Re: Where to start
I used to be completely and entirely mechanically inept. Changing oil in my car was about as far as I would go. Now, if the time allows, I will do almost anything and everything myself. I don't do as much of my own work on my cars or boat anymore, simply because of the time restraints, but, when I did, here's how I was 'forced' into becoming my own mek-a-nik, and it's a bit of a story.
I came across a Corvette that was an absolute steal. It was an '85, 2 owner, bright red, etc., etc. I jumped on it. I am not a man of endless wealth by any means, and to be able to own a (running) Corvette was a head-reeling dream. So my second day driving, I pull away from a stop light, and the car goes about 20 feet, and dies. Kaput.

Have it towed and a mechanic friend determines it's the fuel pump. So I call around, and the lowest I could get it down for was $750.

No way did I have that kind of cash. Called around to the auto parts places, and found the fuel pump was only $139. I could afford that. Bought the pump and the repair manual, and literally, 40 minutes later, the pump was changed, and I was off and running again. I realized that if I was going to be a Corvette owner, but couldn't afford the 'Corvette Tax' on parts and repairs, I better learn to do it myself. So I did.
Since then, I've built a VW from the ground up, replaced an engine in a Cherokee, and a tranny in a Blazer, among tons of other things. Confidence.
It's the same with boats. It's a machine. Someone once told me you only have to be 2% smarter than whatever it is you are dealing with to succeed. I like to think I'm 2% smarter than a hunk of metal (wife might argue that one though).
Dig in, and go for it. If you screw it up, there is always someone out there that make it right. It'll just cost you (more). The price of education.