Mast Pre Bend

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sj24
Posts: 23
Joined: Fri May 06, 2005 12:52 am

Mast Pre Bend

Post by sj24 »

I have hull #132 and am unable to get any pre bend using the Boston tuning gude numbers. The mast is actually inverted 1/2". Is this common or do I have a problem. The mast has not been replaced at least in the last 14 years.

Thanks,

Kevin
John Spierling
Posts: 191
Joined: Tue Mar 16, 2004 3:12 pm
Location: Shelby Twp, Mi.

Post by John Spierling »

Check your headstay length and be sure that it is at class max length of 31'8". Loosen off the lower to about 13 on the old model Loos gauge. Tighten the Uppers to about 30 (old model Loose gauge). Look at your spar now. It should take the inverse rake out of the spar. Make sure your spreader tips are slightly tipped up also. You can then tune your lower to match the sailing conditions.
Tom Elsen
Site Admin
Posts: 419
Joined: Fri Dec 20, 2002 5:42 pm
Location: Minneapolis, MN & Chicago, IL

Mast

Post by Tom Elsen »

I'd agree with John, and add a suggestion. Start your tuning with your backstay on 1/3rd to 1/2, and your inners slack. Center your mast tip, measuring side to side, with the outers at very modest tension. Then working one turn at a time on each side, tension your outers (keeping your mast tip centered) up to a light air setting. Check the side-to-side. Release the backstay. Check the tension. Work the outers up to a medium air setting. Then start working any kinks out with the inners. Remember that the port inner will pull out starboard tip deflection. We try to keep the inners pretty loose, especially in <10 kts.
Good luck
Best wishes,
Tom
sj24
Posts: 23
Joined: Fri May 06, 2005 12:52 am

Post by sj24 »

Thanks for the help guys. I'll give your suggestions a try.

Kevin
DaveR
Posts: 13
Joined: Thu Feb 13, 2003 12:46 am
Location: Chicago, Lake Michigan

Post by DaveR »

how much tension can I use on the uppers before I have to worryabout breaking something - or pulling something out of the deck ?
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