Personal EPIRBs - what use are they really?

More personal EPIRBs are now being sold in the UK than ever before. In this report, Karl Pentin, Director of independent safety equipment specialists, Safety Marine, looks at how these beacons actually work, how they should be used and whether they might be giving sailors and other mariners, a false sense of security.

With prices now starting at around 300, 406mhz personal locator beacons are being sold in record quantities throughout the UK. And if you ask the majority of people what their prime motivation is for this purchase, nine times out of ten it is because they are concerned about being lost overboard.

But of the thousands of sailors and mariners who now have one stuffed in their jacket pocket, how many really understand what personal EPIRBs are actually designed to do. And how many go to sea with a false sense of security, thinking that if they get knocked overboard then rescue is only a button-push away?

How do personal EPIRBs actually work?

All 406 MHz personal locator beacons - or 'personal EPIRBs', as they are most commonly known, work in exactly the same way as their larger vessel-mounted brothers.

Once activated, the beacons all transmit a uniquely-coded signal on a 406 MHz frequency which is picked up by one of the search and rescue satellites that orbit the earth. The satellite works out the beacon's approximate location and forwards that information, along with the beacon's individual identity, to an 'earth' station and then on to a local rescue co-ordination centre.

This co-ordination centre then launches the appropriate search and rescue resource to that approximate location. The beacon will also transmit a second signal on a 121.5 MHz frequency, which is a 'homing' signal. This will be used by the search and rescue teams to home-in on the beacon's final location.

With the incorporation of GPS technology into many of the latest personal EPIRB products, the exact co-ordinates of the beacon can now also be transmitted, together with the beacon's individual identity number. This gives the search and rescue services a significant head start by reducing the sea area that potentially has to be searched in the final phase of the rescue.

All good stuff you might say, a GPS version sounds like just the ticket!

But how long can this rescue process take?

Although the nine COSPAS SARSAT search and rescue satellites provide comprehensive coverage for the whole of the earth's surface, it can take up to 45 minutes before a 406 MHz signal is detected by the satellites and forwarded to a local rescue co-ordination centre. This, however, is certainly more of the exception than the rule, and in the majority of circumstances the response time is typically much quicker.

With the alert now raised, the local rescue co-ordination centre will launch the appropriate search and rescue team. However, the speed of the search and recovery phase will very much depend on the positional accuracy of the beacon, its distance from the rescue services home base and the prevailing weather conditions.

So it would be fair to say that, even in good conditions and with an accurate GPS location, it can still take some time before rescue services actually get to the scene.

This brings us back to why people are actually buying personal EPIRBs?

A crewman in the water, wearing regular sailing oilskins, will rapidly be losing body heat and quickly becoming tired, so every minute is critical. In this situation, will a 406 MHz personal locator beacon really be of any use?

The answer is yes, but you just have to be aware of what they are designed to do in relation to the risk that you are trying to manage.

In a man overboard situation, a 406 MHz personal locator beacon can still provide valuable information to the shore-based search and rescue services, who in turn can co-ordinate a search with the vessel that has lost the crewman.

Positional updates received from the beacon can be passed to the captain or skipper, hopefully enabling the vessel to locate the survivor rapidly and well before any search and rescue services can get to the scene.

Who should consider a personal EPIRB?

There are a number of situations where a personal locator beacon should be considered as an essential piece of safety equipment - and it is really the size of the personal EPIRBs that makes these devices so versatile:

- Crew moving between different vessels. Personal EPIRBs are particularly valuable to delivery crews, charter skippers and racing sailors who frequently move between different boats, many of which will not have their own vessel-mounted beacons.

- Scuba divers. Personal EPIRBs have also proved to be invaluable for scuba divers who have surfaced only to find they have lost contact with their dive vessel. This is a constant concern for divers - and a personal EPIRB will give them the reassurance that search and rescue services can be alerted to look for them in the right location whilst their dry suits, thermal protection and personal flotation devices keep them safe and free from hypothermia for an extended period.

- Life rafts and grab bags. Many skippers and captains are now packing personal EPRIBs into life rafts and grab bags. This means that in the event that their vessel is lost and they have no time to use a VHF radio or even deploy the vessel's own EPIRB, then an emergency signal can still be transmitted to summon assistance from the liferaft.

- Small leisure craft. Many small craft, from kayaks and jet skis to power boats and day fishing boats take to the water every year. Whilst they generally operate close to shore, a sudden change in weather conditions or a mechanical problem can often lead to these small vessels being swept out to sea or battling increasingly dangerous conditions. These small craft rarely carry a VHF radio and so are unlikely to have any other means of raising an alarm in an emergency situation, so a personal EPIRB that can be tucked into a pocket or stowed in a small locker can quite literally be their only life line.

To conclude, a 406 MHz personal EPIRB can perhaps best be described as a 'first alerting' device, to be used in situations where no-one else will know you are in distress and there is no other means of raising the alarm.

In the event of a man overboard situation, a personal EPIRB will certainly alert the rescue services to the emergency and can help in the search and recovery of the missing crewman in the shortest possible time.

But most importantly, the chance of successful search and recovery will be vastly improved if the crew has the benefit of essential high quality safety equipment - such as lifejackets, signal lights and personal distress flares and if the whole crew are properly drilled in emergency procedures.

For further information about the most appropriate personal or vessel-mounted EPIRB for your requirements, contact the Safety Marine advice team on 0870 165 7424 or email


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