EPIRB (Emergency Position-Indicating Radio Beacon)

An EPIRB is a satellite distress beacon that, on activation, transmits a 406 MHz signal carrying the vessel’s coded identity to the Cospas-Sarsat system, which relays the alert and position to rescue coordination centers. Most units mount in a float-free bracket with a hydrostatic release so they deploy and self-activate on sinking, and many add a 121.5 MHz homing signal and GNSS position. SOLAS IV/7.1.6 requires a 406 MHz EPIRB on ships in the GMDSS, and they are battery dated and tested at annual and radio surveys.