Rakesh wrote:There are six SSNs right now, in the planning phase. But the high cost involved of maintaining an all SSN fleet requires the Navy to have SSKs as well. The Soryu has many advantages over the Type 209, Kilo and the Scorpene.
And India does require SSKs to defend from enemies in their littorals. And a SSK is inherently more silent than a SSN. It does not have the reach of a SSN, but that is not required of the SSK. In numerous exercises with Los Angeles Class boats, our Kilos have gotten the better of them every time. That is not because the Los Angeles Class is a bad vessel, but rather that the Kilo is much more quieter.
They do not call a Kilo boat, the black hole for nothing.
Correct. To add, sharing a post I made 1-3-2016 here -
Diesel Electric submarines are very silent when operating in electric batteries. However, speed is very less with batteries. So is endurance. When in transit, or recharging batteries, they are noisier. A DE submarine is a sniper of the deeps. But like every sniper, they're good when nearly motionless. They lose effectiveness when in motion.
Now, nuclear submarines are more noisier because of pumps circulating coolant and steam turbines. All nuclear submarines are capable of high speeds, its the ability to keep noise low at high speed that is critical.
So, for a nuclear submarine to deal with a DE submarine, it has to use active sonar and make high speed interceptor slash & run attacks. If it lingers, it'll be vulnerable to the sniping DE submarine. It also needs the high speed to outrun torpedoes. Even though it'll be noisy at high speeds, the DE submarine wont be able to catch up or keep up with it.
Which is why IN was not euphoric when IN Type 877EKM tracked a US Nuclear Submarine in restricted area in recent Malabar exercises. Had the area not been restricted, the nuclear submarine could've used active sonar over long range and attacked and ran. The DE submarine would not have the speed or endurance under those circumstances.
Diesel Electric submarines are useful for littoral defence; a few are built for extended range. AIP gives DE boats slightly longer endurance/range while submersed. The snorkel can also be used, but only from periscope depth. it renders the sub susceptible to detection in multiple ways.
Nuclear submarine reactors for the last 3 or 4 decades come with passive cooling/natural circulation
features. This means that noisy pumps are not needed below a certain speed; the coolant pathways are optimized and thermal gradient drives flow from heat source lower down (reactor) to heat sink higher.. See the S5G reactor, the S8G reactor used in Ohio class, the S9G etc. Of course, one cannot speak for the Arihant's reactor; it is after all a 1st gen Indian one(though with russian consulting) and details may be classified. Above a certain speed/power, the pumps kick in
Thus nuclear reactors have acquired a lot of the characteristics of diesel electric submarines. Earlier nuclear powered submarines also had potential challenges that if they went into a clayey bottom and went silent, the intakes and struts could get covered up/stuck. However this is true of most other submarines also.
it has to use active sonar and make high speed interceptor slash & run attacks
Loud noise and active sonar are like a man flashing a bright torchlight in a dark room. They make him an obvious target for the other man waiting in the dark. This is a good way to get killed.
A diesel electric submarine cannot use its speed underwater to widen the circle where it might be and thereby escape. It cannot stay underwater for very long without surfacing. It cannot easily use speed underwater to get to where it's mission demands it should be, unless the mission comes to it (hence more useful for defence in littoral waters and in restricted box of an exercise)
A nuclear submarine can simply wait it out, move at slow but continuous speed to move out of the area or come back from a different direction, find appropriate layers of sea that don' mix as well - and can help hide any submarine to some extent (eg temp differences,salinity differences - thermoclines, or hope that the underwater geography- eg mountains or sea floor can mask some of the echo - more rare). Once the diesel is forced to come up and charge batteries, it can detect that noise and attack (though it must remain in near sonar contact for it). Or just leave it to other ASW units to detect and finish it off. The nuke can also slip away to perform it's other missions.
Nuclear attack submarine may detect when a ballistic submarine has come to missile launch depth and is making preparations to do so; and then use high speed sprint to get there and hopefully kill the ballistic submarine before it ends civilization. (ie either before the first nuclear missile launch if lucky,or a later one if good)
Submarines can also use the intermittent sprint and then hide approach - eg sprint under cover of noise or to get out of the kill zone/widen search area and then creep/stay - only to pick up speed when your risk of detection is minimal again. Obviously nuke and de will have different constraints, and situation with surface and planes will also change the trade-offs/actions
Situational awareness is the key in sub vs sub.
If you have excellent quieting measures, design,manufacture, operational excellence, and maintain passive sonar listening techniques,a modern western sub can be so quiet that it may not know that another is there (see the collision of the british and french ssbn submarines
But if your passive sonar is better, or you are able to make more effective use of your equipment and of the sea conditions, or if your quieting is better - you have an advantage.
Generally the western nations that build nukes also have significant electronics(see sonar) and technological advantages. (ie If you are investing that much ,why not splurge for good sonar etc) The russians are not far behind. The first generations of chinese nukes are noisy, but the latest generation is supposed to be good and be able to use towed array sonar etc...India - we won't know; we're hardly likely to get an unbiased/objective picture in open sources now.
You can try to use high speed and active sonar - eg if time is of the essence, but can you outrun a torpedo aimed at you ?
You don't get super excited about DE kills in exercises, because in exercises, the rules are known up front. There is a restricted area and thus you can get your kills in - in exercises everybody kills each other. Swedish,Australian,Soviet, and British boats have 'killed' US carriers.But equally, you don't know how often the sub hs been killed back]