Definitely start with reviewing the CG regs. They are pretty detailed.
You have three choices on propulsion - a straight drive like they have in big inboard boats, an inboard/outboard unit, or a straight outboard. The straight drive will require to also to build a separate steering mechanism (i.e. rudders.) Either of the first two options will require that you have an engine mounted on your deck on a reinforced platform, a highly insulated shield, appropriate exhaust system, cooling system, etc. etc.
If I were undertaking that kind of project, using one or two outboards would seem the best solution.