Anti Submarine Warfare – ASW

Sophisticated sonar equipment
Anti-submarine warfare is a branch of underwater warfare that uses surface warships, aircraft, submarines, or other platforms, to find, track, deter, damage, and/or destroy enemy submarines. Such operations are typically carried out to protect friendly shipping and coastal facilities from submarine attacks and to overcome blockades.

Successful ASW operations typically involved a combination of sensor and weapon technologies, along with effective deployment strategies and sufficiently trained personnel. Typically, sophisticated sonar equipment is used for first detecting, then classifying, locating, and tracking a target submarine. Sensors are therefore a key element of ASW. Common weapons for attacking submarines include torpedoes and naval mines, which can both be launched from an array of air, surface, and underwater platforms. 

The military submarine is still a threat, so ASW remains a key to obtaining sea control. Neutralizing the SSBN has been a key driver and this still remains. However, non-nuclear-powered submarines have become increasingly important. Though the diesel-electric submarine continues to dominate in numbers, several alternative technologies now exist to enhance the endurance of small submarines. Previously the emphasis had been largely on deep water operation, but this has now switched to littoral operation where ASW is generally more difficult.

As sensors for detecting submarines are different  acoustics particularly in active and passive sonar, sonobuoys, and fixed hydrophones aid in the detection of radiated noise. Sonar can be mounted on the hull or in a towed array. The weapons to counter subs are mainly, Naval Mines, Torpedoes (acoustic, wake homing, Wire-guided), Depth charges, Rockets, Anti-submarine missiles, Anti-submarine mortar and Anti-submarine nets.