INTERNATIONAL MARITIME ORGANIZATION
添付資料 7
SUB-COMMITTEE ON SAFETY OF
NAVIGATION
44th- session
Agenda item 5
REVISION OF SOLAS CHAPTER V
Adjustment of Magnetic Compasses
Note by Comite International Radio Maritime (CIRM)
SUMMARY
Executive summary： To propose an amendment to the draft revision of SOLAS chapter v to clarify requirements for the adjustment of magnetic compasses in the interests of safety.
Action to be taken： Paragraph 7.
Related documents： Resolution A.382(X), (NAV 44/5, annex) and (NAV 43/15, annex 21, annex 2).
1 Some CIRM members have reported that an increasing number of ships appear not to be keeping their magnetic or electromagnetic compasses properly adjusted. In an alarming number of cases, errors of such magnitude have been found that it would have been impossible to use the compass for safe navigation.
2 In particular, compasses are often found not to be adjusted for the magnetic latitudes in which the ship is operating, which can cause serious errors.
3 To ensure continued reliability and accuracy, any magnetic compass should be swung and adjusted at least once every year and after every docking or significant structural work. This is a specialist skill that can only be carried out by a trained compass adjuster, who must be licensed by the Administration. It is also important to ensure that compass adjustment includes correction for all magnetic latitudes in which the ship may operate (although an accuracy of 2 degrees may not be possible until the second swing after building).
4 In the existing chapter v, regulation 12(b)(ii) requires that： "Each magnetic compass referred to in subparagraph (i) shall be properly adjusted and its table or curve of residual deviations shall be available at all times". This does not provide for the need to ensure that all magnetic, electromagnetic and transmitting magnetic compasses are kept adjusted; there is no reference to latitude correction, and the term "properly" is open to variable interpretation.
5 In the draft revised SOLAS chapter v (NAV 44/5, annex), the equivalent regulation 20.1.2 would require only that： "Means of correcting headings and bearings to true shall be available at all times". This is even less clearly defined, and sets no requirement for adjustment by a qualified person.
