I built a hardchine Chesapeake 18 from plans and a friend built the CLC 18' multi-chined kayak from the measurements given in an article (I think in Wooden Boat). Both came out fine, it was enjoyable to do the "whole" process, plus I could modify my coaming/cockpit a bit rather than have it already a set size.

Using Okume plywood and System Three epoxy, the cost per boat was about $300.

I could also play around with what I wanted to do with wood grain for appearance.
I don't think I had more than 3-4 hours in extra cutting, planning and sanding.

Randy