What Is an EPIRB?
What Is an EPIRB? — EPIRBs for Dummies
Right. Let us keep this simple. No jargon. No technical waffle. Just a straight answer to what an EPIRB actually is and why it matters.
The Plain English Version
An EPIRB is a button you press when your boat is sinking and you need someone to come and get you.
That is genuinely it. When you activate it — either by pressing the button yourself or automatically when it hits the water — it sends a signal via satellite to the coastguard. The signal includes who you are and exactly where you are. Rescue services then come and find you.
Think of it like this. You are in trouble at sea. You cannot call anyone because there is no phone signal. Your VHF radio might not reach the coastguard. The EPIRB bypasses all of that. It talks directly to a satellite network that covers the entire planet and tells the right people exactly where to find you. No phone mast needed. No VHF range limitations. Works anywhere on Earth.
What Does EPIRB Stand For?
Emergency Position Indicating Radio Beacon. Do not worry about remembering that. Just remember what it does — it tells rescuers where you are in an emergency.
How Does It Actually Work?
You activate the EPIRB. It transmits a signal on 406MHz — a dedicated international distress frequency. That signal is picked up by the Cospas-Sarsat satellite network, a global system of search and rescue satellites that covers the entire world. The satellites relay your signal — and your GPS position if your EPIRB has GPS, which all modern ones do — to the nearest rescue coordination centre. In UK waters that is HM Coastguard. They then dispatch the appropriate rescue resources to your location.
The whole process from activation to coastguard notification happens within minutes.
Where Should It Be Mounted?
On deck, in a bracket that is easy to reach from the cockpit, ideally near the liferaft. High enough to be visible, accessible enough to grab in seconds. Not below decks. Not in a locker. I have seen them mounted on the saloon exterior near the companionway on many vessels — that is the right idea. The point is that in an emergency you should be able to grab it without thinking. Check out our favourites.
Category 1 EPIRBs have a hydrostatic release — they float free and activate automatically if the vessel sinks. Category 2 must be activated manually. Either way it needs to be where someone can reach it instantly.
What Is the Difference Between an EPIRB, a PLB, and a SART?
People get confused between these three because they are all small orange devices that help rescuers find you. Here is the two-sentence version:
An EPIRB is registered to your vessel and stays with the boat — it calls for help when the boat is in trouble. A PLB is registered to you personally and goes wherever you go — it calls for help when you personally are in trouble. A SART does not call for help at all — it guides rescuers to your exact position once they are already in your area looking for you.
All three do different things. Ideally you have all three. At minimum — have an EPIRB on the vessel.
Do You Have to Register It?
Yes — and it is free. Register your EPIRB with the UK Beacon Registry at UK Beacon Registry, It takes 15 minutes. An unregistered EPIRB still transmits but rescuers have no idea who you are or what vessel is in trouble, which significantly slows the response. Register it. Keep the registration up to date whenever your vessel details or contact information changes.
Do You Legally Need One?
For commercial vessels — yes under SOLAS. For recreational vessels under 13.7 metres in UK waters — not by law. But the absence of a legal requirement does not mean the absence of a need. For any passage offshore or out of sight of land, an EPIRB is the single most important piece of safety equipment on the vessel.
FAQs
How much does an EPIRB cost?
Between £250 and £600 for a quality GPS-enabled unit. Battery replacement every 10 years. Servicing every 5 years. Compared to the cost of the rescue operation it enables — negligible.
Can it be tested?
Yes — using the built-in self-test function only. Never fully activate one unless it is a genuine emergency. A false activation is illegal and wastes coastguard resources.
How long does it transmit for?
A minimum of 48 hours once activated. Modern units often transmit for longer.
The information in this article is for general guidance only and does not constitute professional safety advice. Always verify current EPIRB requirements and registration obligations at gov.uk/mca and beaconregistration.admiralty.co.uk. marinesafetyguide.com participates in affiliate programmes including Amazon Associates and the Awin network and may earn a small commission on purchases made through links on this site, at no extra cost to you.
