Navigation lights

A light has colour, sector, range and position; an arrangement communicates a state or activity. These are different questions. Rule 21 defines sectors and Rule 22 minimum ranges, while Rules 23–31 address situations. Rule 20 supplies time and condition scope. One white point does not prove a sailing vessel, and lights should not be selected merely because a lantern fits a bracket. The figure shows defined horizontal sectors rather than an approved installation or complete identification of an actual vessel. Colour is meaningful only within the relevant arrangement.

Part C applies in all weathers. Lights are required from sunset to sunrise; other lights must not be mistaken for them, impair their visibility or distinctive character, or interfere with lookout. Prescribed lights, if carried, are also exhibited in daytime restricted visibility and may be shown when otherwise necessary. Shapes apply by day. Lights and shapes must additionally comply with Annex I. Bright deck decoration can interfere with the message even where prescribed lanterns exist. Time, visibility and technical conformity therefore accompany the question of which arrangement belongs to a vessel’s state.