PLB selection and when to buy one

A PLB is not a nice-to-have item you add after the solar panels and the watermaker get sorted. It's the last-ditch insurance policy that sits between a recoverable emergency and a Coast Guard search for wreckage.

TLDR

• A PLB activates via satellite when everything else has failed, and unlike an EPIRB, it goes in your pocket during an abandon-ship scenario.
• Buy one before you leave the dock for offshore work, it's too late when you are 300 miles from help.
• Register it properly, test the self-check annually, and replace the battery on schedule, because a dead PLB in a ditch bag is just expensive ballast.

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The failure mode that matters most with a PLB is the one where you never find out it didn't work. You're in the water, the boat is gone or going, and you pull the tab on a device you tested once in the cockpit three years ago. The satellite handshake either happens or it doesn't. There's no tech support number to call.

This is why the buy decision is binary. If you're heading offshore, beyond VHF range, beyond the operational range of a Coast Guard helicopter on a single tank, you carry a PLB. If you're daysailing in coastal waters with cell service, you probably don't. The middle ground is where people rationalize themselves into trouble.

What a PLB Actually Does

A Personal Locator Beacon transmits your position and a unique identifier to search and rescue satellites when you activate it manually. It's a 406 MHz distress signal that gets picked up by COSPAS-SARSAT, the international satellite system purpose-built for this. Most units also broadcast on 121.5 MHz, which helps rescuers home in on you once they're close.

Unlike an EPIRB, which is mounted to the boat and designed to float free in a sinking, a PLB is sized to clip onto your life jacket or go into a ditch bag. It's the device that stays with you when the boat does not. The assumption baked into a PLB's design is that you are separated from the vessel, in the water, and the only searchable object left.

The operational difference between a PLB and an EPIRB comes down to this: the EPIRB marks where your boat went down. The PLB marks where you are right now. If you go over the side at night in a gale and the boat sails on without you, the EPIRB is happily nestled in it's mount on the boat while you drift downwind. The PLB in your jacket pocket or on your vest is the only thing broadcasting your actual coordinates.

When to Buy One

You buy a PLB before your first passage that puts you outside helicopter range. That's the bright line. For most cruisers on the U.S. East Coast, that means before you head to Bermuda. For Pacific cruisers, it's before the Baja bash or the first offshore leg to the Marquesas. For anyone in the North Atlantic or high latitudes, it's before you leave the dock.

The rationalization I hear most often is that the EPIRB covers the boat, so the PLB can wait. This logic works right up until someone goes overboard during a night watch and the boat keeps sailing. It works until the hull is holed, the boat goes down in minutes, and the EPIRB canister doesn't release cleanly. It works until you're in the life raft and the EPIRB is still bolted to the stern rail of a boat now twelve feet underwater.

A PLB costs between 250 and 400 dollars depending on the model. Battery replacement runs another 150 to 200 dollars every five to seven years depending on the unit. If that amount of money is a barrier to your offshore cruising budget, your offshore cruising budget has structural problems that a PLB purchase won't solve.

What to Look For

The spec that matters is battery life after activation. Most current PLBs will transmit for a minimum of 24 hours. Some models push that to 48. In a real scenario, search and rescue coordination starts within minutes of satellite acquisition, but the clock that matters is how long you can keep broadcasting if weather grounds the helicopter or the nearest vessel is a day away.

Buoyancy is the other non-negotiable. A PLB that sinks when you drop it is a paperweight. Every unit worth considering floats and has a strobe or signal light integrated. Some models include a GPS chip that speeds up the satellite fix. This cuts the time to first position transmission from 15 minutes down to under five in some cases.

The activation method is critical. You want a single-action design with a clear, positive indication that the unit is transmitting. No multi-step sequence, no ambiguity about whether it fired. In cold water with numb fingers, you will not execute a complicated procedure correctly.

Registration and Maintenance

A PLB is useless if it isn't registered with the national authority that coordinates search and rescue in your flag state. In the U.S., that's NOAA. Registration links the beacon's unique hex code to your name, your boat, and your emergency contacts. When the satellite picks up your signal, that registration data tells the Coast Guard who you are and what they're looking for.

You update the registration any time your contact information changes, any time your vessel changes, and any time you transfer the beacon to another person. This is not optional bureaucracy. It's the mechanism that turns a satellite blip into a coordinated search with your name on it.

Battery replacement is not a maintenance suggestion. It's a hard deadline. The expiration date is stamped on the unit. After that date, the battery's ability to perform under the environmental extremes of a real activation is not guaranteed. Replace it on schedule or replace the entire unit.

Test the self-check function once a year. Do not activate the beacon to test it. A real activation triggers a real search and rescue response, which triggers a real bill and a possible criminal penalty for false distress. The self-check confirms the electronics and battery status without radiating a signal.

You mount the PLB where you can grab it in under ten seconds while wearing a harness in the dark. That means the ditch bag, a jacket pocket, or a tether point in the cockpit. It does not mean down below in a locker behind the spare winch handles.

By Jeffrey Pierce