Flat bottomed swamp boats: three boats of ancient design. free boat plans and building instructions. published september 12. 2008 last updated september 24. 2008. Here are your search results for free plywood boat plans woodworking plans and information the internet’s original and largest free woodworking plans and projects. Free boat plans listed by type including hydroplane plans, motor boat plans, scow plans, paddle and oar plans and miscellaneous boat plans..