Think of cardinal buoys as the traffic signs of the sea.
Unlike road signs that tell you to turn left or right, these buoys use the compass to guide you. They are placed around a hazard—like a hidden rock, a sandbank, or a wreck—to tell mariners exactly which side is the safe, deep water.
An East Cardinal Buoy, for instance, tells you: “The safe water is to the East of me. Pass on my eastern side, because there is danger waiting to the west.”
To make them easy to identify from a distance, even in rough seas or fading light, every cardinal buoy uses three distinct clues: colors, cones (topmarks), and lights.
Here is how to read an East Cardinal buoy using those clues:
1. The Cones (The Topmark)
At the very top of the buoy, you will see two black cones. They act like arrows pointing toward the safe color zones on the buoy’s body:
For an East buoy, the two cones point away from each other—one pointing up, one pointing down (forming a diamond shape).
Memory trick: Think of the wide part of an East or the shape of an egg (Egg).
2. The Colors
The body of the buoy is painted with bold black and yellow horizontal bands. The direction of the cones tells you exactly where the black bands are:
Because the cones point both up and down for East, the black bands are at the top and the bottom, leaving a bright yellow band right in the middle.
3. The Light (At Night)
When the sun goes down, the buoy flashes a white light in a specific rhythm so sailors can count the flashes and know which direction it represents. To make it easy to remember, the rhythms follow a standard 12-hour clock face:
East is at 3 o’clock on a clock face, so an East buoy flashes in groups of 3 quick flashes.
(For comparison, a South buoy at 6 o’clock flashes 6 times, and a West buoy at 9 o’clock flashes 9 times).
The Full Cardinal Family at a Glance
If you can read an East buoy, the rest of the compass points follow a similar logic.
Cardinal buoys (link opens a new page) for official Trinity House website