Norminn wrote:

We originally intended to use fat PVC, but it's pretty heavy and I
don't know how to figure out how much flotation is needed to hold up
the wood frame and the kayak.

To determine cubic inches of PVC interior per running foot...
(square of radius in inches ) * 3.14 * 12
-OR-
http://grapevine.abe.msstate.edu/~ft.../cylinder.html

A cubic foot of dead air will support around 60+ pounds. There are
1,728 cubic inches in a cubic foot.

Weigh what you want to support and go from there. Keep in mind that a
wood platform floats by itself and that the PVC has weight too (which
needs supporting)..

--
dadiOH
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