Maritime Mobile Service Identify (MMSI) is a mouthful. It’s also long – a nine-digit number that works like a phone number on your DSC-VHF radio to call for help. If you have it, all you have to do is push a red button on your VHF (even a child can do this) and the radio will automatically and immediately broadcast your boat’s location, in exact latitude and longitude, to all other boats with DSC-VHF radios within range. It also will show your boat’s location on their chart plotters and determine the distance and bearing back to your boat.
But it can’t do that unless you get a MMSI. And the great majority of boat owners still do not have one, according to the Coast Guard. Sure, you can always pick up the mic and push the button for channel 16 and announce a Mayday, and that’s fine. But in an emergency, will you accurately read the numbers on your chart plotter to get the exact lat/lon to summon help to the right spot? And if you’re incapacitated, can your crew do this accurately? There’s a good chance in an emergency situation that your crew will be so flummoxed that they may not even use the VHF correctly, much less transmit a location accurately. With a DSC-VHF connected to a GPS and a MMSI, you eliminate all possibility of operator error, and that’s an enormous safety advantage in its own right.
All fixed-mount VHF radios made since 1999 have DSC. If you have an older fixed-mount radio on your boat, get rid of it and buy a new one. After all, you aren’t using 19-year-old technology on your computer or your cell phone; why still use it on your boat? And a new radio won’t break the bank; a new Standard Horizon DSC-VHF at West Marine starts at $149.99.
DSC stands for Digital Select Calling, and it does much more than summon emergency help on your VHF. With it, you can call other boats with DSC-VHF without tying up channel 16; or you can create a group to call – people you’re cruising with, for example, or a buddy boat. And you know they’ll get your call without having to monitor a particular channel.
But the safety feature, the red button, is the most important feature of DSC. You can get a MMSI through BoatU.S., Sea Tow and the U.S. Power Squadrons, among other places. And you can take a free DSC-VHF tutorial at: www.boatUS.org/DSC.