An EPIRB is taught as a device that gets activated. What it is, where it is mounted, how it is switched on. And that is usually where the lesson ends, because that is what the exam covers.
What is almost never taught is the calendar. And the calendar is what decides whether the device will transmit on the day it matters.
There are three dates. Two are on the equipment. The third is nowhere visible, and it is the one that causes the most trouble.
1. The battery
It is marked on the body of the beacon, normally on a label with the expiry date printed on it. Depending on the manufacturer and the model, it typically lasts five to six years from manufacture or from the last service.
Once expired, the beacon does not transmit. Not weakly, not briefly: not at all.
And it is not replaced on board. A service centre authorised by the manufacturer does it, for two reasons worth understanding before attempting it: opening the casing without the correct seals and torque compromises the watertight integrity —a beacon that takes on water is a dead beacon exactly when it is needed— and many administrations require the service certificate to consider the equipment compliant at an inspection.
The cost of the replacement is usually a fraction of the cost of the beacon. Replacing the whole unit is almost never the cheaper option.
2. The hydrostatic release unit
This one only applies if the beacon is mounted in a float-free bracket with a hydrostatic release unit, that is, if it is designed to free itself when the vessel sinks. Manually deployed beacons, the ones lifted out of the bracket by hand, do not have this component.
The HRU is replaced two years after installation, unless the manufacturer specifies a different interval. It is a non-repairable, non-testable component: it is not checked, it is changed.
And here is the detail behind most of the mistakes: the two years run from installation, not from purchase. An HRU that spent a year on a supplier’s shelf and is then fitted on the assumption that two full years remain will expire earlier than the vessel’s calendar says. Which is why the fitting date is worth writing down rather than trusting to memory.
Once expired, the outcome is particularly cruel: the beacon works perfectly. The battery is in date, the transmitter is fine, the whole unit is operational. But it does not release from the bracket and it sinks with the vessel. It never reaches the surface, never sees the sky, never transmits anything.
3. Registration: the date that is not on the beacon
An unregistered beacon transmits just the same. The signal reaches the satellite, the position reaches the coordination centre. The equipment did its job.
What does not arrive is the vessel.
Without registration, what appears at the other end is an alert with a position and nothing else: no vessel name, no length, no hull type, no number of people on board, and no phone number to call to confirm whether this is a real emergency or an inadvertent activation in a locker.
This is very visible from the coastal station software side. The difference between an alert that starts a search in twenty minutes and one that starts in two hours is almost never the equipment. It is the registration: when there is a verifiable contact, the operator confirms and dispatches; when there is not, the alert has to be treated as possibly false and held, because the proportion of inadvertent activations is high and search assets are finite.
Registration does not expire with time. It expires with changes: when the vessel is sold, when the contact phone number changes, when the shore emergency contact changes. Each of those leaves the registration pointing at information that no longer works.
It is updated with the maritime administration of the flag State. It is free and takes minutes.
How it is checked, in practice
Once a year, with the beacon in hand:
- Read the battery date on the label and record it in the vessel’s maintenance plan.
- Read the hydrostatic release unit date, if the bracket is float-free, and check that it matches the recorded fitting date plus two years.
- Confirm that the registration holds the correct vessel and a phone number somebody answers.
- Check that the bracket is mounted where the water will reach it, with nothing stowed on top that would block the release.
All four take under ten minutes. None of them requires tools.
What this means for training providers
If a course teaches how to activate the beacon but not the calendar, the student leaves able to operate equipment that may not work. And it is an invisible omission: the error does not show up in the exam, it shows up years later on a vessel.
It is worth asking whether the syllabus includes a session on the maintenance of distress equipment, or whether it is assumed that somebody else takes care of that. In most syllabi, it is assumed.
Advenio Software develops maritime safety solutions: GMDSS training simulators, coastal radio station software and nautical training tools, for both the professional and the recreational sector.