FINDING THE DEVIATION COEFFICINTS B AND C OF MAGNETIC COMPASS WHEN THE VESSEL SAILS IN HER ROUTE

Abstract

Marine magnetic compass is an important equipment which is used to indicate the ship’s course. To ensure the requirerments of maritime safety, magnetic compass needs to be corrected to compensate the deviation between magnetic compass and Gyro compass and then the magnetic compass deviation table is also made before operating the ship. Theorically, when the latitude of ship are significantly different with those in a port where magnetic compass is corrected to compensate the deviation or when the ship carries the iron, then deflected forces have a tendency to change and cause the deviation in magnetic compass compared to gyro compass. When the ship sails in her route, forces (B, and C) change significantly compared to others (A, D, and E). To overcome this problem, the magnetic compass deviation caused by semicircle forces (B, and C) can be corrected, then making the new deviation table with new coefficients (B, and C) and keeping former ones (A, D, and E). In this study, a simple means to determine the compass coefficints (B, and C) when the ship are sailing her route. This method can be seen as a simple refference for the theory of marine magnetic compass.