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Shipbuilding Industry Standard of the People's Republic of China
CB/T 3767—1996
Test Method for Speed Measurement of Seagoing Vessels
Published on September 3, 1996
Published by China State Shipbuilding Corporation
Implemented on April 1, 1997
Shipbuilding Industry Standard of the People's Republic of China
Test Method for Speed Measurement of Seagoing Vessels
1 Subject Content and Scope of Application
CB/T3767-1996
Classification Number: U/O
This standard specifies the method for measuring the sea trial speed of seagoing vessels using the overlapping mark method and the global positioning system (GPS) device. This standard applies to newly built or repaired civilian seagoing vessels. 2 General Requirements
2.1 The test equipment and instruments used in the speed measurement test should have valid certificates. 2.2 Corrections for the effect of shallow water on the speed should be made when necessary. 2.3 Reliable communication tools should be provided during the speed test to ensure that all test items are carried out simultaneously. 2.4 During the speed test, various test records should be kept and a test result report should be compiled after the test. 3 Speed test conditions
3.1 Ship status
3.1.1 Liquid cargo ships should generally be in the design loading state, and other ships can be in the ballast state for speed measurement. 3.1.2 The underwater part of the hull and the propeller surface are in a clean state. 3.2 Test sea area
3.2.1 The water depth of the speed measurement area should meet the requirements of formula (1). h>5.52dV/ L
Where: h-
Water depth of the test area, m;
-Design draft, m
-Maximum speed expected to be achieved in the test, kn; Lp-Length between perpendiculars, m.
3.2.2 The test sea area should have sufficient navigation aid distance and room for maneuver. 3.3 Weather and sea conditions
During the test, the wind force is required to be no greater than Beaufort 4, the waves are required to be no more than level 2, and the tidal current is required to be stable. The visibility in the speed measurement area is good. 4 Speed measurement conditions and status
(1)
4.1 The speed measurement conditions must include a large power range. Usually, the speed measurement conditions are 50%, 75%, 90%, and 100% of the power corresponding to the rated speed of the main engine.
4.2 Each voyage under the same operating condition should be carried out continuously. It is best to conduct three single-trip tests for each operating condition using the overlapping standard method to calculate the average speed. 4.3 The following test data should be recorded during speed measurement: a. Record the name, location and date of the test ship; b. Read the water gauge mark on a small boat and record the left and right draft of the ship; c. Use an anemometer to measure and record the wind direction and wind speed; d. Record the water depth and seawater density in the speed measurement area; China State Shipbuilding Corporation approved on September 3, 1996 and implemented on April 1, 1997
GB/T3767-1996
e. Record the compass heading and flow direction of each voyage; f. Continuously record the speed and shaft power after the start of speed measurement. 5 Speed measurement method
5.1 Speed measurement method with overlapping markers
5.1.1 Speed measurement operation essentials
5.1.1.1 Each voyage must maintain a compass heading orthogonal to the marker position and sail on the same speed measurement line as much as possible. 5.1.1.2 When operating in the speed measurement area, the ship must maintain the stability of the main engine speed within the speed measurement line, and at the same time, the power should be minimized (the maximum power angle should not exceed 5°). After the speed is stable, the speed measurement can be started. 5.1.2 Speed measurement procedure and calculation formula
5.1.2.1 The running time, that is, the time to sail through the stake distance (speed measurement line length) in each voyage, should be calculated according to formula (2) to take the average of the stopwatch readings at three independent observation points.
Where: t-
Running time, s
The first stopwatch records the time, s
The second stopwatch records the time, s;
The third stopwatch records the time, s.
t=i+t+t
5.1.2.2 The speed within the mark distance of the corresponding voyage shall be calculated according to formula (3): V,==×3600
Wherein: V—speed, kn,
marking time, s;
marking distance, n; mile
5.1.2.3 The average speed of the ship on the speed measurement line shall be calculated according to formula (4) and formula (5): V=V+v
Second speed measurement:
Third speed measurement:
Wherein: V—average speed, kn;
V,—first one-way speed, kn;
V—second one-way speed, kn;
V.—third one-way speed, kn.
5.1.3 Speed measurement record and calculation table
V= V+ 2V, +V
Speed measurement record and calculation table are in accordance with Appendix A (Supplement) Table A1. 5.2 GPS speed measurement method
5.2.1 Speed measurement operation instructions
5.2.1.1 Before the start of the speed measurement test, the GPS receiver must be approved by the shipowner and the relevant authorized agency and be in working condition. (2)
(3)
(4)
(5)
5.2.1.2 Keep the ship sailing in a straight line at a constant speed, control the angle between the track angle and the heading so that it does not exceed 5°, and start speed measurement after the speed stabilizes.
5.2.2 Speed measurement procedure and calculation formula
5.2.2.1 Start speed measurement, use GPS to print 5 ship positions continuously at intervals of 20s, and obtain: Pi, P2, Ps, P, Ps and t1, t2, t3, t4, ts data. Where P; is the ship position expressed in longitude and latitude; t; is the specific time of measurement. 2
GB/T3767-1996
5.2.2.2 Sail for 10min or 5min, as required. 5.2.2.3 Then let the GPS receiver continuously print 5 corresponding ship positions at intervals of 20s, and obtain Pi, P2, Ps, P, Ps and t, t2, tt, t data. Where P; is the ship position expressed in longitude and latitude t: is the specific time of measurement. Note: The ship position expressed in longitude and latitude is automatically converted into sailing distance by GPS. 5.2.2.4 Calculate the speed of each section according to formula (6): V = As;/At;
Where: V Calculate the speed in each speed measurement section, kn; As; Navigation distance, nmile;
At; Time interval, min. Www.bzxZ.net
5.2.2.5 Calculate the average speed of the sea trial according to formula (7): Where: V-average speed, kn;
V Calculate the speed in each speed measurement section, kn.
5.2.2.6 Processing of unreliable data
·(6)
If any of V, V2, V3, V, Vs differs from the average speed V by more than 5%, it shall be discarded and the average of the remaining speeds shall be taken as the speed.
5.2.3 Number of speed measurements
Measure once for each round trip according to the speed measurement procedure in 5.2.2. 5.2.4 Speed measurement record table and calculation summary table
Speed measurement record table and calculation summary table are shown in Appendix A (Supplement) Table A2 and Table A3 respectively. A1 Speed measurement record and calculation table of overlapping marker method are shown in Table A1. Ship
Test date
Stake distance
n mile
GB/T3767--1996
Appendix A
Test report and record table
(Supplement)
Marrow draft
Ship draft
Running time
Average speed
Shallow water correction
Tester:
Touching draft
Seawater density
Shaft power
A2 Speed measurement record and calculation summary table of GPS speed measurement method are shown in Table A2 and Table A3 respectively. Table A2
Note: 1) There are 10 positions in total, including the first 5 positions printed by GPS and the last 5 positions printed. The distances between positions 1 and 6, 2 and 7, 3 and 8, 4 and 9, and 5 and 10 are called segment numbers.
Additional notes:
Test date
Shaft power
GB/T3767-1996
Marrow draft
Kun draft
GPS speed
Average speed
This standard was proposed by the National Technical Committee for Standardization of Marine Ships. This standard is under the jurisdiction of Shanghai Ship Research and Design Institute. This standard was drafted by Dalian Ship Design and Research Institute. The main drafter of this standard is Ma Yande.
Shallow water correction
Tester:
Draught
Seawater density
Air conditions in the navigation area during the test
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