I am making a Whitehall Jr. from the
Geodesic AiroLITE Boats - ultra lightweight SOF canoes and boats; plans, projects and tutorials It only weighs 20 lb so should not ruin the mileage to much!!
Mine will be made in Oak and is 10' x 3' The skin is Dacron, the same stuff as they put on aerobatic light aircraft, and it is shrunk to fit with a household iron.
Take a look at the whole range...they are gorgeous, and designed in the USA