1. EPIRB: vessel-level distress alerting
An emergency position-indicating radio beacon is intended for maritime distress and is normally registered to a vessel or owner according to national procedures. Many installations are designed so the beacon can be taken into a liferaft, and some categories can release automatically.
Its job is to send a recognized distress alert through the search-and-rescue satellite system, not to provide ordinary chat.
2. PLB: personal distress beacon
A personal locator beacon uses the same broad 406 MHz distress ecosystem but is carried by an individual rather than serving as the boat’s primary beacon.
It can be valuable for dinghy trips, solo sailors or crew who also use the device ashore, but it does not automatically replace a vessel EPIRB where one is required or appropriate.
3. Satellite messenger: conversation as well as SOS
A two-way communicator can send routine messages and, with an active service, may provide an interactive SOS channel. That allows the user to explain what happened and receive instructions or confirmation.
The service depends on the commercial network, device account and subscription rather than the Cospas-Sarsat distress system.
4. Registration and subscription are different responsibilities
Beacon registration should be kept current so rescue authorities can associate an alert with correct vessel and emergency-contact information.
A messenger needs an active account and appropriate service plan. Both systems fail their purpose if the administrative side was ignored before departure.
5. Battery maintenance
EPIRBs and PLBs use long-life emergency batteries with marked replacement or service dates. Follow those dates and authorized service procedures.
A messenger is usually rechargeable and used more often, so charging belongs on the normal pre-departure checklist.
6. Abandon-ship planning
Crew should know which device goes into the grab bag, which beacon can release automatically and who is responsible for taking portable communications into the liferaft.
A sophisticated equipment list is useless if nobody can find or activate the devices under pressure.
7. Why some boats carry all three
A larger offshore boat may use an EPIRB as the primary vessel distress beacon, PLBs for individual crew and a satellite messenger for routine tracking and two-way communication.
That is not excessive duplication when each layer has a different failure mode and rescue function.
8. Check carriage requirements and local rules
Legal requirements vary by vessel type, flag state, operating area and commercial or recreational use. Follow the rules that apply to the actual boat rather than copying another sailor’s equipment list.
When in doubt, confirm requirements with the flag-state authority, coastguard or recognized marine-safety guidance.
9. Do not confuse ownership with readiness
An emergency device can be physically aboard and still not be ready. Registration may be outdated, the messenger plan may have lapsed, a PLB battery service date may have passed or the beacon may be stored where crew cannot reach it quickly.
Include these checks in the vessel’s normal pre-passage routine. A simple written list with registration details, battery dates and account status is easier to maintain than discovering several years later that nobody knows when the equipment was last serviced.
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