EPIRB (406 MHz) Category II
A Category II EPIRB is manually activated and manually released from its bracket rather than floating free from a hydrostatic release, so it depends on someone reaching it and pulling it clear before the ship goes down.
What to check on an EPIRB (406 MHz) Category II.
2 models from Jotron in EPIRB (406 MHz) Category II. Below: the full model list.
What sets Category II apart
A Category II EPIRB is manually activated and manually released from its bracket; it will not float free and self-activate if the ship sinks, unlike a Category I EPIRB, which sits in a hydrostatic release unit and releases automatically. Category II beacons are typically fitted where a Category I is not required by the vessel's SOLAS category, or as a secondary manually-carried beacon in addition to a Category I unit on the same vessel.
Legend
- bridge wing bulkhead
- antenna
- strobe light
- mounting bracket
- EPIRB beacon
- on/off switch
- manual release lever pull by hand to free the beacon — no hydrostatic release unit
- lanyard tether
Main components
Beacon body and battery
A watertight housing containing the transmitter, GNSS receiver, and a dedicated primary battery sealed for a shelf life typically around five years, after which the battery, and often the whole unit, must be replaced regardless of how little it has been used.
406 MHz distress transmitter
Transmits a digitally coded distress burst on 406 MHz to the Cospas-Sarsat satellite system, encoding the vessel's identity so a rescue coordination centre can trace the ship even before voice contact is made.
Read the full guide
Integrated GNSS position
Modern units include a GPS or GNSS receiver that embeds position in the 406 MHz distress message, cutting the time to an accurate fix from the older Doppler-only satellite method, which could take an orbit pass or more, down to the first transmission.
121.5 MHz homing signal
A secondary low-power homing transmission on 121.5 MHz lets search aircraft and vessels close in on the beacon's exact position using a direction-finding receiver once the search area has been narrowed by the 406 MHz alert.
Manual bracket
Category II beacons are stowed in a bracket on the bridge or another accessible position for quick manual release; the crew must physically retrieve and activate the unit, so bracket accessibility and a clear release action matter as much as the beacon itself.
Regulations and class
SOLAS Ch. IV sets carriage requirements for EPIRBs by ship category and area of operation; GMDSS regulations require the beacon to be registered with the national beacon registry so a Cospas-Sarsat alert resolves immediately to vessel identity and an emergency contact. Battery expiry date is checked at annual radio survey, and an expired battery is a deficiency even if the beacon still passes a self-test.
Typical faults
- Battery past expiry date: beacon may still self-test but cannot be relied on for full transmission duration in an actual distress.
- Registration details out of date, such as an old vessel name or contact number: delays rescue coordination even after a valid alert.
- Corroded or seized bracket release mechanism: beacon cannot be freed quickly in an emergency.
- GPS antenna or receiver fault: beacon transmits a distress alert without position, forcing rescuers to rely on satellite Doppler positioning alone.
- Self-test not performed as part of routine checks: a failing beacon is only discovered during an actual emergency.
What to look for in a supplier
- Cospas-Sarsat type approval certificate for the specific model and, where relevant, flag administration acceptance.
- Battery and unit expiry clearly marked, with a straightforward replacement process rather than a full unit return for minor servicing.
- Support for updating registration details when the vessel is sold or reflagged.
- Self-test function that checks transmitter, GPS, and battery condition without triggering an actual satellite alert.
Run the self-test monthly and log it: a Cospas-Sarsat alert that resolves to outdated contact details wastes exactly the minutes a real distress cannot spare.
Models in this type.
The best-documented model of each manufacturer first, then the next — 2 of 2 models in EPIRB (406 MHz) Category II. Every row links to full specifications, documents and service notes.
Manufacturers.
All 20 manufacturers with models of EPIRB (406 MHz) Category II. Names with a manufacturer page open it; the others open a search across the full library.
All manufacturers in the libraryAlso in EPIRB / SART.
The other equipment types in this category.
Write to us about this model — the answer comes by e-mail.
Name the make and the model and what the job is: a spare, a service call, a second opinion on a data sheet. We answer by e-mail.
No details at hand? A photo of the rating plate or the part is enough — simply attach it to the request.
Questions that come up with this equipment.
Is EPIRB (406 MHz) Category II data free?
Yes. Every model page, every guide and every datasheet for this type is readable without an account. An account adds saved searches and requests, nothing is taken away.
My model is missing — what now?
Send us the nameplate. We identify it by hand, add it to the library, and if you need a part or a service, the request is already on our desk.
Can you source a EPIRB (406 MHz) Category II part?
Yes. Tell us the manufacturer, the model and what you need — a person reads every request and replies by e-mail.