I'm calling BS on this. The stealthiness of a sub, it's only real purpose, is defeated the moment you start transmitting via a big antenna. It wouldn't happen. Subs no doubt are used for surveillance, but the concept of them sitting offshore and actively "hacking" communications is absurd. It would be a suicide mission with a billion-dollar asset.

The OP reads like a funding request. It's a pitch for a world where hackers will live inside submarines close to the action, when we know from experience that even when submarines were used to tap lines that the submarine did nothing other than install the tap and scurry away. (They also retrieved the recorders, but then too scurried away asap.) You don't risk something like a sub, and the lives onboard, on information management that can be done from afar. A drone capable of operating untethered far away from the mother ship might as well be controlled from thousands of miles away. The sub may launch the hacker-drone, but no matter the navy's fantasy, subs won't be at the center of the flowchart.