![]() ![]() ![]() The difference between the magnetic meridian and the direction in which the compass needle points is known as deviation. The magnetic properties of steel will cause the compass needle to deviate from the magnetic meridian. Deviationīecause of the physical characteristics of iron and steel, a magnetic compass placed in a vessel either constructed of steel or having a strong component of steel onboard, will be adversely affected. To distinguish it from a true bearing, a magnetic bearing has the suffix (M) added to it, ie 070° (M). Magnetic bearingĪ magnetic bearing is the angle between the direction of a place or object and the magnetic meridian passing through the site of observation. It is usually recorded inside each compass rose. ![]() It can also be obtained from ordinary charts where the variation for the area is given for a particular year as well as the annual change. Variation can b e obtained from a special isogonic chart where all the places of equal variation are joined by what is called isogonic lines. It is said to be easterly if theĭirection of magnetic north lies to the east of the true meridian and westerly if it lies to the west. It is advisable not to wait until the vessel is close before starting to take bearings.Variation is defined as the angle between the true and magnetic meridians. In open water, bearing should be taken as soon as it comes over the horizon. To be able to decide if a risk of collision exists, bearing on the other vessel should be taken as soon as it is sighted and then repeated in appropriate intervals. How often to take bearing from other vessel depends on situation (range between vessels, vessels relative speed, area of navigation, vessels characteristics, navigational equipment, visibility). Comments: If the bearing (compass or relative) taken visually or with radar at interval of time does not appreciable change, than the risk of collision shall be deemed to exist. In accordance with Rule 7 ( Risk of collision), risk of collision shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change. Rule(s) to be applied: Rule 7 ( Risk of collision).Vessel A: Power-driven vessel Vessel B: Power-driven vessel Area: On the high seas Visibility: Good (Vessels in sight of one another) Vessel A and vessel B are crossing Vessel A has vessel B on her own starboard side (relative bearing STBD 054°) No change in bearing taken at interval of time, CPA=0 ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |