EPIRB stands for Emergency Positioning Indicating Radio Beacon and is a small buoy equipped with an antenna capable of transmitting a powerful emergency signal communicating the exact position of the boat to the rescuers.

The EPIRB is an emergency device now widely used on all types of units, from large ships to small pleasure boats. However, even if the invention of this precious life-saving device dates back a long time, over the years we saw a progressive technological development that led above all to an improvement in the accuracy of the localization, to the benefit of people who are in an emergency situation. 


The EPIRB looks like a small, compact buoy with a visible transmission antenna. The most advanced and latest generation models also are equipped with a GPS antenna capable of locating the point with extreme precision. The device is powered by a lithium battery that ensures EPIRB a continuous transmission time of at least 48 hours at a temperature of -20 ° C, this is a fundamental requirement as no beacon can be called EPIRB and be approved as such if it cannot guarantee a perfect continuous operation in this time frame.

The EPIRB transmits an emergency coded signal with an important power ranging between 5 and 6 W, a signal that is received by a satellite constellation totally dedicated to the reception of this kind of transmissions (COSPAS/SARSAT and MEOSAR system). The transmission takes place mainly on the digital frequency of 406 MHz. EPIRBs that only transmit on the frequency of 121.5 MHz are in fact no longer monitored and too obsolete, they must be removed from service as soon as possible.

On older or less advanced EPIRB models without a GPS receiver, the origin of the transmitted signal can be identified by satellites by triangulation, although with a margin of error that in some cases may be relevant. This inaccuracy, together with a potentially long position calculation time, for more than ten years has recommended the introduction of EPIRBs equipped with GPS receivers, which are able to independently calculate exactly their position and transmit it to the satellites by sending an encoded data string. In this case, detection times are almost instantaneous, as well as the positioning error, which assumes negligible values.

The EPIRB can be activated in a totally autonomous way in case of sinking, if equipped with a device characterized by a hydrostatic release that acts by releasing the EPIRB which goes up to the surface starting to transmit the signal. The EPIRBs capable of being automatically released from their support are classified as "Category 1".

There are also EPIRBs that are not equipped with this automatic device and must therefore be manually released and placed in the water to turn on. They are classified as "Category 2" with manual release only. The most advanced models of the latest generation are able to turn on simply in contact with water, without the need to press any power button. Each EPIRB model from any manufacturer clearly specifies when it is turned on thanks to a series of continuous flashes carried out by a small strobe lamp incorporated in the device itself and which is visible at great distance in the middle of the night. The use is obviously very simple: just make sure that the antenna is pointing directly to the sky and that the cap of the EPIRB, which integrates the GPS antenna is not hindered in any way. 

The signal received by the artificial satellites constantly listening is then retransmitted to the ground and received by special receiving stations that process the signal and decode it, obtaining the information required for the purpose. Through these special receiving stations present all over the world (in Italy, it is located in Bari) help is coordinated and accurately directed to the exact point where the emergency signal generated by the EPIRB is being received.


  • Recreational boats with "unlimited" navigation (navigation over 50 miles) are required to have EPIRB on board.
  • All fishing boats entitled to navigate beyond 6 miles, with the specific obligation to have on board an EPIRB "Category 1" with automatic release.
  • Charter boats that navigate at more than 12 miles or carry more than 12 passengers with the obligation of EPIRB "Category 1" with automatic release.
  • Ships subjected to GMDSS

In all other cases the EPIRB is optional.


The EPIRB is an extremely important device because it is a primary emergency equipment. In the event of a serious emergency at sea, it can really help to save lives.  For this reason, it must be kept efficient and its status must be monitored.

First of all, the first step that the user/owner of the EPIRB must take when purchasing this device is to submit the registration procedure to the competent body. It is essential that the EPIRB is properly programmed by the seller based on the identification data of the boat on which it will be installed (generally the MMSI code is required). The subsequent registration - completely free of charge and in many cases also possible to perform directly online - allows the inclusion of your EPIRB in an international database. The EPIRB will therefore be uniquely identifiable everywhere in the world.

Once registered, the EPIRB is in fact legalized and can be installed on board in the correct position so that it can be easily reached in case of need. It is important that the user complies with the service deadlines, i.e. the battery change and the replacement of the hydrostatic release (only for automatic Category 2 models) must be carried out every two years.

While the replacement of the automatic release can be done directly by the user, the procedure of replacing the batteries must be performed by an authorized center. The replacement of batteries must be carried out at intervals not exceeding five years from manufacturing (according to IMO regulations), however, Italy adopted an even stricter legislation that requires the replacement of batteries every four years. The replacement of batteries must also take place whenever the EPIRB has been turned on, even accidentally and for short periods of transmission. 

The battery change procedure is part of a broader process of general service of the EPIRB called "Shore Based Maintenance" and can only be performed by appropriately licensed companies. This general service involves, in addition to the replacement of the batteries, also the check of the integrity of the EPIRB, its watertightness and the integrity of the signal transmitted by measuring the transmission in a shielded environment to prevent accidental propagation. At the end of the process, the EPIRB is returned to the user accompanied by a specific Shore Based Maintenance certificate that authorizes the return in good operating conditions of the device. 

This service is in fact mandatory for any EPIRB installed on any unit, including recreational boats not subjected to the obligation. Consequently, all those who have an EPIRB installed on board are required to respect the service intervals. The widespread belief that leads many pleasure boaters not to meet the required service deadlines of their EPIRB, just because the boat on which it is installed is exempt from the obligation, is completely wrong and misleading.


The EPIRBs on the market have various features that must be carefully assessed by all those who are planning to buy them, not only because they are required on their boat, but also for a real need to navigate with peace of mind thanks to an effective emergency equipment on board.

The types of EPIRB are essentially automatic and manual. This differentiation shown above refers only to the way in which they are released from their support and not to their activation. All EPIRBs are assembled on a special support that in the case of the EPIRBs with automatic release (Category 1) is a real protective housing that encloses the EPIRB and protects it. This is a particularly desirable manufacturing approach because the EPIRBs with automatic release must necessarily be assembled outdoor, so that the housings can open in the event of sinking and release the EPIRB that must be able to rise to the surface without any hindrance or obstacle. Of course, these EPIRBs can also be manually released and activated. All Category 1 automatic EPIRBs are particularly sophisticated and represent the highest level of safety being able to activate themselves in the event of sinking; however, it should be considered that these EPIRBs are subjected to periodic replacement of the hydrostatic release that controls the opening of the housing. The replacement must be carried out every two years and the release is a component that has an average cost of €100.

The alternative to the EPIRB with automatic release (and the manual version, too) is the EPIRB with only manual release defined as Category 2. This device is nothing less than the Category 1 models being the same identical beacon; however, it does not have the protective housing that contains it and the hydrostatic release. For this reason, the  EPIRB with manual release must be installed indoors and must not be exposed to bad weather. However, it must be placed in a location where it is easily visible and reachable if necessary. This type of EPIRB is the type recommended for pleasure boaters  as it is exempt from the obligation of periodic replacement of the hydrostatic release, a component missing in Category 2 devices. 

At the end, the user must essentially assess this periodic maintenance cost since the price difference for the purchase of an EPIRB of Category 1 compared to one of Category 2 is not significant.

In addition to this basic difference that applies to all EPIRBs of any brand, those who are going to equip themselves with an EPIRB must carefully assess the presence or absence of an integrated GPS. EPIRBs without GPS have a rather attractive purchase price, but they lack something that cannot be considered as a trivial option at all. The GPS reduces the detection time to a few minutes compared to a full hour of an EPIRB model without this system. In addition, an EPIRB not equipped with GPS can be detected at sea with a rather gross error that can be as as significant as three nautical miles, not to be underestimated. The EPIRB with integrated GPS offers almost exact positioning. Therefore, it is necessary to pay close attention to the type of EPIRB you wish to buy, given that some major brands such as ACR Electronics have completely stopped the production of EPIRB without GPS, while the Australian GME still has these types of beacons in the catalog in order to offer a more varied range to its clients.

Another important feature, even if it is not a determining factor such as the presence or absence of GPS, is the integration of an EPIRB activation circuit in the water.  This automatic activation, which must not be confused with the automatic or manual release, takes place thanks to the presence of an electrical contact that closes as soon as the EPIRB is immersed in water or is simply touched with a wet hand. These EPIRBs with automatic activation circuit are all equipped with a power on button. However, it is obvious that only EPIRB of Category 2 can be without this device, as all those of Category 1 are necessarily equipped with it.

The presence of an automatic power on device can represent an extra safety in the rare case that the manual activation command is damaged.  


Accidental activation may occur and it can happen in a wide variety of cases. In most cases, this occurs when the EPIRB is removed from or released from its support for any reason. It is important to know that any EPIRB correctly installed in its housing or in its support may not be activated for any reason, since a magnet is inserted in its support to block  the EPIRB activation. 

If the EPIRB is removed from this simple blocking device and separated from the support, it may turn on. In case of accidental activation, the first thing to do is to try to turn off the beacon. If this happened simply by pressing the power on button or moving the activation lever, it is necessary to press again the power on button to power off the device or to return the lever to its rest position. If the EPIRB has a water contact activation circuit, it is important to ensure that it was not activated. In many cases it may even be sufficient to touch the EPIRB with wet hands to activate it. In this case, it must be accurately dried to stop it within ten seconds.

In any case, no panic! An EPIRB that was powered on for a few seconds does not transmit any signal. The transmission will only start 90 seconds after its activation.

However, it is the responsibility of the user (as well as a civil duty) to contact COSPAS or SARSAT immediately to notify them about the false alarm. Forgetting an EPIRB on and transmitting is an action of extreme irresponsibility that can also cause serious consequences.


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