How an EPIRB Works.
An EPIRB or Emergency Position Indicating Radion Beacon, is a distress beacon used by mariners worldwide to alert Search and Rescue (SAR) forces that they are in distress. EPIRBs transmit a 406 MHz distress signal that contains a unique 15 digit identification number to the Cospas-Sarsat Satellite System (which is a government run system so there are no subscription fees). Search and Rescue forces then pull up your beacon registration (mandatory of all EPIRB owners) which tells them who the beacon belongs to as well as provides additional emerency contact information.
EPIRBs provide Search and Rescue forces with your location either via GPS data if your EPIRB is equipped with a GPS receiver, or via triangulation from the low earth orbiting satellites. This positional data is provided to the Rescue Coordination Center closest to your location. They in turn embark on your rescue mission and use the EPIRBs 121.5 MHz homing signal to ultimately pin-point your location and bring you home safetly.
Learn everything you need to know about EPIRBs in our Boaters Guide to EPIRBs (PDF).
You are required to register your EPIRB with your local authority. If you purchase a new or used 406 MHz beacon, you MUST register it with your local government. If you change any information on your registration (such as phone number, address, bought a new boat, etc.) you MUST update the 406 MHz beacon registration. Also, if you sell your 406 MHz beacon, notify your local government that you have done so, and make sure the buyer registers the beacon personally. Otherwise, you may be contacted by rescue authorities if it is activated! Please provide the new owner a link to our registration web page so he/she can register thier beacon. Visit our Registration Data for more information about your countrys registration requirements.
EPIRBs come in 1 of 2 different brackets. A Category 1 bracket is an automatically deployment bracket, while a Category 2 bracket is a manual deployment only bracket.
|EPIRBs have different categories which define which type of bracket the EPIRB uses||Cat. 1||Cat.2|
|Bracket automatically deployes EPIRB when vessel sinks||Yes||No|
|Contains a Hydrostatic Release Unit (HRU)||Yes||No|
|Built-in deactivation water sensor to prevent false alarms||Yes||Yes|
|Manual activation of beacon while in bracket||Yes||Yes|
|Protects EPIRB from UV exposure||Yes||No|
The Category I bracket is designed to release an EPIRB when the Hydrostatic Release Unit (HRU) in the bracket is submerged in water to a depth of 4 to 14 feet (1.5 - 4m). The regulation specifies a range of depth for deployment to allow for different water temperatures which will affect the release depth. The Hydrostatic Release Unit needs to be replaced every two years.
In an emergency, the EPIRB will release from its bracket, float to the surface and alert search and rescue that you need help fast.
EPIRBs in a Category II bracket need to be manually deployed and activated. They can be mounted above or below deck, in a location that is protected from outside influences (i.e. green water, traffic impacts, cabin doors, etc). Some people prefer to keep their beacon in a Ditchbag without the bracket which is ok if the bag is going to be in a dry spot on the boat.
The Benefits of upgrading to a GPS EPIRB
An EPIRB with a GPS interface or internal GPS greatly reduces the search radius down to 100 meters (110 yards) but also significantly reduces the notification time from less than 1 hour down to 1 minute.
The Cospas-Sarsat satellite system uses 2 dierent satellites. The GEOSAR satellites are stationary over the equator, if your beacon has GPS coordinates, these satellites instantly alert Search and Rescue of your position in as little as 2-3 minutes.
The LEOSAR satellites are low earth orbiting and typically ever hour one flies over your location. These satellites use Doppler shift principles to calculate your position to send to Search and Rescue. However, the notifcation time can be typically less than1 hour while you wait for one to orbit over you.
Learn more about proper EPIRB mounting locations, the differences between an EPIRB and PLB and much more in our Boaters Guide to EPIRBs (PDF)
Tags: EPIRB, EPIRBS, Emergency Position Indicating Radio Beacon, Boater Guide To EPIRBs, Whats an EPIRB, How Do EPIRBs Work