How to Read Navigation Buoys and Channel Markers in the U.S.

Everything You Need to Know About Navigation Buoys and Channel Markers

If you've spent any time on a boat, you've likely seen navigation buoys and channel markers, even if you weren't sure exactly what they were or how they were supposed to function. Learning to recognize and understand these markers is crucial for your own safety, the safety of the people around you, and for the integrity of your local boating community – and it's never too late to learn.

Keep in mind that this article is relevant only to buoys and channel markers in the United States; different countries often have different approaches to signalling, navigation, etc.

Navigation, Safety, and More

On the road, it's important to give drivers visual indications of their surroundings, laws that apply in various areas, safety advisements, and more. That's why we have things like stop signs, traffic lights, warning signs, pylons, and even dotted/solid yellow lines on most roads.

But on the water, there's less of an opportunity for posting visual indications. If there's nearby land, authorities can post signage quite easily, but this isn't always available. That's why we typically use floating or anchored signs and navigation aids to signal to boaters.

What’s the Difference Between Channel Markers and Buoys?

If you take a look around your local waters, you'll probably see a variety of different markers, including signs on poles, pilings, and buoys that are anchored to the bottom of the water. If the water is shallow enough, a piling makes the most sense, since it allows the sign to be secure and stable. If the water is too deep, a floating buoy is more sensible; these can also be indispensable tools if channels change over time, making it easier for authorities to make adjustments when necessary.

For the most part, fixed markers and buoys contain the same information, just in a different format. As a captain or a passenger, you should treat them as functionally identical.

How Buoys and Markers are Lit

In many areas, markers and buoys have lighting. The lights have a dual purpose; not only do they make things more visible in dark or obscured conditions, but they also convey information by showcasing a specific colour or blinking at a specific frequency. For example, you might notice that there is a local buoy that blinks red at an interval of every two seconds.

Light colours and frequencies are typically marked on charts and chart plotters. Because of this, you can quickly identify the markers that are around you, discern your location, and potentially interpret the purpose of the marker at the same time.

Understanding Channel Markers and Buoys

Red and green markers are the most common, and these colours signal your ideal position. Speaking generally, if you're moving from open water to inland water or if you're heading upstream, you should keep red markers to your right and green markers to your left. Older boaters will likely be familiar with the expression, “red right returning:” this is why.

Note that this is a general rule and doesn't apply to all areas or situations.

You may also encounter specific markers that have both red and green on them, usually arranged in parallel, horizontal bands. These typically mark the transition point between two channels, requiring you to use whichever colour is highest as your primary indicating marker.

Other Markers and Aids

There are also other “non lateral” aids and markers to assist you with safety and navigation.

For example, you may find boards that are shaped like diamonds; these are primarily used to help you determine your location in the water.

There are some aids with red and white vertical stripes, indicating that water is unobstructed on both sides.

If you see red and black horizontal stripes, it's a sign that there is some kind of danger that's relatively isolated, which can be passed on either side.

There are also range markers, which come in pairs and have static lights. These two markers should line up vertically if you're in the middle of the channel. Keep in mind that the colours of these range markers are designed to maximise noticeability, so you don't have to analyse what the colours mean.

Some markers have symbols to indicate specific types of messages:

  • Diamond. If you see a diamond shape, it's meant to alert you that there's a specific hazard nearby. The hazard will likely be identified with a word or phrase, such as “rock,” within the diamond.
  • Circle. A circle indicates that there are certain regulated operations in play in this area. Additional context may be provided within or outside of the circle, such as a speed limit or a phrase like “No wake.”
  • Diamond with cross. If there is a diamond with a cross shape in the middle of it, it means that all boats are prohibited from this specific area. Additional context may be provided but is not typically necessary.
  • Square. Markers with a square area typically convey additional helpful information, such as signalling that a gas station is nearby, noting the distance to a specific destination, or providing directions.

Typically, markers that convey specific information or dictate specific regulations will be marked with orange and white colouration.

State Water Obstruction Marks convey that there's an obstruction to navigation, from the nearest shore to the marker itself. If you see this type of mark, do not pass between the mark and the nearest shore. You can identify these marks because they have black and white vertical stripes, and they may be accompanied by a white light that flashes quickly.

You may also encounter “special aids” that are coloured yellow. These typically mark things like anchorages, areas with underwater cables, areas for traffic separation, and other unique conditions. They can come in a wide variety of shapes and sizes and may be marked with a variety of different letters.

Finally, you may encounter white buoys that contain a blue stripe. These markers aren't going to help you with navigation; instead, these are mooring buoys where people can secure their boats.

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