AIDS TO NAVIGATION
The U.S. Aids to Navigation System is a set of signs, symbols, colors and lights that tell you where it is safe for you to navigate your boat; it’s a bit like the system of traffic signals used by cars on the road, except on the water.
Each of the aids in the U.S. Aids to Navigation System, or ATON, has a specific purpose in telling you where to go on the water. For example, by staying on the correct side of the red and green lateral markers we’ll learn about next, you’ll stay in the middle of a safe navigable channel.
Okay, now let’s find out what to do when you encounter different Aids to Navigation.
U.S. AIDS TO NAVIGATION SYSTEM (ATON)
GREEN LATERAL MARKER
Keep this marker on your left (port) side when returning from sea or heading upstream. Odd numbers will be displayed and will increase as you head upstream.
RED LATERAL MARKER
Keep this marker on your right (starboard) side when returning from sea. Even numbers will be displayed and will increase as you head upstream.
This marker is used where a channel splits into two and indicates the main or preferred channel. You may pass on either side, but the main channel is indicated by the color on top. For example, the illustrated marker above indicates the preferred channel is to the right, so you would keep the marker on your left (port) side.
Glossary: Upstream refers to the direction that is against the current.
Nun buoys are cone-shaped and are always red in color, with even numbers.
Keep this marker on your right (starboard) side when heading in the upstream, or returning direction.
Can buoys are cylindrical-shaped and are always green in color, with odd numbers.
Keep this marker on your left (port) side when heading in the upstream, or returning direction.
Day markers are either red triangles with even numbers or green squares with odd numbers.
LIke other colored markers, keep the red markers on your starboard side and the green markers on your port side when heading in the upstream direction..
GENERAL RULE OF THUMB
A rule of thumb to remember is the “3R” rule: Red Right Returning.
That means, keep red markers on the right-hand (starboard) side of your boat when returning from sea. And you’ll keep them on your left
A simple way to know whether you are heading upstream or downstream is by looking at whether the numbers on the markers are increasing or decreasing.