Sounds like you'll be doing too much work (material choice-wise). Building the boat will be plenty enough, so do the model in the lowest cost, fastest way possible - not necessarily my method, but glean best application.
I made a 3/32 scale model of my design of a 14' stitch & glue plywood boat out of two pieces of standard poster board that I glued face to face with polyurethane glue rolled out. This created a stiff enough board/paper to bend my gentle radii and yet transfer the hull patterns - full length - directly to a template sheet to trace around, then scale up from that to full scale.
The upper left shows the 3/32" scale pattern sheet with the patterns taken from the model's actual hull sides/tops/transoms/bulkheads etc. Above that, I am holding a clear "scale grid" I made out of thin plastic sheet that I scored grid lines to 3/32" from my architects scale at 2" x 4" rectangles. The full scale templates were made (lower right) on thin Lexan diffuser film (cuz I had a ton of it) but could have been done on thin paper or vellum. The film is placed over a full scale grid marked with a 'sharpie' pen every 2" (vertical) x every 4" (horiz) over 15 feet by about 3 ft. The reason I made the grid once on the layout table, is so that I could simply lay the film down over the grid - seeing the lines through the film, mark the intersections from the corresponding scale (clear grid taped over the pattern) and fairing the lines uniform with a long, bent batten. I used the same grid for each hull part.
They transferred to the plywood, cut, and after a few on-the-fly changes like lengthening the stern, the plywood stitched together perfectly with only a little carving. This was four months ago and now I am almost halfway done with the boat.
Glean what you can like use the posterboard idea, and for a larger model, just glue up more layers staggering the joints when lengthening. It'll cut well with a razor knife and hot-melt glue will be fun. - JB
Imagination is more important than knowledge - Einstein <a href=\"http://www.pbase.com/dr_dichro\" target=\"_blank\">http://www.pbase.com/dr_dichro</a>