Mates; I've saved the last element of sail trim until last. Since there were zero questions about draft depth and draft position, either my descriptions are getting better or everyone gets it. Since I'm going to be sailing over the horizon at the end of this week, any questions you might have about any aspect of sail trim should be promptly submitted. I devote a number of pages in my book, "The Sail Trim Users Guide" to TWIST but unfortunately, I have to cut it down to fit here. Why is twist so hard to understand? The reason is authors make it confusing. Here is how they define it - "the change in the angle of the chord line of the sail to the center line of the boat at various heights up and down the sail". No wonder beginner sailors have difficulty understanding twist!! Actually, a twisted mainsail and jib are common sights because 75% of the sailors worldwide sail that way all the time. Once you understand and recognize it you'll see what I mean. Simply stated, TWIST is the leeward sag of the leech of the sail. To view it, stand in the cockpit and look up the leech of the sail from bottom to top. Assume your sailing closehauled. When you look up the leech, the bottom half will like your closehauled but the top half will look like it is on a beam reach. You will never see a twisted mainsail on a America Cup boat or a competitive race boat because twist is a power robber. Why do you care about twist? The reason is that there is more wind at the top of a sail than at deck level and the reason is FRICTION. At deck level, the wind is slower because as it passes over the surface of the water friction slow it down. At the top of a 50' mast, the wind is blowing 60% harder due to a lack of friction. Sail makers build twist into a sail because of this friction differential. If they didn't build twist in, the sail would be difficult to control but you can dial it out by use of your sail trim controls. The LESS a sail twist - the straighter its back (picture an America Cup mainsail)-the more power the mainsail and jib develop. The MORE a sail twists - the more the top sags off to leeward and looks like its on a beam reach - the less power it develops because wind is spilling out of the top half. Obviously, the more you control the "spilling of air" by by closing the top so it resembles the bottom of the sail, the more power you develop. OK, is everyone with me so far? The next segment will explain how to adjust twist and I'll give you a set of steps that will allow you correctly set twist in you mainsail.