To provide audible warning and sonic deterrence, APT uses American Technology Corporation's mass notification Long Range Acoustic Devices (LRAD(tm)) that are capable of maximum intelligibility over extended distances. These speakers are fixed in position and arrayed to provide 360º coverage. LRAD is linked to the various detection systems of APT, and automatically targeted by these detection systems. APT can support multiple pre-programmed messages as well as provide clear, authoritative verbal commands through direct audio input from a microphone. The minimum threshold (85 Decibels) is understandable at 500 meters with complete coverage around the vessel (360º). Depending on conditions, the system can provide an understandable audible warning as far as 3,000 meters from the speaker.

A unique feature of LRAD is its ability to provide attention-getting and highly irritating deterrent tones for behavior modification over long distances. At up to 150 dB output, the system has demonstrated its ability to deter intrusion at distances of up to 1 nautical mile. In April 2008, the M/V Resolve repelled a pirate attack at 1,100 meters from the vessel. The Captain stated, “(We) aimed her (LRAD) …went to maximum power and volume and activated. The first time the boat seemed to fall off course momentarily, then come back. I activated the unit a second time, this time holding it for a longer period and ‘waving’ it across the target to make sure I ‘hit’. The boat instantly went dead in the water and broke off its attack. The range was estimated at .6 to .8 nm. …The crew all saw it and they were cheering. I now have a ship full of believers. …Lessons learned: it works.” With APT, precise automatic set-and-forget targeting would achieve full effect without the need to “wave” the device across the target.

LRAD is currently required equipment aboard Princess Cruise Lines, Costa Cruise Lines, ARC Lines, Holland America Lines, P&O UK, P&O Australia, Aida, Cunard, Seabourn and Costa Cruise Lines, and is in use by Residensea, SBX Radar Platform, Red River Shipping, Norwegian Cruise Lines, Tyco, Pacific Tugboat, Chellaram Shipping, Bourbon Agathe, Bourbon Offshore, Beluga, Subsea 7, Hapag Lloyd, Alaska Tanker, Tidewater, and Lürßen, among others.

As a component of APT, LRAD provides the precise, targeted deterrent capabilities needed to ensure the safety of ship, cargo and crew on today’s high seas.