A winch includes a cylinder containing a movable piston to which are respectively mounted a fixed and a movable pulley assembly around which a line to be pulled is entrained. The pulley assemblies are located within the working chamber and the line enters the cylinder through one end formed remote from the chamber and through a one way brake mounted to that remote end. The brake permits line to enter the cylinder as the working chamber is pressurized to move the piston and thereby the movable assembly towards the remote end. The one way brake prevents line from exiting the cylinder at this location. The line extends slidingly through the piston and may exit the cylinder at the opposite end thereof which is also equipped with a one way brake which prevents line from entering the cylinder but allows the line to exit the cylinder. End of stroke positions of the piston are sensed by means of Hall Effect Sensors to control pressurization and venting of the working chamber through a three way valve.
