Ship base line for assigning freeboard and water gauge marks and calculation method of ship base line

Abstract

The invention provides a calculation method of the ship correction base line for assigning the freeboard and the water gauge mark, and the method specifically comprises the following steps: S1, selecting a plurality of measurement positions on a longitudinal plane in the ship bottom in the ship length direction, and respectively recording the measurement positions as F1, F2... Fi; s2, calculating a height difference value Zi between the actual position of the flat keel of the ship body at each measurement position and the theoretical base line M; s3, searching the ship body flat bottom widths B1, B2... Bi corresponding to the positions F1, F2... Fi from the ship molded line graph, wherein the ship body flat bottom widths B1, B2... Bi correspond to the positions F1, F2... Fi; s4, calculating distances L1, L2... Li between adjacent measurement positions of F1, F2... Fi; and S5, defining a ship correction base line used for freeboard assignment and water gauge marking and aircraft handover as N, wherein N is the sum of the numerical value corresponding to the theoretical base line M and the correction value d. The invention further provides a ship correction base line for assigning the freeboard and water gauge marks, the freeboard and water gauge marks of the ship can be accurately calibrated, and the correctness of overall performance parameters of the whole ship is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of shipbuilding, and in particular relates to a ship baseline for surveying freeboard and draft mark and a calculation method thereof. Background Art

[0002] The hull baseline is an important basis for surveying the freeboard and marking the water level of a ship. In theory, it is the horizontal plane where the flat keel of the hull is located. However, during the construction of a ship, due to various reasons such as uneven weight distribution of the hull, segmented manufacturing, and deformation during assembly, the actual contour of the flat keel of the hull is a non-flat wave shape, so the actual baseline of the ship presents a wavy curve along the length of the ship.

[0003] In the prior art, the actual baseline of the ship is measured, and then a simple mathematical average of the measured values ​​is performed to obtain a mean value as a corrected baseline. This method is applicable when the deformation of the bottom of the ship is relatively uniform along the length of the ship, but there are errors in the case of non-uniform deformation of the bottom of the ship. Since the survey of the freeboard and the water level markings of the ship have an important influence on the overall performance parameters of the whole ship, it is necessary to propose a more accurate ship corrected baseline calculation method. Summary of the invention

[0004] In view of the above problems, the present invention provides a ship baseline for surveying freeboard and draft mark and a calculation method thereof.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A ship correction baseline for surveying freeboard and water gauge markings, with multiple measurement position points F1, F2...F marked on the outer plate design contour line along the length of the ship i , the correction value is d, the ship correction baseline is composed of multiple measurement positions F1, F2...F i The value on the ship's theoretical baseline M plus the correction value, where multiple measurement points F1, F2...F i The volume change of the actual position of the flat keel of the hull relative to the ship's corrected baseline is 0.

[0007] A method for calculating the ship's corrected baseline for surveying freeboard and draft markings comprises the following steps:

[0008] S1. Select multiple measurement positions on the longitudinal plane of the bottom of the ship along the length of the ship, and record them as F1, F2...F i ;

[0009] S2. Calculate the height difference Z between the actual position of the keel of the hull plate and the theoretical baseline M at each measurement position i ;

[0010] S3. Find F1, F2...F from the ship line drawing i The corresponding flat bottom width of the hull at each position is B1, B2...B i ;

[0011] S4. Calculate F1, F2....F i The distance between adjacent measuring positions is L1, L2...L i ;

[0012] S5. Define the corrected baseline for ships used for freeboard and draft marking and delivery as N, which is the value corresponding to the theoretical baseline M plus the correction value d. The calculation formula for d is:

[0013]

[0014] Furthermore, in S1, the position F is measured i Select along the stern to bow direction.

[0015] Furthermore, in S1, the position F is measured i is the position of the ship's strong rib, measuring position F i Including every strong rib position, or selecting according to intervals of 1 to 3 strong rib positions.

[0016] Furthermore, in S7, referring to formula d, a calculation table is prepared using EXCEL software, data is input, and step-by-step calculation is performed to obtain the d value.

[0017] Furthermore, the S2 specifically includes the following steps:

[0018] S21. Selecting a baseline X as a baseline measurement;

[0019] S22.Measure F1, F2...F i The height values ​​h1, h2...h of the outer surface of the ship's outer plate at each position from the measurement reference line X i ;

[0020] S23. Taking the theoretical baseline M of the ship in the design state as the reference line, the distance between the measurement baseline X and the theoretical baseline M is calculated as a constant value f;

[0021] S24. From the hull structure diagram, find F1, F2...F i The thickness of the flat keel corresponding to each position is t1, t2...t i ;

[0022] S25. Calculate the height difference Z between the actual position of the hull plate keel and the theoretical baseline M i , the calculation formula is as follows:

[0023] Z i=h i +t i -f.

[0024] Further, in S22, the measurements F1, F2...F i The height value of the outer surface of the ship's outer plate at each position from the measurement reference line X can be measured by a laser total station or other methods capable of measuring distance.

[0025] Further, in S1, the reference line X is any assumed horizontal plane lower than the outer plate of the hull.

[0026] The calculation formula of d is demonstrated and explained as follows:

[0027] Assuming that Δp is expressed as the volume change of the actual position of the keel of the hull along the length direction relative to the corrected baseline N, the integral form formula of Δp is as follows:

[0028] Δp=∫∫(Z i -d)dydx

[0029] In the above formula, dy represents the infinitesimal element in the width direction of the hull, and dx represents the infinitesimal element in the length direction of the hull. It can be understood that Δp should not change with the deformation of the hull flat keel, so the Δp value should be equal to 0; for any cross section at any position, within the range of the bottom plane, B i The value is a constant, so the calculation formula of Δp can also be written as:

[0030] Δp=∫(Z i -d) Bidx = 0,

[0031] Then there is

[0032]

[0033] From step S4, it can be seen that the distance between adjacent measurement positions is L i , then the above formula can be written as:

[0034]

[0035] The present invention proposes a high-precision ship correction baseline calculation method, which uses the measured height values ​​of each section of the ship's flat keel along the ship's length direction, and based on the condition that the volume change of the hull relative to the correction baseline is 0, solves and obtains an accurate correction baseline value, thereby being able to accurately calibrate the ship's freeboard and water gauge mark, thereby improving the accuracy of the overall performance parameters of the entire ship. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is an actual outline diagram of the flat keel of a ship according to an embodiment of the present invention.

[0037] Figure 2 This is a contour diagram of the flat bottom area of ​​a ship according to an embodiment of the present invention.

[0038] Figure 3 This is a design outline drawing of the outer plate of the longitudinal section of a ship according to an embodiment of the present invention.

[0039] Among them, 10-design contour line of the outer plate of the mid-longitudinal section of the ship, 1-theoretical baseline, 2-baseline measurement baseline, 101-contour line of the flat bottom area of ​​the ship, 11-actual contour line of the flat keel of the ship, 30-corrected baseline of the ship. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. These embodiments are only used to illustrate the present invention and are not intended to limit the present invention.

[0041] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the purpose of describing the present invention and simplifying the description, rather than indicating or implying that the positions or elements referred to must have a characteristic direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0042] like Figure 1 to Figure 3 As shown, a method for calculating a ship's corrected baseline for surveying freeboard and draft markings comprises the following steps:

[0043] S1. Select any assumed horizontal plane lower than the hull outer plate as the baseline for baseline measurement as the measurement baseline 2. Select the ship's strong rib positions F1, F2...F in sequence at the middle longitudinal plane of the bottom along the length of the ship. i In this embodiment, the measurement position F i The measurement position F is selected according to the interval of 1 to 3 strong ribs. Of course, in other embodiments, the measurement position F i It can also include each strong rib position;

[0044] S2. Calculate the height difference Z between the actual position of the keel of the hull plate and the theoretical baseline M at each measurement position i , specifically including the following steps:

[0045] S21. Selecting a baseline X as a baseline measurement;

[0046] S22. Use a total station to measure F1, F2...F i The height values ​​h1, h2...h of the outer surface of the ship's outer plate at each position from the measurement reference line 2i , record F1, F2...F i Location information and corresponding h1,h2...h i The values ​​are in the EXCEL table, as shown in Table 1;

[0047] S23, taking the theoretical baseline 1 in the ship design state as the reference line, calculating the distance between the measurement baseline 2 and the theoretical baseline 1 as a fixed value f, which is 10 mm in this embodiment, and is recorded in Table 1;

[0048] S24, from the hull structure diagram, find F1, F2...F i The corresponding plate keel thickness is t1, t2...t i , recorded in Table 1;

[0049] S3, check F1, F2...F from the ship line drawing i The corresponding hull flat bottom width is B1, B2...B i , recorded in Table 1.

[0050] S4. Calculate F1, F2....F i The distance between adjacent measuring positions is L1, L2...L i , recorded in Table 1.

[0051] S5. The ship correction baseline used for surveying freeboard and water gauge marking and delivery is N, where N is the value corresponding to the theoretical baseline M plus the correction value d. The calculation formula of d proposed by the present invention is:

[0052]

[0053] in,

[0054] Z i =h i +t i -f, use EXCEL software to prepare a calculation table, enter data, and calculate step by step to obtain the d value.

[0055] The values ​​obtained from S1 to S5 are recorded as shown in the table below, and the correction value d is calculated according to the S7 formula using data processing tools such as EXCEL. According to Table 1, the corrected baseline value of the ship should be 25.27 mm above the theoretical baseline.

[0056] Table 1 Corrected baseline calculation table

[0057]

[0058] Those skilled in the art should understand that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A ship correction baseline for surveying freeboard and draft mark, characterized in that: There are several measuring points F1, F2...F marked on the outer plate design contour line along the length of the ship. i , the correction value is d, the ship correction baseline is composed of multiple measurement positions F1, F2...F i The value on the ship's theoretical baseline M plus the correction value, where multiple measurement points F1, F2...F i The volume change of the actual position of the flat keel of the hull relative to the ship's corrected baseline is 0.

2. A method for calculating the corrected baseline of a ship for marking freeboard and draft marks, characterized in that: The specific steps include: S1. Select multiple measurement positions on the longitudinal plane of the bottom of the ship along the length of the ship, and record them as F1, F2...F i ; S2. Calculate the height difference Z between the actual position of the keel of the hull plate and the theoretical baseline M at each measurement position i ; S3. Find F1, F2...F from the ship line drawing i The corresponding flat bottom width of the hull at each position is B1, B2...B i ; S4. Calculate F1, F2....F i The distance between adjacent measuring positions is L1, L2...L i ; S5. Define the corrected baseline for ships used for freeboard and draft marking and delivery as N, which is the value corresponding to the theoretical baseline M plus the correction value d. The calculation formula for d is:

3. A method for calculating a ship baseline for surveying freeboard and draft markings according to claim 2, characterized in that: In S1, measure position F i Select along the stern to bow direction.

4. A method for calculating a ship baseline for marking freeboard and draft marks according to claim 2, characterized in that: In S1, measure position F i is the position of the ship's strong rib, measuring position F i Including every strong rib position, or selecting according to intervals of 1 to 3 strong rib positions.

5. The method for calculating the ship baseline for surveying freeboard and draft markings according to claim 2, characterized in that: In S7, referring to formula d, a calculation table was prepared using EXCEL software, and data was entered and calculated step by step to obtain the d value.

6. A method for calculating a ship baseline for surveying freeboard and draft markings according to claim 3, characterized in that: The S2 specifically includes the following steps: S21. Selecting a baseline X as a baseline measurement; S22.Measure F1, F2...F i The height values ​​h1, h2...h of the outer surface of the ship's outer plate at each position from the measurement reference line X i ; S23. Taking the theoretical baseline M of the ship in the design state as the reference line, the distance between the measurement baseline X and the theoretical baseline M is calculated as a constant value f; S24. From the hull structure diagram, find F1, F2...F i The thickness of the flat keel corresponding to each position is t1, t2...t i ; S25. Calculate the height difference Z between the actual position of the hull plate keel and the theoretical baseline M i , the calculation formula is as follows: Z i =h i +t i -f。 7. A method for calculating a ship baseline for surveying freeboard and draft markings according to claim 6, characterized in that: In S22, the measurements F1, F2, ... F i The height value of the outer surface of the ship's outer plate at each position from the measurement reference line X can be measured by a laser total station or other methods capable of measuring distance.

8. A method for calculating a ship baseline for surveying freeboard and draft markings according to claim 4, characterized in that: In S1, the reference line X is any assumed horizontal plane lower than the outer plating of the hull.

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