The International Convention for the Safety of Life at Sea (SOLAS), Chapter V, Regulation 19, establishes the carriage requirements for navigational equipment, including magnetic compasses.

Under SOLAS V/19.2.1, all ships, irrespective of size, are required to have a properly adjusted standard magnetic compass, or other means independent of any power supply, to determine the ship’s heading and display it at the main steering position.

Ships of 150 gross tonnage and upwards, as well as passenger ships irrespective of size, are additionally required to carry a spare magnetic compass or equivalent means to perform the same function.

SOLAS establishes the fundamental carriage requirements. Further guidance on compass performance, maintenance, adjustment and deviation records is provided through IMO resolutions and circulars.

Official reference: SOLAS Chapter V, Regulation 19 – Carriage requirements for shipborne navigational systems and equipment.

The International Maritime Organization (IMO) provides guidance on the performance, maintenance and adjustment of magnetic compasses.

Magnetic compasses should be maintained in good working order, regularly checked for deviation and adjusted when necessary.

Changes to a vessel’s magnetic environment, including structural modifications or the installation of electrical equipment, may affect compass accuracy and require further verification.

The IMO guidance should be considered alongside applicable SOLAS provisions and flag State requirements.

A magnetic compass deviation table records the residual compass deviation on different headings following adjustment or verification.

An accurate deviation table enables bridge officers to apply the appropriate corrections when navigating by magnetic compass.

Compass deviation should be monitored regularly, and the deviation table should be updated when necessary, particularly following changes that may affect the vessel’s magnetic characteristics.

Documentation requirements, including the validity of deviation tables and qualifications of compass adjusters, may vary depending on the vessel’s flag State and applicable local regulations.

Vessels transiting the Panama Canal must comply with specific magnetic compass requirements established by the Panama Canal Authority (ACP).

For vessels of 150 gross tonnage and above, the magnetic compass must have a residual deviation of less than 7°, verified by swinging the vessel on various headings.

According to the ACP’s 2026 Vessel Requirements, verification by a recognized calibration authority and the issuance of an accurate deviation table must have been completed within the preceding 12 months. Deviation cards issued and signed by the vessel’s master are accepted when the deviation is less than 6°.

Failure to meet these requirements may result in transit delays, particularly during periods of restricted visibility.

Scandia Compass Adjusters provides professional magnetic compass adjustment and deviation verification services to help vessels prepare for Panama Canal transit.