General purpose work boat plans with 21′ hull, several other free wooden boat plans to choose from: the work boat design, tour boat, bass boat, deck boat, and center. Plywood boat plans. if you are looking for a way to build an inexpensive boat you should definitely consider plywood boat plans. using plywood is one of the best ways. Intro: sawfish, an unsinkable, lightweight, foam kayak (23 lbs). free diy kayak plans, the hardware store boat. do you really want a kayak? want one so bad you can.