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

ATONs, or Aids to Navigation, are placed as a way of helping 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 riverways. 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
  • Super-fast 10 Hz GPS/GLONASS - With the integration of a 10 Hz GPS/GLONASS receiver, the 721xs refreshes position and heading up to 10 times per second. It displays constant on-screen location and proves to be incredibly accurate when marking waypoints
  • Advanced Sonar Support- Built-in support for a wide selection of Garmin transducers, including 50/200 kHz, 77/200 kHz, DownVü and SideVü scanning sonar and CHIRP. In addition, it will also support Minn Kota and MotorGuide trolling motor transducers.
  • Add the Clearest Scanning Images on the Water - Add the optional GCV 10 black box sonar to enjoy Garmin DownVü and SideVü scanning sonar with the clearest scanning sonar images on the water.
  • Special Features for Sailing - Supported sailing features include laylines, enhanced wind rose, heading and course-over-ground lines, true wind data fields and tide/current/time slider.
  • Get Your Apple Device Onboard with BlueChart Mobile - With BlueChart Mobile, a free app downloaded from the App Store, you can plan marine routes on your iPad or iPhone then wirelessly transfer them to your boat’s compatible networked Garmin chartplotter¹

If you’re interested to learn 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
  • How to Read a Nautical Chart A Complete Guide to Using and Understanding Electronic and Paper Charts
  • Calder, Nigel (Author)
  • English (Publication Language)
  • 272 Pages - 03/08/2012 (Publication Date) - International Marine/Ragged Mountain Press (Publisher)

You can also check out Bluewater 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; 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 is 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
  • A Must for Safe Boating in an Easy to Use Format
  • Full color both sides
  • Punched for binder or bulkhead mounting
  • Weatherproof high strength plastic
  • Full 8 1/2" X 11" (22 X 28 cm) size

Identifying Buoys: Shapes

Cylindrical “cans”

These are a standard type of buoy you’ll see. And 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.

And also just as a pedestrian crosswalk sign, they also 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 which 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 of which way your vessel is headed.

Understand first that the number of buoys will increase the closer to land you become. This is of course 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

And higher they ascend the further you get toward open waterways.

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, assuming 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 need to be able to locate where you are. And 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. But 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 standards—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 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.


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 a 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. And be sure to pack the correct safety equipment.

Although this post is on pontoon safety gear, it should give you a general idea of the necessities. Be sure to keep some essential items on board at all times in open waters.

All in all, just stay calm and have fun!

Brette DeVore is a freelance content writer, editor and marketer. A former interior designer with a love for travel and the outdoors, her specialties range from hospitality and lifestyle to tourism and recreation. Catch her camping beneath the stars, reading by the bonfire.