Marking method for LNG ship dock grid lines
By using total station measurement and marking technology, the problem of accuracy deviation in the construction of dock grid lines was solved, achieving efficient and accurate dock grid line marking and meeting the dock grid line acceptance standards.
Patent Information
- Application Number
- CN202510903494.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-01
- Publication Date
- 2025-11-11
AI Technical Summary
The existing construction methods for dock grid lines cannot meet the acceptance standards for dock grid lines, and often result in deviations in straightness or width accuracy, leading to positioning deviations of the ship's centerline.
By employing total station surveying and marking techniques, and through the precise marking of center lines, straight sections, positioning baselines, and segmented large joint lines, the accuracy and efficiency of the dock grid lines are ensured.
It improved the construction accuracy and efficiency of the dock grid lines, and met the straightness and verticality requirements of the dock grid line acceptance standards.
Smart Images
Figure CN120922301A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of shipbuilding technology, and in particular relates to a method for marking grid lines in the dock of an LNG ship. Background Technology
[0002] Dock grid lines refer to the center lines, half-width lines, section joint marks, and rib inspection marks marked on the dock floor during ship construction. They primarily serve as positioning references when assembling sections (or main sections) in the dock. With the recovery of the shipbuilding market, the technical requirements for shipbuilding are constantly increasing, and the acceptance standards for dock grid lines have been raised to straightness ≤1.5mm, limit deviation ≤2mm, and verticality deviation ≤2mm. Currently, dock grid line construction still uses the old method of manual marking and layout, which often results in deviations in straightness or width accuracy and cannot meet the current dock grid line acceptance standards. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for marking the dock grid lines of an LNG carrier. This method avoids the positioning deviation of the ship's centerline caused by the dock grid lines and improves the construction efficiency and accuracy standards of the dock grid lines.
[0004] To achieve the above-mentioned objectives, the technical solution provided by this invention patent is as follows:
[0005] A method for marking grid lines in the dry dock of an LNG carrier, the method specifically includes the following steps:
[0006] S1, Dock cleaning: Before the dock grid lines are drawn, the area to be drawn is cleaned to ensure that the area is unobstructed and that there is no obvious water accumulation on the dock floor.
[0007] S2, Centerline Determination and Marking: Determine the centerline of the dock grid lines according to the dock layout plan, and mark the centerline at the bottom of the dock.
[0008] S3, straight section line drawing: using the center line of the bottom of the dock as the baseline, use a total station to draw parallel lines to the center line on the top of the dock wall and the bottom of the dock as straight section lines.
[0009] S4. Determining the baseline of the positioning section and FR0: The rib line of the baseline section determined by the dock layout drawing is used as the baseline for drawing each rib line. The position of FR0 is determined according to the construction policy, and then the baseline of the positioning section and FR0 are drawn.
[0010] S5. Determine the segmented large joint lines. Based on the dock grid line diagram, determine the segmented large joint lines, and then draw the segmented large joint lines to complete the dock grid line drawing.
[0011] Furthermore, the centerline delineation in S2 is specifically as follows: place the total station at the bottom of the dock near the dock wall, and select two measurement points P1 and P2 on the dock wall near the ship. According to the distance B between the centerline and the line connecting the measurement points in the dock layout diagram, draw a parallel line connecting the two points P1 and P2 at the bottom of the dock, and mark points every 5 meters on this parallel line. Connect the marked points into a straight line, which is the centerline of the ship.
[0012] Furthermore, the distance between points P1 and P2 is 70m, the starting point P3 of the centerline is the distance L between the stern cap and the dock gate in the dock layout diagram, and the centerline extends forward from the starting point to cover the total length of the vessel.
[0013] Furthermore, the straight section line is a half-width line parallel to the center line. The width of the straight section line is greater than half the width of the ship under construction. According to the dock layout diagram, the straight section line on the side near the dock wall is drawn on the top of the dock wall, and the straight section line on the side far from the dock wall is drawn on the bottom of the dock.
[0014] Furthermore, the positioning general segment baseline and FR0 delineation are specifically as follows: the point of the rib line is determined on the center line by the distance L1 from the rib position of the positioning general segment baseline to the center line starting point P3, and a perpendicular line to the center line is drawn, which is the baseline rib line; the point of the rib line is determined on the center line by the distance L2 from FR0 to the center line starting point P3, and a perpendicular line to the center line is drawn, which is the FR0 line.
[0015] Furthermore, the perpendicularity deviation of the reference rib line is ≤2mm, and the perpendicularity deviation of the FR0 line is ≤2mm.
[0016] Based on the above technical solution, the method for drawing grid lines in the dock of an LNG ship, as described in this invention patent, has achieved the following technical advantages through practical application:
[0017] 1. The grid line marking method of the present invention avoids the positioning deviation of the ship's centerline caused by the dock grid line, and improves the construction efficiency and accuracy standard of the dock grid line. Attached Figure Description
[0018] Figure 1 This is a diagram showing the centerline layout structure in a method for marking grid lines in an LNG carrier dock.
[0019] Figure 2 This is a schematic diagram of the straight section line drawing method in the grid line drawing method of an LNG ship dock.
[0020] Figure 3 This is a schematic diagram of baseline marking in a method for marking grid lines in an LNG ship dock.
[0021] Figure 4This is a schematic diagram of the large joint line marking in a method for marking grid lines in an LNG ship dock. Detailed Implementation
[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is described below with reference to specific examples shown in the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.
[0023] Example 1
[0024] A method for marking grid lines in the dry dock of an LNG carrier, the method specifically includes the following steps:
[0025] S1, Dock cleaning: Before the dock grid lines are drawn, the area to be drawn is cleaned to ensure that the area is unobstructed and that there is no obvious water accumulation on the dock floor.
[0026] S2, Centerline Determination and Marking: Determine the centerline of the dock grid lines according to the dock layout plan, and mark the centerline at the bottom of the dock.
[0027] S3, straight section line drawing: using the center line of the bottom of the dock as the baseline, use a total station to draw parallel lines to the center line on the top of the dock wall and the bottom of the dock as straight section lines.
[0028] S4. Determining the baseline of the positioning section and FR0: The rib line of the baseline section determined by the dock layout drawing is used as the baseline for drawing each rib line. The position of FR0 is determined according to the construction policy, and then the baseline of the positioning section and FR0 are drawn.
[0029] S5. Determine the segmented large joint lines. Based on the dock grid line drawing, determine the segmented large joint lines, then draw the segmented large joint lines to complete the dock grid line drawing; for example... Figure 4 As shown.
[0030] like Figure 1 As shown, the centerline delineation in S2 is specifically as follows: place the total station at the bottom of the dock near the dock wall, and select two measurement points P1 and P2 on the dock wall near the ship. According to the distance B between the centerline and the line connecting the measurement points in the dock layout diagram, draw a line parallel to the line connecting points P1 and P2 at the bottom of the dock. Mark points are made every 5 meters on this parallel line, and the marks are connected into a straight line to form the ship's centerline.
[0031] The distance between points P1 and P2 is 70m. The starting point of the centerline, P3, is the distance L between the stern cap and the dock gate in the dock layout diagram. The centerline extends forward from the starting point to cover the total length of the vessel.
[0032] like Figure 2 As shown, the straight section line is a half-width line parallel to the center line. The width of the straight section line is greater than half the width of the ship under construction. According to the dock layout diagram, the straight section line on the side near the dock wall is drawn on the top of the dock wall, and the straight section line on the side far from the dock wall is drawn on the bottom of the dock.
[0033] like Figure 3 As shown, the positioning general segment baseline and FR0 delineation are specifically as follows: the point of the rib line is determined on the center line by the distance L1 from the rib position of the positioning general segment baseline to the center line starting point P3, and a perpendicular line to the center line is drawn, which is the baseline rib line. The point of the rib line is determined on the center line by the distance L2 from FR0 to the center line starting point P3, and a perpendicular line to the center line is drawn, which is the FR0 line.
[0034] The perpendicularity deviation of the reference rib line is ≤2mm, and the perpendicularity deviation of the FR0 line is ≤2mm.
[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.
Claims
1. A method for marking grid lines in the dock of an LNG carrier, characterized in that, The method specifically includes the following steps: S1, Dock cleaning: Before the dock grid lines are drawn, the area to be drawn is cleaned to ensure that the area is unobstructed and that there is no obvious water accumulation on the dock floor. S2, Centerline Determination and Marking: Determine the centerline of the dock grid lines according to the dock layout plan, and mark the centerline at the bottom of the dock. S3, straight section line drawing: using the center line of the bottom of the dock as the baseline, use a total station to draw parallel lines to the center line on the top of the dock wall and the bottom of the dock as straight section lines. S4. Determining the baseline of the positioning section and FR0: The rib line of the baseline section determined by the dock layout drawing is used as the baseline for drawing each rib line. The position of FR0 is determined according to the construction policy, and then the baseline of the positioning section and FR0 are drawn. S5. Determine the segmented large joint lines. Based on the dock grid line diagram, determine the segmented large joint lines, and then draw the segmented large joint lines to complete the dock grid line drawing.
2. The method for drawing grid lines in an LNG ship dock according to claim 1, characterized in that, The centerline delineation in S2 is specifically as follows: Place the total station at the bottom of the dock near the dock wall, and select two measurement points P1 and P2 on the dock wall near the ship. According to the distance B between the centerline and the line connecting the measurement points in the dock layout diagram, draw a line parallel to the line connecting points P1 and P2 at the bottom of the dock. Mark points every 5 meters on this parallel line, and connect the marked points into a straight line, which is the centerline of the ship.
3. The method for drawing grid lines in an LNG ship dock according to claim 2, characterized in that, The distance between points P1 and P2 is 70m. The starting point of the centerline, P3, is the distance L between the stern cap and the dock gate in the dock layout diagram. The centerline extends forward from the starting point to cover the total length of the vessel.
4. The method for drawing grid lines in an LNG ship dock according to claim 1, characterized in that, The straight section line is a half-width line parallel to the center line. The width of the straight section line is greater than half the width of the ship under construction. According to the dock layout diagram, the straight section line on the side near the dock wall is drawn on the top of the dock wall, and the straight section line on the side far from the dock wall is drawn on the bottom of the dock.
5. The method for drawing grid lines in an LNG ship dock according to claim 1, characterized in that, The positioning baseline and FR0 delineation are as follows: the point of the rib line is determined on the center line by the distance L1 from the rib of the positioning baseline to the center line starting point P3, and a perpendicular line to the center line is drawn, which is the baseline rib line. The point of the rib line is determined on the center line by the distance L2 from FR0 to the center line starting point P3, and a perpendicular line to the center line is drawn, which is the FR0 line.
6. The method for drawing grid lines in an LNG ship dock according to claim 1, characterized in that, The perpendicularity deviation of the reference rib line is ≤2mm, and the perpendicularity deviation of the FR0 line is ≤2mm.