The art of hunting down enemy submarines

Q: Which one is effective ? More ASW ships or more P8Is in sky to check the threat of enemy submarines? ~ Rony

Anti submarine warfare is the linchpin of Sea Control. Probably the most difficult of all forms of operations in Naval warfare, it’s everything about situational awareness. It’s the game of sensors.

Successful anti submarine warfare depends upon presence of some capabilities. And absence of any one of them will result in failure to timely track down the enemy submarine. ASW aircraft like P8I and ASW corvettes complement each other. If either one is absent, we won’t succeed. A balanced presence of both is required.

Submarine Hunting: A brief look

Hunting down enemy submarines is a multi tiered step involving surveillance(usually the enemy naval base, choke points in the ocean, etc) , detection (the crucial step to actually find the submarine) , classifying (to identify if it’s friendly or not, and if not what type. Each detail matters) and finally deterring or damaging the submarine inoperable.

Now we need to acknowledge that oceans are vast spaces not only in the surface area but also in its volume. That’s why its detecting the submarines which is the most crucial portion. To succesfully hunt down an enemy submarine a tiered defence of multitude of platforms is required!

Modern tiered ASW Capability

The important platforms which ideally should be present in our arsenal but not limited to are as follows :

1. Satellites: Optical and radar sensors based on satellites is the first step. It enables the user to continuously monitor the enemy naval bases( this is where we can most easily track down the enemy submarine) and crucial choke points like straits or canals connecting the Oceans of the world. Modern satellites are also capable to intercept the EM signals sent out by enemy submarines during communication. Other techniques used are Synthetic Aperture Radar/Inverse Synthetic Aperture Radar sensors enabling the satellites to monitor the disturbances or wake changes on the surface of sea which might be caused by a submerged submarine. This is one absolute necessity which Indian Navy should start to invest into soon. Our adversary already has such capability although limited in the orbit.

2. Fixed Wing Long Range Patrol Aircraft: This is the work horse of this department. Flying long range and long hour missions in patterns over vast seas trying to listen any hints of the metal enemy beneath the surface. It doesn’t only include P8I but also long range MAD/SAR equipped UAVs. These aircrafts use Magnetic Anomaly Detectors, hydrophones , FLIR sensors to detect the submarines. P8I is capable to detect SSN/SSBN from high altitude just by looking at the heat signature. Radars pick up even the slightest disturbance in wake caused by snorkeling! The key is to have a combination of manned and unmanned systems because it is a 24 hours 365 days non stop operation.

3. ASW Surface Based Assets: These include dedicated Anti Submarine Warfare Ships with Active/Passive Sonar sensors, torpedoes, rockets and depth charges. Larger ships have their own dedicated rotary platform based ASW capability which also carry their own sensor and weapons. Finding a submarine is like finding a needle in hay stack. Therefore once intelligence or surveillance reports comes about enemy submarines in a particular area , the intensive search is carried out by these assets.

These are aided by friendly submarines listening quietly from their passive sensors underwater. And when cleared dash onto the target full speed with active sensors. SSNs are important for this part.

4. Underwater fixed sensors: Seabed fixed listening devices are capable to detect and seperate human/artificial sounds created in the ocean. SOSUS arrays are important sensors which can relay information to us through our friendly nations. Sensors near important ports, naval bases and shipyards are also crucial as these are important targets for enemy to sabotage.

I have tried to give a brief overview of ASW. The problem is the vastness of the ocean and that means every asset is important. A full fledged ASW capability can even take out the nuke strike capability of the enemy, therefore we shouldn’t look to make compromises in this area.


  • An independent analyst with engineering background. Besides covering military affairs, he is also interested in space, airlines, infrastructure, nuclear, energy and related issues.

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