PLAN ASW Capability

AndrewS said:

"Eventually" stumbling onto a nuclear sub will be difficult past the 1st Island Chain.

Also, my understanding is that surface ships operate by sprinting and then drifting silently to allow their towed arrays to work.

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If you have SURTASS ships, SOSUS and enough sea gliders around, they can cue up MPAs to more specific areas to search. The 093s can cue up searches also. Otherwise, your ASW operation is pretty much limited to area where you can maintain air superiority. And you need a lot of them to stumble onto quiet submarines.

So for PLAN, I'd imagine they can find subs all the way down to Spratleys. Beyond that, they will have to rely on helicopters and all the sea gliders they've been out there. Indonesian fisherman found sea gliders all the around java island. So, PLAN is really trying to map out that entire area. Keep in mind, US/Japan did the same thing to China with their own East Asia SOSUS.

If I were China, I'd be developing technology that destroys US/Japanese SOSUS.
For China, they are going to also be relying on SURTASS, SOSUS, UUV, these floating sensors

China is building SOSUS all the way out of Guam, Palau and south Philippines. You can see that as they are building a blue water navy, they are able to build these passive sensors further out, past the first island chain. So with enough effort, they may have enough sensors from Kyushu down to Philippines Sea to give the surface fleet more space to work.

Without cuing, it's really hard even for MPAs to find submarines. Stumbling into is probably the right phrase!

It seems to me as time goes on, low cost AUVs and UUVs are going to be a huge part of your ASW and MCM effort. And they can cut underwater cables and destroy other countries' SOSUS web.

Keep in mind that even a loud 093 has certain advantages over the quietest Japanese diesel subs. They will carry more power sonars and have a larger crew. They can stay protected with their CSG. And they can move so much faster than the diesel subs that as long as China has air/surface superiority, 093s would have the freedom to finding diesel subs and hunting them down.

tphuang said:

If you have SURTASS ships, SOSUS and enough sea gliders around, they can cue up MPAs to more specific areas to search. The 093s can cue up searches also. Otherwise, your ASW operation is pretty much limited to area where you can maintain air superiority. And you need a lot of them to stumble onto quiet submarines.

So for PLAN, I'd imagine they can find subs all the way down to Spratleys. Beyond that, they will have to rely on helicopters and all the sea gliders they've been out there. Indonesian fisherman found sea gliders all the around java island. So, PLAN is really trying to map out that entire area. Keep in mind, US/Japan did the same thing to China with their own East Asia SOSUS.

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If I were China, I'd be developing technology that destroys US/Japanese SOSUS.
For China, they are going to also be relying on SURTASS, SOSUS, UUV, these floating sensors

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Within the 1st Island Chain, I would agree it is very risky for enemy submarines to operate.

tphuang said:

China is building SOSUS all the way out of Guam, Palau and south Philippines. You can see that as they are building a blue water navy, they are able to build these passive sensors further out, past the first island chain. So with enough effort, they may have enough sensors from Kyushu down to Philippines Sea to give the surface fleet more space to work.

Without cuing, it's really hard even for MPAs to find submarines. Stumbling into is probably the right phrase!

It seems to me as time goes on, low cost AUVs and UUVs are going to be a huge part of your ASW and MCM effort. And they can cut underwater cables and destroy other countries' SOSUS web.

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But in the relatively open and deep waters between the 1st Island Chain and 2nd Island Chain, it's a lot easier to operate.
And my impression was the waters are too deep to emplace a SOSUS net.

tphuang said:

Keep in mind that even a loud 093 has certain advantages over the quietest Japanese diesel subs. They will carry more power sonars and have a larger crew. They can stay protected with their CSG. And they can move so much faster than the diesel subs that as long as China has air/surface superiority, 093s would have the freedom to finding diesel subs and hunting them down.

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Japanese submarines aren't the issue, as they don't have that much endurance. It's the US submarines which are the pacing threat.

AndrewS said:

Within the 1st Island Chain, I would agree it is very risky for enemy submarines to operate.

But in the relatively open and deep waters between the 1st Island Chain and 2nd Island Chain, it's a lot easier to operate.
And my impression was the waters are too deep to emplace a SOSUS net.

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I'm not sure how effective it is, but based on that SCMP article, they clearly are trying to put SOSUS between 1st and 2nd island chain. Most likely, they will rely on SURTASS, sea gliders and AUVs for that are I'm talking about. That's a hugely important operating are for PLAN. Also, the area south of Spratleys would still be quite hard for them, since they just can't get as many sensors down there yet. I think it's more a function of distance from mainland vs 1st or 2nd island chain

AndrewS said:

Japanese submarines aren't the issue, as they don't have that much endurance. It's the US submarines which are the pacing threat.

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If Lithium battery submarines turns out to be all it cracks out to be, then they may very well be a much larger issue. I'd be curious of their strategy with these new small single hull subs they are testing out. Are they looking to flood the island chain from Kyushu to Taiwan. It should be shallow there and they might be a low cost way of finding Japanese subs, if they remain silent and the Japanese subs are racing over.

Again, they are trying a lot of things now. It's like they are trying to form a underwater sensory net to catch any sound emissions that are susceptive.

tphuang said:

I'm not sure how effective it is, but based on that SCMP article, they clearly are trying to put SOSUS between 1st and 2nd island chain. Most likely, they will rely on SURTASS, sea gliders and AUVs for that are I'm talking about. That's a hugely important operating are for PLAN. Also, the area south of Spratleys would still be quite hard for them, since they just can't get as many sensors down there yet. I think it's more a function of distance from mainland vs 1st or 2nd island chain

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The key thing is that you need air and maritime superiority in that area, which will allow everything else to operate.

tphuang said:

If Lithium battery submarines turns out to be all it cracks out to be, then they may very well be a much larger issue. I'd be curious of their strategy with these new small single hull subs they are testing out. Are they looking to flood the island chain from Kyushu to Taiwan. It should be shallow there and they might be a low cost way of finding Japanese subs, if they remain silent and the Japanese subs are racing over.

Again, they are trying a lot of things now. It's like they are trying to form a underwater sensory net to catch any sound emissions that are susceptive.

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And China has better battery tech

...cont

Overall, China has way better battery technology than Japan.
So if Japanese lithium battery submarines do work out, there shouldn't be an issue with China building their own equivalents and on a much bigger scale.

here is the thing.. very soon, within the lifetime of a nuclear submarine, there will be just so much human and robot activities going on in the whole of the SCS, and within the first, second and third island chain that any nuclear submarine is going to be spotted easily.

China is planning the marine economy, and it involves everything, food, energy, tourism, environment cleanup and monitoring, climate and science, there won’t be a square cubic kilometer of ocean without a sensor.

There will be millIons, maybe billions of robots swimming in the oceans cleaning up microplastics and sensing every piece of material they encounter.

AndrewS said:

...cont

Overall, China has way better battery technology than Japan.
So if Japanese lithium battery submarines do work out, there shouldn't be an issue with China building their own equivalents and on a much bigger scale.

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Yes, china has better battery technology now, but do you remember which hybrid car was the first big hit? That was Toyota Prius. Japan was actually advanced in this area for a while. Panasonic still was a big player until this year.

So, the question is how they can take advantage of the recent advancement in battery and electric train technology.
It would be interesting to see how they go with those new subs that came out recently. They are single hull, so the pressure hull diameter is 5 m, probably not that much less than song class sub. Given the smaller sub size, the items that make noise (propulsion motor, shaft and such) probably would make less noise than a larger sub of same generation. And Given the more efficient space usage of the electric motor now, they probably do end up with more room for noise isolation technology. Keep in mind that aip also provides for additional noise level, since Stirling engine itself is a combustion engine that makes noise. As such, you can sustain speed and noise level with lithium battery that you cannot with aip. So these are the advantages of using lithium ion battery. Much better endurance, faster charging and maneuverability.

If those recent small subs we saw (type 206 size) get mass produced, they will probably be extremely cheap and can be mass produced easily. They will probably be between song and yuan class in noise level but much better endurance than both. They would be quite ideal in the shallower water around spratleys, paracel, Ryuku islands, around bohai/yellow sea and around Taiwan. They will provide additional sensors with their sonar that can be part of the underwater network of sensors providing a web around shallow waters. This would be a very good way of using small cheap subs to extend your asw coverage and leaving larger subs to operate in deeper water of farther away part of scs or Philippines sea.

Again, I am waiting to see the next generation large Chinese conventional sub. You would think a new class is needed to replace yuan, since it appeared 18 years ago! It's hard to think yuan can get exponentially quieter and replace it's entire drive train and battery pack without having different hull dimensions. That would potentially be a very good asw platform when coupled with air and surface superiority.

tphuang said:

Again, I am waiting to see the next generation large Chinese conventional sub. You would think a new class is needed to replace yuan, since it appeared 18 years ago! It's hard to think yuan can get exponentially quieter and replace it's entire drive train and battery pack without having different hull dimensions. That would potentially be a very good asw platform when coupled with air and surface superiority.

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So what's your theory for why we haven't seen this new large conventional sub? If you believe that the 039As (which are contemporaries of the Soryu) are no longer competitive, and that China has all the pieces to put together a first rate SSK with its present technology, why aren't we even getting an indication that such a submarine is in the works?

ZeEa5KPul said:

So what's your theory for why we haven't seen this new large conventional sub? If you believe that the 039As (which are contemporaries of the Soryu) are no longer competitive, and that China has all the pieces to put together a first rate SSK with its present technology, why aren't we even getting an indication that such a submarine is in the works?

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Perhaps the PLAN is waiting for battery technology to settle down first? We're still in the middle of rapid technological developments in battery technology and costs.

And there was the previous LFP battery specification sheet for a conventional submarine advertised like a decade ago.

More on ASW from AUVs and sea gliders.

China was showcasing AUV with different types and sonar and can move around in the water with different thrusters. And it can be dropped from a low flying drone or helicopter (imo). This to me is like a really jacked up version of sonobuoy. It would have more powerful sensors and can intelligently move around to survey a larger area. If you deploy enough of these things around a fleet, that could offer a lot of enhanced detection capabilities.

According to the Indians, China has been dropping UUVs in Indian Ocean for a long time.

Reading some of these articles, it seems like the water in SCS is very complicated and is still not fully mapped. The sooner they can get enough UUVs/AUVs in there to map the entire area across different operating conditions, the better chance they will have for hunting submarines as well as hiding their own submarines.