Bouys and their meanings

Oct 19, 20212021, boating, Coast Guard, coastal cruising, DEP, EPA, Florida, Florida Keys, USA, waterways, yachting

Before we get started it may be helpful to understand exactly what a bouy is and does.

Do you know what a bouy is and does?

A bouy is a device that floats on the water and assists boaters in navigating the waterways. Bouys are used to warn vessel operators of dangers or obstacles like shallow water.

There are many types of bouys. Not all types of bouys will be highlighted here, but some of the more common ones will be discussed in this article. These include:

  • Lateral Bouys: port and starboard
  • Bifurcation bouy
  • Isolated danger bouy
  • Junction daybeacon: port and starboard
  • Special Purpose Bouys:
  • Anchorage
  • Cautionary
  • Mooring
  • Information
  • Hazard
  • Control
  • Keep out
  • Diving
  • Swimming
  • Cardinal

Lateral bouys are commonly used as channel markers, both the port and starboard sides of the channel so that vessels stay in water that is of a certain depth. These markers pertain to movement both up and down stream. Port is the left side of the channel and starboard is the right. These can be confusing. When traveling upstream the port side bouy is on the left and is green in color. When traveling upstream the starboard bouy is red and on the right. These are conical in shape, numbered, and have a flashing light on the top so they can be seen after dusk and before dawn. All vessel operators need to keep their boats between these markers when moving in the channel.

Port Bouy

Port bouy traveling upstream. (above)

Starboard Bouy

Starboard bouy traveling upstream. (above)

When a channel divides into two channels a bifurcation bouy is used. Usually these are both green and red and allow vessels to pass on either side of them. Lights on top are green or red.

Bifurcation Bouys- port and starboard

Bifurcation Bouys: port or starboard. (above(

The isolated danger bouy marks some type of danger on the water. This can be a sunken boat or other hazard. These should be moored above the danger. Their coloration is black and red with a white colored light on the top.

Isloated Danger Bouy

Isloated danger bouy.

Junction daybeacons are used to mark where channels divide. They are both starboard and port and are affixed to bridges or trees or posts of some sort.

The starboard junction daybeacon is diamond shaped with a red outline and a red triangle inside. Vessels may pass on either side of this bouy.

Junction Bouy - starboard


Starboard junction daybeacon bouy. (above)

The port junction daybeacon bouy is also diamond shaped with a green outline, but has a green square inside. It can also be passed on either side.

Junction Bouy - port

Port junction daybeacon bouy. (above)

Anchorages are designated places for boats/vessels to anchor safely.

The anchorage bouy marks the outer limits of the anchorage. Vessel operators should consult their charts or GPS for exact water depths prior to embarking on anchoring. The anchorage bouy is yellow with a black anchor painted on it. There is a yellow light on top that flashes every 4 seconds.

Anchorage Bouy

Anchorage bouy. (above)

The cautionary bouy is also yellow and marks water dangers or hazards. These dangers can range from raceways to underwater structures or other areas. These are yellow with a yellow light on top.

Cautionary Bouy

Cautionary bouy. (above)

Mooring bouys are white and orange striped and they are used in safe mooring areas. Vessel operators can hook directly onto them for the duration of their anchorage without tossing out an anchor. (see picture below)

Mooring Bouy

See loop attached. That is where the mariner ties their boat line.

Mooring bouy. (above)

The information bouy is white with two orange stripes, top and bottom and a square in the middle. The middle portion usually contains words, symbols, or other information that are of interest to the mariner.

Information Bouy

Information bouy. (above)

The hazard bouy is white with a stripe on the top and bottom that are orange in color and an orange diamond on the center of it. These are used to mark rocky outcroppings or shoals. Please note that not all rocky or shoaled places on the water are marked so use your GPS or chart to ensure you are safe.

Hazard Bouy

Hazard bouy. (above)

Control bouys are used to mark restricted areas or other vessel restrictions such as speed or wake. They are white with two orange bands on the top and bottom and an orange circle in the center. There is a yellow light on top that flashes every 4 seconds. Sometimes there are words inside the circle in black lettering.

Control Bouy

Control bouy. (above)

The keep out bouy is also white with an orange stripe on the top and bottom. The midsection of this bouy has an orange diamond with a cross or x on it. This means that you are not allowed in that area. There may also be black words on it depicting what you are not allowed near, i.e. Damn or swim areas.

Keep Out Bouy

Keep out bouy. (above)

Diving bouys are used to mark areas where there is diving or snorkeling activity. This signals that there are divers or snorkelrs in the water and that all vessels should use slow speed when nearby. These bouys are round and white with a red and white diagonally striped flag atop.

Diver Down Bouy

Diving bouy. (above)

Swimming bouys designate swimming areas. These bouys are white and have a yellow flashing light on top. They may be lined together by a rope.

Swimming Bouys

Swimming bouys. (above)

Cardinal bouys are used to point out danger. Usually, they come 4 bouys at a time surrounding the dangerous place. The four points designate north, south, east, and west. These are black and yellow with two arrows atop. The north bouy is black on the top and yellow on the bottom with arrows pointing upward. The south bouy is yellow on the top and black on the bottom with the arrows pointing downward. The east bouy is black with a yellow stripe in the middle and the arrows point one upward and the other downward. The west bouy is yellow with a black stripe in the middle and the arrows point one upward and the other downward.

Cardinal Bouy - North

Cardinal bouy-North. (above)

Cardinal Bouy - South

Cardinal bouy-South. (above)

Cardinal Bouy - East

Cardinal bouy-East. (above)

Cardinal Bouy - West

Cardinal bouy-West. (above)

Now that you have a basic understanding of the various bouys used on the waterways you can progress safer because you have a certain basic knowledge of what each means and how you, as a vessel operator, ought to navigate. Enjoy!





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