Airbag upper row type water discharge construction method for large ship

Abstract

The application relates to a large ship airbag upper row type water discharge construction method, which comprises the following steps: step S1, site preparation; step S2, installation of a winch device and measurement of a pay-off; step S3, slope bottom airbag placement; step S4, ship posture adjustment and fixation; step S5, cable fixation; step S6, preliminary traction and airbag inflation; step S7, traction forward movement and further airbag filling; and step S8, setting of a support pier and pier falling. The application provides a large ship airbag upper row type water discharge construction method, breaks through infrastructure limitations, provides a feasible path for ship landing in a deep-water wharf area, reduces operation risks under complex hydrological conditions through airbag flexible bearing technology, and provides a technical paradigm for ship operation and maintenance in similar shoal and tide sensitive areas through the technical concept of "adapting to local conditions and dynamically adapting", which has important practical significance for guaranteeing shipping safety and supporting channel engineering emergency repair.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering technology, and in particular relates to a construction method for airbag-type water discharge on large ships. Background Technology

[0002] Coastal shipping maintenance and inland dredging projects are core engineering areas for ensuring smooth water traffic, improving watershed infrastructure, and enhancing water resource utilization. Large vessels (such as cutter suction dredgers and engineering work vessels) are the core equipment for these projects, and their efficient emergency repair and cross-waterway deployment directly determine the project's construction progress and operation and maintenance quality. Currently, large vessel operations face numerous practical bottlenecks: many operating areas lack deep-water wharves, thousand-ton lifting equipment, and other fixed shore-based supporting facilities; coupled with complex hydrological conditions such as insufficient river depth, violent tidal fluctuations, and water level differences of several meters, large vessels themselves possess inherent characteristics such as large weight, long hull size, and uneven center of gravity distribution, making traditional lifting and slipway methods unsuitable for on-site construction needs. Furthermore, traditional methods suffer from inherent drawbacks such as high traction requirements, low operational efficiency, high construction costs, and significant risks of hull structural damage, severely restricting the efficient advancement of large vessel operation and maintenance work and hindering the smooth implementation of coastal shipping maintenance and inland dredging projects.

[0003] When the work area lacks specialized shipyards, deep-water wharves, and large-scale lifting equipment, vessel dredging becomes a critical bottleneck restricting project progress. In such scenarios, shallow river sections make deep-draft vessels prone to grounding, drastic tidal changes shorten the high tide window to just a few hours, and the maximum height difference between the water level and the wharf can reach several meters. Coupled with the large weight, excessive length, and unbalanced center of gravity of the vessels, traditional lifting or slipway methods are difficult to adapt, potentially extending the construction period or even causing structural damage to the hull. Therefore, conducting research on optimizing methods for dredging large vessels to overcome these technical bottlenecks has significant engineering practical value and research significance, and is a key technical problem urgently needing to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a method for airbag-assisted hull-out construction of large ships, which solves the drawbacks of existing methods for hull-out construction of large ships, and constructs a safety assurance system for the entire process of hull-out and landing of large ships in complex working conditions, so as to realize efficient, safe and economical hull-out and landing of large ships in areas without deep-water wharves.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a construction method for airbag-type top-discharge water discharge of large ships, comprising the following steps:

[0006] Step S1, Site preparation: Leveling the site and constructing ramps;

[0007] Step S2, Install the winch equipment and measure and lay out the line: Set up a marker pole and a conspicuous identification line at the intersection of the reverse extension line of the winch cable with the water surface and the waterline of the slope. The position of the pole is the longitudinal midpoint of the airbag.

[0008] Step S3, Installation of airbags at the bottom of the slope: Under low tide conditions, two airbags are pre-installed at the bottom of the slipway and sandbags are used to weigh down the two airbags.

[0009] Step S4, Ship attitude adjustment and fixation: When the ship is ready to move, adjust and fix the ship's landing position, direction and attitude, and ensure that the landing direction is consistent with or in the same plane as the winch cable.

[0010] Step S5, Cable securing: Connect the winch cable to the connection point on the ship;

[0011] Step S6, Initial traction and airbag inflation: When the water level reaches the lowest high tide mark, start the winch and tow the ship forward with the cable. Stop the winch when the bottom of the ship's front end is above the two airbags. Then use an air compressor to inflate the two airbags until the two airbags lift the ship.

[0012] Step S7, towing forward and further filling the airbag: Start the winch to tow the ship forward. When the end of the ship is a certain distance away from the front airbag, fill another airbag at the bottom of the ship and inflate it. Then start the winch to continue towing the ship forward and continue to fill and inflate the airbag. Repeat this alternating process until the ship is completely towed out of the water and onto the shore.

[0013] Step S8, setting up supports and landing supports: When the hull reaches the designated position, multiple sets of supports are set up on the bottom of the ship, each airbag is deflated, and after deflation, the airbags are removed from the bottom of the ship, and the ship lands on each set of supports, completing the ship's launch.

[0014] Preferably, in step S1, the leveled site meets the requirements of smooth airbag movement, uniform stress on the support piers, and stable crane installation, and ensures that there are no sharp objects on the site, the slope ratio of the outer ramp of the wharf is less than 15%, the outer edge of the ramp extending into the water is filled with rubble to secure the foot, the surface of the underwater ramp and the bottom of the connection with the wharf are covered with crushed stone and the upper part is covered with sand and compacted with compaction machinery.

[0015] Preferably, between step S1 and step S2, there is also a step of airbag configuration and airbag pressure testing, which verifies the airbag bearing capacity and matches the number of airbags according to a safety factor of 1.5 times the weight of the ship to be launched, removes unqualified airbags through pressure testing, and sets up spare airbags to consider the potential airbag rupture conditions during the launch construction.

[0016] Preferably, in steps S3 and S7, the distance between two adjacent airbags is greater than or equal to one full-inflated airbag diameter.

[0017] Preferably, in step S4, an anchor boat is used to push and rotate the ship from both sides of the bow and stern to adjust the angle at which the ship goes ashore. After the angle is adjusted to the correct position, the anchor boat moves to one side of the ship and pushes the ship to the shore position along the opposite direction of the current. Once the ship reaches the shore position, it is anchored with a cable or the anchor boat is used to temporarily fix the ship in position downstream.

[0018] Preferably, in step S7, during the forward traction process, airbags of appropriate diameter are filled as appropriate according to the ship's attitude. Smaller diameter airbags are arranged near the outer edge of the dock to reduce the ship's upward angle. During the forward traction process, a dedicated person is assigned to observe the force on both sides of the airbags and the changes in the ship's attitude in a timely manner, and adjust the pressure of individual airbags in a timely manner according to the actual situation. By inflating and deflating one side of the airbags, the ship's attitude in the direction of travel is finely adjusted to ensure that the ship's axis is always in the same vertical plane as the cable.

[0019] Preferably, in step S7, a rope is tied to one end of the airbag to be filled, and a tow bar is used to pull the end of the bottom cable to the other side of the ship. Then, the end of the airbag is manually dragged to the other side of the ship through the rope, and the airbag is spread out under the ship. The direction of the airbag is adjusted to be perpendicular to the ship's axis and in a suitable position.

[0020] Preferably, in step S8, the top of each set of supports is aligned with the bottom of the ship by leveling with a pad, and the airbag is slowly deflated to prevent the supports near the airbag from being suddenly subjected to force and causing impact and settlement.

[0021] Preferably, the high tide window period of the construction site is predicted and accurately determined based on long-term water level monitoring data, and is used as the construction window period of this water discharge construction method. Steps S3 to S7, which are key processes, are concentrated in the window period for completion, while steps S1 and S2, which are non-key processes, are prepared in advance.

[0022] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a construction method for airbag-based surface discharge of large ships, breaking through infrastructure limitations and providing a feasible path for ships to go ashore in areas without deep-water wharves; it reduces operational risks under complex hydrological conditions through airbag flexible bearing technology; its "adaptive to local conditions and dynamic adaptation" technical concept provides a technical paradigm for ship operation and maintenance in areas such as shoals and tidal sensitive areas, and has important practical significance for ensuring navigation safety and supporting emergency repairs of waterway projects.

[0023] The airbag-based water discharge construction method of this invention breaks through the traditional ship buoyancy support and water resistance resistance movement mode, and innovatively adopts the water-land transition mode of "airbag lifting - rolling friction - tidal force", which has the following advantages:

[0024] First, flexible load-bearing and load-dispersing: a large area of ​​uniform stress surface is formed by high-strength composite airbag array, which disperses the concentrated load of the ship into a uniform load, reduces the ground pressure (≤120kPa), adapts to the working conditions of soft foundation in shallow waters, and avoids stress concentration and damage to the hull structure.

[0025] Second, rolling friction reduces resistance: by utilizing the rolling characteristics of airbags, the sliding friction between the hull and the ground / ramp is converted into rolling friction, reducing the coefficient of friction to 0.08 to 0.12, which greatly reduces the ship's traction resistance.

[0026] Third, precise operation adapted to tides: Based on the principle of tidal dynamics, the precise connection between ship buoyancy and airbag landing is achieved during the high tide window. The height is dynamically adjusted by inflating and deflating the airbags to solve the problem of the difference between water level and slipway height. At the same time, with the support of anchor boat pushing and cable anchoring, the ship's attitude is precisely controlled to ensure that the deviation between the traction direction and the ship's axis is ≤1°.

[0027] The entire process of this invention does not rely on fixed facilities such as deep-water wharves or thousand-ton lifting equipment. The operation process is less likely to damage the ship's traction anchor points, effectively avoiding wear and deformation of the ship's bottom. It also has the advantages of wide applicability, high safety factor, and low construction cost. Attached Figure Description

[0028] Figure 1 This is a flowchart of the construction method for the airbag-type water discharge of large ships according to the present invention.

[0029] Figure 2 This is a schematic diagram of the construction method for airbag-type water discharge on large ships according to the present invention. Detailed Implementation

[0030] The core of this construction method is to transform the traditional water buoyancy support and water resistance resistance movement mode of ships into a water-land transition mode driven by airbag lifting and rolling friction through a technical approach of "flexible load-bearing + mechanical traction," enabling large ships to safely and efficiently leave the water and land under complex working conditions. 1) Flexible support replaces rigid load-bearing: High-strength composite airbags are used as "mobile support units," forming a large-area uniform force-bearing surface through low-pressure inflation, dispersing the pressure on the hull (the breaking strength of a single airbag is ≥800N), adapting to soft foundations in shallow waters, and avoiding damage to the hull structure. 2) Rolling friction reduces traction requirements: After inflation, the airbags form "flexible tracks," converting the sliding friction between the ship and the ground / ramp into rolling friction, significantly reducing traction force consumption. Compared with traditional lifting or slipway methods, the traction force requirement is significantly reduced. 3) Dynamically adapt to overcome operating conditions: Select high tide window for operation based on tidal patterns, and dynamically adjust the height by inflating and deflating airbags to overcome the problem of water level and slipway height difference; Combine with anchor boat pushing to adjust the ship's attitude to ensure that the traction direction is consistent with the ship's axis, adapting to complex hydrological conditions with shallow water and large tidal influence.

[0031] Please see Figure 1 This invention provides a construction method for airbag-type top-discharge water discharge on large ships, comprising the following steps:

[0032] Step S1, site preparation; Step S2, installation of winch equipment and measurement and laying out; Step S3, placement of airbags at the bottom of the slope; Step S4, adjustment and fixation of the vessel's attitude; Step S5, fixing of cables; Step S6, initial traction and inflation of airbags; Step S7, traction forward and further inflation of airbags; Step S8, setting up supports and lowering the supports.

[0033] Before implementing this method of launching water from the airbags on the ship, the high tide window period of the construction site was predicted and accurately determined based on long-term water level monitoring data. This window period was used as the construction window for this method of launching water from the airbags. Key processes were concentrated within the window period, while non-key processes were prepared in advance to ensure the efficiency of the connection between processes.

[0034] The steps of this construction method are explained in detail below:

[0035] Step S1, Site Preparation: Level the site and construct ramps.

[0036] In this step, the leveled site must meet the requirements of smooth airbag movement, uniform stress on the piers, and stable crane installation, and ensure that there are no sharp objects on the site. The slope ratio of the outer ramp of the wharf is less than 15%. The outer edge of the ramp extending into the water is reinforced with rubble. The surface of the underwater ramp and the bottom of the connection with the wharf are covered with crushed stone and the upper part is covered with sand and compacted with compaction machinery.

[0037] Taking the "Junchuan," China's first large-depth combined environmentally friendly cutter suction dredger, as an example, the ship is 66.5m long and 9.95m wide. Considering the need for dismantling and transporting the ship later, the wharf length should be at least 80m and the width at least 40m. The ship weighs 650t, and the number of piers used for landing on shore is calculated as 120. Each pier is 55cm high and 76cm in diameter. The pressure of a single pier on the foundation is: 650*9.8 / 120 / (3.14*0.38*0.38) = 117.07kPa. Taking into account the requirements for dismantling the ship's heaviest component, the main buoy (weighing approximately 140t), using two 300t cranes and the bearing capacity of the airbags, the bearing capacity of the wharf foundation should be at least 120kPa.

[0038] The steps for airbag configuration and pressure testing are as follows: Verify the airbag load-bearing capacity and match the number of airbags to a safety factor of 1.5 times the weight of the vessel being launched. Eliminate unqualified airbags through pressure testing. Consider potential airbag rupture during the launch operation and set up backup airbags. In addition, the airbags need to undergo visual inspection, and the manufacturer's certificate of conformity and test reports should be checked. The airbags should be inflated and pressure tested according to specifications to ensure that the airbags and nozzles meet safety requirements.

[0039] Step S2, Install the winch equipment and measure and lay out the line: Set up a marker pole and a conspicuous identification line at the intersection of the reverse extension line of the winch cable with the water surface and the waterline of the slope. The position of the pole is the longitudinal midpoint of the airbag.

[0040] Measurement and setting out are the foundation of the "airbag top discharge" water discharge method. The direction of the ship's travel must be aligned with the winch cable, and the length of the airbag must be perpendicular to the direction of the ship's travel. If the direction of travel deviates, the effective torque of the traction cable will decrease as the angle of the ship's travel deviates. If the limit is exceeded, the cable may break or the traction force may be insufficient, resulting in failure to discharge water.

[0041] The specific method is as follows: erect a marker pole at the intersection of the reverse extension line of the winch cable with the water surface and the waterline of the slope, and draw a conspicuous identification line in 10cm sections. Design the towing water level in advance and make a key mark on the pole. The position of the pole is the longitudinal midpoint of the airbag. That is, when the airbag is set, the midpoint of the airbag is directly opposite the position of the pole.

[0042] Step S3, placement of airbags at the bottom of the slope: Under low tide conditions, two airbags are pre-installed at the bottom of the slipway and sandbags are used to weigh down the two airbags.

[0043] The purpose of the two pre-installed airbags at the bottom of the slipway is to lift the end of the vessel that has been moved near the slipway. The purpose of using sandbags for ballast is to prevent the two airbags at the bottom of the slipway from floating or shifting position due to the buoyancy of the water and the impact of the current as the tide rises. Sandbags are used to weigh down these two pre-installed airbags, ensuring their stability. The weight of the sandbags should be greater than or equal to 1.2 times the buoyancy of the airbags.

[0044] Step S4, Ship attitude adjustment and fixation: When the ship is ready to move, adjust and fix the ship's landing position, direction and attitude, and ensure that the landing direction is consistent with or in the same plane as the winch cable.

[0045] In this step, anchor boats are used to push and rotate the ship from both sides of the bow and stern to adjust the angle at which the ship goes ashore. Once the angle is adjusted, the anchor boats are moved to one side of the ship and push it ashore against the current. After reaching the shore, the ship is anchored with cables or temporarily fixed in position downstream with anchor boats.

[0046] Taking the "Junchuan" combined cutter suction dredger as an example, the bow is equipped with a cutter arm and other facilities. Therefore, when implementing this method of dredging, the bow faces outward and the stern comes ashore first. The specific operation is as follows: as the tide rises and the water level gradually increases, the grounded vessel can gradually move. When the vessel is ready to move, anchor boats are used to push and rotate the vessel on both sides of the bow and stern to adjust the angle of the stern for landing. After the angle is adjusted, both the bow-pushing anchor boat and the stern-pushing anchor boat move to the side of the vessel. The bow-pushing anchor boat and the stern-pushing anchor boat simultaneously push the vessel against the current to the landing position (the vessel's centerline is directly opposite the positioning pole). After reaching the position, the vessel is anchored with cables or temporarily secured downstream with anchor boats. By adjusting and fixing the ship's landing position, direction, and attitude, ensure that the landing direction is consistent with or within the same plane as the winch cable.

[0047] Step S5, Cable Securing: Connect the winch cable to the connection point on the vessel. As mentioned earlier, taking the "Junchuan" combined cutter suction dredger as an example, the winch cable is connected to the eye plate of the port side and / or starboard side buoy at the stern via a locking buckle.

[0048] Step S6, Initial traction and airbag inflation: When the water level reaches the lowest high tide mark, start the winch and tow the ship forward with the cable. Stop the winch when the bottom of the ship's front end is above the two airbags. Then use an air compressor to inflate the two airbags until the two airbags lift the ship.

[0049] Taking the "Junchuan" combined cutter suction dredger as an example, the stern is moved above the two pre-set airbags by towing. It should be ensured that the front bottom of the stern maintains a certain distance from the ground during the movement to avoid bottoming out. The airbags are double-headed airbags, that is, air valves are set at both ends. Air compressors are set on the shore and on both sides of the ship. When inflating, the air valves at both ends of the airbag are connected to the air compressors on both sides. When the airbag is full of air, it lifts the stern.

[0050] Step S7, towing forward and further filling the airbag: Start the winch to tow the ship forward. When the end of the ship is a certain distance away from the front airbag, fill another airbag at the bottom of the ship and inflate it. Then start the winch to continue towing the ship forward and continue to fill and inflate the airbag. Repeat this alternating process until the ship is completely towed out of the water and onto the shore.

[0051] During towing, speed must be strictly controlled (e.g., keep the towing speed below 24 m / min) and ensure that the towing speed remains relatively constant, avoiding sudden changes in speed. Inclinometers can be installed on the vessel to monitor its tilt, and pressure gauges can be configured for each airbag to monitor its pressure.

[0052] In this step, during the forward traction process, airbags of appropriate diameter are filled as appropriate according to the ship's attitude. Smaller diameter airbags are placed near the outer edge of the dock to reduce the ship's upward angle. During the forward traction process, a dedicated person is assigned to observe the force on both sides of the airbags and the changes in the ship's attitude in a timely manner, and adjust the pressure of individual airbags in a timely manner according to the actual situation. By inflating and deflating one side of the airbags, the ship's attitude in the direction of travel is finely adjusted to ensure that the ship's axis is always in the same vertical plane as the cable.

[0053] In this step, the specific operation of filling the airbag is as follows: tie a rope to one end of the airbag to be filled, use a rope bar to pull the end of the bottom cable to the other side of the ship, and then manually drag the end of the airbag to the other side of the ship through the rope. The airbag is spread out under the ship, and the direction of the airbag is adjusted to be perpendicular to the ship's axis and in a suitable position.

[0054] Preferably, in step S8, the top of each set of supports is leveled with the bottom of the ship by using a pad, and the airbag is slowly deflated to prevent the supports near the airbag from being suddenly subjected to force and causing impact and settlement.

[0055] In steps S3 and S7, the distance between two adjacent airbags is greater than or equal to one full-inflated airbag diameter. The purpose of this design is that if the airbags are too close together and the water level is low, the lower airbag may rise to the top of the upper airbag, causing the two airbags to become entangled. In this case, one airbag should be deflated, and the deflated airbag should be towed away from the side of the hull using mechanical equipment. Then, the other airbag should be quickly replenished and inflated at an appropriate location.

[0056] Step S8, setting up supports and landing supports: When the hull reaches the designated position, multiple sets of supports are set up on the bottom of the ship, each airbag is deflated, and after deflation, the airbags are removed from the bottom of the ship, and the ship lands on each set of supports, completing the ship's launch.

[0057] In this step, leveling plates are used to ensure that the tops of each set of supports are on the same plane as the hull. The airbags are then slowly deflated to prevent sudden impact and settlement of the supports near the airbags. During the lowering of the supports, it is essential to ensure that all supports are subjected to uniform force to prevent stress concentration that could cause localized damage and deformation of the hull.

[0058] The core control points of this construction method are: the airbags at the bottom of the slope must be fixed with sandbags (the weight ≥ 1.2 times the buoyancy of the airbags) to resist the impact of water flow and tides; the length of the airbags must be perpendicular to the direction of the ship's travel, and the spacing must be ≥ 1 diameter to avoid entanglement and interference; the towing water level must meet the dual requirements of ship buoyancy and airbag landing; the airbags must be alternately filled during towing to ensure that the hull is always in a flexible support state; small-diameter airbags are deployed near the outer edge of the dock to reduce the upward angle of the stern and avoid stress concentration.

[0059] This construction method can be applied to the following scenarios: covering a variety of needs such as emergency repair of large ships (e.g., hull damage repair, equipment replacement), engineering transfer (cross-waterway dispatch, inter-project allocation), long-term mooring ashore, and overall transfer before dismantling. It is especially suitable for scenarios that traditional construction methods cannot cover, such as emergency response to sudden emergencies (e.g., ship grounding rescue, flood season emergency transfer) and engineering support in remote areas (e.g., inland reservoir dredging vessels, coastal island supply vessel operation and maintenance). It provides a full-scenario solution for the water-land transition of ships under various complex working conditions.

Claims

1. A construction method for airbag-type top-discharge water discharge on large ships, characterized in that: Includes the following steps, Step S1, Site preparation: Leveling the site and constructing ramps; Step S2, Install the winch equipment and measure and lay out the line: Set up a marker pole and a conspicuous identification line at the intersection of the reverse extension line of the winch cable with the water surface and the waterline of the slope. The position of the pole is the longitudinal midpoint of the airbag. Step S3, Installation of airbags at the bottom of the slope: Under low tide conditions, two airbags are pre-installed at the bottom of the slipway and sandbags are used to weigh down the two airbags. Step S4, Ship attitude adjustment and fixation: When the ship is ready to move, adjust and fix the ship's landing position, direction and attitude, and ensure that the landing direction is consistent with or in the same plane as the winch cable. Step S5, Cable securing: Connect the winch cable to the connection point on the ship; Step S6, Initial traction and airbag inflation: When the water level reaches the lowest high tide mark, start the winch and tow the ship forward with the cable. Stop the winch when the bottom of the ship's front end is above the two airbags. Then use an air compressor to inflate the two airbags until the two airbags lift the ship. Step S7, towing forward and further filling the airbag: Start the winch to tow the ship forward. When the end of the ship is a certain distance away from the front airbag, fill another airbag at the bottom of the ship and inflate it. Then start the winch to continue towing the ship forward and continue to fill and inflate the airbag. Repeat this alternating process until the ship is completely towed out of the water and onto the shore. Step S8, setting up supports and landing supports: When the hull reaches the designated position, multiple sets of supports are set up on the bottom of the ship, each airbag is deflated, and after deflation, the airbags are removed from the bottom of the ship, and the ship lands on each set of supports, completing the ship's launch.

2. The construction method for airbag-type water discharge of large ships according to claim 1, characterized in that: In step S1, the leveled site meets the requirements of smooth airbag movement, uniform stress on the piers, and stable crane installation, and ensures that there are no sharp objects on the site. The slope ratio of the outer ramp of the wharf is less than 15%. The outer edge of the ramp extending into the water is filled with rubble to secure the foot. The surface of the underwater ramp and the bottom of the connection with the wharf are covered with crushed stone and the upper part is covered with sand and compacted with compaction machinery.

3. The construction method for airbag-type water discharge of large ships according to claim 2, characterized in that: Between step S1 and step S2, there are also steps of airbag configuration and airbag pressure testing. The airbag bearing capacity is checked and the number of airbags is matched according to a safety factor of 1.5 times the weight of the ship to be launched. Unqualified airbags are removed through pressure testing. Considering the potential airbag rupture during the launch operation, spare airbags are set up.

4. The construction method for airbag-type water discharge of large ships according to claim 3, characterized in that: In steps S3 and S7, the distance between two adjacent airbags is greater than or equal to one full-inflated airbag diameter.

5. The construction method for airbag-type water discharge of large ships according to claim 4, characterized in that: In step S4, the anchor boat is used to push and rotate the ship from both sides of the bow and stern to adjust the angle of the ship going ashore. After the angle is adjusted to the right, the anchor boat moves to one side of the ship and pushes the ship to the shore position along the opposite direction of the current. After reaching the shore position, the ship is anchored with a cable or the anchor boat is used to temporarily fix the ship in position downstream.

6. The construction method for airbag-type water discharge of large ships according to claim 5, characterized in that: In step S7, during the forward traction process, airbags of appropriate diameter are filled as appropriate according to the ship's attitude. Smaller diameter airbags are placed near the outer edge of the dock to reduce the ship's upward angle. During the forward traction process, a dedicated person is assigned to observe the force on both sides of the airbags and the changes in the ship's attitude in a timely manner, and adjust the pressure of individual airbags in a timely manner according to the actual situation. By inflating and deflating one side of the airbags, the ship's attitude in the direction of travel is finely adjusted to ensure that the ship's axis is always in the same vertical plane as the cable.

7. The construction method for airbag-type water discharge of large ships according to claim 6, characterized in that: In step S7, tie a rope to one end of the airbag to be filled, use a rope bar to pull the end of the bottom cable to the other side of the ship, and then manually drag the end of the airbag to the other side of the ship with the rope. The airbag is spread out under the ship, and the direction of the airbag is adjusted to be perpendicular to the ship's axis and in a suitable position.

8. The construction method for airbag-type water discharge of large ships according to claim 7, characterized in that: In step S8, the tops of each set of supports are leveled with the bottom of the ship by using pads, and the airbags are slowly deflated to prevent sudden impact and sinking of the supports near the airbags.

9. The construction method for airbag-type water discharge of large ships according to claim 8, characterized in that: Based on long-term water level monitoring data, the high tide window period of the construction site is predicted and accurately determined. This window period is used as the construction window period for this water discharge construction method. Steps S3 to S7, which are key processes, will be completed within the window period, while steps S1 and S2, which are non-key processes, will be prepared in advance.

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