SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/boat-safe-water-mark

What does a buoy with red and white vertical stripes mean?

Safe water all around it: it often marks a fairway or mid-channel.

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  1. Danger, keep away on all sides
  2. Swimming area, no boats
  3. Navigable water all around it ✔

Why: Safe water marks have red and white vertical stripes and mean there's navigable water all around. They often mark fairways, mid-channels or the seaward end of channels.

Huh, didn't know that: At night a safe water mark flashes white in Morse Code 'A' (short-long).

The dad joke
Why are red and white striped buoys so relaxed? They're surrounded by good water.
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References

Answer: Navigable water all around it. Safe water marks have red and white vertical stripes and mean there's navigable water all around. They often mark fairways, mid-channels or the seaward end of channels.

  1. 33 CFR Part 62, U.S. Aids to Navigation System (62.27) www.ecfr.gov/current/title-33/part-62
    Safe water marks indicate that there is navigable water all around the mark.
    Checked 2026-10-09.

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