submersible craft pressure problem

Wonder how far you could sink a good bottle....I had misread that as 681 feet deep.....don't sound too hard....I'm not sure epoxy will protect you from pressure....but it would protest you from water...I think most of your electronics would survive that psi as they are just chunks of metals....not all...pick the right ones...electric motors will run for a while in water....won't last forever...I like the thought of sound through water...Maybe one sound wave with a carrier wave for the controls and if it losses the wave altogether it would surface....they kind of do this with remote control planes except they circle instead of surfacing....I'm not sure if you want to control this thing but I would put some kind of ballast pump in it ....not only for depth but it will help make it handle better when your not trying to sink or surface all of the time. 681 psi they have rubber brake lines that will stand 3000 psi.. shove a cheap camera in a jack bottle sink it with a hard line to a floating transmitter and have a 24 hour feed of you freak fish