Don: I bought your book last year and tried to used it during the summer. It all made sense and I understand what all of the controls do. BUT... I had real difficulty seeing the changes in the sails as controls were applied or removed. Especially cunningham and vang. Any tips on what to watch for? Please note I'm try to do this during races. Markdb
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Draft Stripes and Tell tales
Do you have draft stripes and tell tales on your sails? Draft stripes - more than one on both the main and headsail, will really help you to visualize what your increased or decreased tensions on the various conrols just did. Relatively inexpensively added by most any sailmaker. Tell tails - more than just the obligatory three pairs on the headsail and one on the top batten of the main - add one to each batten on the main, a pair on either side of the main in about mid sail, and even some placed a few feet back of the mast on the main. Cheap, easy to apply and remove, and they can help you to see the airflow that all those sail controls are trying to manage. Good Luck Tim Brogan April IV C350 #68 Seattle
Do you have draft stripes and tell tales on your sails? Draft stripes - more than one on both the main and headsail, will really help you to visualize what your increased or decreased tensions on the various conrols just did. Relatively inexpensively added by most any sailmaker. Tell tails - more than just the obligatory three pairs on the headsail and one on the top batten of the main - add one to each batten on the main, a pair on either side of the main in about mid sail, and even some placed a few feet back of the mast on the main. Cheap, easy to apply and remove, and they can help you to see the airflow that all those sail controls are trying to manage. Good Luck Tim Brogan April IV C350 #68 Seattle
Mark: Tim is correct that draft stripes will help but most sails don't have them. When you are racing there is too much going on and the cart is in front of the horse. You have to recognize it before you can adjust it. What I suggest you do is set aside a practice day or even about 20 minutes when you go out for a cruise to work specifically on sail trim. you want to ease and trim the controls to see what happens to the shape of the sail. I was working with a new race crew last week and at first they could not see it either - so you are not alone. What I worked on first was twist. I set the boat up for closehaul and was making good speed. I then eased out and trimmed in the boom vang and mainsheet. When you do that you will see the top of the main open up (look like it is on a braod reach) and then close down. This boat has adjustable fairleads so I was able to easily do the same thing with the jib. Next I demonstated draft depth. By releasing the outhaul you can see the belly develop in the main. Pull the outhaul aft and the belly disappears. On the jib, if you change the position of the fairlead, eased the sheet and halyard you would see the same result. Today or tomorrow, I'm going to do a piece on draft depth and indicate how to measure it. Since you have my book, you already know how. Draft position is the toughest to see because you have to draw an imaginary line from top to bottom through the deepest point of the sail and you need a reference mark on the boom. The controls that effect draft position are the boom vang, cunningham (halyard), mainsheet outhaul and mast bend. You can't just move one of these controls and expect to see the draft position move forward and aft. You need all of them. The problem becomes that when you start moving these controls other things start to happen. For example, the boom vang and the mainsheet adjust both twist and draft position. In addition to twist and draft position, the mainsheet also adjusts angle of attack. On the jib, the fairleads adjusts EVERYTHING. So sail trim is a balancing act. Anyway, on your next sail, have a plan in mind and only concentrate on checking out twist, draft depth and draft position. Look closely and you will see it happen.
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