PLA SSNs are much more useful as convoy hunters. Americans needs to supply plenty of materials to its bases in the West Pac and Japan. Imagine a fleet of 10+ SSN moving around the known routes between CONUS and Japan/Guam/Hawaii/etc and inform PLA where to look for the merchant fleets. PLA can either use DF-26, H-6(H-20 in the future) or naval task forces to take them out. US navy will be forced to divert parts of their fleet to hunt down the subs and to protect the convoys instead of attacking PLA assets.
I would agree with this one. Here is what I think is the rationale behind the SSNs, but comments are welcome.
The SSNs will only come into service in the 2025-2030 timeframe.
By then, whilst the US Navy would like to keep its carriers at a standoff distance from mainland China as much as possible, I don't see this happening with respect to Taiwan.
The Taiwan situation would be:
1. Taiwanese airbases knocked out in an initial missile strike
2. follow-up airstrikes conducted
3. followed further by potentially huge numbers of Shaheed-136 type munitions every single day (say 800 Army TELs x 5 munitions per salvo). And each Shaheed is equivalent in cost to a JDAM.
With no electricity and all the 5000-odd fuel distribution storage tanks in destroyed in Taiwan, Taiwan will collapse swiftly unless there is resupply which will require a lot of transport planes and cargo ships. That will require US carriers to provide air cover for extended periods and essentially over Taiwan which is 200-300km from mainland China. Standing off the carriers at 1000-1500km and conducting occasional air sorties will not cut it, as the cargo aircraft and ships will get slaughtered unless there is a constant fighter presence provided by closeby carriers. Those carriers have to take on 600+ air sorties per day from the Chinese Air Force, and there should be a lot more Y-20U tankers in service by then.
In such a scenario, using SSNs to launch AShBMs isn't really required because the carriers have to get that close to mainland China.
But if I look at the situation in 5 year's time, I see Japan also facing the same scenario as Taiwan today, with no electricity and a guesstimate of its 30,000-odd fuel distribution tanks also destroyed.
Again, Japan would need significant resupply from transport planes and cargo ships in order to prevent a collapse. But in the Japanese scenario, because Japan is significantly further away from mainland China, the Chinese military will not be able to field large numbers of affordable land-based missiles to target the carriers. Plus Japan presents a very long (1500km+) geographical barrier which prevents PLAAF aircraft or ISR assets flying through. For comparison, Taiwan is only 350km long, so PLAAF aircraft can easily fly around Taiwan into the open ocean.
So in such a Japan scenario, SSN-launched AShBMs would make a lot more sense. And with a mooted 1.2m missile diameter, that would be comparable to a DF-16/17 class missile in terms of being affordable. Call it $2 Mn.
The length of Japan (1500km+) also means that a smaller missile class (such as the DF-11 with a diameter of 0.86M and a 600km range) doesn't cut it in terms of covering all the potential target locations.
So the next largest missile is a 1.2m diameter DF-16/17 missile. And with a 2500nm range, a submarine could loiter quietly deep in the Pacific and still reach Japan. As a bonus, such submarines could cover targets in the Guam area as well. The greater distance also means the submarine can successfully evade any MPA aircraft sent after the submarine reveals its location by firing. Not that I expect many (if any) MPA aircraft to be available as the closest operating base is now Hawaii
Of course, this assumes that Japan would declare war and intervene if there is a resumption of the China-Taiwan civil war.
But a rational Japanese government should decide neutrality is a better option than a modern-day version of Operation Starvation.
So let's say there are 8 Type-093B SSNs in service. If they follow the USN operating profile, 1 should be on patrol at any time, plus 5? more ready to surge.
Currently the USN has about 50 SSNs with 6 on active patrol at any time, and 3 nominally assigned to the Pacific. If the USN was able to keep all 6 of these SSNs permanently in the Western Pacific, then they could manage to tail or intercept all the outgoing Chinese SSNs. But this isn't realistic because other demands or duties will come up.
So a Chinese SSN surge will see most Chinese SSNs successfully pass through the 1IC and then disappear to the East of Guam/Japan and into the vast expanse of the Pacific.
So there's no need to keep SSNs within air cover of the Chinese mainland and within the 2IC, as the nearest available MPAs will be operating from Hawaii.