In a message dated 4/13/2017 1:23:54 P.M. US Mountain Standard Time, jerry@jerrymontgomery.org writes: (Gary 'Boom Vang' Oberbeck feel free to jump in!) You know what they say "DON'T Encourage him!!!" Vang is essential race or cruise - Upwind the vang should be tensioned to pull the second (if you have four battens on a 17) or top batten parallel to the boom when sighted up the sail from directly below the boom - It can be a bit open if it is breezy (less vang and a bit more twist). In light air it can be pulled on such that the upper batten (or second from top) is angled slightly to weather or hooked - not too much or the sail will stall VERY quickly. The vang also bends the mast down low when applied _ check the rig out some day before you bend on the sails - adjust the vang - on hard and then off - sight up the mast as you adjust the vang and you will see bend down low in the mast - this flattens the mainsail - boat heels less ! ++ (and as a consequence makes the headsail FULLER!) darn ! we didn't want that - More headsail halyard tension is then required - ... Easy to make your 3:1 or 4:1 very powerful by adding one bullet block to the boom bail and a piece of line - 'cascade' - search online or look at Ronstan or Harken sites for examples - makes it almost twice as powerful and easier to use. If you can keep the batten parallel to the boom (or slightly 'open') you should see your upwind performance improve - both angle and speed. Easy. Downwind for another rant. Have Fun Go Sail 'em! GO PS - Personally I like a powerful vang, because 'I' am not so powerful anymore, as rotator cuff / biceps tendon surgery in both shoulders ask me to be 'careful'. - vang is 4:1 with 'cascade'.