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Ruian Shunfeng Navigation Instruments Co.,Ltd

Add: No.20, Heping Road, Jinhu Street, Ruian, Zhejiang, China
Con: april Zhang
Tel: +86-577-65520898
Fax: +86-577-65966926
Mob: +8618158321811

Simple Magnetic Compass Calibration And Adjustment Steps.

The shipping company usually arranges a compass calibration master to calibrate the ship every year and issues a self-contrast curve table. However, due to the characteristics of the bulk cargo, such as the loading of iron ore, the magnetic field on the ship changes drastically, which often causes the magnetic compass on the ship to be too large, and completely contradicts the self-difference curve of the compass correction card, which is easily listed as a missing item when inspected. For example, in some ports such as Vancouver and Australia, if the self-inspection is too large, it will require calibration before the trip, otherwise it is not allowed to sail. Therefore, if the magnetic compass is too large on the ship, it should be self-calibrated to avoid being listed as a missing item by the PSC inspection.

Now I will share with you a simple magnetic compass self-correction method, which can be corrected by the crew of our ship.

(1) In the four main headings (N, E, S, W), the vertical and horizontal magnetic bars can be used to correct the semi-circular self-difference. The mouth can be applied: east east, west west, east and west, west east.

Among the three words of each word group, the first word indicates whether the self-difference is east or west, the second word indicates that the red end of the correction bar is toward the east or west of the compass, and the third word indicates that the correction bar is on the magnetic bar. Move and move up or down or remove.

For example, the ship's heading is north, and the heading is measured as the west self-difference. There is no magnetic bar in the east-west direction (ie, horizontal direction) in the compass. According to the West, the red end of the magnetic bar should be inserted westward (to the port side). If the heading is still self-difference, there is a magnetic bar in the east-west direction (ie, horizontal direction) in the compass cabinet. The horizontal magnetic bar is originally red-ended to the east (ie, starboard), according to the mouth of the west, it should be Move the original horizontal magnetic bar down to eliminate the Westself. When the ship's heading is east or west, the longitudinal correction magnetic bar is in the east-west direction of the compass.

(2) Correcting the quadrant self-difference in the quadrant navigation, the available port is: the southeast and the northwest are large, and the soft iron is leaning inward.

This slogan means that in the southeast (S, E) or northwest (N, W) navigation, the compass position measured by the self-difference is larger than the magnetic orientation (ie, the west self-difference), and the soft iron should be close to the compass, or Add a soft iron piece; if the compass position is smaller than the magnetic direction in these two directions, the soft iron should be moved outward. In the northeast (NE) or southwest (SW) flight direction, if the compass is in a large orientation, the soft iron should be moved outward; if the compass is small, the soft iron should be moved inward.


1. The magnetic heading of the ship N and S is demagnetized (or C-wheel) by adjusting the transverse bar.

2. The magnetic heading of the ship sailing E and W is demagnetized (or B round) by adjusting the longitudinal magnetic bar.

3. The magnetic heading of the ship navigating NW, SE, NE, and SW is demagnetized by adjusting the soft iron box (or ball).