Really? Interesting... Stan sure knows his stuff!
When my boat was consuming zincs (once a week!) it did not yet even HAVE a dc system or connection to the dock. It was however in a marina that was wired soo poorly that you had to wear shoes just to walk on the concrete floating piers, (because of shocks), and if I was in the water, and I reached up and touched a dock cleat, it would almost knock me out! I actually became "persona non grata" for energetically pointing this out! When forced to, they removed the dock's face boards, and found a bare spot every 20' or so on the main AC feed lines, where they rested on the main dock bolts! To solve THEIR problem, they just covered it back up, and eventually I was asked to leave.
Anyway... in this battery atmosphere, or "aquasphere"... My 8' long bonded in copper plate, which was also the CB trunk minikeel's worm shoe, was picking up more of the current than the other underwater metal, consuming the zincs. I had created a battery, in a really bad marina for it. The modifications I mentioned took care of it, as did to a degree,moving to another marina. Years later I also switched to a much smaller 2 sq ft copper plate on the side of the minikeel, as it was easier to wipe down...
When I did wire up my DC system, I tied in an isolater in the green wire, as one should. THIS is good advice!
Many ABYC dictates seem to be geared toward protecting the boat manufacturer from liability, OR only see the safety issue from the point of view of the boat's occupants. It is more complicated than that. If I did something that made me safer in a VERY unlikely situation while aboard, but it vastly increased my time spent scrubbing the bottom, or the associated danger of being in the water in a crowded marina, I sometimes did what I thought was safer for me, while in the water. I won't be specific here, but you get my drift... (Even small amounts of stray current attracts barnacles!)
Mark
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