Why Visual Aids Matter

Before a night or low-light approach, mark the lights, leading marks and sectors you expect to see, the sequence in which they should appear, and what you will do if an expected cue is absent or ambiguous. A light by itself is a line-of-sight observation, not proof of an exact position.

Match position and bearing first, then structure or daymark, colour, rhythmic character, period and nearby aids. Background lighting, poor visibility, an obscured sector, an unlit or unreliable aid, or a different mark on a similar bearing can make one cue misleading.

Use the current chart and applicable publications. The ADMIRALTY List of Lights and Fog Signals covers fixed lights and fog signals of navigational significance plus selected lit floating marks; it is not a claim that every temporary or local light is listed. Check corrections, warnings and local information.