BOATsmart! USA Knowledge Base

Module 05 - Navigating the Waterways

The Lateral Marking System

The Lateral Marking System is standard across every state. Using colors and numbers, these buoys create ‘invisible traffic lanes’ along common routes which boaters are required to use in order to navigate safely. These buoys will also mark a junction (a point where two channels meet) or a bifurcation (the point where a channel splits).

What Do the Numbers Indicate?

With the Lateral System, the numbers on the buoys and markers indicate your position (whether you’re headed upstream or downstream). The numbers climb higher as you head inland (upstream). If the numbers are descending, it means that your boat is headed in the direction of the sea (downstream).

What Do the Colors Indicate?

The Lateral System buoys and markers that are used to indicate direction are red, green or both red and green. The color indicates which side of the buoy your boat should safely pass.