: Bill

In my opinion the need to fiberglass both sides of the plywood for strength is overrated. The glass protects the outside of the hull and ties the panels together inside and out. Seams reinforced with nine ounce tape are obviously going to be stronger than those reinforced with four or six ounce cloth. Note that most of the Chesapeake Light Craft kits use cloth in the cockpit and tape in the end compartments. I've built two kayaks that way, as well as a sailing skiff with only tape on the inside and never had a problem with any of them.
-Wes