An EPIRB is a satellite distress beacon that, when activated, transmits a coded distress signal including the vessel’s identity and GPS position to search and rescue satellite networks, alerting rescue coordination centers worldwide.
How It Activates
- Automatically — most EPIRBs are mounted in a float-free bracket and activate automatically if the vessel sinks, releasing and floating free before transmitting
- Manually — can also be activated by hand in an emergency, without waiting for the vessel to sink
Key Features
- Hydrostatic release unit — the mechanism that releases the EPIRB from its bracket at a set water depth, ensuring it floats free even if crew cannot manually retrieve it
- GPS integration — modern EPIRBs include GPS, transmitting precise position rather than relying solely on satellite Doppler positioning
- Battery expiry — EPIRB batteries have a fixed expiry date and must be replaced/serviced before expiry to remain functional
Registration
EPIRBs must be registered with the relevant national maritime authority, linking the beacon’s unique identifier to vessel details — this registration is what allows rescue authorities to immediately identify which vessel is in distress upon activation.
Exam Relevance
EPIRB operation, hydrostatic release mechanisms, and registration requirements are tested in GMDSS and safety equipment sections of deck officer competency exams.