Think of it this way. You hook in your laptop, give it a program to hug the bottom of the ocean all the way to New York, surface, launch, submerge and return. No other data transfer is necessary other than for navigation.
Pretty Scary.
Why even return? It’s a drone, just detonate the thing entirely.
It sounds like a one way trip. No launch or return. Just a drone with a nuke. It gets to its destination and explodes.
There are some interesting twists. If it can be tracked it can be destroyed. Does the payload have a deadman switch on it? When is the launch process terminal? Or can it be recalled? Can it be captured and controlled? All sorts of interesting C-cubed-I questions arise.
Even more so is for it to make its way into a harbor then detonate, a lot or radioactive fallout that way.