ec120bgt@sdcc3.UUCP (ANDREW VARE) (05/26/85)
>"I kept my main trimmed to the centerline for >maximum pointing ability. However, he let off his traveller a a couple >of inches, and the improved slot increased his speed so he made better VMG." >The folklore 'keep the top batten parallel to the boom' is ok >for beginners, but here's the real way to tell if your main is trimmed > right." (I'd love to see a reply to that one.) >"On a beat, the ill wind from your sails extend in a V about 10 > times the height of the mast astern and to the lee side of your boat. > If you try to cover your competition by tacking directly in front of > them or directly to the side, it won't work." > "On a close reach under spinnaker, keep the pole down, because > the chute needs to act more like a jib and have a tighter luff." > Main trim is, as you've suggested, directly related to pointing ability, but is not the only factor involved, by any stretch of the imagination. Mast rake has an effect equalling that of sheet tension, since all your really doing is moving the center of effort back behind the centerboard or keel. Remember that when you rake your mast more, your jib sheets will lead relatively further forward,since you have effectively lowered the jib's clew closer to the deck. Your mainsheet will sheet shorter, too, since the boom gets closer to the deck as well.Remember, when you change rake to improve the boat's helm [2-3 degrees weather helm at 5-9 degrees of heel is desirable] your marks on the jib tracks will be no longer accurate. When I'm going full speed at the starting gun, [optimally!] and I have decent position [safe leeward with a hole below me if I need speed or someone's rolling me] then I usually go for pinch-mode to try to force the guy to weather to tack off. A scalloping motion is best, since a full pinch mode with strapped mainsheet is slow. A quick luff can be lethal too, but the weather boat must be quite close for the backwinding to slow them down enough. Remember, too, that in luffing them they are responding to you, which means the trimmer is watching your movements, not his sails. So for the first twenty seconds after the gun I like to strap the hell out of the main to gas the guy to weather. THen I ease a bit until I'm up to speed again and can find "the groove". At this point I like to have a look around and make sure I don't miss the first shift [deadly in big fleets], so decision times rears it's ugly head about now. As for spinnaker trim, I've found that for the best results the wave and wind conditions are the most critical elements to consider. If it's choppy, and kind of light, a low pole can be FAST. It tightens the luffs, giving the kite more shape, as well as stabilizes it. The drawback to tighter luffs is that the breaking point is more defined, so if the chute wants to collapse, it COLLAPSES, instead of giving you a little warning with a "lazy luff". So a lower pole needs as little more attention from the trimmer and the helmsman to keep the kite flying. Also, the fuller kite has a lower top-end speed potential, since it has more form drag. In light air this isn't a factor, since you're not up at the top end of the speed range anyway. A high pole can be fast in flat water, or when its considerably more windy. THe high pole flattens the kite, as well as moves the draft aft. The leech breathes much easier, and this can be quite fast. Overall shape is reduced, so less form drag means a higher potential top-end speed. You can also point a hell of a lot better with a higher pole, so if you cant quite lay the wing-pin, try the pole tip up a foot or so. Remember, too, that a flatter sail will not hold air-flow as easily as a fuller shape, so powering up after you hit a big wave may be a problem. The key here is realising that lift and drag come hand in hand-cant have one without the other, so a comprimise must be based on the relative value of each in the conditions present. Light air/choppy water > more lift > fuller sail > lower pole. Heavy air/flat water > less drag > flatter sail > higher pole. If you have a boat small enough, try pumping the guy and sheet at the same time [three pumps per wave in surfing conditions only].Very fast! In really heavy air, let the sheet ride above the boom, so the leech breathes more. Come jibe time this can be a problem, so remember it's like that before you get to the mark and the caca hits the fan because the boom's trapped outside the sheet! I grew up racing on SF bay and had that happen many times-nothing quite like sailing off in the wrong direction while the fleet is jibing behind you! Also, if you're really overpowered under the chute, try letting the pole forward [ie. ease the guy] as this helps augment the high-pole scenario, besides reducing oscillations. Dont let any sailmaker sell you on a spinnaker because it has a racy name or something. "elliptical" spinnakers are designed with no reference to an ellipse at all-just a tech name for some sailmaker. wSame goes for the "GRX"-series; bullshit! A fast kite is adjustable, has good craftsmanship in broadseaming and stitching, and is reasonably stable. Sorry if I seem long-winded (argh argh!) but sailing is indeed one of my passions. Andrew Vare UCSD `86