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post #91 of Old 01-27-2012
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Originally Posted by casey1999 View Post
"Sail & Rig Tuning" by Ivan Dedekam"
I have this book and was re-reading last night- very good book. One thing Dedekam says is to tension the rig as tight as possible, with forestay (as I remember- going above 30% uts). According to other posters, this could lead to fatigue failure over time.- Thoughts?
Do you mean using your formula? I'm looking at the book, and don't see "tight as possible" though I certainly could be missing something. For masthead rigs, he says adjust forestay/backstay to a achive rake, then adjust forestay sag (forestay tension, correct?) by adjusting Backstay. He states that boat designers often choose 30% to 40% of the stays breaking load as Max allowable Backstay tension. He says adjust to 30% and mark as Max., then back off the adjustment to 2/3 of Max. I guess using your formula that does bring the forestay over 30% on your boat. Wonder what "boat designers" would say?
Regarding cap shroud tension he suggests pre tensioning cap shrouds to 150kg, (In one example). "Pre tension acts as a shock absorber in variable wind strengths and the masthead is kept under better control."
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