Progress on the duck punt moves on - I have cleared the space in the garage and worked out where and how to build the boat. I am going to put a strongback together and make the boat around six temporary frames made of 18 mm cladding ply. The main hull is going to be 6mm exterior grade ply with extra stringers where it has gone a bit floppy because the original punts are built like brick out houses.
I have been watching the films of the balanced lug sails used on the Norfolk Broads and I assume that the design will work at 35 square feet which is the same size as a sail from an optimist.