Thanks, Tac - Yes, two 75 ah batteries. That sketch with post 1 isn't really MY sketch, it's one that I found in the papers aboard the boat when I bought it. I don't think those cables are actually #8s, don't know why the sketch has them labeled like that.
The only sketch I take credit for is the rather crude one in post, I believe, 16. After long perusal I am just starting to get some small understanding of the first sketch, and I will study the ones you made for me and hopefully come to understand them. Many thanks for taking the time to make them.
This is getting too deep for me when all I want is to get from the Albemarle Sound to the Pamlico Sound, where I can find a competent mechanic. I'd sail the boat the whole way, except there are two canals enroute, one of them 20 miles long, and I'm going to have to motor through them. I need enough battery power to start the engine a few times and run it for about 8 hours.
So I'm going to wire it up like in my crude sketch, with a couple of marina friends watching me and giving me free advice. I'm going to beg, borrow or steal a small gas generator for backup. And then I'm heading for the Pamlico.
Thanks All for your advice, and thanks especially Tac for taking the time and effort to try to bring me along.