Buoyage: Reading the Signposts of the Sea

Recall from passage planning that a chart shows you where the dangers are — but out on the water, aids to navigation (buoys, beacons and lights) mark those dangers in real time. The international IALA system standardises them into two families: lateral marks and cardinal marks.

Lateral marks show the sides of a channel. In IALA Region A (Europe, Africa, most of Asia and Australia), when you enter a harbour from seaward you keep red cans to port (left) and green cones to starboard (right) — remember it as "red left returning". Crucially, the Americas, Japan, Korea and the Philippines are Region B, where the colours are reversed: red is on your right returning. Always check which region your chart uses.

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Cardinal marks don't mark a channel — they point to the safe water relative to a hazard, using the compass. A North cardinal (two black cone topmarks pointing up, black-over-yellow body) means pass to the north of it; South, East and West work the same way. Their topmark cones are the key: North points up, South points down, East looks like an egg (points apart), West looks like a wineglass (points together). At night, cardinal lights flash white in patterns matching a clock face (e.g. North = continuous quick flashing).