Acoustic warfare

Definition
Acoustic warfare is

"[a]ction involving the use of underwater acoustic energy to determine, exploit, reduce or prevent hostile use of the underwater acoustic spectrum and actions which retain friendly use of the underwater acoustic spectrum."

Overview
"There are three divisions within acoustic warfare: 1. acoustic warfare support measures. That aspect of acoustic warfare involving actions to search for, intercept, locate, record and analyze radiated acoustic energy in water for purpose of exploiting such radiations. The use of acoustic warfare support measures involves no intentional underwater acoustic emission and is generally not detectable by the enemy. 2. acoustic warfare countermeasures. That aspect of acoustic warfare involving actions taken to prevent or reduce an enemy's effective use of the underwater acoustic spectrum. Acoustic warfare countermeasures involve intentional underwater acoustic emissions for deception and jamming. 3. acoustic warfare counter-countermeasures. That aspect of acoustic warfare involving actions taken to ensure friendly effective use of the underwater acoustic spectrum despite the enemy's use of underwater acoustic warfare. Acoustic warfare counter-countermeasures involve anti-acoustic warfare support measures and anti-acoustic warfare countermeasures, and may not involve underwater acoustic emissions."