Changing Foghorns

At Point Bonita Light, in the Marin Headlands, the first fog signal was a cannon, fired every 15-to-30 minutes. It didn’t last long, followed by attempts to use bells, sirens, and finally horns.

For commuters who whisk past it aboard the high-speed ferry from Vallejo to San Francisco, East Brother Island is a quaint dollop of history, plunked near the Richmond shoreline. The 1873 lighthouse is a popular subject for snapshots on the fly.

But my destination on a clear day in March was the smaller structure that few people notice. That’s where lightkeeper Peter Berkhout is taking me to see a genuine rarity: one of perhaps two or three remaining vintage foghorns anywhere in the U.S. that’s still in working order.

“Normally for the first blast I advise our guests to cover their ears,” Berkhout tells me, as he pull-starts a small gasoline engine in the signal house. The pony engine in turn, starts up a diesel-powered air compressor that fills enormous cylindrical tanks against the wall. That’s where the air starts its journey up to the roof-mounted horns. “It is startlingly loud,” he warns, “and it's loud enough that you can actually feel the sound wave going through your torso.”

Technically this is a “diaphone,” so-named because it generates two separate tones that constitute the iconic “BEEE-ohhh” that most Americans still connect with foghorns. When the air pressure comes up and the sound is released, you jump out of your skin no matter how prepared you think you are, even though the second note presents as more of a grunt. The sound wave bounces off the Richmond bluffs and lingers. “I guess you can learn to sleep through anything but I'm glad I haven't had to learn to sleep through this,” Berkhout tells me.


And they don’t. He and his wife, Dina are the caretakers of the Victorian bed & breakfast on East Brother Island, so they live there full-time. But Berkhout only fires up the 1920s-vintage monster for occasional demonstrations. East Brother still has a foghorn that operates from October to April, but it’s three-second “booop” every 30 seconds is almost soothing by comparison.

For decades, though, virtually all major fog signals were diaphones. When the Bay was ringed with diaphones like East Brother’s, they had to be loud.

“Navigating the fog is like driving your car down the highway with your hood up,” says Greg Waugh. And he would know. A fourth-generation San Franciscan, he spent more than 50 years on the Bay, aboard tugs and then piloting merchant ships through the Golden Gate, which he and his fellow pilots calculated gets 1,500 hours of fog in a year’s time. That could help explain why the Golden Gate Bridge has three foghorns. Waugh got to know all of them like family. “Center span of the Golden Gate Bridge is two blasts every 40 seconds,” he recounts, though he’s been retired since 2007. “South tower is one blast every 20 seconds. Lime Pt. on the north tower is one blast every 30 seconds.”

Peter Berkhout prepares to start up the air compressor that powers the diaphone.

Waugh's not quite old enough to remember the first fog signals, like the method used at the original Point Bonita light, in the Marin Headlands.

“When it started gettin' foggy this guy'd get up there and he'd load up a cannon and fire the cannon--boom... and that was the fog signal.”

Present day foghorns are electronic and apart from being less jarring, are considerably low-maintenance. The “new” horn at East Brother is about the size of a fire hydrant, powered by a small solar panel and 12-volt battery. Members of the Coast Guard’s Aids to Navigation Team tell me the biggest maintenance headache with the new horns is people stealing the batteries, thinking they can use them in their boats (they can’t).

Waugh says the present-day foghorn at Point Bonita was dialed back to be audible for only one mile. Otherwise, he says, residents across the Bay in San Francisco would complain.

East Brother Island boasts a treasure missed by most boaters passing by: its 1920’s-vintage foghorn.

Tim Lynch chuckles at this. “I think the iconic sound that we associate with foghorns, while it might be nostalgic, was upsetting to a lot of residents.” Lynch is a historian at the Cal Maritime Academy in Vallejo. “There are newer and some might say better ways to skin the cat,” he tells me. “The amount of technology that mariners have available to them -- the global positioning satellites, and all sorts of aids to navigation have largely rendered foghorns obsolete.”

But try telling that to Duncan MacLean, who skippers a commercial salmon boat out of Pillar Point Harbor in Half Moon Bay. “A lot of those old navigational things, when all else fails, are still there,” he tells me, while tinkering with some fishing tackle aboard his boat, the Barbara Faye. “And that can be critical.”

Like most modern fishermen, MacLean’s wheelhouse is crammed with a laptop computer and all kinds of electronic navigation aids. But not everybody has those, explains MacLean, who says he still uses his eyes and ears. For one thing, urban development near the harbor has created a kaleidoscope of lights competing with the visual aids that mariners use. Traffic lights onshore can mimic the critical red and green buoys that mark safe channels.

The present-day solar-powered East Brother foghorn is less impressive in both sight and sound than its compressed-air predecessor…but also less jolting.

“You've got all of these lights going off everywhere and sometimes it can be a little bit tricky.” He argues that it's made the audible signals even more important. “They're critical pieces of information,” he says. “There will never not be a need.”

Today, young mariners don't have to risk lives and property to learn their way around. At Cal Maritime, a computer-driven walk-in simulator puts students in the virtual wheelhouse of “vessels” ranging from a 60-foot jet boat to a supertanker.

And yet, with all this technology Academy instructors still train students to use a sextant, a centuries-old instrument for navigation, because you never know when modern technology will fail you.

The Walter Fanning fog signal on East Brother Island. Its roomful of apparatus dates back to the 1920s.

And speaking of that, remember that cannon that served as the first Pt. Bonita fog signal? Somebody had to fire it, of course--every 30 minutes, 24-7, as long as the fog was in. They hired a certain "Sergeant Mahoney" for the job.

“Well the fog was always in, says Drew Van Winkle, a volunteer at the Point Bonita light (remember those 1,500 hours). “And poor old Sergeant Mahoney couldn’t get a rest. Mahoney put in a request for relief but there was no budget for that. Request denied. Van Winkle says, “The day must've been relatively nice and they gave him a little leave.”

And leave he did. “They never saw Sergeant Mahoney again,” says Van Winkle. “That was the end of that.”

But it was just the beginning of a whole new soundscape for the Bay. One that’s still changing.


The estimated annual hours of fog in the Golden Gate has been corrected from an earlier post.