Float free EPIRB

A float-free EPIRB is a 406 MHz emergency position-indicating radio beacon mounted so it releases and activates automatically when a ship sinks. SOLAS Chapter IV requires every ship to carry one float-free satellite EPIRB as part of GMDSS. A Category 1 unit sits in a bracket with a hydrostatic release unit that frees the beacon at about 1.5 to 4 meters depth, after which it floats free and transmits to the Cospas-Sarsat satellite system, which relays the alert with the ship identity and position to a rescue coordination center. The HRU is replaced every two years, and the beacon is tested monthly and shore-tested at the annual GMDSS radio survey.