Emergency Position Indicating Radio Beacon

An Emergency Position Indicating Radio Beacon transmits a distress signal on 406 MHz to the Cospas-Sarsat satellite system, alerting rescue co-ordination centres to a vessel in distress. Under SOLAS Regulation IV/7, ocean-going vessels must carry at least one Category I EPIRB fitted with an automatic hydrostatic release so that it floats free and activates if the ship sinks rapidly. The beacon encodes the vessel's MMSI or IMO number in its digital message, allowing the rescue centre to identify the ship, cross-reference its registration and contact details, and co-ordinate response efficiently. This is why registration with the national authority — and keeping that registration current — is a legal obligation, not a formality. An unregistered EPIRB causes critical delays in SAR response. EPIRBs must be tested monthly using the self-test function and serviced every five years or after activation, including battery and hydrostatic release replacement. Port state control and flag state inspectors check the registration sticker, service date, and mounting bracket. Crew must understand that activating an EPIRB unnecessarily creates a false distress call, which is a criminal offence in most flag states and diverts costly SAR resources from genuine emergencies.