Upper Shroud

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Postby evanwellens » Thu Jun 16, 2011 10:17 am

My upper has a few strands that seem to have failed at the upper spreader. Should this be replaced immediately ? If so I noticed APS has bearing surface measurements I need to submit. Are these standard on a J80 ? Can they be measured aloft ?
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Postby aburton » Thu Jun 16, 2011 10:31 am

It should be replaced immediately, yes.

I think the reason APS wants the measurements may be that the older and newer boats have different-sized holes for the clevis pins at the chain plates. Also, on the TPI boats with the Hall spars, the maststep is about 1" lower than on the French-built and new Waterline boats. So the Hall masts were 1" longer than the Sparcraft masts. The lower black band should be still about 14" (IIRC) above the deck on each. I added a spacer to the step when I changed rigs on 265.
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Postby beauly » Thu Jun 16, 2011 11:01 am

Speaking of the lower black band!! I can't get a straight answer on where the top (upper) line of it is? Can anyone help
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Postby aburton » Thu Jun 16, 2011 11:09 am

From the class rules. Measure from the top edge of the bottom band to the bottom edge of the top band:

C.8 SPARS
C.8.1 MAST
(a) Dimensions

Mast band distance .....9144 mm

That's exactly 30 feet
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Postby beauly » Thu Jun 16, 2011 11:14 am

That's where everyone else started! Thanks for that info, but that 9144 mm (30') as you say means nothing to me. From where do you measure the 30'??? From the lower black band. How does one determine the location of the top edge of the lower black band???? Somewhere near top goose neck attachment tang, but where exactly??
This is why I asked the question, which I have not been able to yet find.

Thoughts?
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Postby aburton » Thu Jun 16, 2011 11:29 am

Place the lower black band so the top edge is at the lowest place the main can be on the mast. It works out to be about 14" off the deck. I would get the boom about 90 degrees to the mast and extend a ruler along the top of the boom to the mast; place the top of the lower black band on that line. The idea is that when you honk down on the cunningham, the sail won't come down below the top edge of the lower band. Use that for measuring the 30 feet to the top band.

Personally, I can't see why we need a top band if we measure the luff of the sail...
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Postby beauly » Thu Jun 16, 2011 12:01 pm

now we are talking! so (to be clear for me) we are talking about the bottom edge of the foot of the sail... if we could imagine that line projected onto the mast.. is the 'line' for the top edge of the bottom black band. Then measure up the 30' to mark the lower line/edge of the top black band?
Thanks very much, I had asked Liz Chadwick about this, but she was not specific about the location of the bottom black band.
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Postby aburton » Thu Jun 16, 2011 12:56 pm

<img src="http://j80.org/discus/messages/5/1005.jpg" alt="Band location on Gromit's Sparcraft mast">
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Postby aburton » Thu Jun 16, 2011 12:57 pm

Hope that helps, Jesse. You know what they say about pictures/words.
Andy
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Postby beauly » Thu Jun 16, 2011 4:05 pm

yes it does! Thanks much, I have been caught up by the fact that the band was close to or around the tangs that the goose neck attaches to. It is about the sail though.

Thanks again!

Jesse
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Postby beauly » Thu Jun 16, 2011 4:15 pm

Also I see your sail attached with slugs not bolt rope? Or am I wrong. I just got a new used main and it does not have slugs. Is bolt rope class requirement? (or needed for better performance?)

Thanks,

J
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Postby aburton » Thu Jun 16, 2011 4:25 pm

My racing sail is attached with a bolt rope. What you see bent on is my "cruising" main
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