Kyle-- Scaling stitch and glue plans is tricky. You can reduce the whole boat by a constant percentage, but you've already seen the limitations of that approach: 1) It gets too narrow and tippy very quickly and 2) the volume reduces as the cube of the scaling factor. But the panel fit should be unaffected. This technique works best for small scaling factors, say 95%, but probably no more than 90%.

The other way people scale stitch and glue plans is by reducing one (length) or two (height) dimensions, but leaving the width constant. This again works best for small scaling factors and inevitably leads to some fudging to get panels to fit. The reason this approach doesn't work well is that we always scale along the X, Y, or Z axes. The problem arises in that none of the panels lie flat in a plane that contains one of these axes. Every panel has soom curve to it's shape. The greater the scaling factor the worse the panel fit.

The only way to effectively scale a S'n'G design is to scale the complete boat, adjusting length, height, and width independently, and then generate new panel shapes. There are plenty of computer programs that can do this and there are techniques to do it manually too.

Mike Scarborough
Friendship Kayak