“Once saturation is reached, the diver can stay at the bottom for days, weeks, and months without needing any additional ...

Communicating with underwater drones is harder than with those in the air because radio waves can’t travel through deep water. The vessels can, though, surface to receive instructions.

The Navy's Surveillance Towed Array Sensor System (SURTASS) was built to counter the Soviet submarine threat in deep water, but the Navy now plans to use it against the regional—shallow water ...