You don't want to send out beacons like that from your nuclear sub. Your adversaries can detect those, which negates the purpose of having a nuclear sub in the first place.
Additionally if they communicate through radio, you're back to the same problem because it's the thousand feet of water that blocks most radio waves. If they communicate via ultrasound you've just tied your sub to a nearby active sonar source. If they communicate via laser you have to be very close otherwise the power of the laser creates sonar detectable variations in the water near the sub.
Additionally if they communicate through radio, you're back to the same problem because it's the thousand feet of water that blocks most radio waves. If they communicate via ultrasound you've just tied your sub to a nearby active sonar source. If they communicate via laser you have to be very close otherwise the power of the laser creates sonar detectable variations in the water near the sub.