A vessel is said to be in distress when she is in a state of danger or necessity hindering her to continue her voyage , as due to fire, collision, stranding, heavy weather damage, machinery failure, provision shortage, etc.
The first action a vessel in distress and in need of assistance must take, is to exhibit either together or separately, the distress signals prescribed in Annex IV of theInternational Regulations for Preventing Collisions at Sea (Colregs):
- The following signals, used or exhibited either together or separately, Indicate distress and need of assistance:
- a gun or other explosive signal fired at intervals of about a minute;
- a continuous sounding with any fog signalling apparatus;
- rockets or shells, throwing red stars fired one at a time at short Intervals;a signal made by radiotelegraphy or by any other signalling method consisting of the group · · · — — — · · · (SOS) in the Morse Code;
- a signal sent by radiotelephony consisting of the spoken word "Mayday"
- the International Code of distress Indicated by N.C.;
- a signal consisting of a square flag having above or below it a ball or anything resembling a ball;
- flames on the vessel (as from a burning tar barrel, oil barrel, etc.);
- a rocket parachute flare or a hand flare showing a red light;
- a smoke signal giving off orange-coloured smoke;
- slowly and repeatedly raising and lowering arms outstretched to each side;
- the radiotelegraph alarm signal;
- the radiotelephone alarm signal;
- signals transmitted by emergency position‑indicating radio beacons.