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Old 06-12-2018, 01:55 PM   #2
stripperguy
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Join Date: Sep 2006
Location: Schenectady, NY
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Paul,
It's seems surprising that you would get oil canning with such a lay up.
How wide/flat is the bottom? For a given lay up, the weakest geometric config is flat. As the shallow arch, or vee increases, the hull will flex less for a given load.

If your hull shape is not inordinately flat, I would think the lamination is suspect.

But on to your rib question.
I wouldn't necessarily recommend glassing in cedar ribs. Unless you particularly like the look.
Cedar ribs would need to laminated to shape, or steam bent, to match each section where you plan to install them. If steamed, you would need to allow adequate time for the ribs to dry out before epoxying and glasing in place.
In either case, you would need to profile the ribs so that the glass can conform to the hull/rib interface. A shallow chamfer should be good enough. Or, in lieu of a chamfer on the rib edges, you could add a fillet to the hull/rib interface with some Cabosil thickened epoxy.
You should also use Cabosil thickened epoxy to install the ribs in the hull.

A preferred material for stiffening the hull bottom would be some H80 Divinycell foam. That foam is a closed cell PVC and is intended for structural applications,in other words, it's made for just this sort of work.
The foam could be cut into ribs, or a larger piece could cover a substantial part of your football. Epoxy that in place with some thickened epoxy, bevel/chamfer the edges, and add a layer or so of glass.
If you search back through my thread on the carbon copy Kite, you'll see that I had a very flexible football with my double layers of 6 oz glass and carbon.
After adding a 1/8" thick section of foam with a layer of carbon on top, I could stand in my bare hull (no gunnels) while it was on saw horses!! Very stiff indeed!!

Last edited by stripperguy; 06-12-2018 at 02:32 PM..
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