The Boating Navigation Handbook: Buoys, Beacons, Lights and Charts

The Boating Navigation Handbook: Buoys, Beacons, Lights and Charts

ATONs, or Aids to Navigation, are placed as a way to help us identify routes and maneuver our way around coastal waterways.

It's important to understand what they indicate, as they could be cautioning you of obstructions beneath the water or be there to guide you through channels back to shore.

You'll even find that there are different systems of ATONs based on your location. The United States, for instance, has a much more complicated system and has more navigational buoys and beacons to identify and keep track of compared to our neighbors.

There was even a time when the Uniform State Waterway Marking System (USWMS) found among lakes and inland rivers was phased into the United States Aids To Navigation System (USATONS) to prevent confusion.

Boaters would become confused between the two systems entering and exiting canals and river ways. Today, fortunately, the systems are clearer and a lot safer for boaters. These days, a good GPS Chartplotter is what even experienced boaters rely on.

Garmin 010-01101-00 GPSMAP 721 with Worldwide Basemap




If you're interested in learning more about charts, grab yourself How to Read a Nautical Chart. It's a great book for boaters to have in their library.

How to Read a Nautical Chart, 2nd Edition (Includes ALL of Chart 1): A Complete Guide to Using and Understanding Electronic and Paper Charts




You can also check out Blue water for a vast array of nautical charts pertaining to specific regions. In fact, look for them at boat shows. They might have discounts to show members.

The Difference Between Buoys and Beacons

You should be on the lookout for both buoys and beacons. The easiest way to distinguish between the two is this: A buoy is floating and a beacon is fixed.

Buoys are floating about in the water but moored to the bottom. There's a lot to know about these, because their shape, color and numbering are all significant for navigation.

Beacons don't float around. Lighthouses, for example, are beacons. Beacons can also be anything that's stationary and fixed to the earth. This means they can also be poles and structures out in the water that could cause obstruction.

Purchase this Navigation Rules Quick Reference Card by Davis Instruments about buoys, beacons, lights and other waterway signals, as well as general rules and regulations.

You can keep it on your boat in case you ever need it. I like it because it's made of durable plastic and will never dampen or tear.

Davis Instruments Navigation Rules Quick Reference Card



Identifying Buoys: Shapes

Cylindrical cans

These are a standard type of buoy you'll see. They're always a solid green color. Sometimes, you'll find them to have a number, which is always an odd number.

Triangular nuns

These are also standard, and they're always red. If it's a floating red buoy, expect it to have a cone-shaped top (think nun's cap or a tip of crayon).

If it's a standing marker, expect it to have a triangular metal sign.

Identifying Buoys: Colors

Red and green

Buoys striped with a red and green pattern indicate a junction. You should either turn toward a main channel or a secondary channel. Regardless, if you keep straight ahead you'll hit something, like rocks! There's one more step to know which way to go:

Pay attention to the color on the top to know which direction is preferred.


White buoys can give a variety of different information. Sometimes they're used in camping areas where there's swimming. Sometimes they indicate a speed limit. If you find a white buoy with a blue stripe it's a mooring buoy.


Keep clear! Like any type of yellow street sign, it means caution. There could be something hidden beneath the waterways like dredge lines or shallow shoals.

Also, just as a pedestrian crosswalk sign, they may indicate additional information. In order to know how to proceed or which way to advance, you'll sometimes need to refer to your GPS or read a nautical chart.

Black and red

Black and red buoys indicate danger. You should use caution when approaching these. Sometimes a chart can indicate exactly why it's dangerous.

Banding combinations

Red and white vertical-striped buoys indicate that waters have deep channels without obstacles, or in other words, safe waters for boating freely.

They don't necessarily go to port or starboard, however, and are placed as you leave a channel and enter larger bodies of water. Pass beyond them to enter safe waters.

Instead of a number, they have letters that often represent something. For example: The port and city you're exiting begins with M.

Identifying Buoys: Odd and Even Numbering

Like I mentioned above: Red buoys are even-numbered, green buoys are odd-numbered. But what exactly do the odd and even numbers indicate? Well, they give you a hint to which way your vessel is headed.

Understand first that the number of buoys will increase the closer to land you become. This is, of cours, because as you come into channels or harbors, you'll need more guidance. When you travel out to sea, there are fewer buoys and they're spread farther apart.

Secondly, with this in mind, also understand buoy numbers will descend the closer you become.

Always remember: Red, Right, Returning. It's a common mnemonic device to remind sailors if a red buoy is on your right, you're returning to land. So as you're leaving the marina and heading out further toward coastal waterways, the very first buoys you'll see are these:

  • A green can buoy on your left port side labeled #1
  • A red nun buoy on your right starboard side labeled #2 

The higher they ascend, the further you get toward open waterways. 

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Lights and Flashing Rhythms

Why's that marker blinking?

If you've ever cruised at night, you've probably noticed a lot of blinking lights. In a world of technology, most boaters rely on their GPS and assume they'll never need to know why or for what reasons they're placed there.

But let's say your GPS stops working. When this happens, you'll need to be able to locate where you are. The old-fashioned way of doing this is charts and the help of these lights you once took for granted.

Not every buoy and beacon will have a light. In darker hours, you'll need to have a chart that acts as an abbreviated legend in telling you what each light you observe represents and guide your way back to the marina.

Although there are many chart abbreviations, below are the standard flashing, occulting, quick and isophase you'll find.

On your chart, the colors of the lights will be marked with R, G, Y and W (red, green, yellow and white). Also worth a note: If there's no listed color, assume it's white.

Fixed, Flashing and Occulting Lights

F - Fixed Lights: Steady light beacons without flashing. You won't see these often.

F1 - Flashing: A steady beacon but with seconds of flash less than the dark.

F1 (2) - Group Flashing: Groups of two flashes that are repeated several times a minute.

F1 (2+1) - Composite Group Flashing: A group of two flashes followed by a single flash. The entirety is repeated several times a minute. Iso Isophase All durations of light and dark are equal.

Oc - Occulting: A regular interval beacon. The flash of light stays on longer than the dark.

Mo. (A) - Morse Code Short: A series of flashing lights that represent dots and dashes. Typically flashes for the letter. These are also always white lights.

ISO - Isophase: This light shows equal periods of flashes and darkness. Hint: iso means same.

Q - Quick: A very rapid flashing, roughly 60 to 80 times per minute.

Note: It might be obvious, but never tie up to a buoy or beacon. If you do, the next lights you'll see are going to be flashing blues and there's no chart abbreviation for that! It means you're being approached by law enforcement or the Coast Guard. Get ready for a ticket or a stern talking to (at the very least). 

A firm understanding of buoys and beacons isn't knowledge that you can quickly acquire. Before you run into danger and find yourself in a stressful situation, get some practice and learn how to use your eyes and your charts.

Try to guide your boat once or twice in the dark without GPS and navigate back to shore. You'll feel much more confident should you lose sight of land with broken or faulty equipment.

Also, before you venture out for some night practice, make certain you pick up the proper lighting required for your own vessel. Be sure to pack the correct safety equipment.

This should give you a general idea of the necessities. Be sure to keep safety gear and essential items like anchors, air hornslines and spotlights on board at all times in open waters. All in all, just stay calm and have fun!