I don't know the answer to your question, but I can tell you that 1/4" BC ply with fiberglass on the outside only is very strong. A Bolger/Payson Bobcat can whang against a dock hard enough to rattle your bones and it only makes a small chip in the paint.

> Which one is stronger: 3/8" plywood OR 1/4" plywood with a layer
> of fiberglass on each side? I know the weight of the glass makes a
> difference - lets say it's 7.5 oz.

> This is for a small sailboat and not a kayak in case anyone is wondering.

> DS