The presence of ships rarely goes unnoticed. Aside from their sheer size, they show up on radar and AIS (Automatic Identification System) and are in regular contact with each other by radio. Those of us in small boats often go unseen and literally under the radar. While there are advantages to being so unobtrusive, there are times when it is necessary to make our presence known, if only to convey a very simple message: I’m here. Having a good whistle or horn aboard makes that possible when there is an inattentive boater or fog about.

Among the loudest I’ve used are two foghorns made by Plastimo: the Trump and the Mini-Trump. I don’t know exactly when the horns were first released, but they were listed in Plastimo’s 2014 catalog, a few years before the name became intertwined with American politics. My guess is that the name was a play on the word “trumpet.”

Photographs by the author

The larger horn comes with a wrist lanyard, a case, and two replacement membranes (not shown).

The horns are of the diaphragm type and produce sound by vibrating a membrane that intermittently interrupts the flow of air passing through the horn. I’ve made a few of this type with plastic plumbing parts and in several different pitches. I thought they were loud, but the Plastimo horns are at another level: painfully loud. It takes very little air pressure to make them sound, and an easy puff produces almost full volume.

To get a measure of the volume, I bought a sound-level meter and took readings with the meter set 24″ from the horns. My home-made horns reached 90 decibels (dB), and my classic Perko fog horn hit 106 dB. The Plastimo horns are claimed to exceed 100 dB, though I wasn’t able to find at what distance that reading was taken. At 24″, the large one registered 119 dB on the meter, and the small one, with its tube extended, registered 108 dB. I used a digital tuner to identify the pitches: E-flat for the large and E for the small.

Cupping hands around the ends of either horn protects the ears when hearing protectors aren’t used.

The sound from the Plastimo horns is projected from the ends, which puts it closer to the ears than does a forward-facing horn. To measure that effect on the user, I took readings at 6″. The large horn hit 124 dB and the small hit 121 dB. Many websites with information about sound levels set the threshold for pain and damage to hearing at 120 dB.

I did all my testing with ear-muff hearing protectors, but they don’t seem like a practical addition to my boat’s safety gear. I found I could hold either Plastimo horn in one hand with a finger in one ear and plug the other ear with the free hand. That made a significant difference, and I could use the horns comfortably. It was also effective to cup a hand around each end of the horn to direct the sound forward and away from my ears. That brought the sound down to a level below the pain threshold and had the added benefit of projecting more of the sound forward. At 24″, the large horn hit 124 dB and the small hit 121 dB, the same levels I’d measured at 6″.

The smaller horn has an extension tube, here retracted. The black cap protects the plastic membrane and stretches it tight when installed in the horn.

The horns have no parts that will suffer from exposure to salt water. If the membrane fails, it can be replaced in seconds with a piece of plastic film (grocery-store produce bags and zip-close bags also work well). When dropped overboard, the yellow plastic horns float, are easy to spot, and will quickly drain of water when recovered, ready for use. The smaller of the two horns, with its extension tube retracted, fits easily in a coat or PFD pocket. With either Plastimo foghorn you can effectively make yourself heard and your presence known.

Christopher Cunningham is the editor of Small Boats

The Trump and the Mini-Trump are manufactured by Plastimo in France and distributed in the U.S. by Bainbridge International. I bought mine from Seattle’s Fisheries Supply for $48.94 for the large, $29.66 for the small. They are available from many other marine hardware outlets.

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