By Chris Beattie

Scenario 1: The waves are towering – 10 metres and higher – driven by ferocious winds approaching 150km/h. Every now and then a wall of green water breaks, hurling hundreds of tonnes of swirling white wash onto the deck. Your boat has been dismasted, lines are strewn everywhere and water is flooding into the cabin. The wind howls so loud you can’t hear a word your crewmates are yelling as they struggle to keep the boat afloat. It’s terrifyingly obvious that time is running out. And complicating the situation is the fact that your HF radio antenna has gone over the side and your VHF Channel 16 transceiver is waterlogged. You’ve fired a flare, but there’s no response. So you do the only thing you can in the circumstances; you locate the boat’s Emergency Position Indicating Radio Beacon (EPIRB), and activate it. The EPIRB light flashes and immediately a signal is sent to satellites hundreds of kilometres overhead, and from there to the Australian Search and Rescue Centre in Canberra.

Unfortunately, because the EPIRB is one of the older, 121.5MHz analogue units, it takes a while for the position to be resolved and any distress confirmed. And rescuers don’t have a lot of information to work with. In fact, all they know is that there may be a boat in trouble somewhere within a 20km area. A chopper is sent, but in the atrocious conditions it misses the boat in question, instead locating another less seriously crippled yacht a couple of kilometres away.

With no other information to work with, the helicopter crew concentrates on hauling the crew of the second boat to safety, oblivious to the more serious drama unfolding just a handful of kilometres across the water. With their boat now overturned, the crew desperately scrambles for the one life raft. But in the confusion, three are thrown into the sea. As giant waves continue to batter them, they disappear into the gloom. While the helicopter hovers over the other boat a couple of minutes away, the three are swept to their deaths. A tragic chain of events resulting in multiple fatalities, but the chances of rescue would have been a lot better had the boat been equipped with a new 406MHz digital EPIRB.

In this scenario, had the beacon been a 406MHz EPIRB, even though the helicopter missed the boat on its homing, once it found the second boat it would have known it was the wrong boat. Certainly, the crew of the second boat would still have been rescued, but the helicopter crew could have called for assistance knowing there was another boat in distress nearby.

Scenario 2: An expensive boat with an inexperienced crew runs into difficulties a few kilometres out to sea. The crew panics, activating the analogue 121.5MHz EPIRB, which eventually alerts the search and rescue authorities. The boat is finally located and found to be in relatively good condition, though the crew, seasick and exhausted, is adamant that they want to be taken off. They disembark onto the rescue boat, the rescuers being careful to ensure that the EPIRB is switched off so it doesn’t continue to transmit. If it were left on, it could mask real distress alerts from other boats. The trouble is, the boat is still in pretty good condition, but it’s now abandoned and at the mercy of the winds and currents. There is now no reliable or accurate way of locating it. It’s insured, but a costly and time-consuming search has to be undertaken to locate the boat ­– without the aid of the now-disabled EPIRB. Ultimately, the boat was recovered, but at considerable effort and expense.

Based on actual events, the above scenarios illustrate perfectly why all boat owners should seriously consider switching to digital 406MHz EPIRBs, especially if they spend time offshore and in blue water.

In Australia it is a legal requirement that recreational boats and small commercial craft carry EPIRBs if they venture more than 2nm offshore. However, if you’re about to buy an EPIRB or have an ageing analogue unit that may need replacing, you need to know that international marine rescue authorities, including Australia, have taken the decision to cease processing distress signals from 121.5MHz analogue EPIRBs from February 1, 2009. And for good reason – actually several good reasons.


The AquaFix 406 from ACR.

Radio distress beacons have been around since the early ‘70s, initially used in the aviation industry and employing the 121.5MHz frequency. Prior to the development of a joint US-Soviet satellite network called Cospas-Sarsat in the early ‘80s, the system relied on search aircraft to detect distress signals. It was a system based as much on luck and good intentions as it was on technology and accuracy. But once the new satellite network was up and running, distress beacons could broadcast directly to the satellites, which would then relay the signals to land-based search coordination facilities. Satellites provided much better coverage and had the capacity to speed up the whole process.

From the start, the Cospas-Sarsat system was able to detect both analogue 121.5 and digital 406MHz transmissions. But cost, technology and size meant that the 406MHz beacons were pretty much solely the domain of merchant shipping. The units themselves were generally more than a metre in length, bulky and prohibitively expensive. In recent times though, the march of technology has resulted in miniaturisation and increased efficiency and performance. Prices have come down significantly in recent years, too, so cost isn’t the obstacle it used to be.

Digital EPIRB technology is superior to the 121.5MHz analogue technology in a number of areas. Firstly, although both systems are prone to false alerts, the analogue system is chronically vulnerable to false alarms. In fact, up to 97 per cent of analogue distress signals end up being false alarms. Talk about the boy who cried “wolf”! Other electrical equipment, including such innocuous gadgets as pizza ovens and automatic teller machines, has been found to emit signals on the same 121.5MHz frequency, creating confusion and false alerts. With a registered 406 distress beacon, a false alarm can be resolved by a phone call, whereas scarce rescue resources have to be used to determine whether a 121.5MHz alert is the real thing or not. Also, the older analogue system is relatively inaccurate in pin-pointing boats in distress, being accurate only to within a radius of 20km. And analogue EPIRBs cannot identify the craft in distress or supply other critical information to rescuers. All of these deficiencies have been addressed and corrected in the development of digital 406MHz EPIRBs.

For a start, 406MHz beacons can be detected more quickly (within minutes, compared to the analogue average of an hour and a half) and are far more accurate (to within 5km, and down to 120m if the EPIRB has a built-in GPS). Digital beacons also transmit an exclusive identity that allows rescuers to identify the source of the signal. This is really the key to the adoption of the new digital system.


The Fastfind Plus from RFD.

AMSA’s Planning and Coordination Adviser, Steve Langlands, says registration is the critical key to the new digital system. “When people purchase their 406MHz EPIRB, it is in their own, and their passengers’ interest to register with us.”

Once a digital EPIRB has been purchased, it is a requirement that the owner registers with the Australian Maritime Safety Authority (AMSA). Registration is free and owners are asked to supply such information as owner contact details, emergency contact names and telephone numbers and vessel details. Registration can be completed via the AMSA website at:

A form can be filled in online and emailed back to AMSA or downloaded and then faxed or mailed back to AMSA. This information is input into AMSA’s database and can be instantaneously accessed and cross-referenced in the event of an EPIRB being activated. Langlands said: “Rescuers are immediately able to know what vessel is in distress, the type of boat, its name, and the owner’s details. They will also have an accurate location and emergency contacts that may be able to verify that the vessel is at sea and may also be able to tell them who is onboard. This is all invaluable information that can save lives and ensure critical rescue resources are utilised for the best possible outcome.”

The GlobalFix from ACR.

Langlands said that currently, AMSA has around 11,500 units registered, with an estimated total of approximately 150,000 beacons yet to be switched over.

AMSA is developing on-line registration so that owners will be able to access their accounts over the internet and update details and provide itineraries of longer voyages. This information will be displayed to the Search and Rescue Officers, should the vessel’s beacon be activated. The on-line access is expected to be available in 2007.

It is not hard to see that digital EPIRBs would likely have had profound effects on the two scenarios presented at the start of the text. In the case of the disabled yacht, a 406MHz EPIRB would have told rescuers exactly which boat was in distress and pin-pointed its location, thus allowing them to prioritise rescue resources in a situation in which more than one vessel and crew was at risk. Whether or not more lives might have been saved is open to speculation, but there is no doubt that it would have given rescuers a better picture of the situation they were facing. In Scenario 2, rescuers may have been able to leave the EPIRB on, so that it could continue to transmit the boat’s location to salvagers. There wouldn’t have been any risk of the EPIRB transmissions being confused as another emergency alert as authorities would have recorded exactly which vessel was transmitting and could have kept track of its location, saving both time and money for the salvage operation.

From a boat owner’s point of view, the argument to switch over to digital EPIRBs prior to the February 1, 2009 deadline is compelling. As Club Marine Insurance National Claims Manager, Phil Johnson says, digital EPIRBs enhance safety and make economic sense.

“As Australia’s largest provider of pleasure craft insurance, Club Marine is in a unique position to be able to evaluate the advantages of digital EPIRBs,” he said. “They are so obviously superior to the older, analogue units and offer increased security in all marine situations. They are also especially critical when it comes to high-risk activities like offshore yacht racing, when fast and accurate response is all-important. And from Club Marine’s point of view, they can have a huge impact on boat recovery costs, which ultimately saves all our policyholders. I’d urge all our customers who still rely on analogue EPIRBs to switch over as soon as they can.”

For more information, call AMSA on 1800 406 406, or go to:

Further information on registration can be obtained at: