yes, we had one on a 50 foot powerboat, no problems. Except that after a few years it "copped out" occassionaly and returned to standby. Cured with new batteries, evidently too-low voltage and it won't do it's stuff. Most rain/seawater electronic thing we had.
Yes this works well with hydraulic steering hewever there are two types of pump which look identical a type 1 and type 2 you will need to find out which pump best suits your aplication!!