Module 16 - Pilotage
IALA Buoyage System — Region A
What you will learn
Classify an IALA mark by family, confirm the local direction or charted purpose, and translate recognition into a safe-water decision.
The IALA Maritime Buoyage System uses colour, shape, topmark and light together. Lateral colours differ between Regions A and B; cardinal and the other principal mark families retain their common logic.
The UK uses Region A, where port-hand lateral marks are red and starboard-hand lateral marks are green in the direction of buoyage. Region B reverses those lateral colours. Confirm the region and the local conventional direction from the chart rather than applying an 'entering harbour' rhyme to every branch, river or buoyed route.
First classify the family. Lateral marks define channel sides or a preferred branch; cardinal marks show the named compass side of safer water; isolated danger marks a hazard at or near the mark; safe water indicates navigable water around it; and special marks identify an area or feature whose meaning comes from the chart. A new-danger wreck buoy is another distinctive warning to recognise.
Use at least two available cues. Colour can be lost in glare, shape may be hard to see, a topmark may be absent or damaged and a light is visible only at night. Charted position and light characteristic support identification, but a buoy can be moved off station, so keep checking the surrounding geography and depth.
| Family | Primary message | Next question |
|---|---|---|
| Lateral | Channel side or preferred branch | What is the direction of buoyage? |
| Cardinal | Safer water lies on the named compass side | What danger or feature is charted? |
| Isolated danger | Danger at or near the mark | What clearance does the chart support? |
| Safe water | Navigable water around the mark | How does it relate to the planned fairway or landfall? |
| Special | Special area or feature | What does the chart or local notice say? |
Avoid a colour-only decision
At dusk a mark appears red, but its shape and topmark are indistinct and the vessel is near a junction where the direction of buoyage changes.
1. Delay the label
Red alone is insufficient to distinguish a normal port-hand mark from a preferred-channel pattern or another light.
2. Use the chart
Check the charted mark, junction and direction of buoyage, then compare the observed light rhythm and body pattern.
3. Protect the route
Keep a conservative distance and verify depth and traffic until the family and safe side are clear.
Sense check: Naming the colour without confirming the family and direction has not yet answered which water is safe for this vessel.
Common mistake or limitation
- 'Red to port entering' is a Region A shortcut, not a substitute for the charted direction of buoyage.
- A buoy's charted position is important but not infallible; off-station marks and identification errors require independent checks.
Recap
- Start with family, region and direction rather than colour alone.
- Use independent physical and charted cues to confirm identity.
- Connect every mark to a depth-, hazard- and traffic-aware route decision.
Optional quick check
Section 5 of 8
What should be checked before using a red lateral mark to decide the passing side?
Continue studying Pilotage
This public lesson is part of Revision Module 16. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.