Do we know what kind of communication the sub was outfitted for? They were on that 'corner cutting' 'rule breaking' budget don't ya know. But it does take special ELF tech to pass through water as opposed to 'space'

WhatEVER 'space' is! and I'm not sayin' ... just sayin' .. ;)

As for that 'moon' deal .... mmm ... weeeeell..... er .... ahhh

When the Titan is submerged, communications with the support ship on the surface are conducted over an acoustic link. Crewed submersibles sometimes have two separate systems with independent power supplies: one an acoustic beacon that regularly pings the ship to reveal its location, and another that can carry short text-like messages. This ensures that if the main power supply fails, the beacon keeps working, allowing the surface ship to track the vessel. According to some reports, the Titan did not have an acoustic beacon and had become lost before.

Ummmm yeah, there was no moon landing...