it is mostly mechanical. You do not need to know much about electronics. It usually involves drilling holes and pulling wires. The only electronics you need to know is how to choose wire size and use the standard color code when connecting the wire to your panel. All that is laid out in many DIY books. You can always look at what was done previously in the boat and mimic it.

The only work I have had done for me is welding and, now that I am getting older, grunt work like bottom sanding.

On big projects like engine replacement and windlass installation it is just a matter of think it through and make a plan. When I replaced my engine in 2003 I spent more time staring at and thinking about the job than doing the job itself.