Line Sight Meaning in Sailing

Line sight (or ‘line of sight’) describes a navigation technique where a sailor aligns two distant objects to determine their position or a safe path. If a lighthouse and a specific mountain peak are perfectly lined up, the sailor knows they are on a specific ‘transit’ line. This is a highly accurate way to navigate narrow channels or avoid hidden underwater hazards without relying on electronics. One clear example involves a captain keeping a red buoy aligned with a prominent church steeple to stay in the center of a deep-water channel. This visual reference provides an instant check on whether the boat is drifting off course due to current. It is a fundamental skill in pilotage and is often the most reliable way to enter a difficult harbor.