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Chapter 6: Navigation Aids

The U.S. Aids to Navigation System

In order to ensure that all boaters are safer and better informed, there exists a system of signs, symbols, colors, and lights which directions and information on where it is safe to boat. The U.S. Aids to Navigation System (often referred to as USATONS or simply ATON), has many similarities to the traffic signals one finds, on the road.

ATON tells where to go in the water to remain safe and warns of any hazards one may encounter. As an example, as one crosses through a narrow but navigable channel, one may see a set of green and red markers. These lateral markers help one to stay in the middle of the channel and safely sail through it.

Before explaining the meanings of these different buoys, keep in mind that the term "upstream" refers to the direction which is against the current.

Red Lateral Marker

Red Lateral Marker

Always keep this marker on the starboard (right) side when returning from sea. Even numbers are displayed on these markers and will increase as one heads further upstream.

Green Lateral Marker

Green Lateral Marker

Always keep this marker on the port (left) side when heading upstream or returning from sea. Odd numbers are displayed on these markers and will increase as one heads further upstream.

Junction Buoy

Junction Buoy

This marker is used to indicate the main or preferred channel when a channel splits into two. One may pass these buoys on either side but the preferred channel is indicated by whichever color is on top. As an example, the buoy pictured here indicates that the right channel is preferred. Since green is the color on top one would keep it on the port (left) side when passing to head up the preferred channel.

Can Buoy

Can Buoy

These buoys are green, cylindrical-shaped and display odd numbers. Keep these buoys on the port (left) side if heading in the upstream, or returning direction.

Nun Buoy

Nun Buoy

These buoys are red, cone-shaped and display even numbers. Keep these buoys on the starboard (right) side if heading in the upstream or returning direction.

Day-Markers

Day-Markers

Day-markers are signs which may either be red triangles with even numbers or green squares with odd numbers. Keep red markers on the starboard side and green makers on the port side when heading upstream.

Finally, to help remember these various rules, keep the general rule of thumb in mind.

Rule of thumb:

Remember the "3R" rule: Red Right Returning.

This rule helps one to remember to keep red markers on the right-hand side of the vessel whenever returning from sea. The easiest way to tell whether one is heading upstream (returning) or downstream is to check whether the various numbers on the different buoys and signs are increasing or decreasing.