Only the colours of the lateral marks differ. In IALA A, port-hand marks are red and starboard-hand marks green; in IALA B they are reversed, so you keep red to starboard when entering harbour. Cardinal and other marks are the same in both.
The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) sets the system of buoys and beacons used around the world. There is one system, with two regions that differ in a single respect: the colours of the lateral marks.
- IALA A: entering harbour, port-hand marks are red and starboard-hand marks are green. Used in New Zealand, Australia, Europe, Africa and most of Asia.
- IALA B: entering harbour, port-hand marks are green and starboard-hand marks are red. Used in North, Central and South America, Japan, South Korea and the Philippines. Sailors there remember it as "red right returning".
In both regions the shapes stay with the side, not the colour: port-hand buoys are can-shaped and starboard-hand buoys cone-shaped. The direction of buoyage works the same way too.
Everything else is common to both systems:
- cardinal marks, yellow and black, showing where the safe water is relative to a hazard;
- isolated danger marks, black with red bands;
- safe water marks, red and white vertical stripes;
- special marks, yellow;
- emergency wreck marking buoys, blue and yellow vertical stripes.
If you sail or charter in a region you are not used to, check which system applies before you go, and look carefully at the first few marks on the way out of harbour. The mistake to avoid is applying the habit from home and keeping a mark on the wrong side, which can put you straight onto the bank the mark is there to show.
More in the book: Chapter 14, Buoys, charts and tides