Definition
A vertical column of lights at the harbour entrance. Three flashing red lights mean a serious emergency, all vessels stop or divert. Three fixed red mean vessels shall not proceed. Red over white over red means do not proceed except vessels holding specific orders. Three fixed green mean proceed, one-way traffic; green over white over green means proceed, two-way traffic. A yellow light offset beside the column exempts vessels with specific orders. Local variants persist, so consult the pilot book.
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