Principle And Characteristics Of Magnetic Compass

As an important navigation instrument, magnetic compass has been installed and used on ocean ships for a long time. At present, modern ships have been equipped with gyroscope (electric compass), GPS and other advanced navigation instruments, but because modern magnetic compass has the characteristics of simple structure, reliable performance and independent of external conditions, it is still used as a necessary navigation instrument for marine ships. 

The International Maritime Organization (IMO), classification society and ship inspection organizations all over the world have clearly stipulated that marine ships should be equipped with magnetic compass, and should correct the self deviation and have self deviation table.

1. Classification of magnetic compass

according to whether there is liquid in the magnetic compass basin, there are liquid compass and dry compass. The compass of liquid compass is suspended in the basin full of liquid. 

Due to the damping effect of liquid, the stability of compass is better when the ship sways. In addition, due to the buoyancy of the liquid, the friction between the compass support pin and the bearing can be reduced, thus improving the sensitivity of the compass basin. Our products are liquid compass.

according to the use of magnetic compass, there are mainly standard compass and steering compass. The standard compass is generally vertical and installed on the top deck of the cab (compass deck). 

Because of its high position, no shelter and little influence by ship magnetism, it is used to observe course, determine object orientation and correct steering compass, so it is called standard compass.

The steering compass is generally a table type, which is installed in the cab to observe the course and steer. The company produces various types of standard compass and steering compass.

according to the diameter of the compass, there are 130mm, 165mm and 190mm

2.magnetic compass deviation and correction

The magnetization of steel ship by geomagnetic field will produce ship magnetism, which will affect the pointing accuracy of magnetic compass, namely "self deviation". This deviation can be corrected by the compass master. The magnetic compass produced by our company is equipped with efficient self deviation correction device.

3. Installation of magnetic compass

since the magnetic compass is installed on the ship's longitudinal centerline as far as possible, the first line of the compass cabinet should coincide (or be parallel) with the ship's longitudinal centerline.

the distance between the standard magnetic compass and any ferromagnetic material is 1m.

4.daily maintenance of magnetic compass

 the magnetic compass should be covered with a compass cap (the standard compass should be covered with a compass cover).

keep the liquid in the basin colorless and transparent, and eliminate bubbles.

keep the shaft lubricated and rotate flexibly.

regularly check the half cycle and sensitivity of the compass, and replenish the compass basin if necessary.

no magnetic objects shall be placed near the compass, and the compass shall not be kept in high temperature and vibration environment for a long time.