No brains needed. I call them plankers. This type of plan can be found all over the Internet. Glen-L provides plans that many people find helpful and they have a good reputation. Plans for many of his designs are available at his site.
Complete plans provide a fairly accurate view of the completed boat.
A full table of offsets and construction plans for various steps will definitely help the builder in larger projects. Full plans are a really good investment if you plan to build a boat over 25 feet or any kind of blue water boat. The engineer will think of things you have not and probably has a better idea of why things might or might not work. One of the largest problems facing people building larger boats has nothing to do with the hull. It is installing the systems and meeting various regulations in the process.