How Are Buoys Marked? Understanding Navigation Aids

Understanding signs and markers on roadways is an essential skill to safe driving. Being able to understand navigational aid is, if anything, an even more important skill for any variety of boater.

Lateral Buoys

A fundamental rule of thumb is the mnemonic “red, right, returning,” where by returning we imagine that we are a ship returning to port from open waters. Heading upstream or toward dock, , red marked buoys should be kept to the right (starboard) side of the vessel. Conversely, green lateral buoys should be kept to the left (port) when headed from restricted waters into open waters. By staying between the red and green marked lateral buoys, you are operating in the safely navigable portion of a channel, away from shoals, bars, and other hazards.

At night, lateral buoys may be marked with green or red lights, depending on whether they are to be kept to the port or starboard respectively while a boater is headed upstream or toward port.

In addition to color, buoys are distinguished by their shapes. Red lateral buoys are often fitted with a conical top to the cylinder, whereas green lateral buoys are simple cylinders.

Sometimes, numbers are affixed to buoys that operate like numerical exits on an expressway. The numbers increase as one passes from open waters up a channel or river. Headed downstream, the numbers conversely decrease as one approaches a river mouth or open waters. So, for example, as one floats from north to south on the Mississippi, the numbers decrease until the river actually empties into the Gulf of Mexico. In this case, even numbers will be affixed to the red buoys that you keep to your right as you pass upstream or away from open water, and odd numbers to the green buoys that you keep to the left as you pass upstream or away from open water.

Safe Water Markers

These are white with red vertical stripes and indicate safe open water to either side. They are also used to mark the centers of navigable channels and may be passed to port or to starboard. They may be fitted with a white light.

Inland Waters Obstruction Markers

These give information about hazards. They are white buoys with black vertical stripes. Do not pass between them and the nearest shore. Sometimes they are fitted with lights to indicate in which direction they are best passed. These pole-like structures carry lights that flash depending on which compass point the safest waters lie to an obstruction:
• 3 (quick or very quick) flashes indicate pass to East
• 6 (quick or very quick) flashes followed by a long flash indicate South
• 9 (quick or very quick) flashes indicate West
• continual (quick or very quick) flashes indicate North.

Consult a navigational chart to learn the nature of the obstruction/hazard.

Informational Water Buoy Markers

Give useful information about the waters other than where it is safe or unsafe to navigate. They may indicate protected or restricted areas, for example, or where there is no wake allowed, or where protected species nest.

Mooring Buoys

Are usually white with blue horizontal bands. You will generally find them off of marinas and other places where boats are permitted to anchor. These are generally the only buoys to which boaters are allowed to tie up.

Understanding the language of buoys helps one navigate effectively and safely. Practice your understanding of these aids so that you are prepared when you hit the water.