Electric thrusters and windlass are surely cheaper unless you do the hydraulics cheaply by hunting stuff off ebay. If you can gather the expertise, hydraulics can be cheaper, easier and much more powerful. You will understand that commercial boats go this way for good reasons.
Where can a person find information for 1988 Sleipner Sidepower thruster. Mine gave up the ghost and no longer pushes the 36 Island Gypsy were I want to go. I checked the upper shear pin but been told that most often the prop brakes and needs to be replaced. I'm in Grand Haven, MI and am not able to find any tech wanting to work on it.
36 island Gypsy