Allen, great link... it's like the Rosetta Stone! (My previous post was a response to Benz BTW)
I agree with you about not grounding your mast's lightning protection to your through hulls! I launched our tri 15 years ago, and after standing the rig, I had it, and ALL grounds go to the same point, per ABYC at the time. It was eating shaft zincs at an incredible rate, even though it didn't yet even have an electrical system, and was not connected to the dock. HMMMM?
After a lot of head scratching, I consulted Stan Honey about the issue. I later separated my rig & mast lightning ground system, from the bonding wire, that ran to the shaft, strut, prop, and engine. I even isolated the VHF antennae mount, etc, as the mount screw has continuity with the boat's 12v dc ground. So the lightning ground and its more galvanically active copper plate are totally separated, and my zinc consumption returned to normal.
Just for kicks, I even put a battery cable switch on the negative wire to the engine as well, (which already had a three way red)... This way, when the engine is not running, the boat's DC wiring is not in any way connected to the engine, OR therefore, the shaft, prop, etc.
Three totally separated grounding systems... the mast for lightning protection only, the boat's 12v dc system, and the bonding wire to keep underwater metal happy, and protected by the shaft zinc. (The throughhulls are Maralon)
ABYC doesn't always apply. In many cases I just do what works!
Mark
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