International boating rules

Distress signals

Distress signals must be used only to indicate need of assistance. Misuse of them may put the lives of others at risk and is illegal.

The following signals may be used to indicate distress.

  • Rockets or shells that throw red stars, fired into the air one at a time at short intervals.
  • A signal:
    • made by radiotelegraphy or by any other signalling method consisting of the letters S O S in Morse Code (*** — — — ***)
    • sent by marine radio consisting of the spoken word: mayday.
  • A square flag having above or below it a ball or anything resembling a ball.
  • A rocket parachute flare or a hand-held flare showing a red light.
  • A smoke signal giving off orange-coloured smoke.
  • Slowly and repeatedly raising and lowering arms outstretched to each side.
  • A rectangle of international orange-coloured material with either a:
    • black letter V
    • black square and circle, or
    • dye marker.
  • The International signal of distress indicated by N.C.

    Signal flags of international distress signal on the left is a blue and white chequered flag and on the right a flag with a red stip in the middle with a white stripe either side and blue stripes either side of that on the top and bottom.
  • Continuous sounding of any fog-signalling apparatus.
  • Signal transmitted by an Emergency Position Indicating Radio Beacon (EPIRB).

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Page last updated 14 February 2017

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