Why not buy a sail winch servo which already does what you want e.g. https://www.componentshop.co.uk/61g-digital-sail-winch-servo-6-turn-programmable.html
There are many others.
Steve
Why not buy a sail winch servo which already does what you want e.g. https://www.componentshop.co.uk/61g-digital-sail-winch-servo-6-turn-programmable.html
There are many others.
Steve