Foghorns on demand


To the editor: If you’ve spent time on a foggy coast, the sound of foghorns may be familiar. Technically called “sound signals,” they aren’t intended to be atmospheric but provide information to mariners during periods of restricted visibility and foul weather.

I was surprised to discover recently that Mariner Radio Activated Sound Signals (MRASS) would soon replace older fog detectors as activators on 11 foghorns on Long Island Sound. The MRASS approach uses an automated system radio-controlled by boaters. The horns themselves weren’t being eliminated, only the sensors that turn them on when fog is detected.

My own lack of knowledge about this underscores A) how much we take such things for granted, and B) perhaps what a small part foghorns play in the life of boaters.

There’s an online video from the U.S. Coast Guard that explains MRASS, but it seemed a reasonable idea to test the system prior to need. Other regions are already employing MRASS, and Rhode Island has updated four lighthouse foghorns. Friends have a sailboat on Narragansett Bay, so I enlisted them in our adventure. “I don’t know if I could avoid the temptation to set it off just to see,” said my husband, Tom.

That, I replied, is the idea.

So, in late September, Tom and I found ourselves on a boat ramp at Fort Adams in Newport Harbor launching Velella Velella, a 21-foot Sea Pearl. It’s an open gunkholing boat with two sails roller-furled on easily stepped masts, leeboards and two rowing stations. Though to this deepwater cruiser Velella Velella seemed mighty skimpy protection from anything, our friends have spent many days cruising her under many conditions.

Castle Hill Light on the chart.

It was a warm Sunday with ambient wind virtually zero and no sun to create a sea breeze, and the calm bay was crowded with boats. Our goal was Castle Hill Light, 1.75 miles down the coast from the southern arm of Newport Harbor. After giving us enough speed to tack out to a cruise ship astride the harbor entrance, the wind died to drifting speed. We carried an ebbing tide outside the rocky coast, negotiating the narrow boat over big wakes. For a long time we could see Castle Hill but not make out the lighthouse silhouette, and I steered as we ate a baguette with Camembert cheese and Honeycrisp apples.

The idea of the outing was to mimic what a boater would have to do off this coast in reduced visibility. The Lighthouse Friends website says the Lighthouse Board first requested funds for a navigational aid on Castle Hill in 1869, noting, “Applications have been made at various times in the past, and renewed this year, for a lighthouse and fog-signal on Castle Hill to guide vessels, especially in thick and foggy weather, into Newport Harbor and Narragansett Bay … it is recommended that an efficient fog-signal be authorized for this point.” Congress approved $10,000 in 1875, but nearby land was soon developed into summer cottages and the owners refused to sell, “fearing that a fog signal would depreciate the value of their property.” A fog bell was ultimately permitted with a screen to deflect the sound seaward.

Castle Hill Light is right on the rocks, virtually at sea level; above and behind is Castle Hill Inn, a classic old hotel where we saw guests milling about among white chairs scattered on a grass slope and a bass fiddle played under a white tent. How would they react to the bray of the foghorn?

As the nautical chart shows, the East Passage of Narragansett Bay makes a sharp turn at Castle Hill to avoid the bottom of Jamestown Island. It’s a reasonable place to be concerned about location in poor conditions. We couldn’t simulate fog, but that was okay because we wanted good visual contact to ascertain that we were indeed setting off this particular foghorn. The water was deep up to the rocks, and here the Sea Pearl showed her stuff, allowing us to row right under the light. Then, not to seem too obvious about what our deed would do to the hotel guests, we turned and headed north again. My husband was in charge of our hand-held VHF. With it held in his lap, he tuned to channel 83A and keyed the mic five times. Nothing happened. He tried it again just as I heard a warm-up sound I recognized from the Coast Guard video. Then:


“There she goes!”

We laughed excitedly, feeling vaguely delinquent, though all for a good cause.


It turned out to be easy to activate the horn from close up. The sequence is designed to work for boaters within two to four miles and in direct line of sight. A hand-held VHF like ours could have a shorter range. To ensure activation, the mic clicks should be on a regular beat, neither slow nor fast.

Castle Hill Light at the entrance to Newport Harbor.

Tom Bailey

The wind had completely died and the tide, which should have turned to help us, showed little effect, so we rowed back to Newport. The boat moved easily, and we kept the sails rolled on the masts in hopes for a zephyr that never appeared. Halfway home, we lost the horn either from distance or shielding. MRASS horns are supposed to sound from 45 minutes to an hour after being activated.

Do foghorns have a future in this digitized electronic world? Just as you should back up chartplotters with paper charts, you should back up the boat’s electronic location finders with aids to navigation: lights, horns and buoys. Radar is a good way to “see” land and, let’s face it, ships are going to have multiple ways of fixing their position including sophisticated sonar.

Ships are actually still required to give sound signals. In Maine recently, on a series of dense fog mornings, the trail of cruise ships entering and leaving Bar Harbor moaned out their position. As the Coast Guard’s U.S. Aids to Navigation System booklet says, “You might hear certain sounds before you see the related objects or situations that require you to change course, such as another boat’s engine or sound signals, an Aid’s bell or gong, or noises from shore. (Note that sound travels far over water.)” What the MRASS system does is put the onus on mariners to know they are in need of a sound signal assist, removing the element of aiding someone who is perplexed.

It seems to me that there’s plenty of room for inferior function with the new system, but it’s here to stay. The Coast Guard has decided that MRASS is worthwhile, citing reduced maintenance cost in batteries and person hours as well as improved reliability. The non-upgraded horns depend on VM-100 fog detector sensors that use light beams to read the reflectivity of air caused by suspended water droplets.

In conditions of reduced visibility where lights can’t cut through, a horn will. Each foghorn’s unique sound signal, distinguished by tone and phase characteristics (specified number of blasts and silent periods per minute) helps identify where you are, though raster charts don’t seem to indicate the frequency and duration of the sound; you have to look for that in a Light List. Vector charts do include the information when you double-click on the lighthouse symbol.

It’s probably one of those unanswerable existential questions whether they are needed in the age of combustion engine noise and electronic chartplotters, but as in all safety equipment: When you need it, you really need it. Better a MRASS horn than none.

—Ann Hoffner voyaged for years with her husband Tom Bailey aboard their Peterson 44, Oddly Enough.

By Ocean Navigator