1、BRITISH STANDARD MARINE SERIES BS MA 41:1975 Incorporating Amendment No.1 Specification for Two tonne general purpose davits UDC629.125.65 * 2tBSMA41:1975 This BritishStandard, having been approved by the Shipbuildingand Marine IndustryStandards Committee, was published under the authorityof the Exe
2、cutive Boardon 30 September1975 BSI02-2000 The following BSI references relate to the work on this standard: Committee reference SME/2 Draft for comment73/33795DC ISBN 0 580 08794 8 Foreword This BritishStandard has been prepared under the authority of the Shipbuilding and Marine Industry Standards
3、Committee and is based on a proposal of the British Ship Research Association. Certification. Attention is drawn to the certification facilities described on the inside back cover of this standard. A British Standard does not purport to include all the necessary provisions of a contract. Users of Br
4、itish Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1to8, an inside back cover and a back cover.
5、This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue Comments 2051 June1976 Indicated by a sideline in the marginBSMA41:1975 BS
6、I 02-2000 i Contents Page Foreword Inside front cover 1 Scope 1 2 References 1 3 Shapes and dimensions 1 4 Materials 1 5 Quality of manufacture and finish 1 6 Inspection and tests 1 7 Marking 2 Figure 1 Arrangement of2 tonne SWL general purpose davit 3 Figure 2 Details of jib (drawn for 1500 nominal
7、 size) 4 Figure 3 Details of stool 5 Figure 4 Details of upper bearing 6 Figure 5 Details of lower bearing 7 Figure 6 Details of jib foot and locking plate 8 Table 1 Components and materials 2ii blankBSMA41:1975 BSI 02-2000 1 NOTEUsers of this BritishStandard, Marine Series, should note that while o
8、bserving the requirements of the standard they should at the same time ensure compliance with such statutory requirements, rules and regulations as may be applicable to the individual ship concerned. 1 Scope 1.1 This BritishStandard provides a specification for a general purpose davit with a safe wo
9、rking load of2tonnes and outreaches of1500mm and2250mm. NOTE 1These davits are not intended for use with life saving appliances. NOTE 2The shipbuilder shall ensure that the deck structure in the region of the davit is adequate to withstand the loading expected to be imposed. 2 References This standa
10、rd makes reference to the following BritishStandards. BS MA10, Oval eyeplates. BS MA11, Horncleats. BS499, Welding terms and symbols Part2:Symbols for welding. BS1134, Method for the assessment of surface texture Part1: Method and instrumentation. BS3601, Steel pipes and tubes for pressure purposes:
11、 carbon steel with specified room temperature properties. BS4168, Hexagon socket screws and wrench keys metric series. BS4190, ISO metric black hexagon bolts, screws and nuts. BS4320, Metal washers for general engineering purposes. BS4360, Weldable structural steels. BS4464, Spring washers for gener
12、al engineering and automobile purposes. Metric series. BS4929, Steel hexagon prevailing-torque type nuts Part1: Metric series. BS5135, Metal-arc welding of carbon and carbon manganese steels. 3 Shapes and dimensions 3.1 The davits shall be of the shape and dimensions shown in Figure 1, Figure 2, Fig
13、ure 3, Figure 4, Figure 5 and Figure 6. 3.2 The nominal sizes of the davits shall be designated by reference to outreach in millimetres and are1500 and2250. NOTEThe welding symbols used in the Figure 1 to Figure 6 are in accordance with BS449-2 but the associated dimensions are expressed in terms of
14、 weld throat thickness and NOT leg length. 4 Materials 4.1 The materials used shall be in accordance with Table 1. Other materials may be used provided they are at least as suitable in all respects for the intended duty and are equally acceptable to the purchaser. 5 Quality of manufacture and finish
15、 5.1 The davit shall be of fabricated steel construction comprising the davit jib and support stool (seeFigure 1). 5.2 The welding of the component parts of the davit shall be properly carried out by an experienced operator in accordance with BS5135. 5.3 The jib shall be of “H” section, the web cut
16、to shape from plate and the flanges attached by continuous welding. The foot beating, upper bearing support plate, horncleat, lifting and slewing eyeplates shall be fitted and attached as shown in Figure 2. The jib on completion shall be free from any distortion. 5.4 The support stool shall be made
17、from plate cut rolled and longitudinally welded and fitted with bottom bearing support plate and other fittings as shown in Figure 3. The circularity of the inside diameter of the stool shall be controlled to within 2mm and any internal weld beading shall be ground smooth in way of the top bearing s
18、urface. Alternatively, the stool may be fabricated from nominal size450steel tube(12.5mm wall thickness) complying with the requirements of BS3601. The bottom edge of the stool to be shaped to accommodate the deck camber or sheer. 5.5 The upper bearing plate with bearing pads and the cylindrical foo
19、t shall be made in accordance with details shown in Figure 4, Figure 5 and Figure 6. Machining symbols are in accordance with BS1134-1. 5.6 The davit assembly shall be free from sharp edges and any visible faults likely to be detrimental to its intended duty. All welds shall be smooth and free from
20、undercut or other irregularities. 5.7 After completion, the davit shall be given an anti-corrosive protective finish on all internal and external surfaces with the exception of bearing surfaces. 6 Inspection and tests 6.1 The assembled and completed davit shall be checked for initial lubrication of
21、the lower bearing and the whole assembly visually inspected for any defects. It shall be demonstrated that the unloaded davit operates in a satisfactory manner before delivery to the ship and after installation on board ship. BSMA41:1975 2 BSI 02-2000 Table 1 Components and materials 6.2 After insta
22、llation on board ship a proof load and safe working load (SWL) test shall be carried out in the presence of a representative of the inspecting authorities. The test shall be carried out as follows: a) the davit shall be fitted with a certified2 tonne SWL lifting block and tackle; b) a proof load of2
23、5% in excess of the SWL (i.e.2.5tonnes total) shall be hoisted and held, the davit being rotated through360 of movement, clockwise and counter-clockwise. c) a load of2tonnes shall be hoisted and similarly rotated. After testsb) andc) a thorough inspection shall be made to ensure that no deformation
24、or damage has been sustained. 7 Marking 7.1 The davit shall be permanently and legibly marked with the following particulars: a) SWL2t b) BS MA41 c) Date of test Item Component Material BS No. Remarks 1 Davit jib Carbon steel BS 4360 Grade43A 2 Upper bearing support plate Carbon steel BS 4360 Grade4
25、3A 3 Upper bearing plate Carbon steel BS 4360 Grade43A 4 Bearing pads Synthetic resin bonded fabric Compressive strength200N/mm 2 5 Bearing pad screws nuts Stainless steel Steel BS 4168 BS 4929-1 M8 50 prevailing torque 6 Bearing support plate Bearing support plate Bearing support plate bolts nuts w
26、ashers Steel Steel Steel BS 4190 BS 4190 BS 4320 M20 M20 M20 7 Jib foot Carbon steel BS 4360 Grade43A 8 Horncleat support plate Carbon steel BS 4360 Grade43A 9 Horncleat Carbon steel BS MA11 Nominal size30 10 Slewing eyeplates Carbon steel BS MA10 Nominal size1.6 type A 11 Lifting eyeplate Carbon st
27、eel BS MA10 Nominal size4 type A 12 Locking brackets Carbon steel BS 4360 Grade43A 13 Locking bolt Steel BS 4190 M16 14 Securing chain Steel 15 Davit stool Tube Carbon steel BS 3601 Nominal size450 Plate Carbon steel BS 4360 Grade43A 16 Lower bearing plate Carbon steel BS 4360 Grade43A 17 Lower bear
28、ing bush Synthetic resin bonded fabric Compressive strength200N/mm 2 18 Lower bearing bush screw Stainless steel BS 4168 M8 20 19 Anti-lifting plate Carbon steel BS 4360 Grade43A 20 Anti-lifting screw Stainless steel BS 4190 M16 35 21 Spring washer Steel BS 4464 M16 type BPBS MA 41:1975 BSI 02-2000
29、3 Figure 1 Arrangement of2 tonne SWL general purpose davitBSMA41:1975 4 BSI 02-2000 Figure 2 Details of jib (drawn for1500 nominal size)BSMA41:1975 BSI 02-2000 5 Figure 3 Details of stoolBSMA41:1975 6 BSI 02-2000 Figure 4 Details of upper bearingBSMA41:1975 BSI 02-2000 7 Figure 5 Details of lower be
30、aringBSMA41:1975 8 BSI 02-2000 NOTEAnti-lifting plate to be located as shown in Figure 5 All dimensions in millimetres Figure 6 Details of jib foot and locking plateBSMA41:1975 BSI 02-2000 BSI Certification Trade Mark The Kitemark The Kitemark is the registered certification trade mark of the Britis
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