Thomas Gunn Navigation Services Ltd employ two very experienced and fully qualified D.O.T. certified compass adjusters, who are available 24 hours a day to carry out onboard adjustment and service.

Why Required?

To ensure that all vessels at sea have a Standard Magnetic Compass on which they can rely on in any situation. Unless a magnetic compass is kept properly adjusted, serious errors can develop, such that the compass may no longer be relied upon for safe navigation. In the case of a compass not in continuous use, large errors can build up unnoticed, with potentially disastrous consequences in an emergency situation.

What Causes Deviation?

A ships magnetic compass can be seriously affected by external influences such as structural repairs, magnetic cargoes and cargo handling appliances and even long term lay up in one direction. Other external factors include excessive heat in its exposed position, and vibration common on motor ships, can reduce the accuracy and performance of the compass in a relatively short time. This reduction in performance is potentially critical, and it is therefore imperative that the compass is regularly inspected by a qualified compass adjuster.

Regulations

As per MGN 57 (M+F) all magnetic, electromagnetic and transmitting magnetic compasses should be adjusted:
	When they are first installed or after repairs to the compass or binnacle.
	If the compass becomes unreliable.
	After major dry-docks when the vessel undergoes structural repairs or alterations which affect its permanent and induced magnetism.
	5 day forecast
	10 day forecast
	When electrical or magnetic equipment close to the compass is added to, removed or altered.
	When a period of two years has elapsed since the last adjustment and a record of compass deviation has not been maintained, or the recorded deviations are excessive or when the compass shows physical defects.