What is deviation in the context of navigation?

Deviation in navigation refers specifically to the error that arises in a compass due to local magnetic fields. This phenomenon occurs when the magnetic fields generated by the ship's structure, electrical equipment, or even other magnetic materials in proximity interfere with the Earth's magnetic field. As a result, the compass may not point toward true magnetic north, leading to navigational inaccuracies.

It's important to distinguish deviation from other navigational terms. For example, while deviation is an error, other choices refer to different aspects of navigation, such as compass types, distance calculations, or general navigational advice, which do not describe this specific magnetic error. Understanding deviation is crucial for ensuring accurate navigation at sea, particularly to correct course and ensure safe travel.