Method for transferring and positioning large ring segments of a ship on a variable gradient inclined berth

Abstract

The application discloses a method for transferring and positioning large ring segments of a ship on a slope-changing inclined berth, which comprises the following steps: dividing the ship into multiple total segments and completing total assembly; transforming the inclined berth site to form a continuous slope-changing channel; surveying the module vehicle contour line and controlling the module vehicle to accurately drive into the bottom of the total segment; lifting and adjusting the skids in steps to make the total segment stably leave the pier; transporting the total segment by the module vehicle through different slope-changing areas in steps, and automatically keeping the vehicle plate stable by using the self-provided attitude adjusting system; rotating and adjusting the attitude and centering after reaching the horizontal area; continuing to move to the closing opening, independently lifting each module vehicle by group control, and accurately adjusting the total segment levelness and center line; and finally, falling on the pier to unload and complete the positioning. The application realizes the direct transfer and accurate positioning of the large ring segments on the inclined berth, solves the problems of the attitude control of the module vehicle and the closing precision under the condition of the slope change, significantly shortens the berth period, and improves the shipbuilding efficiency.

Description

Technical Field

[0001] This invention belongs to the field of shipbuilding technology, specifically relating to a method for the transfer and assembly positioning of large ship segments on a variable-slope slipway. Background Technology

[0002] In the shipbuilding industry, slipway cycle time is a key factor determining shipbuilding capacity. This issue is particularly pronounced for shipyards that can only use inclined slipways. Currently, when relying on inclined slipways for shipbuilding, sections, equipment, bulk components, and outfitting parts must be hoisted sequentially during construction, relying solely on a single slipway with a 100t gantry crane and an 80t truck crane for assistance. When two ships are being built simultaneously, the number of sections typically hoisted reaches approximately 120. Combined with a large amount of equipment and outfitting parts, this results in extremely high crane usage and low operational efficiency. As a result, the slipway cycle for a single ship can reach 130 to 150 days, severely limiting capacity release and making it difficult to support mass production targets. Order taking is also negatively impacted by the cycle issue.

[0003] To alleviate pressure on the slipway, some existing technologies attempt to assemble certain sections on a small scale outside the slipway. However, these still rely on slipway cranes for final mounting and positioning, failing to fundamentally solve the slipway resource bottleneck. A few technical documents mention using SPMT (Special Purpose Transport Modular Vehicle) for transporting sections or complete units, but this is usually limited to short-distance transport on flat ground, requiring secondary lifting and positioning by large cranes upon arrival at the slipway. Especially for sloping slipways with varying gradients, there is no mature technology for directly transporting SPMTs along gradients and achieving precise mounting and positioning on the slope. Therefore, how to achieve efficient transport and rapid positioning of large loop sections under limited slipway resources is a pressing technical challenge in this field. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects in the prior art and provide a method for the transfer and positioning of large ring sections of ships on a variable-slope slipway.

[0005] To achieve the above objectives, the technical solution of the present invention is to design a method for the transfer, assembly, and positioning of large ring sections of a ship on a variable-slope slipway, comprising the following steps: S1. Based on the ship's size parameters and overall layout, the entire ship is divided into multiple main sections, each main section is further divided into multiple sub-sections, and the assembly method of each main section is determined. Based on the ship's dimensions, structural characteristics, weight distribution, and the transport capacity of the modular vehicles (including load capacity, number of axles, and power unit configuration), computer-aided design software is used for 3D modeling and finite element analysis to optimize the ship's division into multiple large ring-shaped sections. Each large ring-shaped section is further divided into multiple independently constructable segments. In a dedicated assembly area (e.g., utilizing a hardened area covered by an existing gantry crane in the shipyard), the assembly, welding, and outfitting of each segment are completed according to a predetermined assembly process, forming the large ring-shaped sections ready for transport. This step requires careful consideration of ensuring the section's dimensions and weight match the subsequent modular vehicle transport capacity, and the proper planning of the section's center of gravity.

[0006] S2. Modify the existing inclined slipway to accommodate the continuous variable slope passage for modular vehicles. To accommodate the heavy-load movement of modular vehicles and achieve a smooth transition, the existing inclined slipway will be modified. Specifically, this includes: measuring the original slope of the inclined slipway; leveling or filling local areas to construct a continuous, gently sloping passageway. This passageway will include at least: a horizontal area connecting to the main slipway body; a first inclined section with a slope no greater than the maximum gradeability of a fully loaded modular vehicle (typically required to be ≤6%, corresponding to an angle of approximately 3.43°); and a second inclined section connecting the horizontal area and the first inclined section. The slope of the second inclined section will be between the two, serving as a smooth transition.

[0007] At the junction of slope changes, a smooth curved surface is applied to avoid abrupt steps and ensure that the tires on each axle are evenly stressed when the modular vehicle is moving, without generating severe impacts.

[0008] S3. Using the center line and the beginning and end outlines of the main section as a reference, mark the outline of the module vehicle on the ground of the main assembly site, and operate the module vehicle to drive into the predetermined position at the bottom of the main section according to the outline. At the bottom of the large ring section after assembly, permanent or temporary piers are arranged according to the process design requirements to ensure the stability of the section in the assembly state. Using the centerline and beginning and end outlines of the section as a reference, the outline of the modular vehicle is accurately marked on the ground of its assembly site using high-precision measuring instruments (such as a total station), with a marking accuracy requirement of ≤2mm.

[0009] Based on the weight, center of gravity, and dimensions of the main section, the configuration scheme of the modular vehicles is determined. Typically, a flexible parallel connection is used, with one power unit (PPU) on each side flexibly connected to multiple axle (e.g., 6 or 12 axles) modular vehicles. The longitudinal center position of the modular vehicles must be precisely matched with the center of gravity of the main section, and the impact of the power unit's own weight on the center of gravity of the main section and the force distribution of the modular vehicles must be pre-calculated. The optimal longitudinal offset is determined through calculation to ensure balanced force distribution on each axle of the modular vehicles during transportation.

[0010] The SPMT (Special Supported Mechanism) vehicle slowly and precisely drives into the predetermined support position at the bottom of the main section, following the marked outline. Using plumb bobs or laser positioning devices at the four corners of the vehicle, repeated adjustments are made to ensure that the vehicle's front-to-back position deviation is ≤10mm and its left-to-right parallelism deviation is ≤5mm.

[0011] S4. Operate the modular vehicle to lift the section in stages and adjust the height of the wooden blocks at each support point until all support points are basically under force at the same time. Then lift the section completely so that it is off the pier at the transport height. Wooden blocks are pre-installed between the modular vehicle and the support points of the main section's bottom structure. For flat bottom areas, thin wooden boards with a thickness of 50-100mm are used, with a rubber pad of about 10mm thickness placed on top to increase friction and protect the paint. For areas with changing lines, wedge-shaped wooden blocks are machined according to the actual lines of the outer panels. Claw nails are driven between multiple layers of wooden blocks to ensure stability.

[0012] The control module vehicle is lifted synchronously and slowly in stages: First, lift the jacks until they just touch the hull structure, then pause. Check the tightness of the jacks at each point and mark the unloaded support points and their gaps.

[0013] The second step is to lower the main section and adjust the height of the corresponding wooden blocks according to the markings.

[0014] Repeat the above steps until all support points are subjected to force at approximately the same time.

[0015] The third step involves continuing the synchronous lifting process, pausing at 20%, 50%, and 80% of the theoretical total load capacity. During each pause, a comprehensive inspection is conducted to ensure the normal operation of all components of the modular vehicle, to check for any abnormal deformation of the bottom structure of the main section, and to use pressure sensors to read the actual load on each axle, comparing it with the theoretical calculation values.

[0016] After confirming that everything is normal, continue jacking up until the section is completely detached from the main pier below, and continue jacking up by about 200mm to the preset transport height.

[0017] According to the minimum load requirement of a single axle of the modular vehicle (usually not less than 12t), if the overall weight is light and the load on a single axle is too low, a process solution of "lifting part of the axle" is adopted. That is, the tires of part of the axle are lifted off the ground through the hydraulic system to reduce the number of stressed axles, increase the average load of the remaining axles, and make them work under the best working conditions.

[0018] S5. The control module vehicle carries the main section through different slope areas of the variable slope channel in sequence, and automatically adjusts the lifting height of each axle using the attitude adjustment system on the module vehicle to keep the vehicle platform stable. Test run: Move the modular vehicle 500mm forward and 500mm backward in place, and then perform a short 10m walk on the dedicated track to test its starting, acceleration, constant speed, deceleration, and braking performance. At the same time, check whether there is any relative displacement between the main section and the modular vehicle, and between the various wooden blocks.

[0019] Formal transport: After successful test run, the control module is transported by vehicle along the predetermined route towards the inclined slipway. The travel speed is strictly controlled at ≤1km / h.

[0020] Dynamic monitoring: Dedicated personnel are assigned to monitor the height of each platform throughout the process. The platform level control system of the modular vehicle itself is used to dynamically control the height difference between the platform and the ground within ±50mm.

[0021] Adaptive slope adjustment: When the modular vehicle enters areas with different slopes (such as entering the second slope from a horizontal section and then entering the first slope), the modular vehicle's own electro-hydraulic system will automatically calculate and adjust the lifting height of each axle hydraulic suspension based on preset slope data or signals fed back by real-time sensors (such as inclinometers), so that the chassis platform always remains horizontal or in a preset safe posture, thereby ensuring that the entire section travels smoothly on the slope channel without overturning or local overload.

[0022] S6. After the main section is transported to the horizontal area of ​​the inclined slipway, the control module vehicle is rotated so that the tail end of the main section faces the closing direction, and the center line of the main section is aligned with the center line of the slipway. After the main section is transported to the horizontal area in front of the inclined slipway, the movement is paused. Using surveying tools such as a total station, the centerline of the main section (or the auxiliary inspection line marked on the survey, such as the 600mm centerline) is precisely aligned with the centerline of the slipway that has been marked on the slipway ground by fine-tuning the lateral movement of the module vehicle, with the deviation controlled within ±5mm.

[0023] S7. The modular vehicle carrying the main section continues to move towards the closing point at the mounting angle, stops at the predetermined interval, and adjusts the levelness and centerline deviation of the main section to meet the accuracy requirements by independently lifting or lowering each modular vehicle through group control. Continue to control the modular vehicle, slowly moving it towards the closure opening of the already mounted hull at the loading inclination set by the slipway.

[0024] When the front end of the main section is approximately 0.3m from the closure point, stop the vehicle and set up a total station to measure the levelness of the four corners and the deviation of the centerline. By independently controlling the lifting or lowering of each module vehicle in groups, the attitude of the main section is initially adjusted to ensure that the level deviation is ≤±20mm and the centerline deviation is ≤±5mm.

[0025] Continue moving forward, and stop again when you are 30-50mm away from the closing point. Perform more precise measurements and adjustments.

[0026] Variable-slope attitude adjustment: For sections that need to be mounted across different slope areas (e.g., the stern of a section is on the first slope and the bow is on the second slope), attitude adjustment is crucial. Operators, based on measured vertical clearance data at the hull's joining point (the upper and lower clearances may differ), precisely adjust the pitch angles of the section's bow and stern by independently controlling the lifting and lowering of the front and rear module units located at different slopes. The goal is to ensure that the vertical clearance at the section's joining point is exactly equal to or within the tolerance range required by the welding process, thereby achieving stepless precise joining under variable-slope conditions.

[0027] Meanwhile, using the pre-installed tooling on the hull, once the main section has moved into position, the tooling forms mechanical contact with the main section structure, providing physical limits to prevent the modular vehicle from slipping on the slope due to any accidents (such as hydraulic leakage or slippery road surface), and assisting in achieving final longitudinal positioning.

[0028] S8. After the main section moves closer to the already mounted hull to the closing distance, the modular vehicle is slightly raised to tighten the blocks, and then slowly lowered to unload. After the positioning and assembly are completed, the modular vehicle is completely unloaded and lowered to the lowest height, exiting from the first opening. After the overall section is adjusted to the correct position and the final closing distance between it and the already mounted hull reaches 5-10mm, the operation module vehicle is raised slightly by 5-10mm to tighten and tamp the pre-arranged wooden or steel blocks below.

[0029] The control module vehicle is lowered and unloaded slowly and in stages. First, unload to 30%-50% of the original load capacity, then pause. Check the tightness of each abutment and the overall posture of the section, and re-measure key point data using a total station. If any abutment is found to be overloaded or the overall posture of the section changes, stop immediately, restart the jacking process, and adjust the abutments.

[0030] After confirming that everything is correct, continue unloading to about 20% of the original load capacity, and then perform another precision measurement to confirm that the closing joint meets the requirements.

[0031] Perform positioning and assembly work for the closure joint: Install long bars on the main deck and inner bottom plate, and weld several constraint welds at key positions such as the main deck, outer plate, inner bottom plate, and inner shell plate to fix the relative position of the sections and prevent excessive deformation during subsequent welding.

[0032] After the positioning and assembly are completed, the modular vehicle is completely unloaded, the frame height is lowered to the minimum (about 1170mm), the wooden blocks and other accessories on the frame are removed, and the vehicle is operated to smoothly exit from the first opening (unclosed end) of the main section.

[0033] For a few sections located at special locations at the junction of slope changes, resulting in insufficient height of the ship's bottom above the ground after placement on the pier (e.g., <1170mm), an alternative solution can be adopted: After the section is transported to the pier by a modular vehicle and initially placed on the pier, the modular vehicle is first removed. Then, a large truck crane is rented and works in conjunction with the gantry crane on the slipway to lift the section to a sufficient height for secondary precise adjustment and positioning before lowering it onto the pier position on the slipway. This solution serves as a supplement to the direct positioning method mentioned above.

[0034] Finally, the welding of the closure seam was carried out according to the process requirements, completing the entire installation of the large ring section on the inclined slipway.

[0035] The method also includes an accuracy pre-adjustment step: Before the overall section is transferred, a comprehensive three-dimensional accuracy measurement is conducted on the section closure joint and the already mounted hull closure joint using a high-precision total station. The measurement data is then imported into professional accuracy analysis software (such as NAPA, Tebis, etc.) for data analysis to generate a trimming plan. Based on the analysis results, semi-automatic cutting machines, grinders, and other tools are used on the assembly site to precisely pre-trimme the section closure joint. This mainly includes grinding the plate edges to eliminate wavy or misaligned edges, and trimming the ends of the aggregate to ensure end differences. This step allows a large amount of on-site trimming work to be completed in advance during the assembly stage, which can significantly shorten the positioning time during mounting.

[0036] The advantages and beneficial effects of this invention are as follows: This invention successfully overcomes the technical bottleneck of heavy-load, high-precision positioning of modular vehicles on inclined slipways with varying slopes, especially solving the problem of attitude control and precise assembly when sections simultaneously cross different slope areas. By transferring a large amount of section assembly work to outside the slipway, parallel operations on the slipway and assembly site are achieved. After applying this invention, the slipway setup cycle for 10,000-ton vessels can be shortened from the traditional 130-150 days to 45-60 days, more than doubling the slipway utilization rate. A large number of outfitting components, piping systems, and equipment can be installed in advance during the assembly stage, improving the integrity of the hull before launching by 5%-10%. This not only reduces the risks of high-altitude and cross-operations on the slipway but also improves the working conditions of workers. Through multiple precision control methods such as section pre-adjustment, modular vehicle fine-tuning, and the assistance of tooling, the accuracy of the closure joint (centerline deviation ≤5mm, levelness deviation ≤15mm) is ensured, significantly reducing the workload of on-site cutting and welding, and lowering material and labor costs. Based on the weight, size, and slipway position of different sections, this invention provides two modes: direct positioning with pure modular vehicles and assisted positioning with "modular vehicle + crane". It also provides a solution when the modular vehicle is under insufficient force (lifting the axis of the part), which has strong engineering adaptability and operability.

[0037] This invention utilizes existing idle space and surplus crane capacity in shipyards, requiring only site hardening and modular vehicle rental, resulting in relatively low investment costs. However, the output is substantial, directly manifested in increased production value due to shorter slipway cycles. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the segment division and assembly in the transfer and merging positioning method of the present invention; Figure 2 This is a schematic diagram of the slipway modification in the transfer and assembly positioning method of the present invention; Figure 3 This is a schematic diagram of the distribution of the low piers used in the overall assembly in the transfer and assembly positioning method of the present invention; Figure 4 This is a top view of the module vehicle in the transfer and assembly positioning method of the present invention; Figure 5 These are the main view and side view of the module vehicle in the transfer and assembly positioning method of the present invention; Figure 6 This is a schematic diagram of the ramp transfer method in the transfer and closing positioning method of the present invention; Figure 7 This is a schematic diagram of the double-slope transfer method in the transfer and closing positioning method of the present invention; Figure 8 This is a schematic diagram of the docking of two main sections in the transfer and closure positioning method of the present invention. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0040] This embodiment describes in detail the entire process of using the method of the present invention to transfer a large ring section (numbered 30C) of an 8300t general cargo ship by modular vehicle and to directly position it on the inclined slipway.

[0041] 1. Segmentation and grouping (corresponding to step S1) As attached Figure 1 As shown, the 8300t general cargo ship is divided into sections. The cargo hold area is planned to be grouped into four large ring sections: 30A, 30B, 30C, and 30E. Among them, the 30C section is composed of subsections 306 (left / right), 307, 524, 534, and 602, with external dimensions of 19.8m (length) × 22.8m (width) × 10.3m (height). The theoretical structural weight is 282t, and the estimated weight after completion, including outfitting, is 310t (the actual weight of the first ship was 430t, which is subject to subsequent optimization).

[0042] On the hardened ground area covered by two 120t gantry cranes on the north side of the shipyard, a site for the assembly of section 30C was designated. Following the assembly process, each section was sequentially hoisted, positioned, and welded to form a complete large ring section. During the assembly process, the installation of some outfitting components (such as piping systems and cable trays) was carried out simultaneously.

[0043] 2. Modification of the inclined slipway site (corresponding to step S2) As attached Figure 2 As shown, the original sloping slipway had a 1:40 gradient in the middle and rear sections, with a steeper 1:10 transition zone in the front. To accommodate the movement of modular vehicles, the slipway was modified: The original 1:10 steep slope area and part of the horizontal area were transformed into a second sloping section with a length of 24.3m and a slope of 1:22.

[0044] Smoothly connect the end of the first slope section to the second slope section.

[0045] The bottom baseline of the boat was raised from the conventional 1300mm to 1400mm to ensure that the modular vehicle and the wooden blocks have enough operating space.

[0046] The final continuous gradient channel is: horizontal area → 1:22 second slope section → 1:40 first slope section. The maximum climbing ability of the modular vehicle when fully loaded is 6% (approximately 3.43°), and the maximum slope of the dock after modification is 1:22 (approximately 2.65°), which fully meets the requirements.

[0047] 3. Vehicle preparation and modular vehicle configuration (corresponding to step S3) As attached Figure 3 As shown, low piers for the main assembly are arranged at the bottom of the 30C main section.

[0048] Using a total station, with the center line of the main section as the reference, the outline of the modular vehicle's entry was accurately marked on the main assembly site with an accuracy of ±2mm.

[0049] As attached Figure 4 , 5 As shown, based on the estimated weight of 310t for the 30C main section, it is equipped with 2 power units (PPU) and 4 6-axle modular vehicles. The left and right vehicles are softly connected in parallel, that is, each side consists of "1 PPU + 2 6-axle modular vehicles rigidly connected in parallel". The total length of each side vehicle is 16.8m.

[0050] Calculations show that the center of gravity of the 30C segment is approximately (X=FR118+589, Y=224, Z=3741). To balance the influence of the PPU's self-weight, the longitudinal center of the module vehicle is positioned at FR119+254, resulting in more even force distribution along each axis.

[0051] Operate four modular vehicles to precisely drive them into the bottom of the main section along the outline. The lateral centers of the two modular vehicles are respectively 4150mm (left) and 3850mm (right) from the center line of the main section to adapt to the hull line and the lateral shift of the center of gravity.

[0052] 4. Step-by-step lifting and adjustment of the shims (corresponding to step S4) Wooden blocks are placed between the modular vehicle and the hull structure at each support point (corresponding to the strong ribs FR109, FR111, FR114, FR117, FR120, FR123, FR126, FR129). The flat bottom uses 50mm thick wooden boards + 10mm rubber pads; custom-made wedge-shaped wooden tips are used at the changes in line.

[0053] The jacking process was carried out in stages: First, the jacking was performed until the wooden blocks contacted the hull, and the unloaded points were checked and adjusted. Then, the jacking was performed sequentially to 20%, 50%, and 80% of the theoretical load, with the vehicle's condition and structural deformation checked at each pause. The pressure on each axis was read and compared with the theoretical values.

[0054] Continue lifting to allow the main section to smoothly detach from the pier below, and then raise it another 200mm to reach a transport height of approximately 1700mm.

[0055] 5. Variable slope transportation and attitude adjustment (corresponding to step S5) After the test run, formal transportation will commence. The travel speed will be ≤1km / h, and a dedicated person will monitor the height of the vehicle platform.

[0056] As attached Figure 6 , 7 As shown, when the modular vehicle enters the second ramp section 7 of the 1:22 scale from the horizontal area, the vehicle's electronic control system automatically adjusts the front axle to rise and the rear axle to lower, maintaining the vehicle platform level. The same applies when entering the first ramp section of the 1:40 scale.

[0057] Since the 30C section is quite heavy, with a single axle load of approximately 23t, which is far higher than the minimum load requirement of 12t, there is no need to adopt the "lifting axle" solution.

[0058] 6. Rotate and center the horizontal region (corresponding to step S6) After the modular vehicle carrying the main section moves to the horizontal area in front of the inclined slipway, adjust the lateral position of the modular vehicle so that the center line of the main section is aligned with the center line of the slipway, with a deviation of ≤3mm.

[0059] 7. Ramp fine-tuning and closure (corresponding to step S7) As attached Figure 8 As shown, the 30C section needs to traverse two gradient zones, 1:40 and 1:22, for loading. The stern of the already loaded hull is located on the 1:40 slope.

[0060] The modular vehicle moves towards the closure joint at a 1:40 incline. When it is 0.3m away from the closure joint, it stops to measure the overall levelness and centerline. The modular vehicle is then adjusted in groups to ensure that the level deviation is ≤15mm.

[0061] When the distance reaches 30-50mm, based on the measured gap between the upper and lower sections of the closure (the upper gap may be smaller than the lower gap due to the change in slope), the operator precisely adjusts the pitch angle of the entire section by controlling the lifting and lowering of the front group (located on a 1:22 slope) and the rear group (located on a 1:40 slope) respectively, so that the upper and lower gaps are both 12mm, which meets the welding requirements.

[0062] The pre-installed tooling on the hull of the ship is used to assist in longitudinal positioning and prevent slippage.

[0063] 8. Unloading and positioning on the pier are complete (corresponding to step S8) When the final spacing reaches 8mm, the module vehicle is raised by 5mm to tighten the pre-placed blocks on the slipway.

[0064] Unload in stages to 50%, check the condition of the stumps and the gap at the joint; the condition is good. Continue unloading to 20%, and measure and verify that there are no errors.

[0065] Install long rows and constraint welds to fix the main section.

[0066] The modular vehicle is completely unloaded, lowered to its lowest height (1170mm), the wooden blocks are removed, and it smoothly exits from the first opening of the main section.

[0067] From the moment the vehicle entered the dock to the completion of positioning, the first vessel (vehicle #3) took approximately 4 hours. In subsequent vessels (vehicles #4 and #6), by summarizing experience and optimizing pre-repair procedures and slipway slope, the positioning time was reduced to 2.5 hours and 1.5 hours, respectively.

[0068] Example 2: Transfer and positioning of section 30E of an 8300t general cargo ship (including crane-assisted mode) This embodiment describes some differences in another section (30E), particularly concerning the supplementary scheme for crane-assisted positioning.

[0069] The 30E section is located at the bow, with part of its mounting area situated at the junction of the horizontal area and the 1:22 second ramp section. It weighs 226 tons. During the initial implementation (on ship #3), due to the unoptimized slipway layout, the ship's bottom was only about 750mm above the ground after being placed on the platform at this location, less than the minimum height of the modular vehicle (1170mm), making direct retraction impossible.

[0070] The modular vehicle transported the 30E main section to the designated location and initially placed it on the pier.

[0071] The modular vehicle was removed.

[0072] A 500t truck crane was rented and worked in conjunction with a 100t gantry crane on the slipway. The two cranes were used to lift the 30E section smoothly to a height of about 500mm.

[0073] Operators used a hand-operated hoist and measuring instruments to perform a second precise positioning of the main section, adjusting the center line and correcting any height misalignments.

[0074] After positioning, the main section will be slowly lowered onto the slipway pier.

[0075] In another embodiment, a precision pre-trimming step is also included: Specifically as follows: Taking the 30C section of the 8300t follow-up vessel as an example, three days before the transfer, precision personnel used a Leica TS60 total station to conduct comprehensive measurements on the section's closure joint and the already installed hull closure joint. After the measurement data was imported into the NAPA Steel precision analysis software, the software generated a color deviation cloud map. The analysis revealed that there was an average 3mm wavy edge on the main deck plate edge of the section's closure joint, and some aggregate end differences reached 5mm.

[0076] Based on the trimming plan output by the software, workers used a semi-automatic precision cutting machine to perform linear grinding on the edges of the boards at the main assembly site, and used an angle grinder to trim the ends of the aggregate. The entire pre-trimming work took 8 hours and was completed by 2 workers.

[0077] During the assembly process on the slipway, the connection was successful on the first attempt, requiring no on-site modifications. The entire process, from the module vehicle's arrival to its placement and securing on the pier, was completed in just 1.5 hours. In contrast, sections that did not undergo sufficient pre-assembly (such as section 30C of ship #3) required up to 3 hours of on-site adjustments. This demonstrates that the pre-assembly step significantly improved the assembly efficiency.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the transfer, assembly, and positioning of large ship segments on a variable-slope slipway, characterized in that, Includes the following steps: S1. Based on the ship's size parameters and overall layout, the entire ship is divided into multiple main sections, each main section is further divided into multiple sub-sections, and the assembly method of each main section is determined. S2. Modify the existing inclined slipway to accommodate the continuous variable slope passage for modular vehicles. S3. Using the center line and the beginning and end outlines of the main section as a reference, mark the outline of the module vehicle on the ground of the main assembly site, and operate the module vehicle to drive into the predetermined position at the bottom of the main section according to the outline. S4. Operate the modular vehicle to lift the section in stages and adjust the height of the wooden blocks at each support point until all support points are basically under force at the same time. Then lift the section completely so that it is off the pier at the transport height. S5. The control module vehicle carries the main section through different slope areas of the variable slope channel in sequence, and automatically adjusts the lifting height of each axle using the attitude adjustment system on the module vehicle to keep the vehicle platform stable. S6. After the main section is transported to the horizontal area of ​​the inclined slipway, the control module vehicle is rotated so that the tail end of the main section faces the closing direction, and the center line of the main section is aligned with the center line of the slipway. S7. The modular vehicle carrying the main section continues to move towards the closing point at the mounting angle, stops at the predetermined interval, and adjusts the levelness and centerline deviation of the main section to meet the accuracy requirements by independently lifting or lowering each modular vehicle through group control. S8. After the main section moves closer to the already mounted hull to the closing distance, the modular vehicle is slightly raised to tighten the blocks, and then slowly lowered to unload. After the positioning and assembly are completed, the modular vehicle is completely unloaded and lowered to the lowest height, exiting from the first opening.

2. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 1, characterized in that, In S2, the variable slope channel includes a horizontal section, a first slope section, and a second slope section.

3. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 1, characterized in that, In S3, the modular vehicle adopts a flexible parallel connection between the left and right vehicles, with one power unit on each side flexibly connected in parallel with a 6-axle or 12-axle modular vehicle; the longitudinal center arrangement of the modular vehicle matches the center of gravity of the main section, and the influence of the power unit's own weight is taken into account.

4. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 3, characterized in that, In S4, the step-by-step jacking is specifically as follows: jacking up to 20%, 50%, and 80% of the theoretical load capacity in sequence, then pausing to check the stress and structural deformation of each support point; for support points that are not under stress, marking and adjusting the height of the pads before jacking up again until all support points are basically under stress at the same time.

5. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 1, characterized in that, In S5, the speed during transportation is ≤1km / h, and the height difference between the vehicle platform and the ground is controlled within ±50mm. When the modular vehicle enters areas with different slopes, the modular vehicle system automatically adjusts the lifting height of each axle to keep the vehicle platform stable.

6. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 1, characterized in that, In S7, when the main section is positioned across different slope areas, the following method is used to adjust the attitude: based on the measured upper and lower gaps of the closure opening of the already mounted hull, the lifting heights of the front and rear module vehicles located on different slopes are controlled to make the upper and lower gaps of the closure opening of the main section equal.

7. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 1, characterized in that, In S7, a tooling device is installed on the hull. When the module vehicle moves to the predetermined position, the tooling device contacts the main structure, providing mechanical limit and assisting in precise positioning.

8. The method for transferring and assembling a large ring section of a ship on a variable-slope slipway according to claim 1, characterized in that, In S8, if it is found that individual blocks are under excessive pressure or the posture of the whole section changes during the unloading process of the modular vehicle, the unloading is stopped immediately and the blocks are lifted again. The height of the blocks is adjusted before unloading is carried out again. During positioning and assembly, long rows are installed on the main deck and inner bottom plate, and constraint welds are welded on the main deck, outer plate, inner bottom plate and inner shell plate respectively.

9. A method for the transfer and assembly positioning of a large ring section of a ship on a variable-gradient inclined slipway according to claim 1, characterized in that, When the mounting location is at the junction of the slipway slope and the bottom of the ship is less than the minimum height of the modular vehicle, a crane is used to lift the main section to a certain height after the main section is pierced, and then it is lowered and positioned after the modular vehicle is removed; in other cases, the modular vehicle is directly positioned to complete all operations.

10. A method for the transfer and assembly positioning of a large ring section of a ship on a variable-gradient inclined slipway according to claim 1, characterized in that, It also includes a precision pre-adjustment step: before the main section is transferred, the precision of the main section closure joint and the hull closure joint that has been mounted is measured. After analysis by software, the main section closure joint is pre-adjusted, including plate edge grinding and aggregate end difference adjustment, in order to reduce the amount of on-site adjustment work during mounting.

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