What are lists of Distress signals by ships as per International Regulation for preventing collision at sea?

Distress signals to be used or displayed, either together or separately, by a vessel (or seaplane on the water) in distress requiring assistance from other vessels or from the shore.

  1. A gun or other explosive signal fire at intervals of about a minute.
  2. A continuous sounding with any fog-signaling apparatus.
  3. Rockets or shells, throwing red stars fired one at a time at short intervals.
  4. A signal made by radiotelegraphy or by any other signaling method consisting of the group • • • – – – • • • SOS in the Morse Code.
  5. A signal sent by radiotelephony consisting of the spoken word “MAYDAY”.
  6. The International Code Signal of distress indicated by NC.
  7. A signal consisting of a square flag having above or below it a ball or anything resembling a ball.
  8. Flames on the vessel (as from a burning tar barrel, oil barrel, etc.).
  9. A rocket parachute flare or a hand flare showing a red light.
  10. A smoke signal giving off a volume of orange-colored smoke.
  11. Slowly and repeatedly raising and lowering arms outstretched to each side.
  12. The radiotelegraph alarm signal.*
  13. The radiotelephone alarm signal.**
  14. Signals transmitted by emergency position-indicating beacons.***


  1. Vessels in distress may use the radiotelegraph alarm signal or the radiotelephone alarm signal to secure attention to distress calls and messages.The radiotelegraph alarm signal, which is designed to actuate the radiotelegraph auto alarms of vessels so fitted, consists of a series of twelve dashes, sent in 1 minute, the duration of each dash being 4 seconds and the duration of the interval between 2 consecutive dashes being 1 second. The radiotelephone alarm signal consists of 2 tones transmitted alternately over periods of from 30 seconds to 1 minute.
  2. The use of any of the foregoing signals, except for the purpose of indicating that a vessel or seaplane is in distress, and the use of any signals which may be confused with any of the above signals is prohibited.


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