[Talisker]

It’s just a guess but IMO we very likely have small, stealthy drone subs. No idea if such drones can replace the utility of quiet conventional subs.

How would we control them remotely? Satellites? Isn't signal and power degradation a problem underwater?

[Bobalu]

Slow comms via sound and ultra-low-frequency rf.

When faster data is needed pop loose a tiny transponder to float to the surface with a thin tether of optical fiber back to the boat. The rf device would only need to be the size of a marble... data transfer via the large NRO satellites in geo orbit 23,000 miles out. Power output from the device would be far less than a milliwatt since the big NRO birds can hear anything and so nearby ships would be less likely to notice the signals.

Anyhoo, that’s my guess as a computer and radio geek :-)

[sheik yerbouty]

Long wave radio may fare better..