An EPIRB (or an Emergency Position Indicating Radio Beacon) is a device that enables anyone that is travelling on the sea to be safe, wherever they are. What the EPIRB does it alerts the Search and Rescue Authorities if the boat or any crew member is in danger and needs to be rescued for any reason. An EPIRB is fitted to a boat and is registered to the boat (unlike a PLB which is registered to the owner). An EPIRB can either be manually activated, usually by pulling a switch or pressing a button, or it can be automatically activated, this happens whenever the device comes into contact with enough water. If the EPIRB is going to be manually activated, then there is usually a guard or a tab which needs to be removed before activating, this is to stop an EPIRB being accidentally activated. When it is automatically activated, the device has a knife which cuts the cord keeping the EPIRB in the housing, allowing it to freely float on the water.

EPIRBS can be fitted into any type of boat but they are required by law to have one on all commercial boats such as passenger boats, cargo ships, tankers and containerships which are over 300 tonnes. Those which are fitted need to reach the minimum IMO SOLAS standards (International Maritime Organisation, International Convention for the Safety of Life at Sea).

After an EPIRB is purchased, it must be registered before being fitted. Every country has a different registration contact address, for example in the UK your EPIRB must be registered with the Maritime and Coastguard Agency. You must provide details of the vessel, information on the beacon and personal contact details. These details will be saved and in case of an emergency, they will be used to check to see if the distress signal is genuine.

After being activated, the beacon will transmit a coded distress message on the 408MHz frequency via the COSPAS-SARSAT network of satellites. The COSPAS-SARSAT network of satellites have been designed to have complete global coverage meaning that wherever you are in the world, the beacon will be covered and will work.

The coded distress message that is transmitted from the beacon will have a unique code which links it to the specific EPIRB, from this the location that the EPIRB has been registered with will show the details of the EPIRB. The vessel is then contacted to see if the emergency is genuine and if it is it then the appropriate search and rescue authorities will be contacted and they will then go to rescue the people onboard the vessel. There location will be shown from where the EPIRB is transmitting the coded distress message.

EPIRBS are activated manually by pulling a switch or pressing a button. Or if it is housed in a auto housing unit then it will be activated automatically when it comes into contact with water. Another method of activating the EPIRB is to remove the EPIRB from the housing and then throw it into the water.