I read a pretty good take down of the hydroplate theory by a Geologist.  If all that water, came from all that deep, the pressure release at the surface would turn it instantly to steam.  You wouldn't have had to drown everybody, they would have deep fried the atmosphere with superheated water just from the pressure change.  And to even think about the Noah story.  Really?  God loves us so much sometimes he has to kill us all?  And the little creepy crawly things too? And let's think about one more thing.  In the beginning  God created everything, right?  Well, why did he have to save two of every animal?  Why not just poof them back into existence again after the flood?  For that matter, why a flood?  Why not just Carbon Monoxide everything and start over that why?  Why water at all?  Or heck, why not just poof everything out of existence, then start over fresh from nothing again?  Why subject countless people and animals to the horrible death of drowning?