Ahoy, SteveR23. Just saw your question to me. I''ve been remiss lately keeping up with all these different categories. jeffH is a very knowledgable and obviously experienced sailor and his advice is excellent. I recommend you read his stuff when you come across it. He covered this quite well. I''ll just add the following: Get on your boat with the main up on a calm day. Put your traveler right under your boom. Now, pull up on the end of your boom. You find that it can''t rise. Now let out the mainsheet and push the boom until it is off to the side, not over the car. Now push up on the end of the boom. See how it can rise? The further out it is, the more it can rise. This allows the sail to twist as jeffH mentioned. Now Keep the boom where it is and let the car move down under the boom end and take the slack out of the sheet. You are right back where you were originally, except that the car is down, not on the center
line. Again, the boom can not rise and thus the sail will not twist. Generally speaking, in light air, you will have the car up to keep from adding tension to your leech because you want a fuller, softer sail. On a windy day, you will put the car down so you can pull more or less straight down on the boom, tightening the leech, eliminating twist, and maintaining a flatter sail shape. That is, if you sail has twist because of inadequate leech tension, you drop the car to leeward and tension the mainsheet. On a reach or run, you use the
boom vang to control twist so the position of the car isn''t a consideration. On light days you can actually have the car to windward which will allow you to have the boom on the center
line without the effects of downward pull by the sheet on the leech. Piddle with it. You''ll soon get the idea. Regard. dhartdallas