Lateral marks

An ordinary and modified lateral mark can share principal colour and shape. A broad band of the other colour and composite group 2+1 rhythm add preferred-channel information at a junction. This is neither any light flashing three times nor an arrow choosing every vessel’s route. The first panel identifies port and starboard in A, while the second separates the modified marks. Examples represent no depths or actual approach. Recognition starts with the complete arrangement rather than selecting one familiar feature and ignoring the rest.

In Region A, port marks are red and starboard green. Can and conical bodies are distinctive; other allowed shapes can carry the corresponding can or upward-cone topmark. A fitted light has the colour corresponding to side and region. Ordinary lateral marks allow rhythms except the one reserved for modified marks. They therefore have no single universal period or count. An unlit mark does not automatically belong to another category. Body, topmark, day colour and light characteristics supply complementary identifying evidence rather than being interchangeable words.