How to Tell When an EPIRB Is Too Old to Trust

Key Takeaways: Even if an older EPIRB still passes its self tests, there comes a point where you simply shouldn’t rely on it. The tests only check the basics. They don’t tell you whether the GNSS receiver has lost sensitivity, whether the transmitter still delivers full power under load, or whether the battery can cope with a cold start after years in a damp locker. Once a unit is around 12 to 15 years old, or the manufacturer no longer supports key components, it’s time to retire it.

When a Passing Self Test Gives a False Sense of Security
The Hidden Ageing Processes Inside an EPIRB
Why GNSS Sensitivity Declines Over Time
RF Output and the Problem of Load
Batteries and the Cold Start Question
Water Activation Circuits and Environmental Stress
When Manufacturers Stop Supporting Older Models
Practical Age Limits for Cruising Sailors
A Simple End of Life Checklist
Summing Up

When a Passing Self Test Gives a False Sense of Security

A self test is reassuring, but it’s only a snapshot of the simplest functions. It checks the processor, the beacon ID, the strobe, and a short burst of RF output. It doesn’t simulate a full emergency transmission, it doesn’t stress the battery, and it doesn’t assess the GNSS receiver’s ability to get a fast, accurate fix after years of ageing.

Plenty of sailors have held on to older units because they still “test fine”, only to discover later that the model was long out of support or had known issues that never show up in a self test.

The Hidden Ageing Processes Inside an EPIRB

EPIRBs age quietly. Most of the wear happens inside sealed components you can’t inspect. The main culprits are:

Heat cycling
Moisture ingress
Battery chemistry degradation
Corrosion on internal contacts
Drift in RF components
Decline in GNSS sensitivity

None of these faults will trigger a self test failure until the unit is already well past its best.

Why GNSS Sensitivity Declines Over Time

GNSS receivers rely on tiny, low noise amplifiers and ceramic antennas. These components are sensitive to moisture, vibration, and long term thermal stress. As they age, they lose sensitivity. The result is slower fixes, or in marginal conditions, no fix at all.

A self test doesn’t check this. It doesn’t ask the receiver to acquire satellites. It simply confirms that the GNSS module responds.

For offshore sailors who may need a position fix in poor weather, this decline is a serious concern.

RF Output and the Problem of Load

The transmitter is the heart of the beacon. It must deliver a stable, full power signal for at least 24 hours. Over time, RF components drift, solder joints weaken, and output stages lose efficiency.

A self test only emits a short, low duty cycle burst. It doesn’t test sustained output under load, which is exactly what matters in an emergency.

If the transmitter can no longer maintain full power, the beacon may still “work”, but its range and reliability will be compromised.

Batteries and the Cold Start Question

Batteries are the most predictable ageing component. Even high quality lithium cells degrade with time, heat, and humidity. The biggest risk is a cold start failure, where the battery can’t deliver the required current when first activated in low temperatures.

A self test draws only a tiny amount of power. It doesn’t stress the battery. It won’t reveal a cell that’s marginal or nearing the end of its life.

This is why manufacturers specify replacement intervals based on time, not test results.

Water Activation Circuits and Environmental Stress

Water activation relies on exposed contacts or sensors. These can corrode or lose sensitivity after years in a damp locker or on a bulkhead mount. The circuitry behind them can also degrade.

A self test doesn’t check water activation. It only checks manual activation.

If the water activation fails, the beacon may never trigger when it’s needed most.

When Manufacturers Stop Supporting Older Models

Once a manufacturer stops producing batteries, housings, or key electronic components for a model, the unit is effectively at the end of its life. Even if you can still find a battery kit, the lack of long term support means the beacon is no longer a reliable safety device.

This is especially important for older float free models, where the hydrostatic release and mounting system may also be out of support.

Practical Age Limits for Cruising Sailors

For most cruising sailors, the practical retirement age for an EPIRB is:

12 to 15 years from manufacture, regardless of test results

Immediately, if the model is no longer supported

Immediately, if the battery cannot be replaced with a manufacturer approved kit

Earlier, if the unit has lived in a hot or damp environment

A well cared for EPIRB in a dry cabin may last longer than one kept in a cockpit locker, but once you’re beyond the 12 to 15 year window, you’re relying on luck.

A Simple End of Life Checklist

If any of the following apply, it’s time to replace the unit:

Indicator	What It Means
Model older than 12–15 years	Internal components likely degraded beyond reliable limits
Manufacturer support discontinued	No access to approved batteries or critical parts
Battery kit no longer available	Unit can’t be serviced to original specification
Stored in heat or damp for years	Accelerated ageing of electronics and battery
Slow or unreliable GNSS fixes	Receiver sensitivity likely degraded

Need help choosing the right EPIRB for your boat?
Click here to see my recommended models and comparison table.

Summing Up

A self test is a useful check, but it’s not a verdict on the beacon’s health. Age, moisture, battery decline, and unsupported components all take their toll long before a self test ever fails. Once your EPIRB is into its second decade, or the manufacturer stops supporting it, it’s time to retire it with no hesitation. Offshore safety depends on equipment you can trust without question.

This article was written by Dick McClary, RYA Yachtmaster and author of the RYA publications 'Offshore Sailing' and 'Fishing Afloat', member of The Yachting Journalists Association (YJA), erstwhile member of the Ocean Cruising Club (OCC) and owner/administrator of 'Liveaboard Sailboats for Sale'.