I've just finished the frame for my little SOF, and I built up the frames from solid timber. Mine are mitre jointed and doweled using 3/16" x 1/2" pine strips with tiny bamboo dowels, so there's mostly no doubling of the timbers at joints (except where it made sense or I got lazy).

Having previously been involved in a yost style plywood framed boat of similar scale, although much less complex in design, I can say that my "solid' frames are probably lighter (it's a completely different hull, so a direct comparison isn't possible) BUT what I saved in weight and cost of buying a sheet of ply was far exceeded by the additional cost in time to build them.

Ply frames offer predictability and speed - you can draw out and cut a symmetrical frame in just a few minutes and that's exactly what you'll get.

You could achieve much the same with solid timbers. Mitre the joints, glue and end dowel them - it'd be more elegant, and less expensive to do than plywood, but it will take longer..

I built my frames as I went as an integral part of the whole structure (started with a laminated sheer 'ring'). Getting any level of alignment using a bunch of springy sticks with miminal frame of reference takes a lot longer than either of the other methods!

I can fully appreciate the Yost style of plywood framed SOF construction now - it's a case of simplicity of construction winning over trying to save that last couple of ounces.

Simeon.

: You can reasonably go to 3/8" ply and it'll work, going to
: thinner means the webs have to be much wider to compensate for
: the lack of strength so you don't gain anything. Actually with
: really good plywood you can probably make it lighter using
: 3/4" ply and going for very narrow webs.

: It can certainly be done with regular wood built up frames, won't
: be any lighter though since you have doubling at the joints,
: conventional plywood construction (with frames, chines and
: stringers) was originally done with wood frames built up this
: way.

: Bill H.