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February 1, 2016 “Do telltales on the leech of the jib/genoa aid in trim? I have heard two schools of thought and am undecided as to which is correct. 1) Many say that leech telltales have no use on a headsail and any information they provide is unreliable at best. Luff telltales for the jib, and leech telltales for the main is the way to go since its really all one big sail. 2) Some believe that jib leech telltales are beneficial to trim. They will let you know if there is flow separation prior to the leech. Jib sheet tension should never be so much that the leech tale so much as flutters. If the leech telltale does start to stall, then you need to either ease the sheet, or move the jib lead back twisting the top of the sail and re-establish flow. Do leech tales on the headsail help? If so, are they beneficial on jibs and overlapping genoas? Thanks for any advice.”

David Flynn

December 8, 2015 Quantum Expert Answer

Yes, telltales on the leech of a jib aid in trim; however, telltales on the leech of a genoa do not offer good information. The air exiting the leech of a genoa has too much turbulence rendering a bad telltale read. The second school of thought is sound. If the telltale on the leech of a jib starts to stall or stalls, you should ease the sheet. In breezy and/or wave conditions you want the leech telltale on a jib streaming. As for the additional telltales on the luff of a genoa and leech of a mainsail, you will still use these as tools to adjust your sail trim.

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