Flat bottomed swamp boats: three boats of ancient design. free boat plans and building instructions. published september 12. 2008 last updated september 24. 2008. Scroll down this page for many more plans. this a page of links to some favourite free boat plans at intheboatshed.net. they’ve been chosen because they are derived. Wooden boat plans for amateur boatbuilders – excellent performance, simple construction, step by step instructions australia, usa, uk, hungary, s. africa.