With slight modification you can build an older design PLYWOOD canoe as a SOF.

The current crop of designs for plywood canoes and kayaks tend to favor stitch and glue construction. But years ago there were people building canoes by using the same methods as larger boats were made. They built a frame with ribs made from plywood, or solid wood, connected these frames with chine strips (sometimes called chine logs) then they screwed plywood pieces to the ribs and chines.

Before plywood was around they used more chines and screwed boards to these.

Below is a picture from Clark-Craft's website showing their Niagara canoe being constructed. On the right is the finsihed boat turned rightside up. If you look at the middle frame you'll see the ribs and keel resting on the strongback, or building board. You'll also see how the chines are attached to the ribs. If you built just this much of the boat according to their plans you could wrap that wood frame with your fabric to obtain a skin-on-frame canoe.

That would be pretty minimalistic, though. I'd add several more chines to the bottom of the boat, cutting notches in the ribs so these were flush with the original edgeline of the rib. These would give floorboards that would be more durable. I'd also add a chine in the middle of each side to give the fabric a bit more support.

PGJ