Understanding Emergency Position Indicating Radio Beacons At Sea


  • Emergency Position Indicating Radio Beacons (EPIRBs) serve as vital tools for alerting search and rescue services (SAR) during maritime emergencies.
  • These tracking devices transmit signals to locate distressed vessels, lifeboats, life rafts, or individuals in peril at sea.
  • Let’s delve into the details of what EPIRBs are, how they function, and their significance in maritime safety protocols.

Types of EPIRB

EPIRBs operate under different systems based on their designated sea areas:

1. COSPAS-SARSAT: Utilizing the 406.025 MHz and 121.5 MHz bands, applicable for all sea areas.
2. INMARSAT E: Operates on the 1.6 GHz band, applicable for sea areas A1, A2, and A3.
3. VHF CH 70: Functions on the 156.525 MHz band, suitable for sea area A1 only.

How Does an EPIRB Work?

EPIRBs typically consist of two radio transmitters, one with 5 watts and another with 0.25 watts, operating at 406 MHz. The 5-watt transmitter synchronizes with weather satellites to transmit distress signals. The signals contain encrypted identification numbers, conveying crucial information such as the vessel’s identification, distress nature, and position.

These signals are received by Local User Terminals (satellite receiving units or ground stations), which calculate the casualty’s position using Doppler Shift. The Mission Rescue Co-Ordination Centre (MRCC) then oversees the rescue mission.

Using an EPIRB

EPIRBs can be manually activated or triggered automatically upon contact with water through hydrostatic release. They operate on battery power, typically lasting for 48 hours. Periodic testing and maintenance ensure their operational integrity. False alarms should be promptly reported and canceled to prevent unnecessary rescue efforts.

PLBs (Personal Locator Beacons)

Similar to EPIRBs but designed for individual use, PLBs transmit distress signals via the COSPAS-SARSAT satellite system. They offer a compact alternative for personal distress signaling, with a minimum transmission duration of 24 hours.

In conclusion, EPIRBs are indispensable assets onboard vessels, providing a crucial lifeline during emergencies at sea. Regular maintenance and adherence to safety protocols ensure their reliability when facing distress situations.

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Source: Marine Insight