 The outer skin of the hull was made from 1/8"(3mm) luan plywood also called doorskin. I used birch plywood for the internal structure of the boat. You will see on the plans that the sides overlap the bottom by about 1/16" TO 1/8" This area is filled with epoxy and micro-balloons on my boat to create spray rails on the bottom.  In the pics you will also notice that I put 1/4 inch square strips of wood along the edges of the bottom to give a larger gluing surface for greater strength. They are glued on so they overlap the edges of the bottom and then sanded back to match the angle of the bulkheads so the sides will be flush against them. I do the same thing along the top of the sides for the deck. I only put a strip of glass cloth along the keel. The rest of the boat is epoxy coated inside and out.  Doug