Aren’t diesel subs much more dependent on tenders than nuke boats?
Critically missing in this 3rd world retro WWII technology “what if” discussion is the fact that diesel boats are noisy. Noise= death. So it wouldn’t matter how many could be deployed, they’d provide a target rich environment for the silent, fast killers of ASW and AS killer subs (the, uh, nuclear ones).
Now, there are some extremely quiet new electric subs that are providing a bit of a scare. But the people who know about them, can’t talk freely about them. And they are being acted upon.
Incidentally, the system that makes fresh water onboard- using a catalytic reaction of sea water— that has a lot of danger in its design and technology, have heard from many inside.