Oceanlink Marine Services offer very experienced and fully qualified AMSA certified magnetic compass adjusters working around Australia and New Zealand, who are available round the clock to carry out onboard adjustments and services anywhere in Australia and New Zealand. We ensure cost effective and time efficient magnetic compass adjustment.

Contact us today for Magnetic compass adjustment.

Ships magnetic compass

Magnetic Compass adjustment

A properly adjusted ship’s compass is a crucial navigational equipment. It does not need any power source or connectivity to the satellite. It works on the basis of Earth’s inherent magnetism. Readings from the compass can be interpreted for navigation and corrected with available arrangements onboard.

Magnetic compass adjustment requirements

Annex 13 of the MCA publication – Safety of Navigation – Implementing SOLAS Chapter V which outdated MGN 57 states that each magnetic compass required to be carried by the regulations shall be properly adjusted and its table or curve of residual deviations available at all times.

AMSA guideline for maintenance and adjustment of Magnetic Compass

How does magnetic compass work


A compass point north because all magnets have got two poles, north pole and a south pole. The north pole of one magnet is always attracted to the south pole of the other magnet. Our earth being a magnet itself, interact with other magnets in this way. The north end of a compass magnet is drawn to align with the earth’s magnetic field. Because the earth’s magnetic north pole attracts the north end of all other magnets, which is technically the south pole of earth’s magnetic field.


The principle of the magnetic compass


A magnetic compass is a crucial navigational equipment for a ship. A freely suspended magnetized needle points to the north because of the forces caused by Earth’s magnetic field. Once north is detected, other directions can be ascertained.

Magnetic compass if a ship is located on the monkey island of the ship and reflected into the bridge with the help of periscope.

Magnetic Compass Direction

Magnetic compass deviation is caused by the magnetism present in the ship’s structure itself.

Deviation Card for magnetic compass

Every ship is provided with a deviation card for this purpose and based on the variation from the chart, compass error is found.

How to make the deviation card

  • Ideally, the vessel needs to be on the equator as earth’s magnetic pull is least at the equator and gradually increases towards the poles.
  • Steer the ship from 0 degrees to 360 degrees.
  • Make the course steady at every 10 degrees of movement.
  • Note down the respective magnetic course.
  • Variation from the chart of that specific place can be found.
  • The deviation is calculated from it.
  • Tabulate the data and deviation can be calculated.


Magnetic compass deviation table

Following is a sample deviation table

Magnetic Compass deviation table


Contact us today for Magnetic compass adjustment.