An Introduction to Marine Navigation Lights and Aids

Marine navigation using buoys, beacons, and lights

The water may feel like you have free range to go wherever you like, and while that is somewhat true, there are still plenty of rules and guidelines you need to follow. It can get a bit complicated at times, so I will get right down to everything you need to know about buoys, beacons, and lights for marine navigation. Read below for our guide to marine navigation lights.

Buoys and beacons are the primary navigational tools on the water. If you are new to boating, think of these markers as the signs and traffic lights of marine travel. They come in many shapes, colours, and sizes, and each distinction carries a unique meaning. It can be a lot to learn, so we compiled a few tips.

What are Buoys and Beacons

Before we get ahead of ourselves, buoys are marine navigational aids that float on top of the water. Buoys come in all shapes and sizes, like cones, short cans, tall cylindrical spars, pillars, and more. However, cones and cans are the most common in North America.

Beacons function just like buoys but are fixed to the seafloor. Unlike buoys, however, beacons do not generally vary in shape. The long poles that keep the beacon upright do not allow for as much variation, but they make it easier to add signs or lights to the structure. Depth or speed limit signs are usually attached to a beacon.

Buoys and beacons function in almost the same way. The main difference is how they are attached to the seafloor. For the sake of clarity, when we mention buoys in this blog, we are talking about beacons as well.

Channel Buoys

The buoys encountered most frequently are Port Hand or Starboard Hand buoys. They mark the edge of a channel and highlight where it is safe to travel.

Starboard Hand buoys mark the right edge of a channel when you are moving upstream or heading into a harbor. You will know them by their typical cone shape and distinct red coloring. Sure, not every Starboard Hand buoy is conical, but they will always be red. They even have a convenient rhyme to help you remember what to do: Red Right Returning. Essentially, keep a red buoy on your right (starboard) side when moving upstream or returning to a harbor.

red starboard buoy for navigation

Port Hand buoys are small green cans or pillars. They mark the left side of a channel. When moving upstream, keep green buoys on the left (port) side of your vessel. There is no convenient rhyme for a Port Hand buoy, but if you can remember Red Right Returning, know that it is the opposite for green Port Hand buoys.

Green Port Hand buoy for navigation

Knowing these indicators will make marine navigation safer for you and other boaters, especially in unfamiliar waters. If you are ever unsure about a channel, look for these buoys and guide your boat between them. Oh, there is a rhyme for this to: Red and green, stay in between.

Navigating Between Channel marker buoys

Our buoy extravaganza is just getting started. Have you ever heard of a bifurcation buoy? They are two-toned markers that indicate a preferred channel if there are multiple safe channels available. It is like a floating traffic cop, directing boats in the preferred direction. The top band of the buoy signifies which side is the main channel. For example, if you come across a green buoy with a red stripe in the middle, keep the buoy on your left side. On the other hand, a red buoy with a green band means you should keep the buoy to your right. However, you can move in either direction if it is not safe to go into the preferred channel.

Green Bifurcation buoy for marine navigation

Hazard Buoys

Buoys aren’t just an aid for marine navigation. Many types can also function as warnings. A hazard (or danger) buoy warns boaters of hidden obstacles that could seriously damage a vessel. However, even the danger buoys come in many shapes and colors.

Out on the water, you might come across small orange and white cylindrical capsules, which indicate danger, specific rules for moving within the area, or general information. Depending on the markings, you could be in real trouble. An orange diamond represents danger, and you should watch out for hidden, underwater outcroppings. These buoys typically include text to let the boater know the kind of danger in the area, like rocks, a sandbar, or shallows.

Hazard buoy

If that orange diamond has crosshatches, turn around as soon as you see it. The area is not safe for boats. Essentially, there are too many obstacles to navigate in this area.

The same buoy with a white circle indicates that you are in an area of restricted operations. Typically, there will be text to inform boaters what to do (i.e. ‘No Wake’ or a speed limit). Finally, an orange and white buoy with a square provides helpful information such as directions, distances, and locations. There is no concern for danger with these buoys.

Another buoys to keep a sharp eye out for are Isolated Danger Buoys, which are black with a red horizontal stripe. These are moored to isolated hazards (such as a wreck or large rock) in an otherwise safe body of water. The water around this buoy is still navigable, just don’t get too close.

Buoy Numbering

Buoys and beacons can also have numbers. Red buoys are even-numbered, and green buoys are odd-numbered. This numbering system gives you a hint of which way your vessel is going – numbers ascend as you move away from land and descend as you move closer to shore.

Buoy Lights

Just when you think that buoys can’t get any more complicated, they add flashing lights to the top. Added so that a buoy is visible at night, the interval and frequency of flashes have specific meanings.

The color of the light generally reflects its meaning. A green Port Hand buoy has a green light, and a red Starboard Hand buoy will have a red light, and so on.

The interval and frequency of the light flashes, along with the color, reveals the meaning of a buoy. However, for effective marine navigation you will likely need a nautical chart of the area to correlate a buoy with the light characteristics you see on the water. On a chart, each buoy marker will have a light display abbreviation to indicate the type of flashes the light emits. If you are in the United States, jump to page 21 of the US Coast Guard Aid to Navigation Systems PDF to learn the abbreviations. For Canadian boaters, you can learn more about the lights on each buoy here.

Final Thoughts

Remembering your buoys will make marine navigation so much easier. Sure, nautical charts will keep you heading in the right direction, but the visual cues that buoys provide help you make quick decisions and keep your boat in safe waters.

If you ever find yourself in unknown waters, try to find a way between green and red buoys, and avoid areas with orange and white hazard buoys.

There is a lot to learn about the buoys, beacons, and lights on the water. So much so that we need to reference nautical charts and Coast Guard materials from time to time. To continue learning about the various markings on the water, visit the US Coast Guard PDF ‘US Aids to Navigation Systems’ or the Canadian Buoyage System outline from

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