Far more qualified people than either of us - Colin Brookes included - advise against wasting money on epoxy coating the hull, and against using copper based coatings. I rest my case on that point.
You deserved the last shot. A "sparkie" is the name for the low man on the totem pole in the electrical business. He's usually a guy who learned via apprenticeship and has some basic night school in electrical matters. You'd hire that guy to install wiring in your house. Of course he doesn't know anything about this, he isn't trained to know it.
That is a far cry from either an electrical engineer (which I am not) whose focus is on electrical generation and distribution systems, or an electronics engineer (which I am) who designs, builds and repairs radios, computers, electronics control devices, surface mounted components that have to be worked on under a microscope, audio and video system, industrial lasers, printers and a host of other complex products.
Since you have no idea of my background and I have none about yours, I'll take your word about your "high qualifications" but I can almost guarantee they don't come within a bull's roar of my experience, if for no other reason than lack of opportunity.
But that whole pissing contest is irrelevant, since this is entirely about justifying your choice to epoxy coat your yacht and apply copper coat to it. Go right ahead, but from my viewpoint it's a waste of money. And when the value of a ferro yacht is so low (the one I'm in now cost $2000) then a mere several hundred bucks worth of paint does indeed constitute overcapitalisation.
It's a small mind indeed which can't tolerate an alternative viewpoint. After all, there are as many of them as there are people on this planet. Get used to it.
And before you come back a-blustering some more, go look up the Dunning-Kruger effect.