U.S. Aids To Navigation System (ATON)
Buoys and markers are the "traffic signals" that guide vessel operators safely along some waterways. They also identify dangerous or controlled areas and give directions and information. As a recreational boat or PWC operator, you will need to know the lateral navigation markers and non-lateral markers of the U.S. Aids to Navigation System.
Lateral markers, such as nun buoys and can buoys, mark the edges of safe water areas; for example, directing travel within a channel. The markers use a combination of colors and numbers, which may appear on either buoys or permanently placed markers. Non-lateral markers are navigation aids that give information other than the edges of safe water areas. The most common are regulatory markers that are white and use orange markings and black lettering.