Method and device for determining safe distance between LNG ship emergency anchorage and submarine cable

Abstract

The application provides a LNG ship emergency anchorage and submarine cable safety distance determination method and device, comprising: obtaining historical anchor walking accident information of a LNG ship, basic parameter information of the LNG ship and a fluke, submarine environment parameters and submarine cable buried depth distance, analyzing the historical anchor walking accident information to obtain anchor walking accident data and an anchor walking process; establishing an anchor walking drift model; and calculating the anchor walking accident data according to the anchor walking drift model to obtain a drift safety distance; calculating the basic parameter information to obtain the maximum depth of the fluke into the submarine; calculating the basic parameter information and the submarine environment parameters to obtain the anchor penetration depth of the LNG ship; and determining a target safety distance according to the drift safety distance, the maximum depth, the anchor penetration depth and the submarine cable buried depth distance. The application determines the target safety distance between the anchorage and the submarine cable, and judges whether the ship anchor walking will cause damage to the submarine cable according to the target safety distance.

Description

Technical Field

[0001] This invention relates to the field of anchorage detection technology, specifically to a method and apparatus for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable. Background Technology

[0002] In recent years, with the continuous development of ships, the corresponding auxiliary facilities have also been constantly updated, leading to a growing demand for anchorages. However, the existence of the seabed indirectly limits the layout of anchorages. Submarine cables are expensive, and their short distances can cause damage when ships drop anchor or when they drag anchor due to wind, waves, currents, or other conditions. If the distance is too far, it wastes marine resources. Furthermore, relevant domestic and international regulations regarding the safe distance between anchorages and nearby submarine cables are generally macro-level guidelines, with few specific provisions.

[0003] Therefore, there is an urgent need to propose a method and device for determining the safe distance between the emergency anchorage of LNG ships and submarine cables, in order to solve the technical problem in the existing technology that ships dragging anchor can easily damage submarine cables, resulting in the waste of marine resources. Summary of the Invention

[0004] In view of this, it is necessary to provide a method and device for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable, so as to solve the technical problem in the prior art that when a vessel drags its anchor, it can easily damage the submarine cable, resulting in the waste of marine resources.

[0005] On one hand, the present invention provides a method for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable, including:

[0006] The system acquires historical anchor dragging accident information of LNG vessels, basic parameter information of the LNG vessels and anchor claw bite, seabed environmental parameters and burial depth of submarine cables, analyzes the historical anchor dragging accident information, and obtains anchor dragging accident data and anchor dragging process.

[0007] Based on the anchor dragging process, an anchor dragging drift model is established; and based on the anchor dragging accident data, a drift safety distance is obtained.

[0008] The maximum depth to which the anchor claws engage the seabed is calculated based on the basic parameter information; and the anchoring penetration depth of the LNG vessel is calculated based on the basic parameter information and the seabed environmental parameters.

[0009] The target safety distance is determined based on the drift safety distance, the maximum depth, the anchoring penetration depth, and the burial depth of the submarine cable.

[0010] In some possible implementations, the anchor dragging process includes an anchored vessel yaw phase, an anchor dragging yaw transition phase, and an anchored vessel stable drift phase.

[0011] The step of establishing an anchor dragging drift model based on the anchor dragging process includes:

[0012] When the anchor dragging process is the anchored vessel yaw phase and the anchor dragging yaw transition phase, the motion state of the LNG vessel is determined to be uniform acceleration motion.

[0013] When the anchor dragging process is the stable drifting stage of the anchored vessel, the motion state of the LNG vessel is determined to be uniform motion;

[0014] After the LNG ship vehicle stops the ship from dragging anchor, the motion state of the LNG ship is determined to be uniformly decelerated motion;

[0015] Based on the motion state of the LNG vessel at the corresponding stage of the anchor dragging process, an anchor dragging drift model is established.

[0016] In some possible implementations, the anchor dragging incident data includes the environmental data, basic ship data, and driving data corresponding to each stage of the LNG vessel dragging anchor from the historical anchor dragging incident information.

[0017] The step of calculating the safe drift distance based on the anchor dragging accident data according to the anchor dragging drift model includes:

[0018] The drift speed of the LNG vessel during the stable drift phase of the anchored vessel is obtained by calculating the environmental data and the basic ship data.

[0019] The drift speed and the driving data are calculated based on the anchor-dragging drift model to obtain the safe drift distance of the LNG vessel during the stable drift phase of the anchored vessel.

[0020] In some possible implementations, the basic parameter information includes the effective height of the LNG vessel from the summer load waterline to the top of the uppermost compartment, the beam, the effective orthographic projection area of ​​the funnel, and the deployment angle of the anchor claws.

[0021] The calculation of the basic parameter information to obtain the maximum depth to which the anchor claw engages the seabed includes:

[0022] Based on the effective height, the ship's width, and the effective orthographic projection area of ​​the funnel, the number of outfitting items for the LNG vessel is determined, and based on the number of outfitting items, the anchor weight of the anchor claw is determined.

[0023] Based on the anchor weight, determine the anchor claw height and anchor crown thickness.

[0024] The maximum depth to which the anchor claw engages with the seabed is determined based on the anchor claw height, the anchor crown thickness, and the anchor claw deployment angle.

[0025] In some possible implementations, the basic parameter information includes the shape coefficient of the anchor claw bite; the seabed environmental parameters include the soil coefficient.

[0026] The calculation of the basic parameter information and the seabed environmental parameters to obtain the anchoring penetration depth of the LNG vessel includes:

[0027] The anchoring penetration depth of the LNG vessel is obtained by calculating the shape factor, the soil factor, and the anchor weight.

[0028] In some possible implementations, the calculation of the shape factor, the soil factor, and the anchor weight to obtain the anchoring penetration depth of the LNG vessel includes:

[0029] Based on the anchor weight, the contact velocity and cross-sectional area of ​​the anchor claw when it contacts the soil are calculated;

[0030] The anchoring penetration depth of the LNG vessel is obtained based on the shape factor, the soil factor, the anchor weight, the contact velocity, and the cross-sectional area.

[0031] In some possible implementations, determining the anchoring penetration depth of the LNG vessel based on the shape factor, the soil factor, the anchor weight, the contact velocity, and the cross-sectional area includes:

[0032] Determine whether the contact speed is less than or equal to a preset contact speed;

[0033] If so, the anchoring penetration depth of the LNG vessel is calculated based on the shape factor, the soil factor, the anchor weight, the cross-sectional area, and the contact velocity.

[0034] If not, the anchoring penetration depth of the LNG vessel is calculated based on the soil coefficient, the anchor weight, the cross-sectional area, and the contact velocity.

[0035] In some possible implementations, the calculation formula for the anchor-drift model is as follows:

[0036]

[0037] In the formula, S is the safe drift distance; S0 is the displacement during the anchor dragging process; T1 is the time of the anchored vessel's yaw phase and the transition phase of the anchor dragging yaw phase; S1 is the displacement of the anchored vessel's yaw phase and the transition phase of the anchor dragging yaw phase; V is the drift speed of the anchored vessel during the stable drift phase; T is the emergency standby time; T2 is the time for the LNG vessel to generate rudder effect after the standby is completed.

[0038] In some possible implementations, the anchoring penetration depth is greater than the maximum depth;

[0039] The determination of the target safety distance based on the drift safety distance, the maximum depth, the anchoring penetration depth, and the submarine cable burial depth includes:

[0040] When the burial depth of the submarine cable is greater than the anchoring penetration depth, the target safe distance of the LNG vessel is determined to be the first preset distance;

[0041] When the burial depth of the submarine cable is less than or equal to the maximum depth, the drift safety distance is determined as the target safety distance;

[0042] When the burial depth of the submarine cable is between the anchoring penetration depth and the maximum depth, the target safe distance of the LNG vessel is determined to be the second preset distance; the second preset distance is less than the target safe distance.

[0043] On the other hand, the present invention also provides a device for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable, comprising:

[0044] The information acquisition module is used to acquire historical anchor dragging accident information of LNG vessels, basic parameter information of the LNG vessels and anchor claw bite, seabed environmental parameters and the burial depth of submarine cables, and analyze the historical anchor dragging accident information to obtain anchor dragging accident data and anchor dragging process;

[0045] The drift determination module is used to establish an anchor dragging drift model based on the anchor dragging process; and to calculate the anchor dragging accident data based on the anchor dragging drift model to obtain the drift safety distance;

[0046] The depth calculation module is used to calculate the basic parameter information to obtain the maximum depth of the anchor claw biting into the seabed; and to calculate the basic parameter information and the seabed environment parameters to obtain the anchoring penetration depth of the LNG ship.

[0047] The distance determination module is used to determine the target safety distance based on the drift safety distance, the maximum depth, the anchoring penetration depth, and the burial depth of the submarine cable.

[0048] The beneficial effects of the above embodiments are as follows: The method for determining the safe distance between the emergency anchorage and submarine cable of an LNG vessel provided by the present invention, by analyzing historical anchor dragging accident information, obtains accident data and anchor dragging processes of LNG vessels during historical anchor dragging. This allows for the establishment of an anchor dragging drift model based on the anchor dragging process, enabling accurate modeling according to actual conditions. Furthermore, the drift safety distance during the anchor dragging process can be obtained based on the anchor dragging drift model. Further, the basic parameter information of the LNG vessel and anchor claw engagement, seabed environmental parameters, and submarine cable burial depth can be determined. This allows for the determination of the maximum depth of the anchor claw engagement into the seabed and the anchoring penetration depth of the LNG vessel. Based on the drift safety distance, maximum depth, anchoring penetration depth, and submarine cable burial depth, the target safe distance between the anchorage and the submarine cable can be determined, enabling the LNG vessel to judge whether dragging anchor will cause damage to the submarine cable when anchoring, based on the target safe distance. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A schematic flowchart of an embodiment of the method for determining the safe distance between an LNG vessel's emergency anchorage and a submarine cable provided by the present invention;

[0051] Figure 2 This is a schematic diagram of an embodiment of the single-anchor mooring provided by the present invention;

[0052] Figure 3 A schematic diagram of an embodiment of the anchor dragging process of an LNG ship provided by the present invention; a coordinate schematic diagram of an embodiment of the maximum depth to which Hall anchors of different masses can penetrate the seabed;

[0053] Figure 4 A schematic diagram of an embodiment of the LNG ship emergency anchorage and submarine cable safety distance determination device provided by the present invention;

[0054] Figure 5 A schematic diagram of an embodiment of the electronic device provided by the present invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0056] Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor systems and / or microcontroller systems.

[0057] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0058] This invention provides a method and apparatus for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable, which will be described below.

[0059] Figure 1 This is a schematic flowchart of an embodiment of the method for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable provided by the present invention, as shown below. Figure 1 As shown, the method for determining the safe distance between the emergency anchorage of an LNG vessel and submarine cables includes:

[0060] S101. Obtain historical anchor dragging accident information of LNG vessels, basic parameter information of LNG vessels and anchor claw bite, seabed environmental parameters and burial depth of submarine cables, analyze historical anchor dragging accident information, and obtain anchor dragging accident data and anchor dragging process.

[0061] S102. Based on the anchor dragging process, establish an anchor dragging drift model; and calculate the anchor dragging accident data based on the anchor dragging drift model to obtain the drift safety distance;

[0062] S103. Calculate the basic parameter information to obtain the maximum depth of the anchor claw into the seabed; and calculate the basic parameter information and seabed environmental parameters to obtain the anchoring penetration depth of the LNG ship.

[0063] S104. Determine the target safety distance based on the drift safety distance, maximum depth, anchoring penetration depth, and submarine cable burial depth.

[0064] Compared with existing technologies, the method for determining the safe distance between an LNG vessel's emergency anchorage and a submarine cable provided in this invention analyzes historical anchor dragging accident information to obtain accident data and the anchor dragging process of LNG vessels during historical anchor dragging. This allows for the establishment of an anchor dragging drift model based on the anchor dragging process, enabling accurate modeling according to actual conditions. Furthermore, the drift safety distance during the anchor dragging process can be determined based on the anchor dragging drift model. Further, the basic parameters of the LNG vessel and anchor bite, seabed environmental parameters, and the burial depth of the submarine cable can be determined, thereby obtaining the maximum depth of the anchor bite into the seabed and the anchoring penetration depth of the LNG vessel. Based on the drift safety distance, maximum depth, anchoring penetration depth, and submarine cable burial depth, the target safe distance between the anchorage and the submarine cable can be determined, allowing the LNG vessel to assess whether dragging anchor will cause damage to the submarine cable when anchoring, based on the target safe distance.

[0065] It should be understood that the principles for selecting temporary emergency anchorage sites are as follows:

[0066] (1) The selection of anchorage sites shall comply with relevant plans such as the overall port plan and marine functional zoning;

[0067] (2) The anchorage should be located as close as possible to the liquefied natural gas terminal to facilitate emergency anchoring of LNG vessels;

[0068] (3) Anchor locations should utilize natural water depth as much as possible to facilitate use and maintenance;

[0069] (4) The selection of anchor sites should take into account natural conditions such as water flow, waves, and geology, and meet the anchor holding force requirements.

[0070] (5) The anchorage layout has a relatively small impact on the surrounding ports and waterways;

[0071] (6) Anchorage sites should maintain a safe distance from submarine pipelines, islands, and reefs;

[0072] (7) The anchorage should be located in a way that facilitates the identification and positioning of ships, and should preferably be located in the coverage area of ​​the Automatic Identification System (AIS) and the Vessel Traffic Management System (VTS).

[0073] Furthermore, due to weather conditions, the available anchorage areas are relatively limited in the sea. Some areas may already have dedicated LNG anchorages, but they are relatively far away. Therefore, temporary emergency anchorages can be set up near the shore. The emergency anchorages should meet the requirements for temporary emergency anchorage of LNG vessels under wind conditions of ≤7, and the anchorage method can be single anchor mooring. In contrast, there are relatively fewer restrictions on the available anchorage areas in offshore waters, but the wind and waves are larger. The emergency anchorages should meet the requirements for temporary emergency anchorage of LNG vessels under wind conditions of ≤10, and the anchorage method can be single anchor.

[0074] The temporary emergency anchorages in this embodiment of the invention are mainly for LNG vessels to meet the requirements of temporary emergency anchorage under wind conditions of ≤7. Single anchor mooring, such as Figure 2 As shown, according to the calculation formula for the single anchorage radius in the harbor anchorage design code, the required radius for single anchorage is calculated as shown in formula (1):

[0075] R = L + l c +l d (1)

[0076] In the formula, L is the designed ship length; l c The horizontal projection length of the anchor chain shall not exceed the total anchor chain length of the designed vessel type; for wind speeds of 5-7, the length shall be 6-10 times the anchorage depth below the design high water level, with the larger value used for higher wind speeds; in this case, the wind speed is considered to be 7, and 10 times the anchorage depth below the design high water level shall be used. d To allow for a safe distance, we can use 55m. Taking the waters east of Zhuangyuan'ao Island as an example, we can calculate the distance to the waters east of Zhuangyuan'ao Island as 26.6 * 10. 4 m 3 The radius of the emergency anchorage required for the LNG ship (with wind speed of level 7) is 607.4m, so we take 610m.

[0077] The reference surface for the design water depth of the anchorage should be the local theoretical lowest tide level. The calculation of the design water depth of the anchorage is shown in formula (2):

[0078] D = c × T + Z (2)

[0079] In the formula, c is the anchorage water depth coefficient. Based on the wave conditions of the engineering water area, the nearshore wave height on the east side of Zhuangyuan'ao Island, except for the impact of typhoons, is generally within 2m, and the wave period is generally within 8s, so it is taken as 1.2; for the open sea area southeast of Dongtou Island, large waves also mainly occur during the typhoon period, and the waves are relatively larger than those in the nearshore island chain area, so it is taken as 1.3; T is the full-load draft of the LNG vessel (m); Z is the siltation reserve depth. The seabed in the anchorage area is generally stable, so the natural water depth is taken as 0m, and the dredging reserve depth is taken as 0.4m; therefore, the formula is calculated as 17.5*10 4 m 3 LNG ships and 26.6*104 m 3 Taking LNG ships as an example, 17.5*10 4 m 3 LNG carriers have a full-load draft of 11.5m. The required anchorage depth using natural water depth is 13.8–15.0m, while the required anchorage depth if dredging is necessary is 14.2–15.4m; 26.6*10 4 m 3 LNG vessels have a controlled draft of 12.0m. The required anchorage depth using natural water depth is 14.4–15.6m, while the required anchorage depth if dredged is necessary is 14.8–16.0m. Given the susceptibility to siltation after anchorage excavation, resulting in high operating and maintenance costs, and considering the abundant tidal resources in the sea area and the terminal operator's commitment not to allow LNG vessels with a draft greater than 11.5m to enter the port when the predicted tide level is <0.6m, [further consideration is taken].

[0080] Furthermore, based on the above process, the location of the temporary emergency anchorage and the sailing conditions of the LNG vessel at the temporary emergency anchorage can be determined. Then, based on the location of the temporary emergency anchorage, the surrounding submarine cables and other facilities can be analyzed to obtain the burial depth of the submarine cables. For example, the burial depth of the submarine cables can be determined to be 3-3.5m.

[0081] In a specific embodiment of the present invention, in order to better understand the anchoring process of anchored vessels and the relevant motion parameters of LNG vessels during the anchoring process, relevant literature was consulted and information on 23 typical historical anchor dragging accidents was analyzed. The time taken from the start of anchor dragging to the discovery of anchor dragging is shown in Table 1 based on the statistics of the relevant accidents:

[0082] Table 1. Time elapsed between the discovery of LNG vessels dragging anchor

[0083]

[0084]

[0085] Statistical analysis of relevant accidents also compiled the free anchor drag speed and anchor drag distance over a 20-minute period recorded in accident investigation reports with such information. It should be noted that since the ship may drag anchor for longer or shorter periods, 20 minutes is used as a convenient reference time. To better understand the time elapsed from discovering anchor drag to engine preparation, the time elapsed from the crew's final confirmation of anchor drag to the first engine start was also compiled, and it was determined that a time of 15 minutes from discovering anchor drag to the first engine start should be reasonable. This value is used as the intervention delay time in real-time maneuvering simulation experiments. The anchor drag accident data includes not only anchor drag speed, anchor drag distance, and the time elapsed from discovering anchor drag to the first engine start, but may also include other data, which will not be described in detail in this embodiment of the invention.

[0086] It should be noted that:

[0087] In some embodiments of the present invention, the anchor dragging process includes an anchored vessel yaw stage, an anchor dragging yaw transition stage, and an anchored vessel stable drift stage; step S102 includes:

[0088] When the anchor dragging process is the anchored ship yaw stage and the transition stage of anchor dragging yaw, the motion state of the LNG ship is determined to be uniform acceleration motion.

[0089] When the anchor-dragging process is in the stable drifting stage of the anchored vessel, the motion state of the LNG vessel is determined to be uniform motion.

[0090] After the LNG vessel was stopped from dragging anchor by a vehicle, the motion state of the LNG vessel was determined to be uniformly decelerated motion.

[0091] An anchor-dragging drift model is established based on the motion state of the LNG vessel at the corresponding stage of the anchor-dragging process.

[0092] In specific embodiments of the present invention, such as Figure 3 As shown, an anchored vessel (LNG carrier) will yaw around its anchorage under the influence of wind and current. The yaw trajectory is generally a horizontal figure-eight. This stage is called the anchored vessel yaw stage. Figure 3 As shown in section A; as the wind force continues to increase, the continuous tension and impact tension on the anchor chain will increase. When the maximum anchoring force is exceeded, the anchored vessel will shift slightly downwind. During this stage, the yaw motion and the anchor-dragging motion are superimposed, and this is called the anchor-dragging yaw transition stage, as shown in section A. Figure 3 As shown in section B; when the windward angle and wind chain angle of the LNG vessel tend to a constant value, the vessel will drift stably downwind. This stage is the stable drift stage of the anchored vessel, as shown in section B. Figure 3 As shown in section C, the anchoring yaw phase and the transition phase of anchor dragging yaw can be defined as the initial anchor dragging phase. During the initial anchor dragging phase, the LNG vessel undergoes uniform acceleration. During the stable drift phase of the anchored vessel, the LNG vessel undergoes uniform speed movement. After anchor dragging ends, that is, after the vehicle is used, the LNG vessel will undergo uniform deceleration. Based on the operation of the LNG vessel in each stage of anchor dragging, an anchor dragging drift model can be established, thereby obtaining the motion state of the LNG vessel in different stages based on the anchor dragging drift model.

[0093] In some embodiments of the present invention, the anchor dragging accident data includes environmental data of the LNG vessel at the time of anchor dragging, basic vessel data, and driving data corresponding to each stage from historical anchor dragging accident information; step S102 includes:

[0094] The drift speed of the LNG vessel during the stable drift phase at anchor was obtained by calculating environmental data and basic ship data.

[0095] Based on the anchor-dragging drift model, the drift speed and driving data are calculated to obtain the safe drift distance of the LNG vessel during the stable drift phase at anchor.

[0096] In a specific embodiment of the present invention, a torque balance model can be established. The specific torque balance model can be set according to the actual situation, and the present invention does not impose any limitations on it. The torque balance model can be used to calculate the drift speed of an LNG ship after it has anchored. The balance equations in the torque balance model can be balanced to obtain a general expression for the drift speed of the anchored ship during the stable drift phase, as shown in formula (3):

[0097]

[0098] In the formula, V w ρ is the drift speed of the anchored vessel during its stable drift phase. a C is the density of air. α The wind pressure coefficient; a a θ is the projected area of ​​the hull above the waterline; θ is the windward angle; B a V is the projected area of ​​the hull above the waterline; max For extreme wind speeds; L pp λ is the distance between the two columns; a ′ represents the anchor holding power coefficient during anchor drag; λ c ′ represents the holding power coefficient of the anchor chain during anchor drag; W a For anchor weight in water; W c denoted as weight per meter of anchor chain in water; l is the length of the horizontal chain; ψ is the heading angle. This refers to the anchor chain azimuth; analysis based on anchor dragging conditions is needed. ρ w C is the density of water. Nw The hydrodynamic turning moment coefficient is determined by the water depth-to-draft ratio, drift angle, and the shape of the hull below the waterline; L is the length of the LNG vessel; and D is the draft of the LNG vessel. These parameters can be obtained through analysis of historical anchor dragging incidents, such as basic ship data like the projected area of ​​the hull above the waterline, the distance between the two anchor posts, the weight of the anchor in the water, the weight per meter of anchor chain in the water, the length of the anchor chain, the length of the LNG vessel, and the draft of the LNG vessel. Environmental data can include conventional parameters such as air density, wind pressure coefficient, extreme wind speed, and water density. Some parameters can also be set according to actual conditions, such as the anchor holding power coefficient and the anchor chain holding power coefficient during anchor dragging. This embodiment of the invention does not impose any limitations on these parameters. Some of these parameters are shown in Table 2.

[0099] Table 2. Parameters for Drift Velocity Solution

[0100]

[0101]

[0102] In some embodiments of the present invention, the calculation of the anchor drift model is as shown in formula (4):

[0103]

[0104] In the formula, S is the safe drift distance; S0 is the displacement during the anchor dragging process; T1 is the time of the anchored vessel's yaw phase and the transition phase of the anchor dragging yaw phase; S1 is the displacement of the anchored vessel's yaw phase and the transition phase of the anchor dragging yaw phase; V w T represents the drift speed during the stable drifting phase of the anchored vessel; T represents the emergency standby time; T2 represents the time it takes for the LNG vessel to generate rudder effect after the standby is completed.

[0105] In a specific embodiment of the present invention, the displacement during the anchor dragging process, the time of the anchored vessel yaw phase and the transition phase of the anchor dragging yaw phase, the displacement of the anchored vessel yaw phase and the transition phase of the anchor dragging yaw phase, the emergency standby time, and the time for the LNG vessel to generate rudder effect after standby are all obtained by analyzing historical anchor dragging accident information. These are the driving data for each stage in the anchor dragging accident data. The analysis and summary of the driving data are shown in Table 3.

[0106] Table 3. Parameters for Solving Anchor Drift Distance of LNG Vessels

[0107]

[0108] Based on the parameter information of each historical anchor dragging accident summarized in Tables 2 and 3, it can be calculated that, at the upper limit of wind force 7, 17.5 * 10 4 m 3 The stable drift speeds of the fully loaded and ballasted LNG carriers after anchoring in this waterway are 0.2 m / s (approximately 0.4 kN) and 0.24 m / s (approximately 0.5 kN), respectively. The LNG carrier enters a stable drift phase after drifting approximately 100 meters. 26.6*10 4 m 3 The stable drift speeds of the LNG carrier after anchoring in this waterway are 0.25 m / s (approximately 0.5 kN) when fully loaded and 0.29 m / s (approximately 0.6 kN) when ballasted. The LNG carrier enters a stable drift phase after drifting approximately 150 m. Based on relevant calculations, 17.5 * 10 4 m 3 An LNG vessel, ballasted and fully loaded, anchored with a single anchor, maintains a stable speed of approximately 0.4–0.5 knots after dragging anchor at a wind speed of 17.1 m / s. (26.6*10) 4 m 3LNG vessels drift at a speed of approximately 0.5 to 0.6 knots. Considering the function and nature of temporary emergency anchors, as well as the marine environment, to ensure relative safety, a conservative drift speed of 2.5 knots is adopted for anchor dragging, and this speed is used to determine the drift distance of the LNG vessel.

[0109] Based on the simulated safe distance analysis of ships dragging anchor, under conditions of force 7 winds and a dragging anchor drift speed of 2.5 knots, the main ship type is 17.5*10 4 m 3 The relative distance between the anchor and the LNG vessel is approximately 1.2 km, with a maximum design hull size of 26.6 x 10. 4 m 3 The relative distance between anchor and dragging for LNG vessels is approximately 1.8 km. Therefore, LNG vessels must strictly adhere to relevant regulations and strengthen watchkeeping during anchorage, frequently monitoring anchor positions to prevent dragging. They must also receive timely weather information, and when severe weather such as strong winds is forecast, constantly monitor changes in the LNG vessel's anchor position, maintain effective communication, and have their main engines ready for emergency use. At least two 5200-horsepower tugboats should be deployed for watchkeeping and protection to prevent dragging. If necessary, they should be moved to open waters in advance.

[0110] In some embodiments of the present invention, the basic parameter information includes the effective height from the summer load waterline of the LNG vessel to the top of the uppermost compartment, the beam, the effective orthographic projection area of ​​the funnel, and the deployment angle of the anchor claws; step S103 includes:

[0111] The number of outfitting items for an LNG vessel is determined based on the effective height, beam, and effective orthographic projection area of ​​the funnel, and the anchor weight of the anchor claws is determined based on the number of outfitting items.

[0112] Determine the height of the anchor claw and the thickness of the anchor crown based on the anchor weight;

[0113] The maximum depth to which the anchor claws engage the seabed is determined based on the anchor claw height, anchor crown thickness, and anchor claw deployment angle.

[0114] In a specific embodiment of the present invention, the basic parameters of the anchor claw engagement can be obtained based on the basic parameters of the LNG ship's anchoring. The basic parameters may include the effective height from the summer load waterline in the ship to the top of the uppermost compartment, the beam of the LNG ship, and the effective orthographic projection area of ​​the funnel. Thus, the outfitting count can be calculated as shown in formula (5):

[0115] EN = Δ 2 / 3 +2(XK+S dun )+0.1A (5)

[0116] In the formula, EN represents the outfitting count, △ represents the LNG vessel displacement (t); X represents the effective height from the summer load waterline to the top of the uppermost compartment (m); K represents the beam (m); Sfun Effective projected area of ​​the chimney, m 2 A represents the total side projection area of ​​the hull above the summer load waterline, the superstructure, and deckhouses and funnels with a width greater than B / 4 within the ship's length range, in meters. 2 The displacement of the LNG vessel can be determined based on actual conditions, and this embodiment of the invention does not impose any limitations. Using the aforementioned 17.5*10... 4 m 3 LNG ships and 26.6*10 4 m 3 Taking LNG carriers as an example, the main ship type and the largest design ship type are 17.5*10 4 m 3 LNG ships and 26.6*10 4 m 3 For LNG vessels, △ is taken as 125,000 tons and 165,000 tons respectively, B is taken as 47.9m and 53.8m respectively, h is taken as 19.2m and 20.3m respectively; S fun The effective projected area of ​​the chimney is taken as 25m². 2 The calculation yields 17.5 * 10. 4 m 3 LNG main vessel type and 26.6*10 4 m 3 The outfitting counts (EN) for the largest LNG carrier designs are 4949.4 and 5939.3, respectively.

[0117] Furthermore, the anchor weight can be found in the tables in the domestic shipbuilding specifications, as shown in Table 4:

[0118] Table 4. Outfitting Quantity - Anchor Weight Reference Table

[0119]

[0120]

[0121] By referring to Table 4, we get 17.5 * 10 4 m 3 LNG main vessel type and 26.6*10 4 m 3 The corresponding anchor weights for the largest LNG vessel designs are approximately 14.7t and 17.8t, respectively.

[0122] In a specific embodiment of the present invention, the parameters of various types of Hall anchors are summarized, and the relationship between anchor weight M, anchor claw height and anchor crown thickness can be obtained from the summary. The relationship can also be fitted separately, as shown in formula (6) and formula (7):

[0123] h = 0.6M 1 / 2-0.028M+0.28 (6)

[0124] B = 0.46M 1 / 2 -0.19M+0.18 (7)

[0125] In the formula, h is the height of the anchor claw (m); B is the thickness of the anchor crown (m); and M is the anchor weight.

[0126] Then, the maximum depth of the anchor into the seabed can be calculated based on the anchor crown thickness, anchor claw height, and anchor claw deployment angle, as shown in formula (8):

[0127] D = h sin a + B / 2 (8)

[0128] In the formula, D is the depth to which the anchor claws bite into the seabed when the anchor is dragged, in meters; a is the angle of the anchor claws, which can be up to 45°.

[0129] Furthermore, the maximum depth to which Hall anchors of different masses can penetrate the seabed can be calculated. A coordinate system can be set up with the x-axis representing mass and the y-axis representing the maximum penetration depth. A 10t Hall anchor, when towed, penetrates to a maximum depth of approximately 2m; 20t and 40t Hall anchors penetrate to depths of 2.5m and 3m respectively. According to data from the Equasis database, in 2017, LNG vessels with a gross tonnage of 100-499 tons accounted for 37% of the global fleet, those with a gross tonnage of 500-24999 tons accounted for 43%, those with a gross tonnage of 25000-59999 tons accounted for 13%, and those with a gross tonnage of 60000 tons and above accounted for 7%. Based on the formula for calculating the weight of LNG vessels and the weight of the selected anchor, 70% of global LNG vessels use anchors with a weight of less than 8t, and 93% use anchors with a weight of less than 12t. Meanwhile, approximately 80% of the anchors used in the global LNG carrier market are Hall anchors. Therefore, the maximum depth to which the anchor penetrates the seabed during anchoring is generally no more than 1.5–2 meters. However, accidents involving LNG carriers losing control due to anchoring and damaging subsea pipelines and cables are common both domestically and internationally. According to a pipeline protection risk assessment published by DNV-GL, the probability of pipeline or cable accidents caused by LNG carrier anchoring is 6.4 × 10⁻⁶. -3 This falls under the medium-to-high level category. According to LNG vessel anchoring simulation analysis, the maximum depth to which a 20t Hall anchor penetrates the seabed is 2.5m. The 17.5*10m anchor in this embodiment of the invention... 4 m 3 LNG main vessel type and 26.6*10 4 m 3The anchor weights of LNG vessels are approximately 14.7t and 17.8t, respectively, both less than 20t. Therefore, the maximum anchoring depth is less than 2.5m, which is less than the burial depth of the submarine cable (3-3.5m). Since LNG vessels will pass over the submarine cable while dragging anchor, the maximum depth to which the anchor engages the seabed must be less than the burial depth of the submarine cable.

[0130] In some embodiments of the present invention, the basic parameter information includes the shape coefficient of the anchor claw bite; the seabed environmental parameters include the soil coefficient; step S103 includes:

[0131] The anchoring penetration depth of the LNG vessel is obtained by calculating the shape factor, soil factor, and anchor weight.

[0132] In some embodiments of the present invention, the anchoring penetration depth of an LNG vessel is obtained by calculating the shape factor, soil factor, and anchor weight, including:

[0133] Based on the anchor weight, calculate the contact velocity and cross-sectional area of ​​the anchor claw when it contacts the soil;

[0134] The anchoring penetration depth of an LNG vessel is obtained based on the shape factor, soil factor, anchor weight, contact velocity, and cross-sectional area.

[0135] In a specific embodiment of the present invention, the soil coefficient S corresponds to the general seabed substrate: 10-20 for silty substrate; 6-9 for sandy substrate; 20-30 for soft mud substrate; and 8-15 for mixed silt and sand substrate. If silt is predominant, 15 is recommended; if sand is predominant, 8 is recommended. To calculate the penetration depth of the spare anchor, the soil coefficient S for silty substrate is taken as 18. Based on relevant anchoring experiments, the anchor shape coefficient is generally taken as N=6. The cross-sectional area can also be calculated based on the anchor weight, as shown in formula (9):

[0136] A = 0.00272M 2 +0.3067M+0.4592 (9)

[0137] In the formula, A is the cross-sectional area of ​​the anchor, m 2 M is the anchor weight, in tons (t). For example, 17.5 * 10 4 m 3 LNG ships and 26.6*10 4 m 3 LNG ships, A is taken as 5600m 2 and 7320m 2 .

[0138] The estimated value of the anchor's extreme velocity during its descent can also be calculated, as shown in formula (10):

[0139]

[0140] In the formula, M is the anchor weight, t; v is the anchor dropping speed (contact speed), m / s. The calculated main ship type is 17.5*10 4 m 3 The LNG vessel has an anchor weight of 14.7t and a descent speed of approximately 7.3m / s. The maximum design hull size is 26.6*10. 4 m 3 The LNG vessel has an anchor weight of 17.8t and a descent speed of approximately 7.6m / s.

[0141] In some embodiments of the present invention, the anchoring penetration depth of an LNG vessel is obtained based on a shape factor, soil factor, anchor weight, contact velocity, and cross-sectional area, including:

[0142] Determine if the contact speed is less than or equal to the preset contact speed;

[0143] If so, the anchoring penetration depth of the LNG vessel is calculated based on the shape factor, soil factor, anchor weight, cross-sectional area, and contact velocity.

[0144] If not, the anchoring penetration depth of the LNG vessel is calculated based on the soil coefficient, anchor weight, cross-sectional area, and contact velocity.

[0145] In a specific embodiment of the present invention, there are no established standards for calculating the anchoring penetration depth of LNG vessels. Commonly used calculation methods include the empirical prediction model method, the energy conservation principle method, and the Young formula method. This embodiment of the present invention uses the Young formula method to calculate the anchoring penetration depth. The contact velocity can be used to determine the depth. When the contact velocity is less than or equal to a preset contact velocity (which can be 61 m / s), the anchoring penetration depth can be calculated using formula (11), as shown below:

[0146] D = 0.008SN(W / A) 0.7 ln(1+0.00025V 2 (11)

[0147] In the formula, D is the penetration depth (m); N is the shape factor of the object; S is the soil coefficient; W is the mass of the object (kg); V is the contact velocity of the object when it contacts the soil (m / s); and A is the cross-sectional area of ​​the object (m²). 2 .

[0148] When the contact speed is greater than the preset contact speed, the anchor penetration depth can be calculated using formula (12), as shown below:

[0149] D = 0.000018SV(W / A) 0.7 (V-30.5) (12)

[0150] Therefore, based on formulas (11) and (12), and in combination with the corresponding parameter values, the main ship type 17.5*10 can be calculated. 4 m 3 The emergency anchoring depth for LNG vessels is approximately 2.89m, with a maximum design hull size of 26.6*10. 4 m 3 The emergency anchoring depth of an LNG vessel is approximately 3.03m.

[0151] In some embodiments of the present invention, the anchoring penetration depth is greater than the maximum depth; step S104 includes:

[0152] When the burial depth of the submarine cable is greater than the anchoring penetration depth, the target safe distance for the LNG vessel is determined as the first preset distance.

[0153] When the burial depth of the submarine cable is less than or equal to the maximum depth, the drift safety distance is determined as the target safety distance;

[0154] When the burial depth of the submarine cable is between the anchoring penetration depth and the maximum depth, the target safe distance for the LNG vessel is determined as the second preset distance; the second preset distance is greater than the target safe distance.

[0155] In a specific embodiment of the present invention, when the anchoring penetration depth is greater than the maximum depth, the burial distance of the submarine cable, the anchoring penetration depth, and the maximum depth can be judged. When the burial distance of the submarine cable is greater than the anchoring penetration depth, it means that the LNG ship will not touch the submarine cable when anchoring. At this time, the target safety distance is the second preset distance, and the first preset distance can be set to 0. When the burial distance of the submarine cable is less than or equal to the maximum depth, the target safety distance is the drift safety distance. The farther the LNG ship drifts, the safer it is. When the burial distance of the submarine cable is between the anchoring penetration depth and the maximum depth, the target safety distance of the LNG ship can be determined as the second preset distance. The second preset distance is less than the target safety distance. The second preset distance is set by the staff according to the actual situation. The specific parameter value is not limited in this embodiment of the present invention. According to the above example, the calculation is performed by formula (11) and formula (12). The calculation results are shown in Table 5.

[0156] Table 5. Calculation Results

[0157]

[0158]

[0159] Therefore, based on the analysis of the penetration depth of emergency anchoring, the main ship type is 17.5*10. 4The mLNG vessel's anchor mass is approximately 14.7 tons, and the emergency anchor penetration depth is approximately 2.89 meters, meeting the safety distance requirements. The maximum design hull size is 26.6 x 10 meters. 4 m 3 The emergency anchoring depth of an LNG vessel is 3.03m, which is close to the burial depth of submarine cables (3-3.5m). It is recommended that after the vessel has dragged anchor, it should first be tugged back to its original anchorage area by tugboats before anchoring. Anchoring during the dragging process is prohibited.

[0160] To better implement the method for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable in this invention, this invention also provides a device for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable, based on the method described in this embodiment. Figure 4 As shown, the device for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable includes:

[0161] The information acquisition module 401 is used to acquire historical anchor dragging accident information of LNG ships, basic parameter information of LNG ships and anchor claw bite, seabed environmental parameters and burial depth of submarine cables, analyze historical anchor dragging accident information, and obtain anchor dragging accident data and anchor dragging process.

[0162] The drift determination module 402 is used to establish a drift model based on the anchor dragging process; and to calculate the drift safety distance based on the anchor dragging accident data according to the anchor dragging drift model.

[0163] The depth calculation module 403 is used to calculate the basic parameter information to obtain the maximum depth of the anchor claw biting into the seabed; and to calculate the basic parameter information and seabed environmental parameters to obtain the anchoring penetration depth of the LNG ship.

[0164] The distance determination module 404 is used to determine the target safety distance based on the drift safety distance, maximum depth, anchoring penetration depth and submarine cable burial depth.

[0165] The LNG ship emergency anchorage and submarine cable safety distance determination device provided in the above embodiments can realize the technical solution described in the above embodiments of the LNG ship emergency anchorage and submarine cable safety distance determination method. The specific implementation principle of each module or unit can be found in the corresponding content in the above embodiments of the LNG ship emergency anchorage and submarine cable safety distance determination method, which will not be repeated here.

[0166] like Figure 5 As shown, the present invention also provides an electronic device 500. The electronic device 500 includes a processor 501, a memory 502, and a display 503. Figure 5Only some components of the electronic device 500 are shown, but it should be understood that it is not required to implement all the components shown, and more or fewer components may be implemented instead.

[0167] In some embodiments, memory 502 may be an internal storage unit of electronic device 500, such as a hard disk or memory of electronic device 500. In other embodiments, memory 502 may also be an external storage device of electronic device 500, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc. equipped on electronic device 500.

[0168] Furthermore, the memory 502 may include both internal storage units of the electronic device 500 and external storage devices. The memory 502 is used to store application software and various types of data installed on the electronic device 500.

[0169] In some embodiments, processor 501 may be a central processing unit (CPU), microprocessor, or other data processing chip, used to run program code stored in memory 502 or process data, such as the method for determining the safe distance between LNG ship emergency anchorage and submarine cable in this invention.

[0170] In some embodiments, display 503 may be an LED display, a liquid crystal display, a touch-sensitive liquid crystal display, or an OLED (Organic Light-Emitting Diode) touchscreen. Display 503 is used to display information from electronic device 500 and to display a visual user interface. Components 501-503 of electronic device 500 communicate with each other via a system bus.

[0171] In some embodiments of the present invention, when processor 501 executes the program for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable stored in memory 502, the following steps can be implemented:

[0172] The system acquires historical anchor dragging incident information of LNG vessels, basic parameter information of LNG vessels and anchor claw bite, seabed environmental parameters and burial depth of submarine cables, analyzes historical anchor dragging incident information, and obtains anchor dragging incident data and anchor dragging process.

[0173] Based on the anchor dragging process, an anchor dragging drift model is established; and based on the anchor dragging accident data, the drift safety distance is calculated.

[0174] The maximum depth of the anchor claws into the seabed is obtained by calculating the basic parameter information; and the anchoring penetration depth of the LNG ship is obtained by calculating the basic parameter information and seabed environmental parameters.

[0175] The target safety distance is determined based on the drift safety distance, maximum depth, anchoring penetration depth, and submarine cable burial depth.

[0176] It should be understood that when the processor 501 executes the program for determining the safe distance between the LNG ship's emergency anchorage and the submarine cable in the memory 502, in addition to the functions mentioned above, it can also perform other functions, as described in the preceding corresponding method embodiments.

[0177] Furthermore, this embodiment of the invention does not specifically limit the type of electronic device 500 mentioned. Electronic device 500 can be a mobile phone, tablet computer, personal digital assistant (PDA), wearable device, laptop computer, or other portable electronic device. Exemplary embodiments of portable electronic devices include, but are not limited to, portable electronic devices running iOS, Android, Microsoft, or other operating systems. The aforementioned portable electronic device can also be other portable electronic devices, such as a laptop computer with a touch-sensitive surface (e.g., a touch panel). It should also be understood that in some other embodiments of the invention, electronic device 500 may not be a portable electronic device, but rather a desktop computer with a touch-sensitive surface (e.g., a touch panel).

[0178] Accordingly, this application also provides a computer-readable storage medium for storing computer-readable programs or instructions. When the programs or instructions are executed by a processor, they can implement the steps or functions of the method for determining the safe distance between the emergency anchorage of an LNG ship and the submarine cable provided in the above-described method embodiments.

[0179] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0180] The above provides a detailed description of the method and apparatus for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for determining the safe distance between an emergency anchorage of an LNG vessel and a submarine cable, characterized in that, include: The system acquires historical anchor dragging accident information of LNG vessels, basic parameter information of the LNG vessels and anchor claw bite, seabed environmental parameters and burial depth of submarine cables, analyzes the historical anchor dragging accident information, and obtains anchor dragging accident data and anchor dragging process. Based on the anchor dragging process, an anchor dragging drift model is established; and based on the anchor dragging accident data, a drift safety distance is obtained. The maximum depth to which the anchor claws penetrate the seabed is obtained by calculating the basic parameter information; and the anchoring penetration depth of the LNG vessel is obtained by calculating the basic parameter information and the seabed environmental parameters. The target safety distance is determined based on the drift safety distance, the maximum depth, the anchoring penetration depth, and the burial depth of the submarine cable. The basic parameter information includes the effective height of the LNG ship from the summer load waterline to the top of the uppermost compartment, the ship's width, the effective orthographic projection area of ​​the funnel, and the deployment angle of the anchor claws. The calculation of the basic parameter information to obtain the maximum depth to which the anchor claw engages the seabed includes: Based on the effective height, the ship's width, and the effective orthographic projection area of ​​the funnel, the number of outfitting items for the LNG vessel is determined, and based on the number of outfitting items, the anchor weight of the anchor claw is determined. Based on the anchor weight, determine the anchor claw height and anchor crown thickness. The maximum depth to which the anchor claw engages with the seabed is determined based on the anchor claw height, the anchor crown thickness, and the anchor claw deployment angle. The basic parameter information includes the shape coefficient of the anchor claw bite; the seabed environment parameters include the soil coefficient. The calculation of the basic parameter information and the seabed environmental parameters to obtain the anchoring penetration depth of the LNG vessel includes: The anchoring penetration depth of the LNG vessel is obtained by calculating the shape factor, the soil factor, and the anchor weight. The calculation formula for the anchor drift model is as follows: In the formula, S is the safe drift distance; S0 is the displacement during the anchor dragging process; T1 is the time of the anchored ship's yaw phase and the transition phase of the anchor dragging yaw phase; S1 is the displacement of the anchored ship's yaw phase and the transition phase of the anchor dragging yaw phase; V is the drift speed of the anchored ship during the stable drift phase; T is the emergency standby time; T2 is the time for the LNG ship to generate rudder effect after the standby is completed.

2. The method for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable according to claim 1, characterized in that, The anchor dragging process includes the anchored vessel yaw phase, the anchor dragging yaw transition phase, and the anchored vessel stable drift phase. The step of establishing an anchor dragging drift model based on the anchor dragging process includes: When the anchor dragging process is the anchored vessel yaw phase and the anchor dragging yaw transition phase, the motion state of the LNG vessel is determined to be uniform acceleration motion. When the anchor dragging process is the stable drifting stage of the anchored vessel, the motion state of the LNG vessel is determined to be uniform motion; After the LNG vessel vehicle stops the vessel from dragging anchor, the motion state of the LNG vessel is determined to be uniformly decelerated motion; Based on the motion state of the LNG vessel at the corresponding stage of the anchor dragging process, an anchor dragging drift model is established.

3. The method for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable according to claim 2, characterized in that, The anchor dragging accident data includes the environmental data, basic ship data, and driving data corresponding to each stage of the LNG vessel dragging anchor in the historical anchor dragging accident information. The step of calculating the safe drift distance based on the anchor dragging accident data according to the anchor dragging drift model includes: The drift speed of the LNG vessel during the stable drift phase of the anchored vessel is obtained by calculating the environmental data and the basic ship data. The drift speed and the driving data are calculated based on the anchor-dragging drift model to obtain the safe drift distance of the LNG vessel during the stable drift phase of the anchored vessel.

4. The method for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable according to claim 1, characterized in that, The calculation of the shape factor, the soil factor, and the anchor weight to obtain the anchoring penetration depth of the LNG vessel includes: Based on the anchor weight, the contact velocity and cross-sectional area of ​​the anchor claw when it contacts the soil are calculated; The anchoring penetration depth of the LNG vessel is obtained based on the shape factor, the soil factor, the anchor weight, the contact velocity, and the cross-sectional area.

5. The method for determining the safe distance between the emergency anchorage of an LNG vessel and a submarine cable according to claim 4, characterized in that, The process of determining the anchoring penetration depth of the LNG vessel based on the shape coefficient, the soil coefficient, the anchor weight, the contact velocity, and the cross-sectional area includes: Determine whether the contact speed is less than or equal to a preset contact speed; If so, the anchoring penetration depth of the LNG vessel is calculated based on the shape factor, the soil factor, the anchor weight, the cross-sectional area, and the contact velocity. If not, the anchoring penetration depth of the LNG vessel is calculated based on the soil coefficient, the anchor weight, the cross-sectional area, and the contact velocity.

6. The method for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable according to claim 1, characterized in that, The anchoring penetration depth is greater than the maximum depth; The determination of the target safety distance based on the drift safety distance, the maximum depth, the anchoring penetration depth, and the submarine cable burial depth includes: When the burial depth of the submarine cable is greater than the anchoring penetration depth, the target safe distance of the LNG vessel is determined to be the first preset distance; When the burial depth of the submarine cable is less than or equal to the maximum depth, the drift safety distance is determined as the target safety distance; When the burial depth of the submarine cable is between the anchoring penetration depth and the maximum depth, the target safe distance of the LNG vessel is determined to be the second preset distance; the second preset distance is less than the target safe distance.

7. A device for determining the safe distance between an LNG ship's emergency anchorage and a submarine cable, characterized in that, The method for determining the safe distance between an LNG vessel's emergency anchorage and a submarine cable as described in any one of claims 1 to 6 includes: The information acquisition module is used to acquire historical anchor dragging accident information of LNG vessels, basic parameter information of the LNG vessels and anchor claw bite, seabed environmental parameters and the burial depth of submarine cables, and analyze the historical anchor dragging accident information to obtain anchor dragging accident data and anchor dragging process; The drift determination module is used to establish an anchor dragging drift model based on the anchor dragging process; and to calculate the anchor dragging accident data based on the anchor dragging drift model to obtain the drift safety distance; The depth calculation module is used to calculate the basic parameter information to obtain the maximum depth at which the anchor claw bites into the seabed; and to calculate the anchoring penetration depth of the LNG vessel based on the basic parameter information and the seabed environmental parameters. The distance determination module is used to determine the target safety distance based on the drift safety distance, the maximum depth, the anchoring penetration depth, and the burial depth of the submarine cable.

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