What is the difference between a yacht’s EPIRB and a crew’s PLB?
EPIRB
An EPIRB – Emergency Position Indicating Radio Beacon – is designed for your boat. It floats and is activated by contact with seawater, in addition to having a manual switch. It transmits better when floating than when sitting on a hard surface. If you have to use it and you are still on your boat, put it in a bucket of water. An EPIRB is required to transmit continually for at least 48 hours, and its chunky Lithium-Ion battery has to be periodically replaced.
PLB
A PLB – Personal Locator Beacon – is designed to go in your pocket or lifejacket. It may float, but it won’t float in the transmit position with the antenna pointing vertically up. A PLB must be manually activated; COSPAS/SARSAT does no permit PLBs to be water-activated. It should be held, or strapped to something, to keep it upright and clear of the water. A PLB is required to be able to transmit continually for at least 24 hours, so its battery can be a lot smaller than an EPIRB’s battery, even though its radio performance is said to be the same.