The simplest way to change displacement is to stretch the boat proportionally. If you need 10% more displacement, make the boat 10% longer (or wider, or taller). If you use a combination of all three, but length is the easiest. Just space the forms farther apart.

> Hello all, Yesterday I attended the NW Sea Kayaking Symposium in Port
> Townsend, WA and I am pretty stoked about started to build the Great Auk
> from Nick's book. But I have to say, most of the kayaks I saw looked a
> little on the light side for someone my size. Previously, I e-mailed Nick
> about the capacity of the Great Auk and he responded that it had plenty of
> capacity for me, but a diminished capacity for additional gear. I know
> eventually I'm going to want to explore the Cascadia Marine Trail, so I'm
> still considering building in some increased bouyancy. Being basically
> ignorant of things nautical, I have a couple of basic questions. Since I
> am 70 pounds on the wrong side of 200 (this seems like a reasonable target
> to me) I would have to displace an equivalent weight of water, right?
> Something like 32 liters. Does this have to be done below the shearline?
> Nick listed several options for altering design including increasing the
> length by duplicating the center form. I'm not clear on exactly how to
> change the forms and length to effect a 32 liter alteration on a complex
> shape like a kayak. Does increasing the size of the forms by 1/4"
> around the periphery and increasing the length by six inches seem like a
> reasonable approach or am I in the process of making a good design go bad?
> I really enjoy reading the posts of this group, and I have already
> benefited from your experience. Thanks. Larry