Project Boat vs Bare Hull
It rarely makes economic sense to build your own boat from a hull up. There are some very good reasons why someone might choose to buy a bare hull and build it out themselves but economics rarely works out to be a valid one.
If you look at the economics of a production boat, the hull and deck are roughly 15 to 20% of the overall cost of the boat. The other 80% to 85% is everything else. Labor is something less than 50% of these remaining costs and in a modern production boat, labor can be as little as 30% of the overall cost of the boat.
When you consider that most ''kit boats'' sell for something approaching 40 or 50% of the cost of a new boat of similar design and quality and that boat manufacturers can often buy the hardware, equipment, plumbing and electrical components at 30% to 40% of what we as a general public can buy them for you can see that there is a very little savings potential in building from scratch.
Beyond that kit boats, or even boats that were professionally constructed to a design that is known for construction by amatuer builders, can often result in a decreased resale value, so not only isn''t there much of a savings but you can really get clobbered at resale time.
On the other hand, if you are looking for something unique, you can live with something that is simple (and simplier than normally available on the market) and you really enjoy working with your hands and are good at all of the trades necerssary, building your own can be a good way to go.