How to Use an EPIRB Device (Radio Beacon) and When to Activate It?

How to use an EPIRB device (radio beacon) and when to activate it — every serious sailor knows that safety at sea is not a matter of chance, but is planned in advance. In this detailed guide, we give you all the answers — first-hand, from the field, drawn from the experience of experts who have helped hundreds of sailors equip their vessels for safe navigation on the Adriatic and open seas.

An EPIRB (Emergency Position-Indicating Radio Beacon) is among the most critical safety equipment on board any vessel. It is a device that, in an emergency, automatically or manually transmits a digital signal to the global Search and Rescue network (SAR), enabling rescue teams to find you — quickly and precisely. In an environment where every minute can be decisive, an EPIRB is often the difference between life and a tragic outcome.

What Is an EPIRB and How Does It Work?

EPIRB stands for Emergency Position-Indicating Radio Beacon — a radio transmitter that, in an emergency, shows your exact position. The device emits a digital signal on the 406 MHz frequency to the Cospas-Sarsat satellite system, which receives, decodes and forwards the signal to the nearest Rescue Coordination Centre (RCC).

Every EPIRB carries a unique 15-digit digital identifier linked to your vessel and registered in a national database. This means that the moment rescue services receive your signal, they immediately know who you are, what vessel you have, where it is sailing and which shore contact to call — dramatically accelerating the rescue operation.

In addition to the 406 MHz signal, modern EPIRB devices also transmit a secondary signal on 121.5 MHz, which rescue teams use for final homing to your location. Newer models also include an integrated GPS/GNSS receiver, transmitting your location with an accuracy of just a few metres.

Quick Answer: An EPIRB sends a signal via Cospas-Sarsat satellites to rescue coordination centres. The signal contains your identity, position (GPS) and vessel data. Rescue teams receive an alert within minutes of activation.

What Types of EPIRB Devices Are There?

There are two basic categories of EPIRB devices on the market, differing in their method of activation and mounting.

Category 1 — Automatic Release (Recommended for Offshore Sailing)

A Category 1 EPIRB is mounted in a dedicated bracket fitted with a Hydrostatic Release Unit (HRU). When the vessel sinks and the device reaches a depth of between 1.5 and 4 metres, the HRU automatically releases the EPIRB, which floats to the surface and begins transmitting a signal automatically — even if the crew is unable to activate the device manually.

This is the key distinction: Category 1 protects you even in a scenario of sudden sinking, when there is no time for manual activation. That is precisely why we recommend it to all clients planning offshore or long Mediterranean passages.

Category 2 — Manual Activation

A Category 2 EPIRB requires manual removal from its bracket and manual activation. It can be mounted above or below deck and is activated exclusively by hand — either by immersion in water or by pressing the activation button. It is suitable for sailing closer to shore, but always with the reminder that it must be within reach in an emergency.

When to Activate an EPIRB — and When NOT To?

This is the most common question we hear from sailors. How to use an EPIRB device (radio beacon) and when to activate it in a specific situation? The answer is clear: activate your EPIRB ONLY in the event of a serious and immediate threat to life.

Situations When You SHOULD Activate an EPIRB:

• The vessel is sinking or there is an imminent risk of sinking
• An uncontrollable fire on board
• A serious medical emergency at sea with no possibility of timely assistance
• The vessel has lost steering, propulsion or all means of communication and is drifting into danger
• A crew member has fallen overboard and cannot be found, leaving the vessel without a helmsman
• Any situation in which there is a real risk of loss of life without immediate outside assistance

Situations When You Should NOT Activate an EPIRB:

• Engine failure that does not endanger life — use your VHF radio on Channel 16
• You have lost your bearings — use GPS and VHF to communicate with the shore
• You have run out of fuel near the coast — contact the marine police or towing service
• Testing the device — NEVER activate an EPIRB for testing purposes without prior notification to the relevant authorities

Warning: Every false EPIRB alarm triggers a costly and complex rescue operation, diverts resources away from genuine emergencies and can result in a fine. Always check that your device is properly secured in its bracket and protected from accidental activation.

How to Use an EPIRB Device (Radio Beacon) — Step by Step

Knowing the procedures in calm conditions saves lives in crisis situations. Understanding how to use an EPIRB device and when to activate it correctly can make the difference between a successful rescue and a tragedy. Here are the precise steps.

Automatic Activation (Category 1):

1. The device is mounted in its bracket — no action required from you
2. In the event of sinking, the HRU automatically releases the EPIRB at a depth of 1.5–4 m
3. The EPIRB floats to the surface, the antenna positions itself upward and the device begins transmitting automatically
4. The signal reaches rescue coordination centres within minutes

Manual Activation (Category 1 and 2):

1. Remove the EPIRB from its bracket
2. Activate the device according to the manufacturer’s instructions — typically by flipping the cover and pressing the activation button
3. Ensure the antenna is ALWAYS pointing towards the sky — this is critical for signal reception
4. Hold the device or attach it to your body, life raft or rescue dinghy
5. Do not switch the device off — let it transmit continuously until the rescue team confirms receipt
6. Monitor the strobe light — it confirms the device is operating

What to Do After Activation?

After activation, remain with the vessel or as close to the point of activation as possible — rescue teams are homing in on the signal’s location. Also activate all other distress signalling equipment: VHF radio (Channel 16), flares and strobe lights. If you have an AIS EPIRB, nearby vessels equipped with AIS transponders will receive an alert in real time.

AIS EPIRB — Technology That Saves Lives

The latest generation of EPIRB devices integrates AIS (Automatic Identification System) technology, bringing a key advantage: nearby vessels fitted with AIS transponders receive an alert immediately upon activation — without waiting for the satellite signal.
A combined AIS EPIRB reduces the search radius from several kilometres to just 10 metres thanks to GPS precision, while simultaneously alerting all AIS-equipped vessels within VHF range — which in the busy Adriatic can mean a rescue response within minutes.

At Adria Yachts, we recommend AIS EPIRB devices to all clients planning to sail beyond sight of the coast or taking part in offshore races and long-distance passages.

Return Link Service (RLS) — Confirmation That Rescuers Are on Their Way

One of the greatest psychological challenges in a life-threatening situation is uncertainty: have they received my signal? This is precisely where Return Link Service (RLS) comes in — a recent feature available in RLS-enabled EPIRB devices. Via the Galileo satellite network, the EPIRB receives a return signal manifested as a flashing blue LED light — a visual confirmation that rescue coordination centres have received your distress message.

This is enormously important for the psychological stability of the crew in a crisis — you know that help is coming.

EPIRB Registration — A Legal Obligation and Vital Information

Registering your EPIRB is not merely a legal obligation — it literally saves lives. When a rescue coordination centre receives your EPIRB signal, it immediately has access to your data: your name, the type and description of your vessel, the number of persons on board, a shore contact and your planned route.

When and How to Register an EPIRB?

• Immediately upon purchasing a new or second-hand EPIRB device
• Every time you change your vessel, contact details or address
• After selling the device — notify the relevant authority and ensure the new owner registers it in their own name
• Renew your registration at least every 2 years (for serial-number EPIRB devices)

For vessels registered in Croatia, EPIRB registration is handled through the Ministry of the Sea, Transport and Infrastructure or via the online MMSI registration system. Always verify that your details are up to date before any longer voyage.

EPIRB Maintenance — Don’t Overlook This!

An EPIRB is a device you hope you will never need to use — but it must be ready when you do. Regular maintenance is not optional; it is an obligation.

Battery: Replace the battery according to the manufacturer’s instructions, or at the latest by the expiry date marked on the device. Many authorities require battery replacement at every scheduled service, typically every 4–5 years.

HRU Unit (Category 1): The Hydrostatic Release Unit must be replaced every 2 years, without exception. This is the critical component that ensures automatic activation — an expired HRU can fail at the most critical moment.

Mounting Bracket: Regularly inspect the condition of the bracket, retaining clip and release mechanism. Salt water and UV radiation accelerate the degradation of materials.

Self-Testing: Carry out a self-test once a month according to the manufacturer’s instructions. Modern EPIRB2 and EPIRB3 devices offer NFC technology — simply hold your smartphone next to the device and the app will display all diagnostic data: battery status, GPS lock and the date of the last test.

Adria Yachts Tip: Always prepare a Ditch Bag alongside your EPIRB — a grab bag for abandoning ship that contains a VHF radio, flares, a bottle of water, a first aid kit and personal documents. A Category 2 EPIRB can be stored in the Ditch Bag, but ensure it is properly secured, as accidental activation can occur upon contact with water.

Legal Requirements and Obligations in Croatia

Under current regulations, an EPIRB is not mandatory for all recreational vessels in Croatian waters, but the Croatian Coast Guard and experienced sailors strongly recommend carrying one for any passage beyond the immediate vicinity of the coast.

For vessels engaged in international voyages or offshore waters, the International Maritime Organization (IMO) requires a Category 1, 406 MHz EPIRB to be carried on board. The same standard is recommended by the United States Coast Guard (USCG) for recreational vessels.

In any case: if we are planning a voyage on which we cannot reach VHF contact with the shore — an EPIRB is not a luxury; it is a necessity.

Which EPIRB to Choose? — Recommendations from the Adria Yachts Team

After years of experience equipping vessels and advising sailors, at Adria Yachts we recommend the following:

• Always choose a 406 MHz EPIRB — older 121.5 MHz models are obsolete and were withdrawn from use in 2009
• For offshore and Mediterranean passages — Category 1 with GPS and an AIS module
• For Adriatic coastal sailing — Category 2 as a minimum, but Category 1 for any passage beyond VHF range
• Consider the RLS option for the crew’s peace of mind in a crisis situation
• Verify that the EPIRB is approved by the relevant authorities (Cospas-Sarsat certification)

Conclusion: An EPIRB Is Not About Fear — It Is About Responsibility

The question of how to use an EPIRB device (radio beacon) and when to activate it should be part of every pre-departure briefing. We never know when we will need it — but a sailor who understands their equipment, knows the activation procedure and has a properly registered and serviced EPIRB has a real chance of surviving even the most extreme situations at sea.

At Adria Yachts, we believe that knowledge is just as important as equipment. That is precisely why the education of our clients sits at the very top of what we offer — from advising on the purchase of Bavaria motor yachts to fully equipping vessels for safe offshore voyages.

Do you have questions about EPIRB devices, safety equipment or fitting out your vessel? Feel free to contact us — the Adria Yachts team is always here for you.

Frequently Asked Questions (FAQ) — How to Use an EPIRB Device (Radio Beacon) and When to Activate It?

Q: How far does an EPIRB transmit its signal?

A: An EPIRB signal is received by the Cospas-Sarsat satellite network, which covers the entire globe — there is no range limitation. The signal is received regardless of location, from the Adriatic to the open Atlantic or Pacific Ocean.

Q: How long does an EPIRB battery last?

A: A standard EPIRB must have sufficient battery capacity for at least 48 hours of continuous signal transmission. The service life of the battery between replacements is typically 5–6 years, but always check the instructions for your specific model.

Q: Can an EPIRB operate underwater?

A: EPIRB devices are waterproof and designed to operate on the water’s surface. Category 1 units are activated by immersion, but the signal is transmitted from the surface — the antenna must be above water.

Q: Do I need an EPIRB if I have a VHF radio?

A: Yes — VHF and an EPIRB are complementary, not interchangeable. VHF operates within a range of 20–50 nautical miles and requires active communication, whereas an EPIRB automatically transmits a signal to the global satellite network without any manual operation.

Q: How much does EPIRB registration cost?

A: In most countries, including Croatia, EPIRB registration is free of charge. The device must nevertheless be registered — without registration, the signal contains no identifying data and rescue operations are considerably more difficult to execute.