Ive scaled several boats using my naval archetecture programs but you can do the same manually using Nick's offsets.

You can just scale the length dimensions (all of them) to get a shorter boat. You can leave the vertical and transverse dimensions alone (use the same forms to make a shorter boat) Obviously, in doing this you will have to make the bow and stern forms shorter by the scaling factor.

You can probably use the same cockpit cutout if you center it over the scaled location or use a scaled one if you prefer. If you want a really small cockpit (like the greenlanders use) it should be located more aft as your body should be in the same place with your legs under deck.

: I have the plans for a kayak that is almost 19' and would like to change the
: design into a 17' for storage and building reasons (basically room). Has
: anyone here used the formula in Nick's book to scale down (or even UP) a
: design? I know I have to take into consideration displacement, but by
: scaling it down it better suits my weight. If I keep the cockpit in the
: same location, balance shouldn't be a problem either. I plan on keeping
: the width the same too.

: Any experiences? Thoughts?