CB/T 3688-1995 Technical requirements for repair of marine windlasses and anchor capstans
Some standard content:
Shipbuilding Industry Standard of the People's Republic of China
CB/T3688—1995
Technical requirements for the repair of marine anchor winches and anchor capstans, issued on June 19, 1995
Issued by China State Shipbuilding Corporation
Implemented on April 1, 1996
Shipbuilding Industry Standard of the People's Republic of China
Technical requirements for the repair of marine anchor winches and anchor capstans 1 Subject content and scope of application
CB/T3688-1995
Classification number: R32
This standard specifies the technical requirements for the inspection, repair, replacement of parts, installation and test acceptance of marine anchor winches and anchor capstans (hereinafter referred to as anchor winches).
This standard applies to electric, hydraulic, steam or externally driven anchor winches for steel seagoing vessels, and can also be used as a reference for other types of ships. 2 Reference standards
GB1095—79
Cross-sectional dimensions of flat keys and keyways
Type dimensions of ordinary flat keys
GB1096—79
GB1097—79
GB 1144—87
GB1184—80
GB1563--79
GB1565—79
Type dimensions of guide flat keys
Dimensions, tolerances and inspections of rectangular splines
Shape and position tolerances Provisions for unmarked tolerances Sectional dimensions of wedge keys and keyways
Type dimensions of hook wedge keys
GB10089—88
Precision of cylindrical worms and worm wheels
GB10095-88
Precision of involute cylindrical gears
GB11365—89
Precision of bevel gears and hypoid gears
ZB/TR32003-90 Technical requirements for repair of marine hydraulic components CB*3179—84
Anchor chain wheel
JT4061～4084—65 Technical standards for repair of marine steam engines 3 Inspection
3.1 Operation inspection
Inspect the operation and working condition of the windlass before dismantling and keep records. The inspection contents are as follows: a. Check whether the anchor chain wheel has any chain slip, chain jumping or jamming, and the working condition of the cable drum or capstan; b. Check the sealing condition of the reduction box and whether there are any abnormal noises and vibrations in the box; Check the meshing condition of the open gears and whether there are any vibrations and abnormal noises; c. Check whether the clutch and brake devices are flexible and reliable in operation: e. Check the bearing temperature; f. For winches with human-powered drive mechanisms, check whether the check valve has good contact and works flexibly and reliably. 3.2 Disassembly inspection
3.2.1 The clearance inspection before disassembly includes the following contents: a.
Measure the clearance between the anchor chain wheel bushing and the shaft, the capstan body bushing and the support shaft. If it exceeds 2.5 times the maximum installation clearance, it should be repaired. Measure the clearance of each bearing. If it exceeds 2 times the maximum installation clearance, it should be repaired: b.
China State Shipbuilding Corporation approved on June 19, 1995 and implemented on April 1, 1996
CB/T3688—1995
c. Measure the side clearance of the gear. If it exceeds 2 times the maximum installation clearance, it should be repaired. 3.2.2 Check the wear, rust, cracks, deformation and damage on the working surface of the anchor chain wheel, cable drum or capstan, tooth clutch and check valve.
3.2.3 For the sprocket shaft, cable drum shaft, support shaft, center shaft and crank shaft, the following inspections should be carried out: a. Check the shaft for wear, rust, cracks, bending deformation and damage; b.
For keyways, check whether the key and keyway are damaged and whether the fit is good; c. Measure the roundness and cylindricity of each main working shaft neck. If it exceeds 2.5 times the installation value, it should be repaired. 3.2.4 The following inspections should be conducted on gears, worm wheels and worms: a. Check the wear and rust of the tooth surface and whether there are pitting, depressions, cracks and other damages; check the rust of the wheel rim, spokes and hub and whether there are cracks and damages b.
c. Check whether the worm has bending deformation and the wear and rust of the working shaft neck; d. Check the tooth thickness of the gear on the pitch circle. The maximum allowable wear amount is: 15% of the original tooth thickness for parallel gears; 10% of the original tooth thickness for closed gears, and 15% of the original tooth thickness for worm wheels and worms; if it is proven to be safe and reliable after strength verification, it is allowed to exceed this limit. 3.2.5 The following inspections should be conducted on bearings:
a. Check whether there are scratches, pitting, depressions, cracks, burns and other defects on the working surface of the sliding bearing. The outer circle of the bearing bushing should be in good contact with the bearing seat hole. Use a 0.05mm feeler gauge to check that it cannot be inserted; b. Check the inner and outer bearing rings and balls (rollers) of the rolling bearings for wear, rust, pitting, cracks, depressions, burns and other defects, and whether the rotation is flexible and stable.
3.2.6 Check the wear, rust and damage of the brake device. When the rivets that fix the brake pads are exposed on the friction surface, the pads must be replaced.
3.2.7 Check the reducer body and sealing surface for rust, cracks, obvious deformation and damage. 3.2.8 Check the rust and damage of the bearing bracket, base and base bolts. When the base is worn to 25% of the original thickness, it should be replaced or strengthened. When the base bolts and nuts are seriously worn, they should be replaced. 3.2.9 The inspection of hydraulic components shall be in accordance with the provisions of ZB/TR32003. 3.2.10 The inspection of steam prime mover parts shall be in accordance with the provisions of JT4061~4084. 4 Repair
4.1 Anchor sprocket, cable drum or capstanWww.bzxZ.net
Wear, rust, cracks and other defects on the working surface of the anchor sprocket, cable drum or capstan can be repaired by welding. 4.2 Tooth clutch
4.2.1 Wear, cracks, deformation, damage and other defects of the tooth can be repaired by welding. The repair technical requirements are as follows: a. The tooth index angle (tooth socket center angle plus tooth center angle) is allowed to be ±10°; b. The tooth socket center angle is 1°~2° greater than the tooth center angle; c. The tooth working surface roughness Ra≤3.2μm. 4.2.2. The shaft hole repair technical requirements are as follows: a. The shaft hole size tolerance is H9; the surface roughness R.≤3.2μm; the cylindricity is in accordance with the 8th grade accuracy in GB1184; b. The guide keyway size tolerance is in accordance with the provisions of GB1095; c. The internal spline size tolerance is in accordance with the provisions of GB1144. 4.3 The repair of sprocket shafts, cable shafts, support shafts, center shafts, and crankshafts shall meet the following requirements: a. For defects such as rust, cracks, and damage on the surface of non-working journals, those with shallow depths can be manually trimmed and the remaining traces should be smoothed, and those with deeper depths should be strength checked;
b. For defects such as wear, rust, and damage on the surface of working journals, those with deeper depths should be strength checked. When the strength check meets the requirements, chrome plating, iron plating, spraying, and other methods can be used for repair; 2
Technical requirements for processing working journals are shown in Table 1
Dimensional deviation
Shaft diameter
>50~80
>80~120
>120～180
>180～250|| tt||Match with winch
Match with gear
CB/T3688-1995
Match with sliding bearing
Cylindricity
Radial runout
Surface roughness R.
The keyway of the winch shaft shall comply with the provisions of GB1095 when installed with a flat key and with the provisions of GB1565 when installed with a hook key. The symmetry of the keyway d.
to the center line of the shaft shall comply with the 8th grade accuracy in GB1184; the perpendicularity of the end face of the capstan support shaft to the axis shall comply with the 7th grade accuracy in GB1184, and the radial runout of each matching journal shall comply with the 8th grade accuracy in GB1184;
The geometric tolerance of the center axis of the capstan shall comply with Table 2.
Tolerance name
Radial runout of each matching journal surface
End runout of bottom plane
Verticality of pin hole centerline to bottom surface
Deviation of pin hole spacing
Cumulative deviation of pin hole spacing
4.4 Gear, worm wheel, worm
Difference, mm
According to GB1184 8th grade accuracy
According to GB1184 7th grade accuracy
According to GB1184 6th grade accuracy
According to GB1095 8th grade accuracy Tooth pitch limit deviation provisions According to GB1095 8th grade accuracy Tooth pitch cumulative tolerance provisions 4.4.1 Wear of steel gears can be repaired by surfacing welding and then processing, cracks can be repaired by opening a U-shaped groove to remove the defects and then welding repair methods, and single tooth breakage can be repaired by welding embedded teeth or welding repair methods. 4.4.2 The processing technical requirements for gears, worm wheels and worms are shown in Table 3. Table 3
Parts name
Pin gear housing
Technical requirements
The verticality of the center line of the pin hole to the bottom surface shall be in accordance with the 6th grade accuracy in GB1184; the coaxiality of each matching circle surface shall be in accordance with the 8th grade accuracy in GB1184; the roundness and cylindricity of each matching circle surface shall be in accordance with the 8th grade accuracy in GB1184; the parallelism of the two end faces shall be in accordance with the 7th grade accuracy in GB1184; the pin hole spacing deviation shall be in accordance with the 8th grade accuracy in GB10095. Provisions; The cumulative deviation of the pin hole spacing shall comply with the cumulative tolerance of the 8th grade precision pitch in GB10095. The radial deviation of the pin hole centerline shall comply with the radial runout tolerance of the 8th grade precision gear ring in GB10095. 3
Part name
Cycloidal gear
Cylindrical gear
Bevel gear
Worm gear ring
Worm gear hub
Worm gear shaft
CB/T3688—1995||tt ||Continued Table 3
Technical requirements
Parallelism of both end faces shall be in accordance with the 7th grade precision in GB1184; Pin hole spacing deviation shall be in accordance with the 8th grade precision pitch limit deviation in GB10095; Cumulative deviation of pin hole spacing shall be in accordance with the 8th grade precision pitch cumulative tolerance in GB10095; Radial deviation of pin hole centerline shall be in accordance with the 8th grade precision gear ring radial runout tolerance in GB10095; Gear machining accuracy: Open gear shall be in accordance with 10-9-9 (IGB10 095
（E：）GB10095）
【Open gears of steam windlass shall be in accordance with 10-11-11】E.
Closed gears shall be in accordance with 9-9-8
GB10095
The symmetry of keyway to centerline of hole shall be in accordance with Grade 8 precision in GB1184; the roundness and cylindricity of shaft hole shall be in accordance with Grade 8 precision in GB1184; the runout of hub end face shall be in accordance with Grade 8 precision in GB1184; the gear processing precision shall be in accordance with 8!
GB11365;
The symmetry of the keyway to the centerline of the hole shall be in accordance with the 8th grade accuracy of GB1184; the degree and cylindricity of the hub hole shall be in accordance with the 8th grade accuracy of GB1184. The processing accuracy of the worm gear shall be in accordance with 8 ()
GB10089
[The processing accuracy of the worm gear of the steam windlass shall be in accordance with 9IGB100897
The perpendicularity of the end face matching with the hub to the centerline of the hole shall be in accordance with the 8th grade accuracy of GB1184; the roundness and cylindricity of the inner hole of the gear ring shall be in accordance with the 8th grade accuracy of GB1184; the radial runout of the tooth top circle to the centerline of the hole shall be in accordance with the 8th grade accuracy of GB1184; the end face runout shall be in accordance with the 8th grade accuracy of GB1184
The roundness and cylindricity of the shaft hole shall be in accordance with GB1184. The roundness and cylindricity of the hub outer circle shall be in accordance with the 8th grade accuracy of GB1184; the perpendicularity of the end face of the gear ring to the center line of the shaft hole shall be in accordance with the 8th grade accuracy of GB1184. The roundness and cylindricity of the journal shall be in accordance with the 8th grade accuracy of GB1184. The processing accuracy of the worm shall be in accordance with 8 ()
E|GB10089;
［The processing accuracy of the worm of the steam windlass shall be in accordance with 9 ((E:)GB10089)
The roundness and cylindricity of the journal shall be in accordance with the 8th grade accuracy of GB1184; the radial runout of the tooth circle to the journal shall be in accordance with the 8th grade accuracy of GB1184; the end face runout of the journal shoulder shall be in accordance with the 8th grade accuracy of GB1184. Note: In the table, E is the upper deviation of the tooth thickness, and E is the lower deviation of the tooth thickness. 4.4.3 The technical requirements for the processing of the shaft hole of the gear or worm wheel are shown in Table 4. Aperture
>50～80
>80～120
>120～180
>180～250
>250～315
Dimension deviation
CB/T3688--1995
Roundness, cylindricity
4.4.4 The keyway machining of gear or worm wheel shall comply with the provisions of GB1095. 4.4.5 The symmetry of keyway to the center line of shaft hole shall comply with the 8th grade accuracy in GB1184. 4.4.6 The rust, cracks and damage of wheel rim, spoke, hub and hub keyway shall be repaired by welding. 4.5 Gearbox body
Surface roughness R.
Leakage caused by defects in the reduction gearbox joint surface can be repaired by scraping or machining. The repair technical requirements are as follows: 4.5.1
a.. Flatness is not greater than the 8th grade accuracy in GB1184; b.
Surface roughness R≤3.2um;
The contact area of the color inspection should reach no less than one spot per 10mm×10mm. ·Cracks or local leakage in the reduction gearbox housing can be repaired by welding, metal buckling or bonding. 4.5.3
Deformation and misalignment of the reduction gearbox bearing seat hole can be repaired by the hole method, and sleeves can be inserted if necessary. The repair technical requirements are specified in Tables 5 and 6. Table 5
Bearing seat aperture
>50～80
>80～120
>120～180
>180～250
Bearing bracket
Coaxiality with common axis
Bearing seat hole center distance
≤250
>250～315
>315～400
>400～ 500
>500～630
Verticality of the centerline of the two ends to the shaft hole
Parallelism of the centerlines of the two bearing seat holes
Roundness, cylindricity
Dimensional deviation of center distance
Surface roughness R.
CB/T3688-1995
4.6.1 The roundness and cylindricity of the bearing seat hole shall be in accordance with the 8th grade accuracy in GB1184. 4.6.2 The parallelism of the centerline of the bearing seat hole to the mounting plane shall be in accordance with the 8th grade accuracy in GB1184. 4.7 Hydraulic components
The repair of hydraulic components shall be in accordance with the provisions of ZB/TR32003. 4.8 Steam prime mover parts
The repair of steam prime mover parts shall be in accordance with the provisions of JT4061～4084. 5 Technical requirements for replacement of main parts of anchor winch
5.1 Materials
Material and heat treatment requirements of main parts shall be selected according to Table 7. Other materials may be used as substitutes without reducing strength or meeting the requirements of relevant classification society rules.
Part name
Anchor chain wheel,
Cable drum
Tooth clutch
Worm gear ring
Worm gear hub
Gray cast iron
High-quality carbon structural steel
High-quality carbon structural steel
Alloy structural steel| |tt||Cast copper alloy
Gray cast iron
ZG230-450
ZG260-520C
ZG310-570
ZG250-520C
ZG260-520C
ZG310-570
ZG340-640
-ZCuSn10Zn2
ZCuSn10Pb1
ZCuAl10Fe3
ZCuA19Mn2
HT 200, HT 250.
ZG230-450
ZG260-520C
Standard No.
GB9439—88
CB772—88
GB 699—88
CB772—88
GB699—88
CB 772-88
GB3077—88
GB1176—87
GB9439-88
GB5676—85
Heat treatment
Aging treatment
Annealing treatment
Quenching and tempering treatment
Aging treatment
Annealing treatment
HB,N/mm2
≤1834
1530~2128
1402~1932
≤1834
1529~2128
1931~2803
1402~1932
1597~1 931
1754~2030
2362~2803
686~883
785~980
≥980
≥834
Parts name
Anchor chain wheel, gear shaft, crank
Shaft, center shaft, cable drum shaft
Support shaft
Crank Pin
Crank plate
Sliding bearing,
Bearing bushing
Bearing bracket,
Brake pad
High-quality carbon structural steel
Alloy structural steel
High-quality carbon structural steel
High-quality carbon structural steel
Gray cast iron
Cast copper alloy
Gray cast iron
High-quality carbon Plain structural steel
Carbon structural steel
Asbestos brake lining
CB/T3688—1995
Continued Table 7
ZG260-520C
ZCuAl10Fe3
ZCuA19Mn2
ZCuSn10Zn2
ZCuSn10Pb1
ZCuZn38Mn2Pb2
HT200,HT250
ZG230-—450
Q255-A.Q275-A||tt ||Standard number
GB699—88
GB3077—88
GB699—88
CB772—88
GB 699—88
GB9439--88
GB1176—87
GB9434--88
CB 772—88
GB 699—88
GB700—88
JG48—61
Heat treatment
Quenching and tempering + tooth surface quenching
Quenching and tempering + tooth surface quenching
Quenching and tempering + surface quenching
Aging treatment
Aging treatment
Annealing treatment
HB,N/mm2
≤2030
[38~45
2128~2501
2363~2805
≤18 34
1589~2128
1402~1932
1589~2128
Note: It is recommended that large and small gears be made of different grades of steel. If the same grade of steel is used, different heat treatments are required. The hardness difference between the large and small gears with soft tooth surface and straight teeth is HB20~25; the hardness difference between the large and small gears with soft tooth surface and helical teeth and herringbone teeth is HB40~50b.
The surface of the forging should not have defects such as interlayer, folding, cracks, scars, slag inclusions, dense hairline and overburning. It is allowed to repair defects without reducing strength; e
Repair.
The casting surface should not have defects such as cracks, shrinkage holes, looseness, etc. that affect the quality. It is allowed to make corrections to the defects without reducing the strength. 5.2 Anchor chain wheel
The dimensional tolerance and geometric tolerance of the anchor chain wheel shall comply with the provisions of Chapter 5 of CB*3179. The dimensional tolerance of the hole matching the bushing shall be H8, the cylindricity shall comply with the 8th grade accuracy in GB1184, and the surface roughness R≤3.2μm. 5.3 Cable drum
The cable drum shall meet the following requirements:
The technical requirements for the keyway of the cable drum are shown in 4.3d;
The technical requirements for the machining of the shaft hole of the cable drum are shown in Table 8. Aperture
>50～80
>80～120
>120~180
>180～250
>250～315
>315～400
5.4 Capstan body and capstan cover
Dimensional deviation
The capstan body and capstan cover shall meet the following requirements: a.
CB/T3688--1995
Coaxiality of the shaft holes at both ends
Roundness and cylindricity of the shaft holes
The roundness and cylindricity of the surfaces of the matching shaft holes shall be in accordance with the 9th grade accuracy in GB1184; the perpendicularity of the combined end face to the axis shall be in accordance with the 8th grade accuracy in GB1184. b.
5.5.1 The processing technical requirements for the working journals of the sprocket shaft, cable drum shaft and crank shaft shall comply with 4.3 c and d. 5.5.2 The processing technical requirements for the support shaft of the winch shall comply with 4.3 c, d and e. 5.5.3 The processing technical requirements for the center shaft of the winch shall comply with 4.3 c, d and f. 5.6 Bearing bracket seat hole, reducer seat hole and bearing bushing 5.6.1 The processing technical requirements for the bearing bracket seat hole shall comply with 4.6. 5.6.2 The processing technical requirements for the reducer seat hole are shown in Table 5 and Table 6. 5.6.3 Bearing bushing
The bearing bushing shall meet the following requirements:
The processing technical requirements for the bearing bracket and reducer bushing are shown in Table 9. mm
Surface roughness
The inner hole size tolerance of the anchor chain wheel bushing shall comply with H9, and the surface roughness R≤3.2um. The outer circle dimension tolerance of the anchor chain wheel bushing is in accordance with S6, Table B.
Surface roughness R≤1.6m.
Shaft hole diameter
>50～80
>80～120
>120～180
>180～250
>250～400
Tooth clutch
Cylindricity of inner and outer circle surfaces
Tooth clutch processing technical requirements are in accordance with Article 4.2. 5.8 Gear, worm wheel, worm
Gear, worm wheel, worm processing technical requirements are as follows: Gear processing technical requirements are shown in Table 3;
Gear or worm wheel shaft hole processing technical requirements are shown in Article 4.4.3. The verticality of the center line of the two ends facing the shaft hole
The parallelism of the center line of the two split faces facing the shaft hole
5.9 Braking device
CB/T3688-1995
The rivet head of the riveted brake pad should be embedded in the pad by no less than 30% of the pad thickness. 5.10 Hydraulic components
The replacement of hydraulic components shall comply with the provisions of ZB/TR32003. 5.11 Steam engine parts
The replacement of steam engine parts shall comply with the provisions of JT4061~4084. 6 Windlass installation
6.1 The radial assembly clearance of the anchor chain wheel shaft, cable shaft, crankshaft and bracket bearing is 0.0010~0.0015 times the journal diameter, and the axial clearance is 0.5~1.0mm.
6.2 The radial assembly clearance between the sprocket shaft or support shaft and the sprocket bushing is 0.001 times the journal diameter plus 0.15~0.20mm. The axial clearance is 0.5~1.0mm.
6.3 The contact angle between the sprocket shaft, cable drum shaft, crank shaft and the bearing surface should be within 45° on both sides of the bearing center line, and the contact should be uniform.
6.4 The inner hole of the sprocket and the bushing should match H8/s6, and the bushing and the shaft should match H9/f9. 6.5 The outer circle of the bearing bushing should be in good contact with its seat hole. After assembly, check with a 0.05mm feeler gauge and it should not be inserted. 6.6 The match between the cable drum shaft hole and the shaft should be in accordance with Js8/h7. 6.7 The match between the cable drum key and the keyway should be in accordance with the provisions of GB1095 when installed with a flat key; and in accordance with the provisions of GB1565 when installed with a hook key. 6.8 The tooth side clearance shall comply with the following provisions:
a. 24Aum for open gears;
b. 12/Aμm for closed gears and worm wheels. Where: A is the center distance of the gear pair, in mm. 6.9 The limit deviation of the center distance of the worm pair, the limit deviation of the intermediate plane of the worm pair and the limit deviation of the angle of intersection of the worm pair shafts shall comply with the provisions of GB10089.
6.10 The fit between the hub and the gear ring of the combined gear or worm wheel shall comply with the following provisions; a. When the H7/n6 fit is adopted, there shall be no less than 50% of the total number of tight fitting bolts in the connecting bolts, and the fit shall be H7/k6. . When the H7/6 fit is adopted, a set screw shall be added after assembly. 6.11 After the two bearing frames are installed on the machine base, the coaxiality of each corresponding bearing hole to its common axis shall be in accordance with the 8th grade accuracy in GB1184. 6.12 The fit between the gear and the shaft shall be H7/k6.
6.13 After running-in, the contact spots of the gear pair shall be in accordance with the provisions of Table 10, and the distribution position of the contact spots shall be close to the middle of the tooth surface. Contact spots are not allowed to appear at the tooth top and the edge of the tooth end. Table 10
Accuracy grade
Along the tooth height direction
Contact area
Along the tooth length direction
Cylindrical gear
Note: ①The values in brackets are used for helical gears with axial overlap greater than 0.8. Closed
Bevel gear
Worm wheel, worm
②For bevel gears, the value range in the table is used for gears with modified tooth surfaces. For gears without modified tooth surfaces, the percentage value of the contact spots should not be less than the average value.
③For worm transmissions with modified tooth surfaces for worm wheels and worms, the contact spot requirements may not be restricted by this provision. 6.14 The tooth clutch shall meet the following requirements: CB/T 3688--1995
a: The fit between the tooth clutch shaft hole and the shaft shall be in accordance with H9/d9, and the fit between the guide key and the keyway shall be in accordance with the provisions of GB1097 and GB1095; b. The number of teeth in contact with the tooth clutch at the same time shall not be less than half of the total number of teeth, and the operation shall be flexible and reliable. 6.15 The contact area between the brake pad and the brake wheel of the brake device shall not be less than 75% of the total area. 6.16 The fit between the crank pin and the crank plate shall be in accordance with H7/u6. 6.17. The fit between the crankshaft and the crank plate: When the journal is not larger than 100mm, it shall be in accordance with H7/r6; when the journal is larger than 100mm, it shall be in accordance with H7/s6. After installation, the end face runout of the crank plate shall not be greater than 0.05mm, and the crank angle deviation shall not exceed ±1°. 7 Test acceptance
7.1 Mooring test
7.1.1 Running-in test
During the running-in test, the windlass must run continuously at no load for 30 minutes at a speed not lower than the nominal speed, and 15 minutes for each turn. After the above test, it should be run at other gears as soon as possible, with 5 minutes for each gear and each turn. 7.1.2 During the test, the following inspections or measurements should be carried out: a. Oil seal condition;
b. Bearing temperature;
c. Whether there is any abnormal sound.
7.2 Anchoring and releasing test
During the test, all components should work smoothly, flexibly and reliably; there should be no chain jumping, chain slipping and jamming when the anchor chain passes through the sprocket. 7.3 Navigation test
7.3.1 Anchoring test
During the test, the anchor chain should move smoothly when passing through the sprocket. During the anchoring process, the brake should be tested 2 to 3 times and the brake should work reliably. 7.3.2 Anchoring test
After the anchor breaks the ground, the average anchoring speed should be no less than 9m/min. All moving parts should work smoothly, and the operating mechanism should work flexibly and reliably. Additional remarks:
This standard was proposed by the Ship Repair Sub-Technical Committee of the National Technical Committee for Standardization of Marine Ships. This standard is under the jurisdiction of Tianjin Ship Repair Technology Research Institute. This standard was drafted by Tianjin Xingang Shipyard. The main persons in charge of this standard are Wang Huiqin, Zhang Xinsheng, and Wang Fuhong.
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