Needs some opinions. The 70 wood sportfish has hydraulic windlass that is on deck barrel type and electric 24v windlass ( w dead battery bank). Both batteries and res tank are in bow bilge. Easy access. I definitely need / want a new windlass. Some thing that is more low profile. It's a heavy boat. And costs are a big factor. I'm pretty sure an large electric 24v windlass could use same batteries as the thruster. Or could new windlass use the same hyraulic pump as the 1986 windlass? If I was replacing the thruster I'd go all hydraulic.
I wouldn't trust a hydraulic system from 1986 unless I physically inspected it and knew it's history, as well as when the last time the pump was serviced/replaced, hoses replaced, etc etc. There is also not enough info to give you an informed response at this point in time. Where does the hydraulic pressure come from (what is making the hydraulic pressure)? How do you know that the electric windlass doesn't work? You could probably use the same battery bank as the thruster, but I'd also have a battery switch where one could parallel them with another bank (engine/house etc) for emergency purposes. Almost all of the windlasses you see on 70' these days are electric so that might tell you something.