EPIRB (406 MHz)
A 406 MHz EPIRB alerts satellites and reports a ship's identity and position without anyone needing to act, unlike a SART, which makes survivors visible on radar only once a search is already under way and stays silent otherwise.
What to check on an EPIRB (406 MHz).
92 models from Jotron in EPIRB (406 MHz). Below: the full model list.
What sets a 406 MHz EPIRB apart from other distress equipment
A 406 MHz EPIRB transmits a distress signal to satellites, giving rescue authorities a ship's identity and position with no action needed from anyone still able to reach the equipment — that is the entire point of the device, and it is what separates it from a SART, which does not alert anyone by itself but instead makes survivors visible to a searching vessel's radar once a search is already under way. An EPIRB works globally through the COSPAS-SARSAT satellite system; a SART works locally, within radar range of a searching ship or aircraft, and the two are carried together precisely because they cover different phases of a rescue.
Legend
- strobe light
- antenna
- floats free on release
- buoyant housing
- activation switch
- release pin
- hydrostatic release unit (HRU)
- battery compartment
- lanyard
- mounting bracket
Main components
Transmitter
Sends a coded 406 MHz burst to satellites, containing a unique identification number registered to the ship, and increasingly also transmits on 121.5 MHz as a homing signal for the final approach by rescue craft.
GPS receiver
Modern EPIRBs include an internal GPS module that encodes position into the distress message, cutting the time to an accurate fix compared with the older Doppler-only satellite method, which could take much longer and was far less precise.
Read the full guide
Float-free bracket (hydrostatic release)
Releases the EPIRB automatically if the ship sinks before anyone can activate it manually, using a hydrostatic release unit that dissolves or releases under water pressure at a shallow depth.
Battery pack
Sealed primary battery with a fixed expiry date, sized to guarantee at least 48 hours of continuous transmission, and it is a one-time-use component — it cannot be topped up or reconditioned.
Selection and sizing
- Category I (automatic float-free release) versus Category II (manual release only), decided by SOLAS ship type and area of operation requirements rather than owner preference.
- GPS-integrated versus non-GPS models — GPS integration is now close to universal on new units and significantly reduces search time.
- AIS-equipped EPIRBs, which additionally transmit an AIS distress signal received by any AIS-fitted vessel within radio range, giving a much faster local response than waiting for satellite relay alone.
- Mounting location — clear of obstructions overhead so the hydrostatic release can actually let the unit float clear of a sinking hull.
Regulations and class
SOLAS Chapter IV (GMDSS) requires EPIRB carriage on all SOLAS cargo ships and passenger ships, with the specific category determined by ship type and trading area. The unit must carry COSPAS-SARSAT type approval, and the ship's identification data must be registered with the relevant national beacon registry — an unregistered or incorrectly registered EPIRB delays rescue coordination even if the transmission itself works perfectly. Battery and hydrostatic release unit expiry dates are checked at every annual GMDSS survey, and both are hard expiry items that class will not extend.
Typical faults
| Fault | Cause | Consequence |
|---|---|---|
| False activation | Rough handling, heavy weather green water over the bracket, or a worn manual release mechanism | Unnecessary SAR resources dispatched, and repeated false alerts can affect the vessel's standing with the coordinating authority |
| No GPS fix in the transmitted message | GPS antenna obstruction or an internal GPS module fault | Rescue services fall back on the slower satellite Doppler position, adding hours to localisation |
| Hydrostatic release fails to activate | Expired hydrostatic release unit left in service past its date, or corrosion of the release mechanism | EPIRB does not float free if the ship sinks quickly, defeating the entire automatic-alert purpose |
| Registration mismatch | Beacon re-registered to a new ship name or owner without updating the national registry | Rescue coordination centre cannot identify the vessel quickly from the beacon ID, slowing the response |
What to look for in a supplier
- Current COSPAS-SARSAT type approval and confirmation of which registry, flag state or a recognised alternative, the beacon ID will be registered under.
- Battery and hydrostatic release unit expiry dates clearly marked and matched to the ship's upcoming survey cycle.
- GPS and, where required by the operator, AIS integration confirmed rather than assumed.
- Bracket and mounting hardware suited to the specific deck location, since a poor mounting is a common cause of both false activation and release failure.
Confirm the beacon registration details every time the ship changes name, owner, or flag — a perfectly functioning EPIRB is only as useful as the registry record a rescue coordination centre pulls up when it activates.
Models in this type.
The best-documented model of each manufacturer first, then the next — 92 of 92 models in EPIRB (406 MHz). Every row links to full specifications, documents and service notes.
Manufacturers.
All 18 manufacturers with models of EPIRB (406 MHz). 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.
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Questions that come up with this equipment.
Is EPIRB (406 MHz) 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) part?
Yes. Tell us the manufacturer, the model and what you need — a person reads every request and replies by e-mail.