VHF Radio Know-How Can Save Your Life

Modern VHF radios like this ICOM fixed-mount IC-M424 can do a lot with DSC and MMSI, but the most important function of a VHF is to broadcast a distress call on Channel 16 to other boats within antenna range.

Back in the day, a boat with a VHF radio on board had to have an FCC license, and anyone who used the radio was required to use the boat’s call sign in a radio transmission. I can still recite my call sign many years later, along with all the other numbers that get attached to a person and work their way into deep memory. There was a lot less idle chatter and bad protocol on the radio back then. (Might have been because there were a lot fewer boats, too.)

Today’s VHF radios are equipped with Digital Selective Calling (DSC) features that can send out a distress signal immediately, and report your position, too, as long as your radio is connected to your GPS or carries its own receiver. With a Marine Mobile Service Identity (MMSI) number, you can take advantage of some other DSC features, including making direct calls to another MMSI-equipped boat. Together, DCS and MMSI can take in and send out real boatloads of information automatically and instantly – again, as long as you’ve taken the time to hook things together, fill out all your information, and register your radio.

But despite all the modern conveniences, there are three things about marine VHF that haven’t changed, and these are the most important things to remember:

First, the system is line-of-sight, antenna-to-antenna. The height of your antenna, and the ones you’re trying to reach, make all the difference. (Luckily, the U.S. Coast Guard mount their antennae way, way up.)

Second, despite the new ability to make more or less private line-of-sight calls to other DSC/MMSI-equipped boats, the essence of VHF is that it’s a broadcast, meaning your voice is cast broadly — to anyone within antenna range who is monitoring Channel 16 (as anyone with a radio on board should be). And when you’re in trouble, this is exactly what you want — a good, big, old-fashioned broadcast.  Sure, you can use your cell phone to call SeaTow or BoatUS if you run out of gas or wrap your painter in your prop and can’t free it. Those aren’t (usually) true emergencies. But if you’re in serious trouble and lives are in immediate danger, you want to get on Channel 16 and send out a Mayday call to everyone within earshot. And the Rule of the Sea says that anyone and everyone who hears your call is duty-bound to respond. That’s comforting. And effective.

Which brings me to the third thing: Channel 16 is sacred. Do not gab on it. Do not ask for radio checks on it. If you use it to establish contact with another boat, switch immediately to a working channel. Better yet, just agree with your friends to use Channel 9 to get in touch. For radio checks, Sea Tow has established a great automated radio check service, so no one ever needs to call for a radio check on the distress channel (as if they ever did). In short, do not abuse Channel 16. The life you save by remembering that Channel 16 is sacred may be your own. Or mine. Thanks in advance.

For more detailed advice on how to do marine radio right, read VHF Radio Protocol by Peter d’Anjou and How to Use a VHF Radio by Lenny Rudow.

Doug Logan

Written by: Doug Logan

Doug Logan has been a senior editor of YachtWorld.com since 2010. He's a former editor-in-chief of Practical Sailor, managing editor and technical editor of Sailing World, webmaster for Sailing World and Cruising World, contributing editor to Powerboat Reports, and the editor of dozens of books about boats, boat gear, and the sea.