One of the simplest ways to alert fellow boaters and first responders to a problem on the water is with a sound-producing device. For most of us this isn’t just a good idea; it’s the law. Under Rule 33 of the U.S. Coast Guard Navigation Rules, boats 39.4 feet long and shorter must have on board a sound-producing device that is capable of creating a minimum sound level of 111 decibels and that must be capable of providing at least one-half-mile range of audibility. (Your mother-in-law may be able to, but she does not count.) Let’s take a closer look at the noisiest features of three of the most popular portable sound-producing devices you can bring on any boat. — Eric Colby
*Sound carries a mile over water, half a mile over land.
*Maximum output is 112 db.
*The Super Sound is ozone safe.
*It’s 4½ inches tall and only 1½ ounces, so kids can use it.
*Its finite lifespan ends when the gas runs out.
*It works as long as you can draw a breath and exhale.
*It’s one of the loudest whistles available at 122 decibels (db).
*Plastic construction ensures that it won’t freeze or rust.
*Lanyard attaches to life jacket or goes around wrist, but it’s small enough to fit in your pocket.
*It can be used for emergency signaling or boat-to-boat hailing.
*It runs on 9-volt battery power, so carry backups on board.
*The horn produces a four-second, 112 db blast.
*This isn’t submersible, unlike the plastic whistle.
*It has an ergonomic pistol grip.