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What is an EPIRB? | Everything You Need to Know About EPIRBs

What is EPIRB?

What is an EPIRB?

An Emergency Position Indicating Radio Beacon (EPIRB) is a radio transmitter that will broadcast the position of any vessel experiencing distress. The device can be activated automatically once submerged in water or manually. A Personal Locator Beacon (PLB) functions similarly to an EPIRB but is smaller and registered to one individual. 

The acronym of EPIRB stands for Emergency Position Indicating Radio Beacon and refers to the safety device meant to be equipped on vessels venturing offshore. Upon activation, an EPIRB will alert search and rescue services that a vessel is in distress. 

As opposed to a PLB, which we’ll discuss in further detail later, an EPIRB is registered and connected to a particular vessel, not an individual user. Therefore, when it releases a distress signal, authorities will search for the associated vessel rather than one or multiple people.  

The EPIRB ensures the vessel can be found by transmitting a coded message with the vessel’s identity on the 406 MHz distress signal. 

This signal sent to this satellite is extremely accurate at 2 to 5 km vice 25 km, which is one of the reasons the 406 MHz EPIRB is the model currently permitted for international use rather than the previous 121.5 MHz and 243 MHz devices that were far less accurate.

How Does an EPIRB Work?

It is always beneficial to know how your safety equipment works to guarantee they are utilized properly and provide peace of mind in the event of an emergency. 

One benefit of EPIRBs is that they can work in one of two ways. There are two EPIRB classes of functionality when you need to release a distress signal:

  • Class I: this is the automatic activation that occurs when the EPIRB is submerged underwater
  • Class II: this is the manual activation that occurs when the user operates the distress signal switch

In the event of imminent danger or an emergency, you can either opt to activate the EPIRB using the Class I or II functions, but make sure the device is always connected to your vessel to ensure location accuracy. 

If you opt to activate it manually, you’ll want to connect the EPIRB line to you or your vessel and then toss it into the water. These devices work best when floating, so you’ll want to toss them into the water rather than hold on to them. If necessary, the EPIRB will emit its distress signal for the next 48 hours.  

Upon activation, the EPIRB’s distress signal will reach the COSPAS-SARSAT satellite system mentioned previously. Utilizing these polar-orbiting satellites is another benefit of EPIRBs, as the satellite’s position means consistent and complete global coverage, so there is virtually no chance of your distress alert going undetected.

What happens to the distress signal once the COSPAS-SARSAT satellite systems have received it?

 It depends on where you are when the EPIRB signal is emitted. Ultimately, the distress signal and your EPIRB’s location will be sent from the COSPAS-SARSAT satellites to the nearest Rescue Coordination Centre (RCC).

From there, the nearest rescue team will be dispatched to search for your EPIRB’s location, and, as long as you have stayed with your device, they will ultimately find you as well. 

If you have a U.S registered EPIRB, NOAA will receive the distress signal, which will relay relevant information to the U.S. Mission Control Center.

Different Kinds of EPIRBs

If you’re searching for the optimal EPIRB to have on your vessel, you might be unsure which type is best for you. 

EPIRB Class Types

There are a few ways you can distinguish different EPIRBs from one another. We’ve already discussed the first way, meaning Class I and Class II EPIRBs.

The difference between Class I and Class II EPIRBs is their activations. A Class I EPIRB is activated automatically once submerged and floating in the water. Conversely, a Class II EPIRB is activated manually by the user. 

Which class you choose is ultimately up to your personal preference, but Class II seem to be a popular choice. If you are purchasing one of these EPIRBs, make sure you store it somewhere on your vessel that is easily accessible in the event of an emergency. 

Sea Area Types

Another way your EPIRBs might differ is in terms of the sea areas they function within. The GMDSS system subdivides the world into 4 main geographical Sea Areas. Before purchasing your EPIRB, you’ll want to know which sea area you will be traversing to ensure your device can function properly here if necessary. 

We’ve discussed the first type at length previously because this is the most popular for EPIRBs.

COSPAS-SARSAT EPIRBs are connected to the COSPAS-SARSAT satellite system and function on the 406.025 MHz and 121.5 MHz bands. Because of the polar-orbiting satellites used here, these EPIRBs are applicable for all sea areas, which is why they are typically the first choice. 

Alternatively, you could opt for the INMARSAT E EPIRB, which uses the  1.6 GHz band and is only applicable for sea areas A1, A2, and A3.

The final type is the VHF CH 70 EPIRB. This device works on the 156.525 MHz band and is exclusively applicable for sea area A1. As a result, it is a rare choice in the world of EPIRB due to its limitations. 

If you’re ever in doubt about where you might be traveling or prefer one EPIRB that will function anywhere with the best results, we recommend the COSPAS-SARSAT EPIRB. 

It is the most reliable of the options and mitigates the concern of your device functioning if you ever find yourself off course.

Who Receives EPIRB Distress Signals?

The EPIRB’s signal is received by polar-orbiting satellites, known as the COSPAS-SARSAT satellite systems, which are consistently monitored by The International Cospas-Sarsat Programme, an intergovernmental satellite-aided search and rescue initiative.

If the EPIRB is purchased and sold in the United States, its signal will also be received and monitored by the National Oceanic and Atmospheric Administration (NOAA). 

This American scientific agency is dedicated to detecting and locating distress calls, such as those made by an EPIRB. By law, any new or used U.S. EPIRB is required to be registered with the NOAA and up to date. 

This guarantees ultimate safety and efficiency when the device releases a distress signal. It also minimizes the number of false EPIRB alerts that waste search and rescue resources and potentially unnecessarily put these individuals into dangerous situations. 

In addition to the COSPAS-SARSAT polar-orbiting satellites, your EPIRB’s signal can also be received by geostationary (GOES) weather satellites. However, this is less useful than the COSPAS-SARSAT satellites because GOES satellites do not receive a location with the distress signal unless the EPIRB is equipped with an integral GPS receiver. 

Luckily, many EPIRBs are GPS-enabled, so they can communicate with the Global Positioning Satellite system to precisely pinpoint your EPIRB’s location and transmit this information with the COSPAS-SARSAT network.

If your EPIRB isn’t GPS enabled, don’t panic. The COSPAS-SARSAT satellites will always provide rescue authorities with a location of your EPIRB, regardless of GEOS satellite assistance or an internal GPS. However, this could come with a delay of up to two hours, so having a GPS-enabled EPIRB is recommended. 


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