Unless you're tackle is hanging off the bottom, you're not really lifting the entire weight at any given time.. If you motor up on the hook you should only be lifting the chain that is equivalent to your depth... but of course you may one day slide off a ledge and indeed have everything hanging...
How about adapting these newer hi torque battery drills? Enough power there?
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)