Lateral and cardinal systems
Marine navigation marks communicate channel edges, isolated dangers, safe water and the side on which to pass hazards. Buoyage conventions depend on the IALA region and the type of mark.
Cardinal marks
| Mark | General message |
|---|---|
| North cardinal | Safe water lies to the north of the mark. |
| East cardinal | Safe water lies to the east. |
| South cardinal | Safe water lies to the south. |
| West cardinal | Safe water lies to the west. |
Navigation lights and day shapes
Vessels use combinations of red, green and white lights plus special configurations for towing, fishing, restricted manoeuvrability, anchoring and other states. Day shapes communicate certain statuses in daylight.
Navigation decisions must use current charts, COLREGs/local regulations, proper lookout and approved bridge/boating procedures.