Changes to EPIRB Frequencies and the Implications for Mariners

There has been some confusion in the press about the impending changes to the EPIRB frequencies being used. Here, Safety Marine looks at what is actually happening and what the implications are for commercial mariners, fishermen, small craft operators and leisure boat owners.

The Changes

The Maritime and Coastguard Agency (MCA) has announced that from 1st February 2009, only 406MHz and not 121.5MHz emergency beacons will be processed by the international search and rescue satellite system known as COSPAS-SARSAT.

This will affect all maritime beacons (EPIRBs), and all personal locator beacons (PLBs) that operate solely on the 121.5MHz frequency.

The COSPAS-SARSAT search and rescue satellites were originally designed to work on the 406MHz EPIRB frequency. However, the satellites have also been able to pick up a 121.5MHz signal and relay it to the appropriate rescue authorities.

However, there are some problems:

  • The 121.5MHz signal will not identify the vessel or the owner.
  • The satellite must be in contact with a ground station at the same time as it receives the 121.5MHz signal from the vessel - or the signal will not be relayed.

Because of these limitations - and because ownership of 406MHz EPIRBs has increased dramatically in recent years as prices have fallen, the international organisations who are responsible for operating and maintaining the satellite systems have decided that it is no longer practicable to support the processing of 121.5MHz signals.

The MCA and its partner organisations are now encouraging all mariners to take the necessary action to ensure they have an alternative means of FIRST ALERTING the rescue services in the event of an emergency, such as using a 406MHz beacon system.

The MCA's View

Commenting on the changes, Chris Blockley-Webb, of the MCA's Navigation Safety Branch, said:

"The 406MHz system is far superior to its older 121.5 MHz sibling. Each beacon has a unique code which means that specific information about the vessel and its owners is available from the EPIRB Registry, and any vessel in difficulty can be pinpointed down to a distance of 120 metres"

"Seafarers can STILL USE a 121.5MHz beacons if they so wish, but they should be aware that these can only be used as a homing device for search and rescue services to home-in on, and not as an initial alerting system."

How useful are the 406MHz beacons in practice?

The 406MHz beacon has now been available to mariners for well over two decades and has already contributed to the saving of many lives at sea.

In January 2007 the 406MHz beacon from an Irish fishing vessel 'Discovery' started transmitting. The boat was 160 miles west of the Isles of Scilly. There were seven people on board the vessel which had capsized and had no communications other than the 406MHz beacon. Five fishermen took to one life raft and the other two took to another. Unfortunately as the boat turned over, it punctured the life raft with the two fishermen in and it started to deflate.

Following the 406MHz beacon alert, Falmouth Coastguard worked with the Irish Coastguard to send resources to the seven fishermen. They were able to pinpoint exactly where to send the search and rescue team following the signal from the 406MHz beacon.

The Irish Coastguard aircraft 'Casa Maritime Patrol' located the fishermen relatively quickly and a nearby ship, the ultra large crude carrier 'Front Commander' was asked to turn around and send its ship's lifeboats out to rescue the fishermen who were then taken back to the ship, before being airlifted off by a UK military helicopter.

"These seven fishermen almost certainly owe their lives to the 406MHz beacon which they had onboard", said Andy Cattrell, a Watch Manager at Falmouth Coastguard.

"The two men whose life raft was deflated had been in the water for nearly five hours by the time they were found and it is incredible that they survived as long as they did. It would have been very difficult to find them if they had only had the old 121.5MHz beacon onboard. The crude carrier also did an impressive job of manoeuvring close to the life rafts, launching their ship's boat and rescuing the fishermen."

"For all vessels, from the smallest yacht to the largest ship, the 406MHz beacon really can make a massive difference in the time that it will take us to find you".

For independent technical advice about 406MHz EPIRBs, call the Safety Marine technical team on 0870 165 7424 or email Or for further information about the EPIRB frequency changes, visit


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