Before I begin, I would like to ask some professionals about what materials to build the ship with: Wooden, plastic, or fiberglass hull? (Leaning towards one of the first 2) Stationary or swiveling cannons? (Leaning towards stationary) What is a good balsa and electronics supplier? (good quality but not over the roof prices)
wood is cheapest and simplest to build with but you will need fiberglass to get a smooth keel. stationary is recommended for first cannon and are significantly cheaper. hobby king has some acceptable electronics but you will get some duds with them. balsa i tend to go to my local hobby stores but someone around here has a link for a website that has better quality balsa then i tend to get at hobby stores.
Are you working with a local club? Do you live in Georgia? There are lots of guys in that area that can help you out in person which is the best way. Take a look at the member map and see how it goes.
You should try pick a format before going too far..... most fast guns ships do not have rotatable cannons, most big gun do. Most people who scratch build do so with wood, sometimes fiberglass sheet is used for decks. Most guys who are scratch building a one off hull don't go through the time and trouble to make a mold to make a full fiberglass hull from.
I buy from National Balsa or Balsa USA (they both sell plywood as well as balsa), and sometimes from Rockler.com which is a woodworking supply place that has nice plywood.