When you want to grind, the mill has always to be in the right wind direction, so that the sails can take full advantage from the blowing wind. On this mill a winch is attached to the tail. A chain can rolled out in the right direction and can be fixed to the floor with a hook. By operating the winch the mill will be turned. Sometimes you need to turn the mill all around if the wind comes from the back. You see Miller laurens doing this job. In the previous 2 images more detail on the winch and the course to become a miller.