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Old 03-08-2015, 17:03   #61
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Re: Offshore Sailing in Thunderstorm far from land

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Originally Posted by flyingnut40 View Post
Let me give you a bit of info on how a lightning rod protects a barn. First thing to understand is that the cable running to the ground rod could NEVER pass several hundred thousand volts at thousands of amps! But what it does do really well is emit electrons from the ground to neutralize passing rain clouds. So using that line of thinking, the electrons are going UP and therefore you should not climb up on the barn and put your hand betrween the rod and the sky, a burn is guaranteed. They are also pointed to allow better emmission efficiency.
I assume that your mast is akin to a lightning rod and that you are actually pasifying the clouds electron imbalance and therefore most sailboats left alone by the lightning.
Therefore, making your lightning rod (mast) a better emmitter of electrons would be most effective with a good ground connection to the water...... Your cone of protection looks a lot like your stays only inverted......
So, donate lots of electrons to the cloud and you should be ok.
Thank you for finally adding this to the discussion. Contrary to common belief, lightning does not follow the lightning rod to ground - in fact if lightning hit a lightning rod (or your antenna) it would probably vaporize immediately.

So, anything you can do to improve the grounding of your mast - lots of good ideas above including chain on the mast, battery cables to the stays, aluminum boat - should help.

Edit: realized this may not have been clear. Improving the grounding of the mast will improve the ionization effect described which will improve your protection. You're not providing a path for lightning to follow because, as noted, it would still destroy everything on its way by.
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Old 03-08-2015, 17:28   #62
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Re: Offshore Sailing in Thunderstorm far from land

I don't know, if you are grounded doesn't electricity seek that? I once observed a strike on a lightning rod on top of a farm silo. The silo was right next to the taller barn. We teenagers were goofing around in the yard. Bam! Knocked us off our feet. The lightning rod was still there too.
When I use my welder, the rod wont arc if I don't ground the plate I'm welding. Are you saying if I add a diffuser the arc wont transfer?
A tree seems like it ought to b e a pretty good grounded diffuser, yet they are often struck.
:>) just sayin'.....
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Old 03-08-2015, 17:46   #63
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Re: Offshore Sailing in Thunderstorm far from land

It's hard to determine what happened in specific situations, and probably hard (i've never had the opportunity :big grin: to experience it) to distinguish between direct and nearby hits. So whatever I have to say is based on what I learned when studying this stuff.

And to me the bottom line is that it's a powerful, unpredictable force, and you do what you can to improve your chances. A better conductor, and a pointier end on top (trees are missing that one) improves the protection. But there may be cases where a lightning rod or other conductor has actually directed the charge to ground, in which case: if it works, don't knock it!
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Old 03-08-2015, 19:08   #64
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Re: Offshore Sailing in Thunderstorm far from land

Barns?


That's ignoring the recent research showing the downstrike goes into the ionized layer of moistened air that sits in the top foot or two above sea level, a critical difference from any land-based situation, unless there's a salty ground fog writhing around your barn.


Sorry, but if these guys are right, it would explain why "boat strikes" have always been so much at odds with "land strikes". It is a tentative but exceptionally logical reason for the real observed differences.
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