It's a high-powered directional loudspeaker that allows a ship to hail an approaching vessel more than a mile away. And it comes with recordings of useful phrases, like "You must leave the area immediately," in Somali and dozens of other languages.
That keeps harmless fisherman from getting into trouble and gives pirates pause," says Robert Putnam, who handles media relations at American Technology Corp. in San Diego, which developed the LRAD.
"Knowing that they've lost the element of surprise is half the battle," Putnam says. "Most pirate incidents would never occur once they know at that distance that they've been discovered."
For pirates who keep coming anyway, the LRAD has another feature. It's a piercing "deterrent tone" that sounds a bit like a smoke detector alarm.
The tone can be transmitted with enough intensity to cause extreme pain and even permanent hearing loss for anyone directly in the beam of sound that comes from the device.
Putnam says a Japanese destroyer used the hailing function of an LRAD to turn away pirates who were attacking a tanker from Singapore.
But Capt. John Konrad, who blogs for the Web site Gcaptain.com, says no anti-pirate device is perfect.
Ear protection can defeat an acoustic device. Goggles can nullify blinding lasers. Electric fences can be cut.
Konrad, who is in Korea while his next ship is being built, says nothing works unless you know a pirate is on the way. And that can be tricky.
"How do you determine who is a pirate and when the pirate is coming through," he says. After all, pirate ships often look like fishing vessels until the ladders and guns and grenade launchers come out.
So Konrad is a big fan of having ships travel in convoys. That means there are more eyes looking for trouble and that pirates will have a harder time attacking any single ship.
Konrad also likes the idea of unmanned aerial vehicles, or UAVS. They can be launched from the deck of a ship, fly high overhead and spot suspicious vessels while they're still a long way off.
"The best case scenario is that you find these vessels early enough that you can get a Navy ship detached to your location and let them handle the situation," Konrad says.
Pictures courtesy Southwest Research Institute, Unifire and American Technology Corp.