At the planning stage.  As I said before, the idea is to build a scale model of the boat I want to build later.  I've decided on a trailable boat, max length 22'6" x 6'9" beam with the single feathering wheel, well aft, between the hulls.  I want to use an electric motor and batteries for propulsion, possibly a small steam engine later on.  A 1:12 model would be best, not too fiddly to build.  Looking at other designs, the wheel would be 5' diameter with about 1' submerged.  With flat-bottomed hulls 2'3" beam, I calculate I'd need ballast, so narrower hulls with vee bottoms may be better, this would also allow a wider wheel. A cabin with 5'6" headroom would be good, giving a hull depth to gunwales of about 3'.  What do you think?

Hi Mooncat, I don't know if this will work for you but have a look anyway http://www.atkinboatplans.com/ and in the miscellaneous section for "Gwen O' the river"

cheers 

Jim

Thanks for the link.  Some interesting designs in there.

Where do you buy your plywood?  I am looking for 1, 2, and 3mm thick birch ply, sizes 300 x 600mm sheets.  I'll be coming from west Wales, to Gloucestershire, and then on to the Midlands, from next weekend.