No, it's not nearly enough. The exact number of weapons onboard is largely irrelevant. At any given time only about one third of a nation's attack submarines can be out on active patrol while the others are in transit, undergoing maintenance, or working up. During a crisis they can maybe surge two thirds of the force for a few months but that isn't sustainable. Each submarine can only be in one place at a time and they're likely to take some losses against a competent adversary.
That's so naive. Those robot submarines will be useful for local defense but they lack the range, speed, and staying power to project power and protect sea lines of communication over thousands of miles on a sustained basis. The notion of doing that with robots remains firmly in the realm of science fiction today. Maybe in 30 years.
And my point is it's not about a physical blockade.
If you buy your ships from half way around the world, then the shipyards can be destroyed before you get anywhere near them. And certainly now preventing that is politically commiting to a war on the other side of the planet which may not immediately effect you, but is likely to eventually.
But the other part is: you don't have to physically do anything. You could deny shipping to your opponent by someone just outbidding you for the output. Why not? You're already outsourcing so you're cost sensitive, and guaranteed volume is cat nip to manufacturers - no amount of strategic alliance wording is going to save you if an adversary reliably buys 10x as much.
Say, with satellite coverage to find out where any blockade runners are and a lot of cruise missiles you could enforce a blockade from a thousand miles away.
That would be extremely difficult to defend against unless you have enough ships to defend every single convoy. WWII showed how helpless big surface ships were against u-boats in defending shipping.
