I started building the Snipe as it seemed to be an easy design and for most it probably is. I thought of molding the sides by laminating ply in a mold, my first sides were three layers of 1/8" ply. It's a birch ply but not the really good stuff that you associate with the word birch, I am not sure of the grade but it is quite soft and probably used for furniture, it is quite cheap which is what drew me to it...
The first sides weren't quite curved enough and being 3/8" thick were impossible to bend, the floor was done in a similar manner at two layers and was a bit better. The side mold was glued back together and a new curvier curve was cut. A second pair of sides were laminated at two layers (1/4") which fitted quite well but they still felt too heavy for me. I abandoned the build at this point but I consider my failed experiment a real success!
For comparison, the snipe is about 26" long, about 2.75" high, a three ply side weighed 180g, the bottom 243g. The hull with three plys all around would weigh about 600g plus a bit for the stern.
The hull with two plys all around would weigh about 400g plus a bit for the stern, still seemed a bit heavy. I also tried a sheet of pine, 5/16" thick, a side would weigh about 160g (about 126g if it were 1/4"), this is a little lighter than the ply. I have since bought some bass, poplar and spruce to continue experiments, I suspect these will be lighter than the pine.
My resistance to using only a single layer for a side and bottom would be the very weak joint in the corner but I guess you could add a gusset and then round the corner off a bit but you really don't need more than 1/8".
I have drawn the Celia May but I am not quite done with it, I'll post the files here when finished with the laser cut files. Once again the sides are drawn quite thick at 5/16" (I think). The originals were probably made from hand planed wood by a very crafty fellow and thinner than 5/16 was probably getting more difficult.