How Long Does An EPIRB Last? – Casual Navigation

If you have thought about buying an EPIRB, I am sure you have already looked at its cost. But, have you considered its value? Value is the cost, compared to the benefits, spread across the lifetime. To find the value therefore, we need to know: how long will the EPIRB actually last in storage or in an emergency?

Once activated, an EPIRB must have a battery that will transmit for a minimum of 48 hours. Most manufacturers offer a 10 year battery life, after which they no longer guarantee that the EPIRB would meet its performance requirements and transmit for at least 48 hours.

There are, however, a number of things that will have an impact on how long your EPIRB will last.

What are the Minimum Requirements for EPIRBs?

EPIRB performance standards are published by the International Maritime Organisation in Resolution A.810(19).

These state that the battery of a GMDSS standard EPIRB “should have sufficient capacity to operate the satellite EPIRB for a period of at least 48h”.

It also states a range of other performance standards that could have an impact on how long the EPIRB lasts.

In terms of things that affect how it lasts, it should be:

watertight at a depth of 10m for at least 5 minutes.
capable of surviving being dropped into the water from a height of 20m.
resistant to deterioration in prolonged exposure to sunlight.
designed for ambient temperatures of -20°C to +55°C, then operate in temperatures of -30°C to +70°C.

There are no requirements for manufacturers to give a specific lifetime of an EPIRB battery. That is more of a commercial decision for individual manufacturers.

To give you an idea of the current market you can see what some of the most popular leisure units are capable of, according to their promotional material:

Model	Battery Life	Replacable?
GlobalFix V4 406 GPS EPIRB (Cat II)	10y	Yes
Ocean Signal RescueME EPIRB1 Class 2 GPS EPIRB	10y	Unknown
Mcmurdo G8 EPIRB/AIS Smartfind	10y	Yes

Pro Tip: Cat 2 EPIRBS are pretty much the same as Cat 1 EPIRBS. The main difference is that only Cat 1 EPIRBS are recognized within GMDSS as float free & automatically activated.

Is 48h Activation Time Enough?

When you activate an EPIRB, you want to know that it is going to transmit for long enough for you to be rescued.

Once it is activated, it will begin to transmit your location to satellites, which relay the signal down to ground stations and finally to the coast guard. The nationality of the coast guard will depend on where your EPIRB is registered.

EPIRBs registered in the US will be sent to the USCG. Those in the UK will go to the UK coastguard.

The coastguard will then use their registration database to find information about the vessel in distress. They will then dispatch search and rescue services to your location.

Pro Tip: If you do not register your EPIRB, it can take longer for the signal to reach the coast guard. They may also dispatch insufficient rescue resources as they do not know what vessel is in trouble.

How Long does an EPIRB Survive Underwater?

EPIRBs don’t spend much time underwater, but it does happen.

Often it is just waves crashing over the deck on a small boat, but it could be much more. If your boat sinks and you rely on a float free EPIRB, it is going to go be completely submerged.

A hydrostatic release uses water pressure to activate. The vessel and EPIRB will be a couple of meters underwater before the HRU activates and the EPIRB floats to the surface.

A few years ago I made a video about how a HRU works.

As EPIRBS are required to float free, submersion resistance is part of the performance requirements. EPIRBS need to be watertight to a depth of at least 10m for at least 5 minutes.

Most HRUs will activate around 4m underwater, so you can already see that the depth requirement is plenty. More of a concern, however, is the time requirement.

Boats and ships may take a lot longer than 5 minutes to sink below the 4 meters to activate a HRU. This is one of the reasons why EPIRBS must be mounted at the highest point on your boat or ship. By the time the EPIRB is submerged, there is minimum reserve buoyancy left so the sinking from that point onwards should be relatively fast.

Pro Tip: You should always mount your EPIRB high and clear of obstructions.

What are the Service Requirements for an EPIRB?

A GMDSS and SOLAS compliant EPIRB needs to be serviced annually. The service will include a full transmission test where the EPIRB is placed into a shielded container and activated. The tester will check that it actually sends the correct transmission on 406MHz.

In addition to the annual test, you need to perform a monthly check yourself. As part of the check you should:

Check the EPIRB is in date.
Ensure the EPIRB is in good overall condition.
Check the HRU is in date and correctly fitted.
Confirm that the EPIRB location is suitable and it would float free in an emergency.
Follow the instructions on the EPIRB to perform the self-test.

Pro Tip: The self-test is an internal test only and does not send a transmission.

For leisure users, you probably don’t have any legal obligation to check or test your EPIRB. It is best practise, however, to perform the same monthly checks that a professional mariner would. You just want to make sure your EPIRB is ready at all times.

When it is time to complete a full transmission test, you need to take your EPIRB to a suitable service station. Most EPIRBs will give you contact details for the manufacturer service, but you always have the option of taking it to an independent supplier.

You need to check your EPIRB documentation for when the manufacturer recommends a full service. Most will require servicing after 5 years, which is approximately halfway through the typical battery life of the popular models.

How can I make my EPIRB Last Longer?

EPIRBS have a definite expiry date, so you cannot make it last any longer than that. What you can do, however, is ensure it stays in top condition so that it is safe and usable right up until its expiry. If your EPIRB is well maintained, you will be able to repair and service it to extend its life rather than buy a new one.

Commercial operators will need to follow the monthly and annual service routines that we discussed above.

Leisure operators should follow the same monthly checks as commercial users when the EPIRB is on a boat. When you take your boat out of the water at the end of the season, you should make sure your EPIRB is stored safely. Make sure you do everything according to the manufacturer’s instructions.

If your EPIRB is well cared for, you will hopefully find that repairs are not needed when you send it for servicing. This not only lowers the costs of a service, but reduces the chance of you needing to purchase a replacement EPIRB.

How do PLBs and EPIRBs Compare?

Unlike EPIRBs, PLBs are not defined within the GMDSS regulations so do not have specific operational requirements. As such, there is no official definition of how long they should last.

Pro Tip: I have written a detailed article about the differences between PLBs and EPIRBs which you can read here: What Is The Difference Between An EPIRB And A PLB?

The actual lifespan of a PLB is a decision made by the manufacturer. I have listed a few of the popular models below:

Model	Life
ACR ResQLink 400 406MHz GPS Buoyant PLB	5 years
Mcmurdo Fastfind 220 PLB	6 years
Ocean Signal RescueME PLB1	7 years

As you can see, the shortest lifespan is 5 years, and the longest is 7. This is broadly in line with an EPIRB where you would need to send it off for servicing after 5 years.

In terms of activation time, all three models claim at least 24 hours. The McMurdo Fastfind breaks it down further and gives a longer activation time of at least 35 hours in temperatures >10°C.

In general, PLBs have lower design parameters than EPIRBs. This makes sense when you think that they are not compulsory. EPIRBs are designed to comply with international regulations for global maritime distress. PLBs, on the other hand, are supplementary, designed to be carried by an individual.