Aids to Navigation - Road Signs of the Waterway

Table of Contents:

MetLife Boat Safety Tips

Aids to Navigation are placed along coasts and navigable waters as guides to mark safe water and to assist mariners in determining their position in relation to land and hidden dangers. Each is used to provide specific information. Several aids to navigation are usually used together to form a local system that helps the mariner follow natural and improved channels. They also provide a continuous system of charted marks for coastal piloting.

Lateral Marks are buoys or beacons that indicate sides of a route to be followed. They follow the traditional 3R rule of "red, right, returning" when returning from seaward and proceeding toward the head of navigation. Along the coast this is generally considered moving southerly along the Atlantic, westerly along the Gulf and northerly along the Pacific. In the Great Lakes it is westerly and northerly, except on Lake Michigan where southerly movement is toward head of navigation system.

Image of a small boat traveling between lateral marks. The image includes three lateral marks or buoys indicating sides of a route to be followed.

The Intracoastal Waterway employs special markings that consist of a yellow square or triangle. When following the conventional direction of buoyage:
YELLOW SQUARE - is kept on LEFT SIDE
YELLOW TRIANGLE - is kept on RIGHT SIDE

The Western River System varies from the standard system in that aids are not numbered. It contains crossing daymarks that indicate where the river channel crosses from one bank to the other. Lights on green aids may be green or white and those on red aids may be red or white.

The U.S. Aids to Navigation System is intended for use with nautical charts. The meaning of a particular aid may not be clear unless the appropriate chart is consulted. Publications such as Light Lists and Coast Pilots contain additional, important information. Each Coast Guard District also publishes a Local Notice to Mariners reporting changes to and deficiencies in aids to navigation and other marine information. DO NOT rely on buoys alone to determine your position!

For the complete U.S. Aids to Navigation, click here.