Distress Signals at Sea: How to Call for Help

When something goes seriously wrong at sea, being able to signal for help clearly and unmistakably is vital. Rescuers can only come to your aid if they know you are in trouble and can find you. Over centuries, an internationally recognised set of distress signals has developed so that a call for help is understood the same way everywhere.

This guide explains the main distress signals, when to use them, and how a layered approach gives you the best chance of being seen and reached. Knowing these signals is not just exam material; it is knowledge that saves lives.

What Counts as a Distress Signal

A distress signal indicates grave and imminent danger to a vessel or person, and a need for immediate assistance. The internationally recognised signals are set out in the collision regulations, and using them when you are not in genuine distress is both dangerous and, in most jurisdictions, an offence.

Recognised signals include radio distress calls, red flares and parachute rockets, orange smoke, a continuous sounding of a fog signal, flames on the vessel, the raising and lowering of outstretched arms, an EPIRB signal, and the code flags “NC”, among others. In practice, recreational boaters rely most on a handful of these.

Radio: The Fastest Way to Raise the Alarm

For most boats within range of the coast or other vessels, VHF radio is the primary and fastest means of calling for help.

• A DSC distress alert sent from a set with Digital Selective Calling transmits your identity and, if connected to GPS, your position digitally at the press of a dedicated button. Coastguards and nearby vessels receive it instantly.
• A spoken Mayday call on channel 16 follows, giving your position, the nature of the emergency, the number of people on board and the help you need.

Radio has the advantage of two-way communication: rescuers can talk to you, confirm they are coming and coordinate. Always send a radio call first if you have one, before relying on visual signals.

Visual Signals: Flares and Electronic Lights

Visual signals show rescuers exactly where you are once they are looking in your direction.

• Red hand-held flares are for use when help is close and you need to pinpoint your position. They burn brightly for a short time.
• Red parachute rockets climb high and are visible over a long distance, used to attract attention when no help is yet in sight.
• Orange smoke signals are effective by day, showing your position and the wind direction to aircraft and boats.
• Electronic distress lights are increasingly available as a non-pyrotechnic alternative, flashing an internationally recognised distress pattern. They do not expire like flares or carry the same fire risk.

Use flares with care: they burn extremely hot and produce hot slag. Point them away from yourself, your crew and anything flammable, and follow the instructions printed on each one.

Sound, Light and Body Signals

When electronic and pyrotechnic means are unavailable, simpler signals still count.

• A continuous sound on a horn, whistle or fog signal indicates distress.
• Flashing a light, particularly the Morse code group for SOS, can attract attention at night.
• Slowly raising and lowering outstretched arms on each side is a recognised visual distress signal, useful when a rescuer or aircraft is already in view.
• Flames on the vessel, such as from a burning tar barrel, are a traditional recognised signal, though rarely practical today.

These low-tech signals matter because equipment can fail or run out, and rescuers scanning the water will recognise them.

Beacons: Reaching Rescue Beyond the Horizon

When you are beyond VHF range or want to guarantee an alert reaches search-and-rescue services, satellite beacons are the answer.

• An EPIRB is registered to the vessel and, once activated, transmits a distress signal via satellite that identifies you and gives your position. Many float free and activate automatically if the vessel sinks.
• A PLB is a smaller personal beacon registered to an individual, carried on your person, and activated by hand.

Register beacons correctly and keep the details up to date, because the registration information helps rescuers respond faster and rule out false alarms.

Building a Layered Approach

No single signal is reliable in every situation, so competent skippers carry a combination and use them in a sensible order.

• Start with the fastest, most informative method you have, usually a DSC alert and Mayday call on VHF.
• Back it up with a satellite beacon if you are far offshore or losing power.
• Use visual and sound signals to guide rescuers in once they are near.

Practise handling your equipment before you ever need it, and make sure your crew knows where everything is stowed and how it works. Understanding how and when to use each signal is a standard part of boating theory, and the boatingexamine course sets it in context so you remember it under pressure, not just for the exam.

FAQ

Should I use a flare or the radio first? Use the radio first if you have one, ideally a DSC alert followed by a spoken Mayday. Radio raises the alarm quickly, gives your position and allows two-way contact. Save flares to pinpoint your position once rescuers are near or looking your way.

Is it illegal to fire a flare when I am not in danger? Yes. Distress signals indicate grave and imminent danger. Using them without genuine cause diverts rescue resources, endangers others and is an offence in most jurisdictions. Dispose of expired flares properly rather than firing them for practice.

What if I am beyond VHF radio range? Rely on a satellite beacon such as an EPIRB or PLB, which alerts search-and-rescue services via satellite regardless of your distance from shore. Keep the beacon registered and its details current so responders can act quickly.