《BS-MA-2-3-1969.pdf》由会员分享，可在线阅读，更多相关《BS-MA-2-3-1969.pdf（10页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD MARINE SERIES BS MA 2-3: 1969 Incorporating Amendment No. 1 Specification for Magnetic compasses and binnacles Part 3: Recommendations for the positioning of compasses UDC 692.12.053.11:538.74 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:1
2、3:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 2-3:1969 This British Standard, having been approved by the Shipbuilding & Marine Industry Standards Committee, was published under the authority of the Executive Board on 28 November 1969 BSI 02-2000 The following BSI references relate to the wo
3、rk on this standard: Committee reference SME/5 Draft for approval 69/8444 ISBN 0 580 05933 2 Foreword This Part of this British Standard has been prepared under the authority of the Shipbuilding and Marine Industry Standards Committee, and is based on ISO Recommendation R 694, “Positioning of magnet
4、ic compasses in ships”. It forms Part 3 of BS MA 2 dealing with magnetic compasses and their accessories. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Sta
5、ndard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 4 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be in
6、dicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.Date of issueComments 5029March 1986Indicated by a sideline in the margin Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled
7、Copy, (c) BSI BS MA 2-3:1969 BSI 02-2000i Contents Page ForewordInside front cover 1Scope1 2Functions of magnetic compasses1 3Minimum distance requirements in relation to the ships structure1 4Safe distance requirements for magnetic and electrical equipment and electric cables2 Appendix A Determinat
8、ion of safe distances4 Figure 1 Minimum distance requirements in relation to the ships structure for standard compasses3 Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: London South Bank
9、 University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 2-3:1969 BSI 02-20001 1 Scope 1.1 This Part of this British Standard sets out recommendations for the minimum distances in relation to the ships structure, and the safe distance for magnet
10、ic and electrical equipment, and electrical cables. The functions of the magnetic compasses installed in ships are defined. 1.2 The minimum distances recommended in this Part of the standard take into consideration the accuracy required of each compass for normal navigation. The safe distances recom
11、mended are the minimum considered necessary, for the items specified, in order to eliminate or greatly reduce interference with the performance of the compass. 2 Functions of magnetic compasses 2.1 Magnetic compasses are classified according to the functions they are intended to perform in ships. In
12、 the following description of the functions of the standard magnetic compass no account has been taken of the possible fitting of one or more gyro-compasses in the ship. The fitting of a gyro-compass should not be taken as a reason for reducing in any way the accuracy to be expected from the ships s
13、tandard magnetic compass, which is the primary means of navigating the ship. The main functions of magnetic compasses in ships are defined as follows: 2.1.1 Standard compass. A magnetic compass which provides the primary means of navigating a ship. If there is only one magnetic compass, it is the St
14、andard compass. Such a compass, or a repeater from it, should be sited in the vicinity of the position from which the ship is ordinarily navigated and the view of the horizon from this position should be as uninterrupted as possible, for the purpose of taking bearings. In the sector from right ahead
15、 to 115 on either side, the view of the horizon may be interrupted only by masts, derrick posts, cranes and similar obstructions. 2.1.2 Steering compass. A magnetic compass which provides the primary means by which the ship is steered. If the standard compass sited on the wheelhouse top is of the pr
16、ojector or reflector type, it may also act as the steering compass. 2.1.3 Stand-by steering and emergency compasses (if fitted). Magnetic compasses which provide the secondary means by which the ship is steered. One example of a stand-by steering compass is a steering compass fitted in a ships wheel
17、house wherein the reflected or projected image of the standard compass is already available, and principally used for steering. An emergency compass is one fitted for the purpose of conning or steering the ship after damage or breakdown of all other means of doing so. 2.1.4 Magnetic control element.
18、 As defined in BS MA 2-4. 3 Minimum distance requirements in relation to the ships structure 3.1 The standard compass should be so positioned that it complies with the minimum distance requirements for magnetic material which may be regarded as part of the ships structure, as indicated in Figure 1.
19、Any magnetic material in the vicinity of the compass but outside the minimum distances (see Figure 1) should be disposed symmetrically relative to the compass. NOTEIt is emphasized that these distances are minimum permissible distances and should prove satisfactory in the majority of ships. Special
20、cases will, however, arise, where the masses of iron in the vicinity of the compass are such that the compass does not work satisfactorily and in these cases the distances should of necessity be increased. 3.2 For the steering compasses, the distance in Figure 1 may be reduced to 65 % and for stand-
21、by steering compasses and magnetic control elements referred to in 2.1.4 may be reduced to 50 % of those required for the standard compass, provided that no distance is less than 1.0 m. For emergency compasses (if fitted), the minimum distance is 1.0 m. 3.2.1 For steering compasses, the distance fro
22、m the deck below the compass may be reduced to 1.0 m provided the distance from the extremities of the iron decks, bulkheads and girders is not less than 65 % of the distances shown in Figure 1 for the standard compass. 3.3 Items which are permanently fixed to the ships structure should be treated a
23、s part of the latter. 3.4 By “funnel” is understood that part of the funnel up-take or exhaust pipe which is liable to heating. The funnel casing may be regarded as fixed magnetic material. 3.5 Movable magnetic parts in the vicinity of the steering compass, e.g. the steering gear, should not influen
24、ce the indication of such a compass. 3.6 The steering compass should not be placed in a wheelhouse completely constructed of magnetic material. If the wheelhouse is partly constructed of magnetic material, the magnetic parts should be disposed symmetrically relative to the compass. Licensed Copy: Lo
25、ndon South Bank University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 2-3:1969 2 BSI 02-2000 4 Safe distance requirements for magnetic and electrical equipment and electric cables 4.1 Magnetic and electrical equipment and cables carrying direc
26、t current close to a magnetic compass may produce a deviation in that compass. In order that the removal or replacement of any item of equipment will not introduce any unacceptable deviation, such an item should not be placed closer to the compass than its safe distance. 4.1.1 The safe distance for
27、any item, which is defined as the distance measured from the centre of the compass to the nearest point of the item concerned, should be determined by the method outlined in Appendix A. 4.2 Manufacturers of magnetic and electrical equipment should arrange for the safe distances of such equipment lik
28、ely to be placed in the vicinity of the magnetic compass to be determined by laboratory test, by the method described in Appendix A. The manufacturer should declare the compass safe distance for each item of equipment. 4.2.1 Items for which the safe distance is not known should not be placed nearer
29、to the standard compass or the steering compass than 7 m. This distance may however be reduced to 5 m for standard compasses in ships of less than 60 m overall length. For stand-by steering compasses, for the steering compass of a ship of less than 60 m overall length, and for magnetic control eleme
30、nts referred to in 2.1.4, these distances may be reduced to 3.5 m. 4.3 When determining the safe distance of large items of equipment such as radar sets, it is sometimes permissible to make a distinction between those items which are readily interchangeable and those which consist of large masses, t
31、he exchange of which would entail a considerable amount of work. In such cases, the safe distance of any item which is readily interchangeable is determined in accordance with 4.1.1 so that it may be removed or exchanged without appreciably affecting the compass. The remainder of the equipment, comp
32、rising the “large masses”, is treated as part of the ships structure (see 3.3) and if it is removed or exchanged, the compass affected should be re-adjusted. 4.4 Electric wiring carrying direct current, other than coils used for compass correction, within 5 m of magnetic compasses, should be arrange
33、d non-inductively. Clips and conduits in the vicinity of magnetic compasses should be of non-magnetic material. 4.5 Magnetic compasses should not be placed nearer than 2 m to one another or to the magnetic control elements referred to in 2.1.4. In ships of less than 60 m overall length, the distance
34、 between magnetic compasses may be reduced to 1.8 m, and the distance between a magnetic compass and these magnetic elements to 1.5 m. Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 2-3:1969 BSI 02-20003
35、 NOTE 1By “funnel” is understood that part of the funnel up-take or exhaust pipe which is liable to heating. The funnel casing may be regarded as fixed magnetic material (see 3.4). NOTE 2For minimum distance from steering and other compasses see 3.2. Figure 1 Minimum distance requirements in relatio
36、n to the ships structure for standard compasses Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 2-3:1969 4 BSI 02-2000 Appendix A Determination of safe distances A.1 General The safe distance for any item
37、 of equipment should be determined by the method described A.2. Each item should be tested in the position and attitude relative to the compass or magnetometer at which the error produced at the compass would be a maximum, provided the item can be fitted in this way. A.2 Method The safe distance of
38、any item is defined as the distance measured between the nearest point of the item and the centre of the compass or magnetometer at which it will not produce a deviation in the standard compass of more than, where H is the horizontal magnetic flux density in 4T (microtesla)1). For the steering compa
39、ss, the stand-by steering compass, the emergency compass and any magnetic control elements, this deviation is, H being defined as above. Test each item as follows: 1) In the magnetic condition in which it is received. 2) After magnetization in a d.c. field of 1.0 A/m2) with a superimposed stabilizin
40、g a.c. field of 18 A/m r.m.s. at 50 Hz. NOTEIf damage to the equipment under test might result, the stabilizing field should be omitted. The direction of the field is that in which, as estimated by inspection or from drawings, the resultant magnetization will be greatest (e.g. the long axis of a fer
41、romagnetic box). 3) In the energized condition, if the item is capable of being energized electrically. In each of these tests rotate the item to determine the direction in which it produces the maximum deviation. The greatest distance obtained under all these conditions is the safe distance. 1) 1 4
42、T u 0.01 Oe. 5.4 H - - 18 H - 2) The ampere per metre (A/m) is the unit of magnetic field strength in the International System (SI) and corresponds to 4II 103 oersted (Oe). The values obtained will be rounded up to the nearest 5 cm or 10 cm. 103 4 - - 103 4 - - Licensed Copy: London South Bank Unive
43、rsity, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: London South Bank University, London South Bank University, Sat Dec 09 02:13:44 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS MA 2-3: 1969 BSI 389 Chiswick High Road London W4 4AL
44、 BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. U
45、sers of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secr
46、etary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000. Fax: 020 8996 7400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standards. Buy
47、ing standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: 020 8996 9001. Fax: 020 8996 7001. In response to orders for international standards, it is BSI policy to supply the BSI implementation of those that have been published
48、as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic information services are also available which
49、give details on all its products and services. Contact the Information Centre. Tel: 020 8996 7111. Fax: 020 8996 7048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Membership Administration. Tel: 020 8996 7002. Fax: 020 8996 7001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international stan