What is a closed leech? Is it where the leech curves back to windward? I should probably look in my book, but I am sitting here at work daydreaming when I should be working, and if I remember, a closed leech is generally bad, and especially so in light air. Last night there was a race on the lake - so - from a respectable distance - we played a bit to see how well we could do against the racers. Really light air, some of the racers had trouble filling spinnakers on the first leg (135+ deg wind shift within a minute or so of the start) - I was surprised how little we lost downwind & how long we were able to keep a pair of J24's at bay going back upwind, but still trying to compare speed. I wish I could have been closer to the 20-22 foot boats, to compare speed, but the way things were we would have risked getting in the racer's way. I think we did OK upwind, but of course lost some to their spinnakers down. In this light wind, looking at the sail shape, the 'closed leech' question seemed a question to ask. BTW: Just following what I could remember from the charts resulted in noticibly more speed than I have seen before in the light air! Should have taken the charts along, but it was just my 9 year old and me, and we were planning an easy sail - but then the light air 'forced' me to start thinking - else you really sit!
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Open/Closed leeches .....
A closed leech is another term of a leech that is hooking to weather. Results are increased weather helm and decreased speed .... but gains in ability to 'point' / pinch. Open leech is where the shape is straight back... best power AND speed. Dropped leech is one that is falling off to lee ... always bad and indicates the need for new sails!! Actually the first two conditions are beneficial; the second is obviousl -- but, the first is beneficial at a few ( or more) boat lengths to a lay-line/ tacking point as the pinching at the end of a leg will not adversly affect VMG of the original course to the next 'mark' but will sometimes save MANY boat lengths on the next leg. hope this helps.
A closed leech is another term of a leech that is hooking to weather. Results are increased weather helm and decreased speed .... but gains in ability to 'point' / pinch. Open leech is where the shape is straight back... best power AND speed. Dropped leech is one that is falling off to lee ... always bad and indicates the need for new sails!! Actually the first two conditions are beneficial; the second is obviousl -- but, the first is beneficial at a few ( or more) boat lengths to a lay-line/ tacking point as the pinching at the end of a leg will not adversly affect VMG of the original course to the next 'mark' but will sometimes save MANY boat lengths on the next leg. hope this helps.
Yup, but thats not all .....
If you take any cloth triangle and stretch only one edge, the first thing that you will notice is that the other two edges seem to relax. So, to go from a closed/hooked leech to a smooth leech you can: 1. increase luff tension with the halyard, 2. decrease mainsheet tension, 3. increase the outhaul tension (but not very efficient due to the angles involved). 4.add tension to a topping lift (to counteract the weight of a heavy boom) 5. bend (preload or bow) the mast (bulge forward in the middle - same as 'flattening'). ;-)
If you take any cloth triangle and stretch only one edge, the first thing that you will notice is that the other two edges seem to relax. So, to go from a closed/hooked leech to a smooth leech you can: 1. increase luff tension with the halyard, 2. decrease mainsheet tension, 3. increase the outhaul tension (but not very efficient due to the angles involved). 4.add tension to a topping lift (to counteract the weight of a heavy boom) 5. bend (preload or bow) the mast (bulge forward in the middle - same as 'flattening'). ;-)
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