What Autopilot can do for you:
A sailing boat does not have an engine and cannot go along a programmed path from harbour to the beach, then to the fishing spot, turn around the Lighthouse and back, all itself, it cannot.
Whole work is done by the Sailor, we have to understand it at this point: trimming sails, take under control weather and the wind source/speed, harden or release ropes, mind other boats, decide direction and steering... When the Sailor decide for a break, let say just 10 seconds or up a few minutes (the famous "tea time"), he switches Autopilot on. In a cup of seconds its GPS acquire position, speed and direction of the boat and is able to mantain the direction (route). The steering system, a stick connected to the rudder, usually moved by the expert Sailor hands, now is under control by Autopilot through the Stepper Motor connected to it by pulleys and ropes.
An interesting link found among my daily reading