Ideas for Improving the Top section

Re: Top section

Glasky,
You are right, that is another potential benefit of that solution. Overall, I believe the cup design provides a cost effective solution to one of the prominent problems of our one design boat.
 
Re: Top section

Perhaps it helps to state the problems ?

1. Inconsistent sections resulting in changes in stiffness - IIRC this is caused by both material spec and the dies producing a thicker section the more they are used..

2. Breaking at the collar caused by the hole thru the spar for the rivet.

3. Perm. bends caused by both mis-use and inconsistent material


Anything else ?


IMHO, The class should fix #2 right now, that doesn't need a change to a composite spar, I believe there was a proposal for a change that would eliminate having to drill the section. Any progress on that ?

I don't see #1 and #3 getting solved if we stay with aluminum.
Why not move the rivet down to the small diameter part of the collar? You could even use two (countersunk) rivets. At this location they'd be below the top of the bottom section and much less likely to break.
 
Why not move the rivet down to the small diameter part of the collar? You could even use two (countersunk) rivets. At this location they'd be below the top of the bottom section and much less likely to break.
 
Sorry. I see the "move the rivet" idea was discussed much earlier. Regarding adhesive failure of a glued joint, wrapping duct tape 4-5 times around the top section immediately above the collar would prevent telescoping as long as the collar itself didn't fail, just the adhesive bond.
 
Using $.25 worth of duct tape to prevent catastrophic damage to a $500 sail in the event of a rivet failure (present design) or adhesive failure (possible new design) is prohibited? I was NOT talking about fairing the collar to the mast, just adding enuff tape so the mast couldn't slide thru the collar in the event of a failure. This would only take 4-5 turns and would not remotely come close to fairing the junction. If this is really "unlawful", then I suppose sealing the hull/deck joint to prevent leaks and putting a bit of sail tape at the ends of the batten pockets to prevent batten loss (or for that matter sewing them in if one chose) are also illegal since they are not specifically allowed in Section 3. Such positions seem silly to me since none of these alterations can possibly increase boat speed unless the intent of the rule is to force sailors to "roll the dice" poor designs and/or sloppy manufacturing.

BTW, I looked up the test results on Scotch-Weld material. When testing the shear strength of a joint bonding plastic to aluminum, in most cases the substrate (ie, the plastic) failed before the bond failed. So strength is apparently not an issue. However, the appln insts call for sanding both surfaces first. If this scratches thru the anodizing, then a potentially serious corrosion problem could well result if the joint were not perfectly sealed.
 
Didn't we just approve being able to wrap some tape around the mast joints?
You voted to allow tape to be applied to the mast - collar joint to prevent the upper mast from rotating. You did not vote to permit tape above the mast collar to fair the lower to upper mast connection which would be done with tape above the mast collar joint. That part is still illegal.
 
Tracy said - You did not vote to permit tape above the mast collar to fair the lower to upper mast connection which would be done with tape above the mast collar joint. That part is still illegal.

What is meant by "fair"? I would think it would mean the creation of a taper from the OD of the collar to the OD of the top section. In this case, I fail to see how putting 4-5 turns of tape on the aluminum (but not on the OD of the collar, just butted against the edge) creates a "faired joint". So this should not IMO be illegal unless you fall back to the "if it's not specifically allowed, it's illegal" position. In which case sail tape on the batten pockets and a bead of epoxy on the hull/deck joint as preventative measures rather than repairs are also illegal. Which, as Ross has pointed out, seems pretty stupid.
 
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