Guardbearing

Guardbearing is a navigational term used in maritime and aerial contexts to describe a specific method of establishing a directional reference or bearing from a fixed point, such as a lighthouse, lighthouse station, or other maritime aid, to a passing or targeted vessel or aircraft. This technique helps navigators determine their position, avoid hazards, or maintain correct course by aligning their instruments with a known bearing.

The concept of guardbearing involves marking or calculating a bearing line from a known, prominent object to aid in navigation. By observing the vessel’s or aircraft’s relative position to this bearing, navigators can establish their location on a chart or maintain a steady course. Guardbearing is particularly useful in conditions of limited visibility or in navigating through narrow channels, congested areas, or near hazards like rocks, reefs, or offshore structures.

In practice, a guardbearing is typically determined using a compass or other directional instrument, with the known object serving as a reference point. The bearing is then used as a guiding line; if the vessel or aircraft remains on the bearing line, it is on the correct course relative to the reference point. Adjustments are made if the bearing shifts, indicating deviation from the desired track.

Guardbearing plays a vital role in safe navigation, especially before the advent of modern electronic navigation systems. Despite technological advancements, it remains a fundamental skill in visual navigation and aid to navigation practices worldwide. Its effectiveness depends on accurate measurements, clear visibility, and the correct identification of the reference object.