Hi milos, plywood used for kayak on pictures and videos is a regular one. this same non waterproof plywood is used in doubletrouble too. and for more then a 3 years. Stitch and glue is a simple boat building method which uses plywood panels stitched together, usually with copper wire, and glued together with epoxy resin.. Free kayak and canoe plans what is the difference between free and paid for plans? often nothing! proven free canoe and kayak plans have been made available.