Greetings, Adrian;
After some thinking about your situation, I realized that every possible answer to your questions about the sizes of your framing members cam be found in one volume:
It is titled WOOD As An Engineering Material; I forget the author, but it's published by the Forest Service...
Hi,
I'm not sure I understand your question as it's posed... Is the vessel already finished? Are you working on a restoration? What's going on here, really? :)
As far as rules of thumb for addressing scantling sizes: Look to the past. The old designer/builders such as Herreshoff, Fife, and...