So here you are, searching for the point in the fog. No radar, and GPS these days can be a little iffy. You would rather not hit the reef off the point, or, the breakwater/jetty where the harbor is hidden behind that point. You’re blowing the your horn and/or ringing the bell as required. And going just fast enough to be able to dodge the usual idiot doing 20 knots when five is borderline.
And the foghorn on the point isn’t blowing. Because it’s fog-activated, and the sensors may be above the fog, and the system has never been particularly reliable. Hence, you and others who rely on that sound to determine the direction of a critical navigation point may wind up in a difficult situation.
We now have the Mariner Radio Activated Sound System (MRASS). Many of the horns in foggy areas, such as New England, Great Lakes and the California Coast, have been updated with the new system, which allows boaters to activate the foghorns themselves using their VHF radios. You can read the Local Notices to Mariners online to see which local horns have been equipped.
The chart details shown below are examples of newer chart/GPS/Plotter updates, calling out the MRASS-equipped horns.
Go on your VHF radio (it is either channel 81A or 83A) and click the transmit key five times in a row. The horn will activate for 30 minutes. It works, and it can be real life saver. I’ve tried it outside Marina Del Rey, and it works.
Just another reason to love the Coasties.