Flat bottomed swamp boats: three boats of ancient design. free boat plans and building instructions. published september 12. 2008 last updated september 24. 2008. Boatplans.dk – online free and inexpensive boat plans for canoes, small boats, sail boats, motorboats and powerboats. download boat plans right away. – boatplans.dk. International orders – to inquire, please email or call (503-559-0204 10-5 pt). to order send check or money order payable to roger fletcher, along.