Variation Meaning in Sailing

Variation represents the angular difference between True North (the geographic North Pole) and Magnetic North (where a compass points). This value changes depending on your location on Earth because the magnetic poles are not aligned with the Earth’s axis. One specific example involves a navigator in the Caribbean seeing a variation of 14 degrees West on their chart, meaning they must subtract 14 degrees from their True heading to find their Compass heading. Failure to account for variation can lead to significant navigation errors over long distances. Most charts include a ‘compass rose’ that provides the local variation and the rate at which it changes each year. It is a fundamental calculation for any traditional navigator.