The low-tech way is to make a model. If you can produce scaled cross-sections, cut half sections out of card stock. Cut a copy of the profile out at the same scale, glue the half sections in place on the profile. Bend some card stock over the resulting ribs and mark the chines on the card stock. Connect the dots and cut out a panel. Lay the panel back on the "ribs" and check. Tweak as necessary. When you think you have good panels, tape them together without the ribs and see if they still make the shape you want. Then trace the panels onto graph paper to scale them up to full size.

You can also carve a half-model out of wood and lay paper on the panels to trace them.

> I am trying to design a stitch and glue kayak for a class and I am stuck.
> I have all of the lines drawings, yet I have a problem. I can't figure out
> how to get from there to drawing the actual shape of the plywood panels.
> Right now I'm thinking that I need to measure the length of each
> cross-section, but how do you translate that to the correct shape? I mean,
> the top edge of the plywood is curved--so you would somehow have to find
> that curve. Then you can measure the lengths of the cross sections....

> Anyway, if you have designed one of these, I'd greatly appreciate any
> imput on the design procedure.