navigation lights

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navigation lights, the lights laid down by the International Regulations for Preventing Collisions at Sea which vessels must display when under way at sea at night. The most common are as follows:(a) A power-driven vessel under way at night, less than 46 metres (150 ft) in length, carries one white steaming light, port (red) and starboard (green) sidelights, also sometimes referred to as bow lights, and a white overtaking light. If over 46 metres in length, it carries two white steaming lights, port and starboard sidelights, and a white overtaking light.(b) A power-driven vessel towing another vessel carries its sidelights, overtaking light, and steaming light. If the length of the two is less than 183 metres (600 ft) an additional steaming light is carried; if the length of two is more than 183 metres a third steaming light is carried.(c) Vessels engaged in trawling show an all-round green light above an all-round white light, both visible 3.2 kilometres (2 mls.). They may carry in addition one steaming light, lower than and abaft the all-round green and white lights. When making way through the water they show sidelights and overtaking light. Drift net vessels show an all-round red light above an all-round white light. When under way they show sidelights and an overtaking light. If outlying gear extends more than 152 metres (500 ft) an additional all-round white light shows the direction of the gear. See also fisheries.(d) A vessel under way at night, but not under command and stopped, hoists two all-round red lights, one above the other, visible 3.2 kilometres (2 mls.), and switches off all other navigation lights. If the ship is making way through the water it also shows sidelights and overtaking light.(e) A power-driven pilot vessel on duty and under way carries sidelights, overtaking light, and, at the masthead, a white all-round light above a red all-round light, both visible 4.8 kilometres (3 mls.). The vessel also shows one or more flare-ups at intervals not exceeding ten minutes or an intermittent all-round white light.(f) A sailing vessel under way at night carries sidelights and an overtaking light. In addition she may carry on the top of the foremast a red light above a green light, visible 3.2 kilometres (2 mls.) and showing from ahead to two points abaft the beam.(g) A vessel of less than 46 metres (150 ft), when at anchor, carries in the forepart a white all-round light visible 3.2 kilometres (2 mls.). If 46 metres or more in length, the anchored ship carries two white all-round lights, visible 4.8 kilometres (3 mls.); one near the bow, the other at or near the stern and 4.5 metres (15 ft) lower.

navigation lights a set of lights shown by a ship or aircraft at night to indicate its position and orientation.