Date: 1/3/2006
Name: Mark Weinheimer
email: sailscanvas@pinelink.org
subject:
rig tune


First - setting the rake of the rig is most easily accomplished by adjusting the headstay length. We have been using 24' 5" for the length, measured from the pin on the mast to the pin on the deck. Per Joe Arnold's post, it will probably take about a 4" link plate in the headstay to get to that number. Note that this isn't measured with a halyard - if your mast isn't down, take it down and check all the fittings and set the length, record the length from the top pin to the top of the bottom swage or something at the bottom for reference and you'll have the info at ground level.

Shroud tensions we've been very fast with as follows: Uppers at 21 on the Loos gauge, lowers at 29. This is essentially the same set-up used by Bill McClure (Eastern Natl champ and LONG time Chief Measurer and SJ sailor)- it translates to approx 200 on the uppers and 300 on the lowers. The lowers are tighter than the uppers because of the geometry of swept back spreaders. If the spreader base on the mast is allowed to go forward when you bend the mast with the backstay, the upper shrouds will get progressively looser and your headstay will get slacker instead of tighter - not good for going to weather. Also, unless your main is very full down low, the bottom section will overflatten and invert. When you are trying to flatten the sail, it is most effective to flatten the top and twist off the leech up high. Keeping the lowers tight keeps most of the bend above the spreaders, opening the upper leech and maintaining upper shroud tension.

When our boat #2577 (twice NA champ in Working Sails and once E'Nat)is set up with these numbers, the headstay is quite loose until we put on the backstay - makes putting the mast up really easy. Between full on and full off on the backstay we have about 14" of fore and aft travel on the masthead and the mast doesn't go past vertical downwind - per class rule. We seem to be fast in virtually any condition as well - makes things much easier as the conditions change.


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