A buoy is a floating device anchored to the seabed or riverbed, used as a navigational aid for ships and boats. Buoys come in many forms: some mark safe channels, others warn of hazards, some moor vessels, and scientific buoys collect oceanographic data like temperature, salinity, and wave height.
The classic image is a brightly colored, cone-shaped or spherical marker bobbing on the water. Lateral buoys (red and green) indicate the edges of safe channels. Cardinal buoys** (yellow and black) point to safe water relative to a hazard. **Mooring buoys** provide a place to tie up without dropping anchor.
Why It Matters
Before electronic navigation, buoys were the primary way mariners knew where it was safe to sail. They still serve as critical backup systems when GPS fails. The International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA) maintains two global systems — System A and System B — which use opposite color schemes in different regions, confusing sailors who cross between them.
Buoys also appear in metaphor: “buoyed by hope” means kept afloat by optimism, drawing on the device’s literal function of keeping things from sinking.
Examples
- IALA System A: Red = port (left) when returning from sea; used in Europe, Africa, Asia.
- IALA System B: Red = starboard (right) when returning from sea; used in the Americas.
- Weather buoys: NOAA maintains a network of ocean buoys for hurricane tracking and climate research.
Related Terms
- Beacon, lighthouse, marker
- Navigation, maritime, channel
- Mooring, anchorage, seamanship