Lateral mark
An IALA lateral buoy or lateral post marks the edge of a channel or shallow water and is a pilotage aid for vessels operating close to shore.
There are two types of lateral buoys:
- port buoys - the vessel keeps these to their left when passing upstream
- starboard buoys - the vessel keeps these to their right when passing upstream
There are two different IALA lateral buoyage systems:
- System B is used by nations in the American spere of influence.
- System A is used by the rest of the world.
In System A:
- port buoys are red, square shaped and may have a red flashing light.
- starboard buoys are green, triangular shaped and may have a green flashing light.
In System B, port buoys are usually green or black, with red buoys to starboard.
- port buoys are green, square shaped and may have a red flashing light.
- starboard buoys are red, triangular shaped and may have a green flashing light.
