Reading the road markings

Buoys are the sea’s road markings, and like road markings they only make sense once you know which way the road runs. The system used across Europe (and most of the world) is IALAIALAThe international buoyage authority. Region A (Europe and most of the world): red to port entering harbour.full glossary → Region A; the Americas use Region B, where the lateral colours swap. Everything in this course is Region A.

Lateral markslateral marksThe channel-edge buoys: red cans to port, green cones to starboard, entering from seaward (Region A).full glossary → edge a channel. Entering from seaward — going with the flood, into harbour — you leave port-hand marks to port and starboard-hand marks to starboard. Port-hand marks are red cans (flat-topped); starboard-hand marks are green cones (pointed). Their lights, if fitted, match: red on red cans, green on green cones, in any rhythm.

Leaving harbour, everything reads in reverse: the red cans now pass down your starboard side. The marks have not changed — your direction against the direction of buoyage has. Around the UK the general direction of buoyage runs clockwise: northward up the west coast, eastward along the Channel, then southward down the North Sea coast. Where it is ambiguous, the chart prints a broad magenta arrow.

When the channel forks

At a junction one route is usually the main channel, and the mark at the fork says so: a red can with a green band means the preferred channel lies to starboard of the mark — treat it as a port-hand mark if you want the main route. Green cone, red band: preferred channel to port. Their lights flash in the composite rhythm FlFlFlashing — a light on for less time than it is off (e.g. Fl.R.4s).full glossary →(2+1) in the body colour — the one rhythm ordinary laterals never use, so a 2+1 flash always means a junction.

One habit beats all the theory: before entering anywhere unfamiliar, trace the buoyed channel on the chart and write the marks down in the order you will meet them. At night, identify each light positively before you trust it — the harbour’s shore lights are excellent liars.