: I think your test is biased by the fact that the test panel is arched on a
: rather tight radius. That's an ideal shape for stiffness and it transfers
: it's load well. With your setup a lot of the loads are compressive.
: On a hull the 4 oz. interior glass would be subjected to a severe trensile
: (stretching) load if the hull was hit from the outside. Those kinds of
: loads are most common. The exterior glass would be subjected to tensile
: loads if a force capable of bending the hull was applied. Because of the
: tubular shape of hardbody kayaks they usually have enough stiffness to
: tolerate ordinary bending loads.
: I have an older design kayak made from 3mm plywood with no glass sheathing in
: or out. It is extremely stiff because it is extremely tubular but it's
: ability to ward of pentration is not it's strong point. That's the
: situation you will be facing with very light glass sheathing.

4 ounce works ok, I use that both inside and out. Course I'm not running into things either

I also double it in high stress areas, under the seat and at the feet and a tiny football on the bottom.

Bill H.