Lateral system

The United States principally uses IALA Region B lateral conventions, but not every waterway or U.S.-associated jurisdiction can be reduced to "red right returning." Use the chart and the established conventional direction of buoyage.

Returning from seaward or proceeding in the conventional direction

Starboard side

red

even numbers

nun shape where buoy shape is significant

triangular daymarks on fixed aids

Port side

green

odd numbers

can shape

square daymarks on fixed aids

Numbers generally increase in the conventional direction of buoyage.

The limitation of "Red Right Returning"

It is useful only when you know what "returning" means for that waterway.

On rivers, the conventional direction is generally upstream. On complex waterways, junctions, ICW routes and other systems, the chart remains the authority.