lsmith@ut-sally.UUCP (Larry Smith) (01/03/84)
In SAIL POWER by Wallace Ross, page 135, is a picture showing the best locations for telltales on jib and main. This book has everything in it anyone would want to know, it is a must. (Get it as a freeby for joining the Dolphin Book Club.) Anyway, he points out that, as you mentioned, the mast causes too much turbulence for the telltales to be much use on the luff. He recommends one in the middle of the sail to detect stalling, one centered high up to show twist, and a streamer near the leech to detect separated flow caused by bad sail shape. Another book, which I've loaned out so I can't cite it, recommends a streamer attached to the leech instead of two on either side in front of it. This works for me.
sam@rocksvax.UUCP (Sam Houston) (01/04/84)
Most of the racer/cruisers in this area (Great Lakes) use several (3 or 4) Organization: Xerox, Rochester, N.Y. Lines: 14 telltales on the leach of the main to use as a guide in sail trim. I guess my position (somewhat supported by North Sails' literature) is that in light to moderate conditions you want to adjust angle of attack (close-hauled to close reach) and twist to achieve attached flow over the full length of the leach; with particular attention to the top of the sail. When it starts to honk, I'm usually using using the main for heel control; dumping wind off the leach--and don't pay much attention to the telltales, at least in the gusts. This seems to make sense for masthead rig boats with relatively large headsails (wrt the main), but I don't know how it applies to fractional rigs or boats with largish mainsails. sam (Xerox, Rochester, N.Y.) the "P.R.N."-- C&C 29, Sodus Bay, N.Y.