The crew of a luxury cruise ship used a sonic weapon that blasts earsplitting noise in a directed beam, as it tried to ward off an attack by a gang of pirates off the Somalian coast this weekend, the cruise line said on Monday.
The Seabourn Spirit was about 161km off the coast of Somalia when pirates fired rocket-propelled grenades and machine guns as they tried to get onboard.
The ship had a Long Range Acoustic Device (LRAD), installed as a part of its defense systems, said Bruce Good, a spokesman for Miami-based Seabourn Cruise Line, a subsidiary of Carnival Corp.
The LRAD is a so-called "non-lethal weapon" developed for the US military after the 2000 attack on the USS Cole off Yemen as a way to keep operators of small boats from approaching US warships.
The military version is a 20kg, dish-shaped device that can direct a high-pitched, piercing tone with a tight beam.
The cruise line was investigating whether the weapon was successful in warding off the pirates, Good said, since the ship's captain also changed its course, shifted into high speed and headed out into the open sea to elude the pirates.
The maker of the device, American Technology Corp, based in San Diego, California, said earsplitting "bangs" were directed by trained personnel toward the pirates. That, combined with ship maneuvers, caused the attackers to leave the area, it said.
The firm compares LRAD's shrill tone to that of smoke detectors, only much louder.
LRADs have been deployed on commercial and naval vessels worldwide since summer 2003, the company said.