Muir make some great
anchor windlasses. They are a fairly small company that is used to doing custom jobs for large superyachts etc.
If you asked them make a particular
windlass as hydraulic my guess is they would do it, even if it was not a standard offering. I suspect this is probably what was originally done. If so it should be a great
windlass, but there is always he possibility it was a backyard conversion, in which case the engineering would be suspect.
Muir have good customer
service. You will get an answer from an
engineer rather than a salesman, so I would contact them directly.