I undertook this project with a youth group. We built 4 boats simultaneously. Each boat took approximately 45 hours to build with minimal power tools. We ordered cedar pre cut. All the other wood was purchased at the local box store. The kids helped with the roughing out of the plywood parts and helped with the layout on the strongbacks. We used 8 oz ballistic nylon with water base varnish (no added color). The kids did all the varnishing and helped with all other aspects of the project.
The kids took it to Puget Sound for shakedown paddling. They loved it and found the boats to be stable, easy to paddle, and quick. They did not go any great distance but had a blast with them. They are fairly light weight and paddle easy.