Marine flares and distress signals
Red flares, orange smoke and the other COLREG Annex IV signals mean you are in distress and need help.
Reviewed by Ramon Curto, Nautical teacher at IECNPC · Last reviewed:
Which signal when?
DSC + MAYDAY
Send a DSC distress alert if equipped, then voice MAYDAY on VHF channel 16; tell rescuers your position and emergency.
EPIRB / PLB
Activate the appropriate registered distress beacon in grave and imminent danger; a satellite alert complements your radio call.
Orange smoke
In daylight with rescuers nearby, smoke marks your position and helps an aircraft see the wind; never aim a flare at aircraft.
Study aid: no distance guarantees. Alert rescue services promptly; follow equipment instructions and local rules.
Worked example
Day · Nearby / in sight · Grave and imminent danger
- DSC + MAYDAY: Send a DSC distress alert if equipped, then voice MAYDAY on VHF channel 16; tell rescuers your position and emergency.
- EPIRB / PLB: Activate the appropriate registered distress beacon in grave and imminent danger; a satellite alert complements your radio call.
- Orange smoke: In daylight with rescuers nearby, smoke marks your position and helps an aircraft see the wind; never aim a flare at aircraft.
- Red parachute rocket
- ≥ 300 m · ≥ 40 s
- Red hand flare
- ≥ 60 s
- Orange smoke
- ≥ 180 s
Study aid: no distance guarantees. Alert rescue services promptly; follow equipment instructions and local rules.
COLREG Annex IV: all 15 signals
Rule 37(a) Gun or explosive signal at intervals of about one minute.
(b) Continuous sounding of any fog-signalling apparatus.
(c) Rockets or shells throwing red stars, one at a time at short intervals.
(d) SOS in Morse code, by any signalling method: ··· −−− ···.
(e) The spoken word MAYDAY transmitted by radio.
(f) International Code of Signals flags N over C.
(g) A square flag with a ball or ball-like object above or below it.
(h) Flames on the vessel, for example from a burning barrel; recognition, not advice to start a fire.
(i) A red rocket parachute flare or red hand flare.
(j) A smoke signal giving off orange smoke.
(k) Slowly and repeatedly raise and lower arms outstretched to each side.
(l) DSC distress alert on VHF channel 70 or the designated MF/HF distress frequencies.
(m) Ship-to-shore distress alert through Inmarsat or another mobile satellite service ship earth station.
(n) Signals from an emergency position-indicating radio beacon (EPIRB).
(o) Approved radiocommunication distress signals, including survival-craft radar transponders.
How it works
Rule 37 sends you to Annex IV when a vessel is in distress and needs assistance. The signals may be used together or separately, but Annex IV prohibits their use for any other purpose and also prohibits signals that could be confused with them. Learn the whole list, including sound, flags, body movements and radio, rather than treating flares as the only way to ask for help. The flames entry is a recognition question, not an instruction to create a dangerous fire aboard.
First alert the rescue service. If your VHF has DSC, send the distress alert on channel 70 and follow with a voice MAYDAY on channel 16. Give your position, the nature of the emergency and the help you need. A registered EPIRB, or a suitable personal locator beacon (PLB), can alert the satellite rescue system when lives are in grave and imminent danger. A PLB is a personal device, not automatically a legal replacement for a required EPIRB. Radios and beacons alert; visual signals help rescuers locate you.
Choose the visual signal for the conditions. Orange smoke is for daylight; a red hand flare helps pinpoint your position at close quarters, especially at night. A red parachute rocket attracts attention higher above the water. The IMO LSA Code specifies a minimum vertical height of 300 metres and a red burning period of at least 40 seconds for its rocket parachute flare standard, at least one minute for a hand flare and at least three minutes for buoyant smoke. These are standards, not a promise about every leisure product or a guaranteed viewing distance.
For example, by day with rescuers already in sight, send the radio alert and use orange smoke to mark your location; at night in the same situation, choose a red hand flare. Read the instructions before departure, keep pyrotechnics dry and accessible, hold a hand flare downwind clear of people and the boat, and never fire toward an aircraft. White collision-warning flares are not distress signals. Check the printed expiry: US-approved pyrotechnics commonly have a 42-month maximum labelled life from manufacture; expired devices do not meet the carriage requirement. US carriage rules are in 33 CFR 175 Subpart C. Disposal and carriage vary by country: in the UK arrange a specialist third-party disposal service, rather than assuming HM Coastguard accepts them. Annex IV recognition is relevant to RYA, PER and SBF See preparation; practise the exact colours and distinguish distress from collision warnings.
Frequently asked questions
Is orange smoke a night signal?
No. It is a daylight visual distress signal; darkness makes smoke difficult to see.
Is a white flare a distress signal?
No. A white collision-warning flare is not the red distress flare in Annex IV.
How high does a red parachute rocket go?
The IMO LSA Code standard requires at least 300 metres when fired vertically and a red burn of at least 40 seconds. Check your product's approval and instructions.
When should I use a hand flare?
To help nearby rescuers identify your position, particularly at night; alert the rescue service as well.
Can a PLB replace every required EPIRB?
No. A registered personal beacon can raise a distress alert, but carriage and approved-equipment requirements depend on your vessel and jurisdiction.
What does the US expiry date mean?
US-approved flares commonly show a service-life expiry no more than 42 months after manufacture. Carry in-date approved signals as required by 33 CFR 175 Subpart C.
Where can I dispose of expired flares?
Use an authorised local disposal service. Never fire them for disposal, put them in household rubbish or throw them overboard. UK HM Coastguard no longer accepts private individuals' unwanted flares.