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Due to the high frequency nature of lightning it always hard to give advice because it doesn’t have to behave like DC once it lights up. The interesting thing is it doesn’t no the nature of the path it strikes until the ionization path is established. What I mean is it selects a target based on greatest point of attraction (potential – charge) then follows the rules of RF conduction once going.
It doesn’t know a wet kite string won’t handle the energy of the main bolt but it looks like a much closer point to strike so it does. After that the air along the string ionizes (becomes conductive) to provide the real conduction path. Researchers use to shoot little rockets into storms with salts mixed in the solid rocket fuel so it would leave a trail of ionized gas so they could draw a strike.
So a relatively small bronze contact point could be used to light it off and after that it would punch through you bottom paint. The question is can you keep the ionization path focused on the keel bolts. I’ve toured one factory bonding boats right as they come out of the mold and they were using a wide ribbons of heavy copper foil just like you would expect for RF. The battery cable approach doesn’t offer a good path to RF, which only runs on a conductor’s surface, since a battery cable has a heavy cross section but minimal surface area it’s not the best choice. RF also hates bends so even the ribbon conductors do broad curves, no creased corners.
Phil Agur s/v Wing Tip Commodore, Call Sign WCW3485 IC27/270A
www.catalina27.org Vessel Doc# 1039809 -----Original Message-----
I'm finally convinced I should bond my mast and shrouds to an exposed metal plate below the waterline in order to dissipate electrical charges and minimize the risks of lightning damage to my precious electronics. But rather than adding more weight and drag, I'm considering leaving a section of my lead keel exposed, and bonding to the keel bolts in the bilge. I have concerns: electrolysis, fouling, and legal ramifications/pollution... What else am I missing? What suggestions do you all have, especially addressing my concerns?
Thanks for any advice! David Shaddock 1977 C27 Pixie, Rockford IL |
- RE: catalina27-talk: Lead keel question Phil Agur
