OVERVIEW: The ADC Mk 4 Mod 0 Torpedo Decoy is a battery-powered expendable sonar countermeasure for use by  submarines to counter torpedo and sonar threats.

DETAILS:   The ADC (Acoustic Device Countermeasure) MK3 is a 6.25-inch (16 cm) diameter torpedo and sonar countermeasures externally stored and launched from all USN submarines. The ADC hovers vertically at a pre-selected depth, using a pressure-controlled motor driving a small, shrouded propeller in the tail of the decoy.  Once deployed, it emits an acoustic signal to decoy sonar and torpedoes.  

NOTES:  IOC 1995.   

  
SOURCES:  Friedman, Norman, and Norman Friedman. The Naval Institute Guide to World Naval Weapon Systems. Annapolis, Md: Naval Institute Press, 2006, pg 769 ; Ultra Electronics Ocean Systems - Home. "Ultra Electronics Ocean Systems - Acoustic Countermeasures." Accessed December 13, 2014. http://www.ultra-os.com/acoustic.php.

