Distress Signals

Rule 37 in the Rules of the Road states:

"When a vessel is in distress and requires assistance she shall use or exhibit the signals described in Annex IV to these regulations."

Red Star
Fog Horn
Flames on
A Vessel
Gun Fired at Intervals of One Minute
Black Ball &
SOS "Mayday"
by Radio
Red Flare
Dye Marker
(any color)
Code Flags
Square Flag
and Ball
Epirb Smoke

Distress signal used
only on inland waters:

A high intensity white light
flashing at regular intervals
from 50 to 70 times per minute

Annex IV - Distress Signals further states:

-- International -- -- Inland --
1. Need of assistance § 87.1 Need of assistance
The following signals, used or exhibited together or separately, indicate distress and need of assistance. Same as International
(a) a gun or other explosive signal fired at intervals of about a minute; Same as International
(b) a continuous sounding with any fog-signalling apparatus; Same as International
(c) rockets or shells, throwing red stars fired one at a time at short intervals; Same as International
(d) a signal made by radiotelegraphy or by any other signaling method consisting of the group ... - - - ... (SOS) in the Morse Code; Same as International
(e) a signal sent by radiotelephony consisting of the spoken word "Mayday"; Same as International
(f) the International Code Signal of distress indicated by N.C. (November, Charlie); Same as International
(g) a signal consisting of a square flag having above or below it a ball or anything resembling a ball; Same as International
(h) flames on the vessel (as from a burning tar barrel, oil barrel, etc.); Same as International
(i) a rocket parachute flare or a hand flare showing a red light; Same as International
(j) a smoke signal giving off orange-colored smoke; Same as International
(k) slowly and repeatedly raising and lowering arms outstretched to each side; Same as International
(l) the radiotelegraph alarm signal; Same as International
(m) the radiotelephone alarm signal; Same as International
(n) signals transmitted by emergency position-indicating rado beacons; Same as International
(o) approved signals transmitted by radiocommunication systems. Same as International
(p) A high intensity white light flashing at regular intervals from 50 to 70 times per minute.
-- International -- (continued) -- Inland -- (continued)
2. The use or exhibition of any of the foregoing signals except for the purpose of indicating distress and need of assistance and the use of other signals which may be confused with any of the above signals is prohibited. § 87.3 Exclusive Use.
Same as International
3. Attention is drawn to the relevant sections of the International Code of Signals, the Merchant Ship Search and Rescue Manual and the following signals:
---(a) a piece of orange-colored canvas with either a black square and circle or other appropriate symbol (for identification from the air);
---(b) a dye marker.
§ 87.5 Supplemental signals.
Same as International except reference is make also to the relevant sections of the International Telecommunication Union Regulations.

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