Check out this site:
http://www.smallboats.com/bolger.htm
Phil Bolger is a near-legendary designer with a special flair for
designs that are easy to build for inexperienced builders in plywood
and other easy-to-find and inexpensive materials. His designs are
being kept alive by "Dynamite" Payson, a Maine Boatbuilder, who sells
plans and runs his own website:
http://www.instantboats.com/
I highly recommend his book, "Build the New Istant Boats", which has
several designs, and which is also simply and well written, an easy
cover-to-cover read that will give you a good feel for a simple,
complete boatbuilding project. These boats are so well designed and
easy to build that you probably wouldn't have to buy separate plans.