increases the ability to verify the anchor tension through the tension of the bow winch. Compared with the prior art, the present invention has lower requirements for the propulsion system because it only needs to meet the displacement within a small distance. Compared with the thruster, the investment cost and operating cost of generating unit tension through the winch are much lower, and it has higher economy. The ship of the present invention is more convenient to use, has a lower investment cost, is more economical, and can solve the problem of offshore anchor tension verification of large floating wind turbine foundations. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a side view of a preferred embodiment of the present invention.

[0029] Figure 2 It is a top view of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0030] A preferred embodiment is given below, and the present invention is described more clearly and completely in conjunction with the accompanying drawings.

[0031] like Figure 1 and Figure 2 As shown, a vessel used for offshore anchor tension verification comprises a main hull 10.

[0032] The main hull 10 is provided with a bow winch system which can provide the main hull with a pulling force from the stern toward the bow.

[0033] The bow winch system comprises a bow winch 21, which is fixed to the bow of the main hull. The number of the bow winch 21 is one or more.

[0034] The bow winch system further includes a reaction force anchor 22 and a reaction force anchor chain 23 ; the reaction force anchor 22 is connected to the bow winch 21 via the reaction force anchor chain 23 .

[0035] The bow of the main hull 10 is provided with a bow roller 24 for providing rolling support for the reaction anchor chain. The bow roller is also equipped with a shark clamp and a stop pin. The bow roller can reduce the wear and friction resistance between the reaction anchor chain and the main hull. The main function of the shark clamp is to hold the reaction anchor chain tightly to prevent the reaction anchor chain from sliding.

[0036] The main hull is provided with a propulsion system capable of providing the main hull with thrust from the stern toward the bow.

[0037] The propulsion system includes a tail propeller 31, which is arranged at the tail of the main hull; the number of the tail propeller 31 is 1 or more.

[0038] The propulsion system further comprises a bow thruster 32 , which is arranged at the bow of the main hull.

[0039] The propulsion system also includes a telescopic thruster 33; the telescopic thruster 33 is arranged at the bow of the main hull.

[0040] In one embodiment, the propulsion system includes a bow thruster disposed at the bow of the main hull; however, the propulsion system does not include a retractable thruster.

[0041] In another embodiment, the propulsion system includes a telescopic thruster, which is arranged at the bow of the main hull; but the propulsion system does not include a bow thruster.

[0042] The main hull 10 is also provided with a chain stopping system for connecting with the anchoring system 50 to be verified. The chain stopping system includes a chain stopping device 41 with a tension display; the chain stopping device 41 is fixedly arranged in the middle or middle rear part of the main hull.

[0043] The chain stopping device 41 is a chain stopper, or a towing winch.

[0044] The tail of the main hull 10 is provided with a tail drum 42 for providing rolling support for the anchor chain 51 between the chain stopper 41 and the anchor system 50 to be verified. The tail drum is also equipped with a shark clamp and a stop pin. The tail drum can reduce the wear and friction resistance between the anchor chain and the main hull. The main function of the shark clamp is to hold the anchor chain tightly to prevent the anchor chain from sliding.

[0045] The ship of the present invention comprises a main hull, and a bow winch system, a propulsion system and a chain stopper system arranged on the main hull.

[0046] By tightening the bow winch, under the action of the reaction anchor, the ship is provided with a pulling force from the stern to the bow; through the stern thruster, the ship is thrusted from the stern to the bow. The bow winch system and the propulsion system form a combined force. The anchor to be verified is connected to a chain stop device with a tension display, which can display the tension on the anchor to be verified. Through the joint action of various devices, the tension verification of the anchor to be verified that needs to be verified is completed.

[0047] For smaller anchors (e.g. less than 850t) that require tension verification, the tension verification can be completed by tightening the bow winch or the stern thruster, or both, and using the chain stop system.

[0048] For larger anchors (e.g. greater than 850t) that require tension verification, the bow winch system, propulsion system and chain stop system work together to complete the tension verification.

[0049] Compared with the existing technology (relying only on the bollard pull of the tail thruster), it is impossible to increase the thruster power significantly due to the limitation that the thruster power cannot be increased significantly. At present, the ship with the largest bollard pull in the world is 477t, which requires a total propulsion power of about 26,000kW. If only the thruster is used to generate a bollard pull of 1,000t, at least 55,000kW of propulsion power is required, which is very uneconomical.

[0050] The present invention increases the ability to verify the anchor tension through the tension of the bow winch. Compared with the prior art, the present invention has lower requirements for the propulsion system because it only needs to meet the displacement within a small distance range. Compared with the thruster, the investment cost and operating cost of generating unit tension through the winch are much lower, and it has higher economic efficiency.

[0051] The ship of the present invention is more convenient to use, has lower investment cost, is more economical, and can solve the problem of offshore anchor tension verification of large floating wind turbine foundations.

[0052] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A ship used for offshore anchor tension verification, comprising a main hull, characterized in that: The main hull is provided with a bow winch system capable of providing pulling force from the stern toward the bow for the main hull and a propulsion system capable of providing thrust from the stern toward the bow for the main hull; the bow winch system includes a bow winch, which is fixed at the bow of the main hull; the main hull is also provided with a chain stop system for connecting to the anchor to be verified; the chain stop system includes a chain stop device with a tension display; the chain stop device is fixed at the middle or middle rear of the main hull.

2. The ship used for offshore anchor tension verification according to claim 1, characterized in that: The bow winch system also includes a reaction force anchor and a reaction force anchor chain; the reaction force anchor is connected to the bow winch through the reaction force anchor chain.

3. The ship used for offshore anchor tension verification according to claim 2, characterized in that: A bow roller is provided at the bow of the main hull for providing rolling support for the reaction force anchor chain.

4. The ship used for offshore anchor tension verification according to claim 1, characterized in that: The number of the head winch is 1 or more.

5. The ship used for offshore anchor tension verification according to claim 1, characterized in that: The chain stopping device is a chain stopper or a towing winch.

6. The ship used for offshore anchor tension verification according to claim 1, characterized in that: The propulsion system comprises a tail thruster which is arranged at the tail of the main hull.

7. The ship used for offshore anchor tension verification according to claim 6, characterized in that: The number of tail thrusters is 1 or more.

8. The ship used for offshore anchor tension verification according to claim 1, characterized in that: The propulsion system also includes a bow thruster; the bow thruster is located at the bow of the main hull.

9. The ship used for offshore anchor tension verification according to claim 1, characterized in that: The propulsion system also includes a telescopic thruster; the telescopic thruster is arranged at the bow of the main hull.

10. The ship used for offshore anchor tension verification according to claim 1, characterized in that: A stern roller is provided at the stern of the main hull for providing rolling support for the anchor chain between the chain-stopping device and the anchor system to be verified.

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