Modular construction method for shuttle tanker bow loading system

Abstract

The application discloses a shuttle tanker bow loading system modular construction method, and belongs to the technical field of ship construction. The method divides the bow loading system into a plurality of construction modules according to function division and interface boundary, and prepares a module information table for each construction module, which contains a module number, an interface coordinate origin and a compensation allowance. A base frame is installed on a hull bow section and a positioning reference point is set. The construction modules are hoisted into the base frame in sequence according to a total assembly sequence, the relative position of the positioning reference point and the interface coordinate origin is measured, and the interface coordinate is updated. The assembly sequence and fastening torque sequence of adjacent construction modules are determined according to the updated interface coordinate. The installation of all construction modules is completed according to the assembly sequence and fastening torque sequence, and the bow loading system is formed. The method can reduce on-site adjustment and forced assembly in the construction of the bow loading system, and improve interface alignment accuracy and assembly consistency.

Description

Technical Field

[0001] This invention relates to the field of shipbuilding technology, specifically to a modular construction method for the bow loading system of a shuttle tanker. Background Technology

[0002] The bow loading system of a shuttle tanker centrally arranges pipelines and equipment for different working media, such as oil transportation, hydraulics, and control, at the bow of the hull. It has numerous interfaces, and the interface boundaries are constrained by the hull structure. Current construction methods typically involve on-site bulk assembly or segmented pre-assembly, with construction personnel positioning the base, pipelines, and valve assemblies based on design drawings and theoretical coordinates. After the module boundaries and interface coordinates are determined during the drawing stage, they rely primarily on theoretical dimensions for transfer. The coplanarity adjustments after the base frame installation and the structural deformation during the segmented assembly process are not synchronously fed back to the module interfaces. When the interface flange clearance and centerline relative position are inconsistent with the theoretical state after the module is hoisted into the base frame, adjustments can only be made on-site by cutting, repairing, or adding temporary gaskets. The assembly sequence and tightening torque of adjacent construction modules are usually determined according to general processes or experience, without establishing a correspondence with the measured interface clearances and coordinate deviations. This easily leads to uneven loading of the flange sealing surface, additional stress on the pipelines, and localized deformation. The oil delivery module, hydraulic module, and control module of the bow loading system need to be hoisted in batches at different stages of the bow section assembly. There is a lack of continuity and transfer of interface coordinates between hoisting batches, making it difficult to use the actual interface positions of already hoisted modules for subsequent module positioning and assembly decisions. Deviations caused by section assembly and base adjustments accumulate to significant rework and difficulty in controlling assembly quality during later interface connections. Under these circumstances, it is necessary to solve the problem of accurately measuring and updating module interface coordinates under batch hoisting conditions, and to determine the assembly sequence and tightening torque order using the updated interface status. Summary of the Invention

[0003] To address the issues of outdated interface coordinates not being updated with actual measurements and assembly sequence and fastening torque not being determined based on measured interface conditions in the modular construction of existing shuttle tanker bow loading systems, a modular construction method for shuttle tanker bow loading systems is provided. This method utilizes the relative position measurement of the base frame positioning datum and the module interface coordinate origin to update the module information table, and determines the assembly sequence and fastening torque order of adjacent construction modules based on the updated interface coordinates. This reduces on-site adjustments and forced assembly, and improves interface alignment accuracy and assembly consistency.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a modular construction method for a shuttle tanker bow loading system, comprising: dividing the bow loading system into several construction modules according to the functional zoning and interface boundaries of the bow section of the hull, and compiling a module information table for each construction module, including module number, interface coordinate origin, and compensation margin; installing a bow loading system base frame on the bow section of the hull according to the module information table, and setting positioning reference points on the mounting surface of the base frame; sequentially hoisting the construction modules into the base frame according to the assembly sequence of the bow section of the hull, measuring the relative position of the positioning reference point and the corresponding interface coordinate origin after each construction module is hoisted in, and updating the interface coordinates in the module information table; determining the assembly sequence and fastening torque order between adjacent construction modules according to the updated interface coordinates; and completing the installation of all construction modules according to the assembly sequence and fastening torque order to form the bow loading system. This method reduces cumulative assembly deviations and improves the accuracy and efficiency of modular construction by dynamically measuring and updating interface coordinates in complex structural environments at the bow of a ship.

[0005] As a technical solution of this invention, when dividing the construction modules, the bow loading system is divided into an oil delivery module, a hydraulic module, and a control module according to the type of working medium and the pipe diameter. Independent module boundaries are set for each of the oil delivery module, hydraulic module, and control module, and flange interfaces with temporary sealing are set at the module boundaries. The origin of the interface coordinates is generated based on the coordinates of the flange interface in the ship's coordinate system, and the sealing surface orientation and compensation margin of the flange interface are recorded in the module information table. This ensures consistency in the interfaces of different functional modules, facilitating subsequent positioning and docking.

[0006] As a technical solution of the present invention, during the installation of the base frame, in the anti-topping stage of the bow section of the hull, the segmented bases of the base frame are assembled with the bow loading system base frame according to the module number in the module information table, and the coplanarity data between the segmented bases and the bow loading system base frame is measured after assembly; the thickness of the support pads of the bow loading system base frame is adjusted according to the coplanarity data; positioning reference points are set on the bow loading system base frame, including first-type reference points set at the four corners of the base frame and second-type reference points set in the middle of the longitudinal beams of the base frame; the coordinates of the first-type and second-type reference points are written into the module information table. By completing the precision adjustment of the base frame in the anti-topping stage, the positioning risk in the subsequent final assembly stage is reduced.

[0007] As a technical solution of this invention, when measuring the relative position of the positioning reference point and the interface coordinate origin, two mutually perpendicular measurement control bases are set up at the assembly site of the bow section of the hull, and laser trackers are installed on the measurement control bases respectively; the laser trackers are aligned with the interface coordinate origin that has been hoisted into the construction module, and the three-dimensional position data of the interface coordinate origin relative to the positioning reference point are read; the coordinate consistency of the interface coordinate origin of adjacent construction modules is checked with the measured positioning reference point, and the interface coordinates in the module information table are updated according to the check result. By using dual-station laser tracking measurement, the reliability and consistency of the interface coordinate data are improved.

[0008] As a technical solution of the present invention, during the laser tracker measurement process, a target seat coaxially arranged with the interface coordinate origin is set on the construction module, and a spherical reflector is installed on the target seat. After the construction module is hoisted in, the laser tracker is aligned with the spherical reflector in sequence to read the three-dimensional position data of the interface coordinate origin in the ship coordinate system. The three-dimensional position data is stored according to the module number and the positioning reference point number to generate the interface coordinate record table of the construction module. By arranging the target seat coaxially, the conversion error between the measurement point and the interface coordinate origin is reduced.

[0009] As a technical solution of the present invention, when generating the interface coordinate record table, the three-dimensional position data is divided into multiple groups according to the hoisting batches of the construction modules; the three-dimensional position data within the same hoisting batch are sorted according to the positioning reference point number to generate the module interface coordinate sequence for that hoisting batch; the module interface coordinate sequences of different hoisting batches are merged according to the overall group order of the bow section of the hull, and the interface coordinate origin shared by adjacent hoisting batches is used as the continuation point during the merging process to generate the interface coordinate record table. Through batch data management and continuation point setting, coordinate confusion during parallel measurement of multiple modules is avoided.

[0010] As a technical solution of this invention, when determining the assembly sequence and tightening torque sequence, the updated interface coordinates are paired according to the module number to obtain the interface flange gap value of adjacent construction modules; initial tightening torque value and final tightening torque value are generated based on the interface flange gap value; the tightening sequence of adjacent construction modules is divided into an initial tightening stage and a final tightening stage; in the initial tightening stage, tightening is performed in the order from both sides of the longitudinal section of the hull towards the hull side, and in the final tightening stage, tightening is performed in the order from the bow of the hull towards the stern of the hull; the tightening sequence of the initial tightening stage and the final tightening stage are written into the assembly sequence card, and the initial tightening torque value and the final tightening torque value are written into the tightening torque card. By controlling the torque and direction in stages, the interface flanges are subjected to uniform stress, reducing assembly deformation.

[0011] As a technical solution of the present invention, when completing the installation of the construction modules, a temporary adjusting pad with scale lines is set at the bottom of each construction module, and an indicator pointer corresponding to the scale lines is set on the mounting surface of the base frame; when hoisting the construction module, the thickness of the temporary adjusting pad is adjusted according to the interface flange gap value and the reading of the indicator pointer; after the construction module is placed in position, fasteners are inserted in the order of the assembly sequence card, and initial tightening is performed according to the initial tightening torque value of the tightening torque card, and then final tightening is performed according to the final tightening torque value; after all construction modules are installed, permanent sealing gaskets are installed at the interface flanges of adjacent construction modules, and the temporary protective covers at the interface flanges are removed. Through the cooperation of the temporary pad and the indicator pointer, the positional deviation during the module placement process can be visually judged and corrected.

[0012] As a technical solution of this invention, when determining the assembly sequence and tightening torque order based on the updated interface coordinates, the updated interface coordinates are grouped to obtain the pipeline flange coordinate group of the oil delivery module and the valve assembly mounting surface coordinate group of the hydraulic module in the bow loading system. The coordinates in the pipeline flange coordinate group are sorted according to the pipeline direction, and the sorted coordinates are aligned with the coordinates of the pre-embedded pipe openings in the bow tunnel of the hull. The installation priority of the oil delivery module and the hydraulic module is determined based on the alignment result. The installation priority is that the hydraulic module is installed before the oil delivery module, and the control module is installed after the hydraulic module. By aligning the interface coordinates of different media modules, installation conflicts between pipelines and valve assemblies are avoided.

[0013] As a technical solution of the present invention, when determining the installation priority based on the alignment results, the difference between the pipeline flange coordinate group and the pre-embedded pipe port coordinates is converted into the flange gasket adjustment thickness; when the adjustment thickness exceeds the maximum thickness of the flange gasket, a transition short pipe is set at the pre-embedded pipe port of the bow tunnel of the hull; the interface coordinates in the module information table are updated according to the length of the transition short pipe, and the installation priority is executed according to the updated interface coordinates. The transition short pipe compensates for the deviation, enhancing the adaptability of the pipeline interface.

[0014] The technical effects and advantages provided by the present invention in the above technical solution are as follows: During the modular construction phase, a module information table is created for each module, including module number, interface coordinate origin, and compensation allowance. Positioning reference points are then established on the mounting surface of the base frame in the bow section of the hull. After the construction modules are hoisted into the base frame in the overall assembly sequence, the relative positions of the positioning reference points and the corresponding interface coordinate origins are measured. The measured three-dimensional position data are written into the module information table, and the interface coordinates are updated using the measured data. The interface coordinates are converted from theoretical values ​​to actual values ​​reflecting the current installation state. The compensation allowance is updated according to the actual deviation of the interface, enabling adjacent construction modules to be continuously positioned based on unified interface coordinates between hoisting batches. This reduces interface misalignment, uneven flange gaps, and non-parallel sealing surfaces caused by cumulative deviations in theoretical coordinates and structural deformation, avoiding repeated cutting, repair, and the addition of temporary gaskets at the interfaces.

[0015] Adjacent construction modules are paired based on the updated interface coordinates to obtain the interface flange clearance values. Initial and final tightening torque values ​​are then generated from these clearance values, dividing the tightening process into initial and final tightening stages. The initial tightening stage proceeds from both sides of the mid-section of the hull towards the hull side, while the final tightening stage proceeds from the bow towards the stern. The assembly sequence and tightening torque directly correspond to the measured interface conditions, ensuring that the tightening amount of each interface flange is distributed according to the actual clearance and coordinate deviation. This avoids localized stress concentration and uneven gasket compression caused by tightening in a fixed sequence or with empirical torques, reduces additional deformation of the piping and valve assembly surfaces, improves the uniformity of stress on the flange sealing surfaces, and enhances the overall assembly consistency of the bow-mounted system. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a flowchart of the modular construction method for the bow loading system of a shuttle tanker; Figure 2 This is a flowchart of the construction module division and interface coordinate origin generation for the bow loading system; Figure 3 This is a probability density distribution diagram of the X-axis coordinates of the origin of the module interface. Figure 4 This is a diagram showing the relative positional deviation of the interface coordinates of the construction module; Figure 5 It is a curve showing the relationship between the flange clearance and the tightening torque; Figure 6 This is a distribution diagram of the difference between the coordinates of the flange and the pre-embedded pipe opening of the oil transfer module. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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 some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] See Figure 1 This invention provides a modular construction method for a shuttle tanker bow loading system, comprising: dividing the bow loading system into several construction modules according to the functional zoning and interface boundaries of the bow section of the hull, and compiling a module information table for each construction module, including module number, interface coordinate origin, and compensation margin; installing the bow loading system base frame on the bow section of the hull according to the module information table, and setting positioning reference points on the mounting surface of the base frame; sequentially hoisting the construction modules into the base frame according to the assembly sequence of the bow section of the hull, measuring the relative position of the positioning reference point and the corresponding interface coordinate origin after each construction module is hoisted in, and updating the interface coordinates in the module information table; determining the assembly sequence and fastening torque order between adjacent construction modules according to the updated interface coordinates; and completing the installation of all construction modules according to the assembly sequence and fastening torque order to form the bow loading system.

[0020] In specific implementation, please refer to Figure 2 Based on the functional zoning and interface boundaries of the bow loading system at the bow of the hull, the bow loading system is divided into several construction modules. According to the type of working medium and pipeline diameter, the bow loading system is divided into an oil delivery module, a hydraulic module, and a control module. When dividing into oil delivery modules, pipe sections containing crude oil with a pipeline diameter of not less than DN300 are included. The oil delivery module also includes the main oil delivery pipe and branch oil delivery pipes. When dividing into hydraulic modules, pipe sections containing hydraulic oil with a pipeline diameter of not more than DN50, as well as hydraulic valve assemblies, are included. The hydraulic module also includes hydraulic pump stations and hydraulic actuators. When dividing into control modules, control cables, control boxes, and control pipelines with a pipeline diameter of not more than DN25 are included. Optionally, the module boundaries of the oil delivery module, hydraulic module, and control module are marked with different colors in the 3D model of the bow of the hull.

[0021] Independent module boundaries were set for the oil transportation module, hydraulic module, and control module. When setting independent module boundaries, the positions of the hull structural partition surfaces, bulkheads, and tunnel walls were extracted from the 3D model of the bow section of the ship, and these extracted positions served as the boundaries between adjacent construction modules. Flange interfaces with temporary sealing were installed at the module boundaries, with the flange specifications matching the pipe diameter of the corresponding pipeline. The temporary sealing included a blind flange and a gasket. The blind flange was connected to the flange interface with fasteners, and the gasket was placed between the sealing surface of the flange interface and the blind flange. After the temporary sealing was installed, a protective cover was installed on the outer surface of the flange interface.

[0022] The origin of the flange interface coordinates is generated based on its coordinates in the ship's hull coordinate system. The hull coordinate system has its origin at the intersection of the hull baseline, the midship section, and the bow perpendicular. The X-axis points longitudinally towards the stern, the Y-axis points laterally towards the port side, and the Z-axis points vertically towards the top of the hull. The coordinates of the flange interface in the hull coordinate system are obtained from the 3D model of the bow of the hull, with the reading location being the center point of the flange interface sealing surface. The following formula is used to generate the origin of the interface coordinates: in, This represents the three-dimensional position vector of the interface coordinate origin in the ship's coordinate system. This represents the three-dimensional position vector of the center point of the flange interface sealing surface in the ship's coordinate system. This represents the compensation margin, ranging from 0 mm to 50 mm. It is obtained by adding the manufacturing tolerance of the flange interface to the installation error of the bow section of the hull. This represents the unit vector indicating the orientation of the sealing surface of the flange interface. It is obtained by normalizing the outer normal direction of the sealing surface of the flange interface.

[0023] The module information table records the sealing surface orientation and compensation margin of the flange interface. The sealing surface orientation is recorded as a three-dimensional unit vector component, and the compensation margin is recorded as a value in millimeters. The module information table also includes the module number and the interface coordinate origin. The module number uses character encoding: "OM" for oil transfer modules, "HM" for hydraulic modules, and "CM" for control modules. The interface coordinate origin is recorded as a three-dimensional coordinate value in the ship's coordinate system, rounded to one decimal place. Optionally, the module information table also records the flange specifications and temporary sealing status of the flange interface; the temporary sealing status is recorded as "sealed".

[0024] See Figure 3The figure shows the probability density distribution curves of the interface coordinate origins of the oil supply module, hydraulic module, and control module in the X-axis direction of the ship's coordinate system, categorized by module number. The horizontal axis represents the X-axis coordinate value of the interface coordinate origin in the ship's coordinate system, in millimeters, ranging from -18000 mm to -2000 mm. The vertical axis represents the probability density of the interface coordinate origin, reflecting the relative frequency of the interface at the corresponding location.

[0025] The probability density curve for the oil transfer module is represented by a solid blue line, mainly distributed between approximately -16,000 mm and -10,000 mm on the X-axis, with a peak at approximately -12,000 mm, indicating that the oil transfer module interfaces are primarily concentrated in the forward section of the bow. The probability density curve for the control module is represented by a dashed green line, distributed between approximately -10,000 mm and -6,000 mm on the X-axis, with a peak concentrated between approximately -8,000 mm and -9,000 mm. The probability density curve for the hydraulic module is represented by a dashed red line, concentrated between approximately -6,000 mm and -3,000 mm on the X-axis, with a maximum peak at approximately -4,500 mm, indicating that the hydraulic module interfaces are mainly concentrated in the relatively aft area of ​​the bow, consistent with the functional zoning of modules with smaller hydraulic oil pipeline diameters and containing hydraulic pump stations and actuators.

[0026] In practice, based on the module information table, the bow loading system base frame is installed on the bow section of the hull, and positioning reference points are set on the mounting surface of the base frame. During the top-down phase of the bow section, the bow section is flipped to its top-down position, with the bottom of the bow section facing upwards. According to the module numbers in the module information table, the corresponding base frame segments for the oil transfer module, hydraulic module, and control module are identified. The segment bases of the base frame are then assembled with the bow loading system base frame. During assembly, the interface coordinate origin in the module information table is used as the alignment reference, and the corresponding interface marks on the segment bases are aligned with the interface marks on the bow loading system base frame. After assembly, a temporary connecting plate is placed on the contact surface between the segment bases and the bow loading system base frame, and the segment bases are connected to the bow loading system base frame via the temporary connecting plate.

[0027] In some embodiments, the coplanarity data between the segmented base and the bow loading system base frame is measured after assembly. Measurement points are selected on the contact surface between the segmented base and the bow loading system base frame, with the measurement points evenly arranged along the length of the contact surface and the distance between adjacent measurement points not exceeding 500 mm. A laser rangefinder is placed at the measurement point, with the laser beam perpendicular to the contact surface, and the reading of the laser rangefinder is taken to obtain the gap value between the segmented base and the bow loading system base frame. All gap values ​​on the same contact surface are recorded as coplanarity data, which includes the maximum gap value, the minimum gap value, and the gap value distribution sequence.

[0028] The thickness of the support shims for the bow loading system base frame is adjusted based on coplanarity data. The support shims are installed between the bow loading system base frame and the bow section of the hull, and are arranged along the longitudinal and transverse beams of the bow loading system base frame. The following formula is used to adjust the thickness of the support shims: in, This indicates the adjusted thickness of the support pad, in millimeters. This represents the maximum gap value in the coplanarity data between the segmented base and the bow loading system base frame, in millimeters. It is obtained by taking the maximum value of all gap values ​​in the coplanarity data. This indicates the allowable compression of the support gasket, ranging from 1 mm to 5 mm. It is determined based on the material of the support gasket and the preload of the fasteners. In this embodiment, the support gasket is made of polytetrafluoroethylene (PTFE), the fastener preload is 70% of the design torque, and the compression deformation of the support gasket under the fastener preload is 2 mm. The value is 2 millimeters.

[0029] Positioning reference points are set on the bow loading system base frame. First-type reference points are set at the four corners of the bow loading system base frame, located on the upper surface of the four corners. These first-type reference points are 10 mm diameter stainless steel hemispheres, welded to the base frame. Second-type reference points are set at the center of each longitudinal beam of the bow loading system base frame, located at the center of the upper surface of the beam. These second-type reference points are 6 mm diameter steel balls, bonded to the beam. One second-type reference point is set for each longitudinal beam. If the length of a longitudinal beam exceeds 6 meters, additional second-type reference points are added at equal intervals along the beam's length, with a spacing not exceeding 3 meters between the additional reference points.

[0030] In some embodiments, the coordinates of the first and second type reference points are written into the module information table. With the bow section of the hull in its reverse-top position, a laser tracker is used to measure the three-dimensional coordinates of the centers of the first and second type reference points in the hull coordinate system. During measurement, the laser tracker is positioned on one side of the bow section, with its measurement base point aligned with the origin of the hull coordinate system. The X-axis, Y-axis, and Z-axis coordinate values ​​of each first and second type reference point are read and recorded in the module information table under the corresponding first and second type reference point numbers. The first type reference point numbers in the module information table are represented by "PB1" to "PB4", and the second type reference point numbers are represented by "SB1" to "SBn", where n is the total number of second type reference points.

[0031] In specific implementation, according to the general assembly sequence of the hull bow section, the construction modules are sequentially lifted into the base frame. After each construction module is lifted in, the relative position between the positioning reference point and the coordinate origin of the corresponding interface is measured, and the interface coordinates in the module information table are updated. Two mutually perpendicular measurement control bases are set at the general assembly site of the hull bow section. The first measurement control base is arranged at the starboard side position of the bow of the hull bow section, and the second measurement control base is arranged at the forward position of the bow of the hull bow section. The mounting surface of the first measurement control base faces the starboard direction of the hull bow section, the mounting surface of the second measurement control base faces the forward direction of the hull bow section, and the mounting surface of the first measurement control base and the mounting surface of the second measurement control base are mutually perpendicular. A laser tracker is respectively installed on each measurement control base. The laser tracker is connected to the measurement control base through a transition plate. The transition plate and the measurement control base are fixed by bolts, and the tightening torque of the bolts is 80 N·m.

[0032] In some embodiments, a target holder arranged coaxially with the coordinate origin of the interface is provided on the construction module. A target holder is arranged at each interface coordinate origin of each construction module. The target holder is a cylindrical stainless steel base body, and the target holder is fixed on the back side of the interface flange of the construction module by welding. The inner hole axis of the target holder is arranged coaxially with the normal direction of the interface coordinate origin, and the coaxiality deviation is no more than 0.1 mm. A spherical reflector is installed on the target holder. The spherical reflector is a spherical prism reflector matched with the laser tracker, the spherical center of the spherical reflector coincides with the axis of the inner hole of the target holder, and the spherical reflector is adsorbed on the end face of the inner hole of the target holder by magnetic attraction.

[0033] Aim the laser tracker at the spherical reflector on the lifted construction module, and read the three-dimensional position data of the interface coordinate origin in the hull coordinate system. After the construction module is lifted into the base frame and positioned, operate the laser tracker to sequentially aim at the spherical reflectors on different construction modules. The laser tracker emits a laser beam to irradiate the spherical reflector, the spherical reflector reflects the laser beam back to the laser tracker, and the laser tracker calculates the three-dimensional coordinates of the spherical center of the spherical reflector in the hull coordinate system according to the emission angle, emission time difference and return time difference of the laser beam. The laser tracker converts the three-dimensional coordinates of the spherical center of the spherical reflector into the corresponding three-dimensional coordinates of the interface coordinate origin. During conversion, based on the coaxial arrangement relationship between the inner hole axis of the target holder and the normal direction of the interface coordinate origin, the three-dimensional coordinates of the spherical center of the spherical reflector are translated by the length of the inner hole axis of the target holder along the direction of the inner hole axis of the target holder, so as to obtain the three-dimensional position data of the interface coordinate origin in the hull coordinate system, and the three-dimensional position data includes the X-axis coordinate value, Y-axis coordinate value and Z-axis coordinate value.

[0034] The three-dimensional position data is stored according to module number and positioning reference point number, generating an interface coordinate record table for the construction module. During storage, the module number from the corresponding module information table is used as the storage key, and the positioning reference point number is used as the subkey. The positioning reference point number includes both first-type and second-type reference point numbers. Both the module number and the positioning reference point number are stored in character encoding format, and the X-axis, Y-axis, and Z-axis coordinate values ​​are stored in double-precision floating-point format, with values ​​retained to one decimal place. The interface coordinate record table is created in spreadsheet format. Each row in the spreadsheet records the three-dimensional position data of an interface coordinate origin relative to a positioning reference point. The columns in the spreadsheet are, in order: module number, positioning reference point number, X-axis coordinate value, Y-axis value, Z-axis value, and hoisting batch number.

[0035] When generating the interface coordinate record table, the three-dimensional position data is divided into multiple groups according to the hoisting batches of the construction modules. Each construction module hoisting batch corresponds to a hoisting batch number, which increases sequentially according to the overall group order of the bow section of the hull. Construction modules within the same hoisting batch have the same hoisting batch number. The three-dimensional position data within the same hoisting batch are sorted according to the positioning reference point number, with the sorting rule being ascending order of the positioning reference point number characters. After sorting, the module interface coordinate sequence for that hoisting batch is generated, and each record in the module interface coordinate sequence is arranged consecutively in ascending order of the positioning reference point number.

[0036] The module interface coordinate sequences from different lifting batches are merged according to the overall grouping order of the bow section of the hull. During merging, the module interface coordinate sequence of the first lifting batch is used as the merging starting point. The module interface coordinate sequences of subsequent lifting batches are read in sequentially and appended to the module interface coordinate sequences of the previous lifting batch. During the appending process, it is checked whether there is a shared interface coordinate origin in adjacent lifting batches. A shared interface coordinate origin means that the same interface coordinate origin appears in the module interface coordinate sequences of two adjacent lifting batches. When a shared interface coordinate origin is detected between adjacent lifting batches, the shared interface coordinate origin is used as the continuation point. The record corresponding to the continuation point is deleted in the module interface coordinate sequence of the next lifting batch, and then the deleted module interface coordinate sequence is appended to the merged sequence, so that the continuation point appears only once in the merged interface coordinate record table.

[0037] The coordinate consistency of the interface coordinate origins of adjacent construction modules is checked against the measured positioning reference points. After the hoisting of every two adjacent construction modules, the three-dimensional coordinates of the interface coordinate origins of each adjacent construction module in the ship's coordinate system are remeasured using a laser tracker. The remeasured interface coordinate origins of the adjacent construction modules are compared with the interface coordinate origins of the adjacent construction modules already stored in the module information table. At the same time, the relative positions of the remeasured interface coordinate origins of the adjacent construction modules and the positioning reference points are compared, and the relative position vector is calculated. The relative position vector is the three-dimensional vector obtained by subtracting the three-dimensional coordinates of the positioning reference point in the ship's coordinate system from the three-dimensional coordinates of the interface coordinate origin in the ship's coordinate system. It is then determined whether the relative position vector is within the allowable deviation range, which is ±2 mm. The allowable deviation is based on the compression amount of the flange interface gasket and the fastener installation clearance requirements.

[0038] When the relative position vector is within the allowable deviation range, update the interface coordinates in the module information table based on the verification results. The following formula is used to update the interface coordinates in the module information table: in, This represents the three-dimensional position vector of the updated interface coordinate origin in the ship's coordinate system, in millimeters. This represents the three-dimensional position vector of the interface coordinate origin in the ship's coordinate system, read by the laser tracker during the coordinate consistency verification process, in millimeters. This represents the offset vector of the positioning reference point relative to the origin of the ship's coordinate system. It is obtained by subtracting the corresponding components of the three-dimensional coordinates of the positioning reference point in the ship's coordinate system from the three-dimensional coordinates of the origin of the ship's coordinate system. The unit is millimeters.

[0039] When the relative position vector exceeds the allowable deviation range, adjust the position of the adjacent construction module with the largest positional deviation, and remeasure the positioning reference point and the interface coordinate origin until the relative position vector falls within the allowable deviation range. Write the updated interface coordinates into the module information table, overwriting the original interface coordinate record, and simultaneously write the updated interface coordinates into the interface coordinate record table.

[0040] See Figure 4 In the graph, the horizontal axis represents the measurement sequence number, and the vertical axis represents the relative displacement, in millimeters. The graph uses scatter plots to show the distribution of relative displacement values ​​for the oil delivery module (blue dots), hydraulic module (orange squares), and control module (green triangles) at each measurement sequence number. The graph also indicates the upper and lower limits of the allowable deviation range, with horizontal dashed lines at +2 mm and -2 mm positions, clearly defining the required accuracy standards for the measurement data.

[0041] As shown in the figure, the relative displacement values ​​of the vast majority of measurement points are within the allowable deviation range, indicating that the relative position control between the interface coordinates and the positioning reference points of each module after hoisting is good. The data points of the oil delivery module are relatively evenly distributed, with a few points approaching the upper or lower limit of deviation, but no obvious exceedances were observed. The data points of the hydraulic module are concentrated near 0, with a small fluctuation range, indicating that the interface coordinate stability of the hydraulic module is good. The data points of the control module show larger fluctuations, with some data points approaching or even slightly exceeding the upper limit of deviation by 2 mm, but overall still within the allowable range.

[0042] In practice, based on the updated interface coordinates, the assembly sequence and tightening torque order between adjacent construction modules are determined, and all construction modules are installed according to the assembly sequence and tightening torque order. The updated interface coordinates are paired according to the module numbers to obtain the interface flange clearance values ​​of adjacent construction modules. During pairing, the module numbers and interface coordinate origins of different construction modules are read from the module information table, and the interface coordinate origins belonging to different construction modules but located in adjacent positions on the bow structure of the hull are paired. Adjacent positions refer to two interface coordinate origins whose distance in the hull coordinate system is no greater than 1.5 times the nominal diameter of the corresponding flange interface, and whose flange interface sealing surface normal directions are opposite. After pairing, the interface flange gap value of adjacent construction modules is calculated. The calculation method is to obtain the three-dimensional coordinates of the two interface coordinate origins in the ship coordinate system, calculate the Euclidean distance between the two interface coordinate origins, subtract the thickness from the sealing surface of the two flange interfaces to the back of the flange from the distance, and then subtract the reserved gap between the sealing surfaces of the matching flange interfaces to obtain the interface flange gap value. The unit is millimeters, and it is retained to one decimal place.

[0043] In some embodiments, initial and final fixing torque values ​​are generated based on the flange gap value. A correspondence table is established between the flange gap value, initial fixing torque value, and final fixing torque value. The flange gap values ​​in the table are set at 0.5 mm intervals, ranging from 0 mm to 20 mm, for a total of 41 positions. Each position corresponds to one initial fixing torque value and one final fixing torque value. The correspondence between the initial and final fixing torque values ​​is determined by correcting the standard tightening torque value of flange interfaces of the same diameter using a gasket compression test. When the flange gap value falls between two positions in the correspondence table, the initial and final fixing torque values ​​are calculated using a linear interpolation method. The linear interpolation method uses the flange gap value and the corresponding stress torque value of the two positions as endpoints, and calculates the corresponding initial and final fixing torque values ​​according to the proportional position of the flange gap value between the two positions. The initial fixing torque is 40% of the final fixing torque. The final fixing torque is determined according to the fastener specifications and the nominal pressure of the flange interface. The final fixing torque is obtained by referring to the fastener torque standard table and multiplying it by the compression coefficient of the flange interface gasket.

[0044] In some embodiments, the fastening sequence of adjacent construction modules is divided into an initial fastening stage and a final fastening stage. In the initial fastening stage, fastening proceeds from both sides of the longitudinal section of the hull towards the hull side. Specifically, at the interface flanges of the same adjacent construction module, fasteners arranged transversely along the hull are fastened sequentially from the first fastener on the left side of the longitudinal section towards the port side of the hull, and then from the first fastener on the right side of the longitudinal section towards the starboard side of the hull, all fasteners at the first interface flange are fastened sequentially. In the final fastening stage, fastening proceeds from the bow towards the stern of the hull. Specifically, according to the longitudinal arrangement of adjacent construction modules on the hull, fastening begins from the interface flange of the adjacent construction module closest to the bow and proceeds sequentially towards the stern of the hull. The fastening sequence of the initial and final fastening stages is written into an assembly sequence card, with fastener sequence numbers starting from 1 and sequentially numbered. The same set of fastener sequence numbers is used for both the initial and final fastening stages. Write the initial and final clamping torque values ​​into the clamping torque card. Record the corresponding initial and final clamping torque values ​​in the clamping torque card according to the fastener sequence number. The unit of the initial and final clamping torque values ​​is Newton-meter.

[0045] In practice, temporary adjustment pads with graduated lines are installed at the bottom of each construction module, and corresponding indicator pointers are installed on the mounting surface of the base frame. The temporary adjustment pads are placed at the support between the construction module and the mounting surface of the base frame. One temporary adjustment pad is installed at each of the four corners of the bottom of each construction module. If the bottom length of the construction module exceeds 4 meters, an additional temporary adjustment pad is added in the middle of the bottom length direction. The temporary adjustment pads are rectangular steel plates with graduated lines machined on one side along the thickness direction. The graduated lines have millimeter as the smallest scale, and the range is 0 mm to 30 mm. Indicator pointers are installed on the mounting surface of the base frame at the positions corresponding to the temporary adjustment pads. The indicator pointers are made of stainless steel, with one end welded to the mounting surface of the base frame, and the other end extending over the graduated line surface of the temporary adjustment pad, maintaining a 0.2 mm gap between the tip of the indicator pointer and the graduated line.

[0046] When hoisting and installing the construction modules, adjust the thickness of the temporary adjusting shims according to the interface flange gap value and the indicator reading. The following formula is used to adjust the thickness of the temporary adjusting shims: in, This indicates the adjusted thickness of the temporary adjusting shim, in millimeters. This indicates the thickness of the temporary adjusting shim before adjustment, in millimeters. It is obtained by measuring the actual thickness of the temporary adjusting shim with vernier calipers and reading the value. This indicates the flange clearance value, in millimeters, which is obtained by reading it from the calculated flange clearance value. This indicates the current reading of the pointer on the scale line of the temporary adjustment pad, in millimeters. It is obtained by visually reading the value of the scale line corresponding to the tip of the pointer when the bottom of the construction module is close to the mounting surface of the base frame during hoisting.

[0047] when If the thickness exceeds the maximum of 30 mm for the temporary adjusting shim, replace the entire temporary adjusting shim with a thicker spare shim and recalculate the adjustment. After adjustment, ensure the current reading of the indicator pointer matches the interface flange clearance value, and then continue positioning the construction module. After the construction module is positioned, insert the fasteners according to the assembly sequence card, performing initial tightening according to the initial tightening torque value on the tightening torque card, and then final tightening according to the final tightening torque value. When inserting fasteners, first insert the fastener with sequence number 1 on the assembly sequence card, and then insert the fasteners with increasing sequence numbers in sequence. Use a torque wrench for both initial and final tightening. Set the initial tightening torque value on the torque wrench during the initial tightening stage and the final tightening torque value during the final tightening stage. After all fasteners reach the initial tightening torque value during the initial tightening stage, proceed to the final tightening stage. During the final tightening stage, tighten all fasteners to the final tightening torque value in sequence according to the same assembly sequence card.

[0048] In some embodiments, after all construction modules are installed, permanent sealing gaskets are installed at the interface flanges of adjacent construction modules, and temporary protective covers at the interface flanges are removed. When installing the permanent sealing gaskets, first loosen some fasteners at the interface flanges to create a gap between the interface flanges of adjacent construction modules. Insert the permanent sealing gasket between the sealing surfaces of the interface flanges. The specifications of the permanent sealing gasket should match the dimensions of the flange interface sealing surfaces. The material of the permanent sealing gasket is selected based on the type of working medium and design pressure of the loading system. After installing the permanent sealing gaskets, re-tighten all fasteners at the interface flanges according to the final tightening torque value in the tightening torque card. When removing the temporary protective covers, remove the temporary protective covers from the flange interface. The temporary protective covers are protective covers and blind flanges. After removal, check that the flange interface sealing surfaces are undamaged, and collect the removed temporary protective covers.

[0049] See Figure 5 In the graph, the horizontal axis represents the flange clearance value in millimeters, ranging from 0 mm to 20 mm, and the vertical axis represents the tightening torque value in Newton-meters. The graph contains two sets of discrete data points and their fitted curves. Red dots represent the initial tightening torque value, and blue squares represent the final tightening torque value. The red dashed line and the blue solid line are the fitted curves for the corresponding data.

[0050] The curves show that both the initial and final fixing moments increase linearly with the increase of the flange clearance, reflecting a positive correlation between the initial and final fixing moments and the flange clearance. The initial fixing moment ranges from approximately 30 N·m to nearly 60 N·m, while the final fixing moment ranges from approximately 80 N·m to nearly 150 N·m. The fitted curves are smooth and well-fitted, indicating that the data conforms to the preset linear interpolation method.

[0051] This figure illustrates the technical solution for calculating the initial and final fixing moments of adjacent construction module interface flanges based on the interface flange gap value. The interface flange gap value covers the design range of 0 to 20 mm, conforming to the 41 settings in the corresponding relationship table, and supports the linear interpolation calculation method described in the embodiment. The distribution and trend of the moment values ​​are consistent with the 40% ratio of the initial fixing moment to the final fixing moment determined in the embodiment, verifying the rationality of the moment division.

[0052] In practical implementation, the assembly sequence and tightening torque order between adjacent construction modules are determined based on the updated interface coordinates. The updated interface coordinates are grouped to obtain the pipeline flange coordinate group for the oil transportation module and the valve assembly mounting surface coordinate group for the hydraulic module. The updated interface coordinates are derived from the interface coordinates in the module information table, which has been verified and updated for coordinate consistency. During grouping, modules are categorized by their module numbers. When the module number is for an oil transportation module, the origin of the interface coordinates corresponding to all flange interfaces in the oil transportation module is assigned to the pipeline flange coordinate group. When the module number is for a hydraulic module, the origin of the interface coordinates corresponding to all valve assembly mounting surfaces in the hydraulic module is assigned to the valve assembly mounting surface coordinate group. The pipeline flange coordinate group for the oil transportation module contains the origin of the interface coordinates for all pipeline flange interfaces in the oil transportation module, and the valve assembly mounting surface coordinate group for the hydraulic module contains the origin of the interface coordinates for all hydraulic valve assembly mounting surfaces in the hydraulic module.

[0053] The coordinates in the pipeline flange coordinate group are sorted according to the pipeline direction, and the sorted coordinates are aligned with the coordinates of the pre-embedded pipe openings in the bow tunnel of the hull. The sorting of the pipeline direction is determined based on the medium flow direction in the oil transfer module. The medium flow direction in the oil transfer module is from the pre-embedded pipe openings in the bow tunnel of the hull to the bow oil transfer manifold. Therefore, the origin of the interface coordinates on the bow tunnel side is sorted first, then the origin of the interface coordinates of the internal pipeline nodes of the oil transfer module is sorted, and then the origin of the outlet interface coordinates of the oil transfer module is sorted. The sorted pipeline flange coordinate group forms an ordered coordinate sequence, and each coordinate in the ordered coordinate sequence has a sequential number. The coordinates of the pre-embedded pipe openings in the bow tunnel of the hull are read from the pre-embedded pipe opening layout diagram of the bow tunnel of the hull. The coordinates of the pre-embedded pipe openings are the three-dimensional coordinates of the center of the sealing surface of the pre-embedded pipe opening flange in the hull coordinate system. Align the first coordinate in the sorted pipeline flange coordinate group with the coordinate of the pre-embedded pipe opening in the bow tunnel of the hull. During alignment, make the two coordinates coincide in the hull coordinate system and record the alignment offset.

[0054] The installation priority of the oil delivery module and the hydraulic module is determined based on the alignment results. The hydraulic module is installed before the oil delivery module, and the control module is installed after the hydraulic module. In the alignment results, if the deviation between the first coordinate in the pipeline flange coordinate group and the pre-embedded pipe port coordinates in the X-axis and Z-axis directions does not exceed 3 mm, and the deviation in the Y-axis direction does not exceed 5 mm, then the pipeline flange coordinate group is considered aligned with the pre-embedded pipe port coordinates. When determining the installation priority, the hydraulic module is installed before the oil delivery module, and the control module is installed after the hydraulic module. The reason for installing the hydraulic module first is that the valve assembly mounting surface of the hydraulic module is not directly connected to the bow tunnel of the hull, and the installation of the hydraulic module first will not be affected by the alignment deviation between the pipeline flange coordinate group of the oil delivery module and the pre-embedded pipe port coordinates. The reason for installing the control module after the hydraulic module is that the control cable of the control module is laid along the outside of the valve assembly mounting surface of the hydraulic module, and the installation position of the control module can only be determined after the hydraulic module is in place.

[0055] The difference between the pipeline flange coordinate set and the pre-embedded pipe port coordinates is converted into the flange gasket adjustment thickness. The difference is obtained by calculating the three-dimensional coordinate difference between the first coordinate in the pipeline flange coordinate set and the pre-embedded pipe port coordinate. This three-dimensional coordinate difference includes differences in the X-axis, Y-axis, and Z-axis directions. This three-dimensional coordinate difference is then converted into a scalar difference, which is the Euclidean length of the three-dimensional coordinate difference, in millimeters. This scalar difference is used as the flange gasket adjustment thickness, using the following formula: in, This indicates the adjusted thickness of the flange gasket, in millimeters. This represents the coordinate difference between the first coordinate in the pipeline flange coordinate group and the pre-embedded pipe opening coordinate in the X-axis direction of the ship coordinate system, in millimeters. It is obtained by subtracting the X-axis coordinate value of the pre-embedded pipe opening coordinate from the X-axis coordinate value of the first coordinate in the pipeline flange coordinate group. This represents the coordinate difference between the first coordinate in the pipeline flange coordinate group and the pre-embedded pipe opening coordinate in the Y-axis direction of the ship coordinate system, in millimeters. It is obtained by subtracting the Y-axis coordinate value of the pre-embedded pipe opening coordinate from the Y-axis coordinate value of the first coordinate in the pipeline flange coordinate group. This represents the coordinate difference between the first coordinate in the pipeline flange coordinate group and the pre-embedded pipe opening coordinate in the Z-axis direction of the ship's coordinate system, in millimeters. It is obtained by subtracting the Z-axis coordinate value of the pre-embedded pipe opening from the Z-axis coordinate value of the first coordinate in the pipeline flange coordinate group. If the flange gasket adjustment thickness is 0 mm, no adjustment is required; if the flange gasket adjustment thickness is greater than 0 mm, the flange gasket adjustment thickness is used as the thickness of the optional flange gasket.

[0056] When the adjusted thickness exceeds the maximum thickness of the flange gasket, a transition short pipe is installed at the pre-embedded pipe opening in the bow tunnel of the hull. The maximum thickness of the flange gasket is determined based on the allowable deformation of the sealing surface of the oil transfer module pipeline flange interface. The allowable deformation of the sealing surface of the oil transfer module pipeline flange interface is 3 mm, and the maximum thickness of the flange gasket is set to 10 mm. The basis for this setting is that when the flange gasket thickness exceeds 10 mm, the compression deformation of the flange gasket under the tightening torque will exceed the allowable deformation of the sealing surface by 3 mm, leading to flange interface sealing failure. When the adjusted thickness of the flange gasket is greater than 10 mm, a transition short pipe is installed at the pre-embedded pipe opening in the bow tunnel of the hull. The transition short pipe is positioned between the pre-embedded pipe opening in the bow tunnel of the hull and the first pipeline flange interface of the oil transfer module. Two flange joints are welded to each end of the transition short pipe. The first flange joint of the transition short pipe connects to the pre-embedded pipe opening in the bow tunnel of the hull, and the second flange joint of the transition short pipe connects to the first pipeline flange interface of the oil transfer module. The length of the transition short pipe is the distance between the two flange sealing surfaces of the transition short pipe. The length of the transition short pipe is determined based on the difference between the flange gasket adjustment thickness and the flange gasket maximum thickness. The length of the transition short pipe is equal to the flange gasket adjustment thickness minus the flange gasket maximum thickness plus the fixed installation gap, which is 5 mm.

[0057] The interface coordinates in the module information table are updated based on the length of the transition short pipe, and the installation priority is executed according to the updated interface coordinates. When updating the interface coordinates in the module information table, the origin of the interface coordinates of the flange interface of the oil delivery module connected to the transition short pipe is shifted along the axial direction of the transition short pipe by the length of the transition short pipe. The axial direction of the transition short pipe is the direction of the line connecting the center of the sealing surface of the first flange joint to the center of the sealing surface of the second flange joint. The updated interface coordinate origin is written into the corresponding interface coordinate origin of the oil delivery module in the module information table. After the update is completed, the installation is executed according to the installation priority: first the hydraulic module, then the oil delivery module, and then the control module. When installing the hydraulic module, it is hoisted into the bow loading system base frame, and the valve assembly mounting surface coordinate group of the hydraulic module is aligned with the corresponding positioning reference point and tightened. After installing the hydraulic module, the oil delivery module is installed. It is hoisted into the bow loading system base frame, and the pipeline flange coordinate group of the oil delivery module is aligned with the updated interface coordinates. The pre-embedded pipe ports are connected using the corresponding flange gaskets and transition short pipes. After the hydraulic module and oil delivery module are installed, the control module is installed.

[0058] See Figure 6 The figure uses the measurement sequence number as the x-axis and the coordinate difference (unit: mm) as the y-axis, showing the scatter distribution of the coordinate differences between the first coordinate in the oil pipeline flange coordinate group and the pre-embedded pipe opening in the bow tunnel of the ship in the X, Y, and Z directions. Different symbols are used to indicate the differences in each direction: blue dots represent the difference in the X-axis direction, orange squares represent the difference in the Y-axis direction, and green triangles represent the difference in the Z-axis direction. The dashed line in the figure represents the reference line for the maximum thickness of the flange gasket, 10 mm.

[0059] Looking at the distribution trend of coordinate differences, the differences in the X-axis direction are mostly concentrated within ±5 mm, with relatively uniform fluctuations and no continuous offset trend. The differences in the Y-axis direction fluctuate more, with some points reaching about ±9 mm, exceeding the reference line for the maximum thickness of the flange gasket, indicating a large deviation in this direction. The differences in the Z-axis direction are generally concentrated, basically within ±5 mm, and most points are close to zero, indicating a small deviation in this direction.

[0060] Ideally, the first coordinate in the pipeline flange coordinate set should not deviate from the pre-embedded pipe port coordinate in the X and Z axes by more than 3 mm. A slightly larger deviation is permissible in the Y-axis direction. The fact that multiple measurement points in the diagram show Y-axis differences exceeding 5 mm indicates that the flange gasket thickness needs to be adjusted or a transition short pipe needs to be installed for compensation. Y-axis deviations exceeding the maximum flange gasket thickness of 10 mm suggest that a transition short pipe may be needed between the pre-embedded pipe port and the oil transfer module pipeline flange interface to meet installation requirements.

[0061] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A modular construction method for a shuttle tanker bow loading system, characterized in that, include: Based on the functional zoning and interface boundaries of the bow loading system at the bow of the hull, the bow loading system is divided into several construction modules, and a module information table containing module number, interface coordinate origin and compensation margin is compiled for each construction module. According to the module information table, a bow loading system base frame is installed on the bow section of the hull, and positioning reference points are set on the mounting surface of the base frame. According to the assembly sequence of the bow section of the hull, the construction modules are hoisted into the base frame in sequence. After each construction module is hoisted in, the relative position of the positioning reference point and the corresponding interface coordinate origin is measured, and the interface coordinates in the module information table are updated. Based on the updated interface coordinates, determine the assembly sequence and fastening torque order between adjacent building modules; Complete the installation of all construction modules according to the assembly sequence and tightening torque order to form the bow loading system.

2. The modular construction method for the shuttle tanker bow loading system according to claim 1, characterized in that, Based on the functional zoning and interface boundaries of the bow loading system at the bow of the hull, the bow loading system is divided into several construction modules, and a module information table is compiled for each construction module, including module number, interface coordinate origin, and compensation margin, including: Based on the type of working medium and pipeline diameter, the bow loading system is divided into an oil delivery module, a hydraulic module, and a control module. Independent module boundaries are set for the oil delivery module, hydraulic module and control module respectively, and flange interfaces with temporary sealing are set at the module boundaries; The origin of the flange interface coordinates is generated based on the coordinates of the flange interface in the ship's coordinate system, and the sealing surface orientation and compensation margin of the flange interface are recorded in the module information table.

3. The modular construction method for the shuttle tanker bow loading system according to claim 2, characterized in that, According to the module information table, the installation of the bow loading system base frame on the bow section of the hull, and the setting of positioning reference points on the mounting surface of the base frame, includes: During the anti-topping stage of the bow section of the hull, the segmented base of the base frame and the bow loading system base frame are assembled according to the module number in the module information table, and the coplanarity data between the segmented base and the bow loading system base frame are measured after assembly. The thickness of the support pads of the bow loading system base frame is adjusted according to the coplanarity data; Positioning reference points are set on the base frame of the bow loading system. The positioning reference points include first-type reference points set at the four corners of the base frame and second-type reference points set in the middle of the longitudinal beams of the base frame. Write the coordinates of the first type of reference point and the second type of reference point into the module information table.

4. The modular construction method for the bow loading system of a shuttle tanker according to claim 1, characterized in that, The construction modules are sequentially hoisted into the base frame according to the assembly order of the bow sections of the hull. After each construction module is hoisted in, the relative position of the positioning reference point and the corresponding interface coordinate origin is measured, and the interface coordinates in the module information table are updated, including: Two mutually perpendicular measurement and control bases are set up at the assembly site of the bow section of the hull, and laser trackers are installed on the measurement and control bases respectively; Align the laser tracker with the interface coordinate origin that has been hoisted into the construction module, and read the three-dimensional position data of the interface coordinate origin relative to the positioning reference point; The coordinates of the origin of the interface coordinates of adjacent construction modules are checked against the measured positioning reference points, and the interface coordinates in the module information table are updated according to the check results.

5. The modular construction method for the bow loading system of a shuttle tanker according to claim 4, characterized in that, The step of determining the assembly sequence and fastening torque order between adjacent construction modules based on the updated interface coordinates includes: The updated interface coordinates are paired according to the module number to obtain the interface flange gap value of adjacent construction modules; The initial and final fixing torque values ​​are generated based on the interface flange clearance value. The fastening sequence of adjacent building modules is divided into an initial fastening stage and a final fastening stage; In the initial securing stage, the fasteners are tightened in sequence from both sides of the longitudinal section of the hull toward the hull side, and in the final securing stage, the fasteners are tightened in sequence from the bow of the hull toward the stern of the hull. Write the tightening sequence of the initial and final curing stages into the assembly sequence card, and write the initial and final curing torque values ​​into the tightening torque card.

6. The modular construction method for the bow loading system of a shuttle tanker according to claim 5, characterized in that, The installation of all construction modules according to the assembly sequence and tightening torque order to form the bow loading system includes: A temporary adjustment pad with scale lines is set at the bottom of each construction module, and an indicator pointer corresponding to the scale lines is set on the mounting surface of the base frame; When hoisting the construction module, the thickness of the temporary adjusting pad is adjusted according to the interface flange gap value and the reading of the indicator pointer; After the construction module is in place, fasteners are inserted in the order of the assembly sequence card, and initial fastening is performed according to the initial fastening torque value of the fastening torque card, and then final fastening is performed according to the final fastening torque value. After all construction modules are installed, install permanent sealing gaskets at the interface flanges of adjacent construction modules and remove the temporary protective covers at the interface flanges.

7. The modular construction method for the bow loading system of a shuttle tanker according to claim 4, characterized in that, The step of aligning the laser tracker with the interface coordinate origin already hoisted onto the construction module and reading the three-dimensional position data of the interface coordinate origin relative to the positioning reference point includes: A target base is set on the construction module and arranged coaxially with the origin of the interface coordinates, and a spherical reflector is installed on the target base; After the construction module is hoisted in, the laser tracker is aligned with the spherical reflector in sequence to read the three-dimensional position data of the interface coordinate origin in the ship coordinate system. The three-dimensional position data are stored according to the module number and the positioning reference point number to generate the interface coordinate record table of the construction module.

8. The modular construction method for the bow loading system of a shuttle tanker according to claim 7, characterized in that, The step of storing the three-dimensional position data according to the module number and the positioning reference point number, and generating the interface coordinate record table of the construction module, includes: The three-dimensional position data is divided into multiple groups according to the hoisting batches of the construction modules; The three-dimensional position data within the same hoisting batch are sorted according to the positioning reference point number to generate the module interface coordinate sequence of that hoisting batch; The module interface coordinate sequences of different hoisting batches are merged according to the overall grouping order of the bow section of the hull, and the interface coordinate origin shared by adjacent hoisting batches is used as the continuation point during the merging process to generate the interface coordinate record table.

9. The modular construction method for the bow loading system of a shuttle tanker according to claim 1, characterized in that, The step of determining the assembly sequence and fastening torque order between adjacent construction modules based on the updated interface coordinates includes: The updated interface coordinates are grouped to obtain the pipeline flange coordinate group of the oil delivery module of the bow loading system and the valve assembly mounting surface coordinate group of the hydraulic module. The coordinates in the pipeline flange coordinate group are sorted according to the pipeline direction, and the sorted coordinates are aligned with the coordinates of the pre-embedded pipe openings in the bow tunnel of the ship. The installation priority of the oil delivery module and the hydraulic module is determined based on the alignment results; The installation priority is that the hydraulic module is installed before the oil delivery module, and the control module is installed after the hydraulic module.

10. The modular construction method for the bow loading system of a shuttle tanker according to claim 9, characterized in that, The process of determining the installation priority of the oil delivery module and the hydraulic module based on the alignment results includes: The difference between the pipeline flange coordinate set and the pre-embedded pipe port coordinate is converted into the flange gasket adjustment thickness. When the adjusted thickness exceeds the maximum thickness of the flange gasket, a transition short pipe is installed at the pre-embedded pipe opening of the bow tunnel of the hull. The interface coordinates in the module information table are updated according to the length of the transition short tube, and the installation priority is executed according to the updated interface coordinates.

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