Loudspeaker wages war on pirates
The shipping industry was offered a formidable weapon in the war against pirates, when a loudspeaker was demonstrated in Virginia, USA. LRAD, or long range acoustic devices, developed by a partnership between the Office of Naval Research and American Technology, are very loud, directional speakers that can communicate with other vessels at safe distances.
The recent pirate hijacking of a Saudi oil tanker has propelled the issue into the limelight and regular attacks around the coast of Africa mean weapons designed to dissuade aggressors are necessary. LRADs can be mounted on ships and controlled remotely with devices boasting a range of several thousand yards.
Speakers can be used for communication purposes or can send out piercing, non-lethal sounds. Furthermore, pre-recorded messages in various languages can be broadcast via an MP3 player.
And it's not just pirates the speakers can keep away. Predatory sounds can ward off dolphins and small birds.
Witnesses of the Virginia demonstration said at nearly 200m, the sound was “crystal clear, cutting through the ambient sound or aeroplanes overhead”. The unit operates in a 30- to 60-degree cone and outside of that the sound drops off drastically.