China already have the full SSK production and operational infrastructure in place. More importantly, its SSK production base is distinct from its SSN production, so simultaneous production has almost no direct opportunity cost as one more SSK-N doesn’t have to mean one less SSN.
Yes, it’s wasteful, but in war, overkill is infinitely preferable to defeat.
The PLAN can rapidly replace its existing SSKs with SSK-Ns and be able to spin those up into combat capable units far faster than it can spin up additional SSN boats. That’s not just in terms of production timescale, but also crew training and experience.
I view the SSK-N as similar to the leap from a J11 to J16. It’s a quantum leap in capabilities, but you can still use a lot of existing legacy support facilities and pilots don’t need to learn a totally new way of fighting. Whereas SSNs are more like 5th gens that gives you an entirely different class of capabilities. And just like how the PLAAF is dual procuring legacy and 5th gens, there is every chance the PLAN will do the same with SSK-Ns and SSNs.
Unless they are trying to be silly, they would be building the nuclear element as a self-contained unit that would not need any specialist equipment to install. The whole point of an SSK-N is to keep as much of the SSK as possible, otherwise you might as well just go full SSN.
Now that you mentioned it:
At the present state (and for the foreseeable future) - Huludao is capable of launching 3-4x SSNs per year.
Besides, assuming that both Wuchang and (to a more certain degree) Jiangnan are capable of building SSK-Ns, I'd put the capability of 1-3x SSK-Ns per year for both shipyards (that is, 1x for Jiangnan and/or 1-2x for Wuchang), depending on how urgent the PLAN needs SSK-Ns to supplement (before replacing) their SSK fleet.
Tallying all three shipyards, this means a combined total SSN + SSK-N launch capability of
at least 4x boats per year (3x SSNs + 1x SSK-N) and
at most 7x boats per year (4x SSNs + 3x SSK-Ns). With sustained production rates for all the involved shipyards, this
translates into the potential of 40x - 70x boats being launched in a decade.
(Technically speaking, without constructing any new SSBN, Huludao could potentially add another 1x SSN to the tabulation, meaning a
theoretical maximum of
8x boats per year. However, let's keep that additional SSN out for the sake of this discussion.)
In contrast, the US aims to raise the production rate of the Virginias to 2x boats per year by 2028, 2.3x boats per year in the early-2030s and potentially 2.5-3x boats per year later on.
The last time the US had comparable build rates of nuclear submarines (of all types) was in the 1960s, followed by the 1980s and 1970s.
(From the latest Binkov Battleground's Virginia vs 093B video)
UUVs and AUVs aside, it's only going to be extremely hard for the US to attempt such stunts again like what they did during the heat of the 1st Cold War. But even so - Nowadays, China is a major player in the UUV and AUV domain, too.
That is to say - Even if/when the 093B is incomparable to the early-Virginias, the mere potential number (and thus, subsurface firepower delivery capabilities) of the PLAN SSNs + SSK-Ns that is concentrated in the Western Pacific and Eastern Indian Oceans in the coming years will become increasingly staggering, if not daunting for the opposing side.
