Hi Skip, After raising the main sail, you have to slack off on the topping lift, so that the sail can achieve it's proper shape. How much to slack off....? Just enough so that the topping lift isn't carrying any of the weight of the boom and the main; i.e., the main is holding the boom, and the main has it's proper shape. If you don't slack off on the topping lift, you'll see that your main will be very "baggy", and the boat won't sail well. Connie