Static dissipaters, was..Re: Through Hull: now grounding

Just my guess, but I'd bet a tree, with all its leaves and branches, and being a living organism with electrolyte, makes a good static dissipater. Therefore, one should always sit under a tree, or better yet, climb into a tree, during a lightening storm. So why is it that it isn't recommended to do so during a strom, and why does lightening frequently strike trees? I don't think lightening is very smart. I saw a video on lightning strikes, and one victim was a teller working in a bank in an office, at his desk, who was struck, even tho the storm clouds were miles away. The discharge came in through the metal frame of the outdoor teller window and followed electric cables through the office. The strike left him permanently disabled. Just a guess, but isn't grounding the mast make it more likely to attract a lightening strike, in the first place? Then grounding bronze through holes to the mast sounds like looking for trouble. If you must, leave the through holes ungrounded, and clamp a heavy electric cable, the thickest one you can find, to the mast and trail it overboard, away from where you're sitting Jerry

I have seen the aftermath of trees hit by lightning and they (at least, the trees I have seen) look like and exploded pile of toothpicks. Conductivity in trees is not good. So they cannot conduct the energy efficiently to the ground. So the lighting often comes out the sides of the trunk simply because it can't drain to the ground quickly enough. Kind of like a sewer backing up. And that is why you DON'T want to be near a tree in a lightning storm. The lightning hits the tree because it is the most convenient item around but because it is a poor conductor the energy leaves the tree (no pun intended :) ) in multiple places. I am not certain, but I strongly suspect the human body is a much better conductor than the tree. This makes the human a likely target if he is close to the tree. Lighting is likely to hit the mast anyway if one is near a potential discharge area. The idea is to make the pathway easier to go to ground and hope the mast (and every everything else) is spared. I am NOT an expert in lighting. But I worked as a high voltage electrician for about 8 years for the Federal Gov't. I worked with voltages up to 12 KV. Lighting is WAY higher than that. It is a whole other ball game. Don't stand near any trees and get as far away from the mast and shrouds as you can :) Walter MacArthur Tejana '70 Cal34 #301 Gerald Sobel wrote: Just my guess, but I'd bet a tree, with all its leaves and branches, and being a living organism with electrolyte, makes a good static dissipater. Therefore, one should always sit under a tree, or better yet, climb into a tree, during a lightening storm. So why is it that it isn't recommended to do so during a strom, and why does lightening frequently strike trees? I don't think lightening is very smart. I saw a video on lightning strikes, and one victim was a teller working in a bank in an office, at his desk, who was struck, even tho the storm clouds were miles away. The discharge came in through the metal frame of the outdoor teller window and followed electric cables through the office. The strike left him permanently disabled. Just a guess, but isn't grounding the mast make it more likely to attract a lightening strike, in the first place? Then grounding bronze through holes to the mast sounds like looking for trouble. If you must, leave the through holes ungrounded, and clamp a heavy electric cable, the thickest one you can find, to the mast and trail it overboard, away from where you're sitting Jerry

Back on the farm in Kansas, I have had lightning strike a tree outside my home and then jump across to an upstairs breaker box (probably a 6' gap, if I remember right,) blowing the panel cover completely off but doing otherwise minor damage. The siding was split and singed, the tree split in places but not destroyed. Very strange stuff, lightning. David Wilkie Owen From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of walter Sent: Tuesday, December 26, 2006 6:55 AM To: Ca… [at] yahoogroups.com Subject: Re: [Cal_Boats] Static dissipaters, was..Re: Through Hull: now grounding I have seen the aftermath of trees hit by lightning and they (at least, the trees I have seen) look like and exploded pile of toothpicks. Conductivity in trees is not good. So they cannot conduct the energy efficiently to the ground. So the lighting often comes out the sides of the trunk simply because it can't drain to the ground quickly enough. Kind of like a sewer backing up. And that is why you DON'T want to be near a tree in a lightning storm. The lightning hits the tree because it is the most convenient item around but because it is a poor conductor the energy leaves the tree (no pun intended :) ) in multiple places. I am not certain, but I strongly suspect the human body is a much better conductor than the tree. This makes the human a likely target if he is close to the tree. Lighting is likely to hit the mast anyway if one is near a potential discharge area. The idea is to make the pathway easier to go to ground and hope the mast (and every everything else) is spared. I am NOT an expert in lighting. But I worked as a high voltage electrician for about 8 years for the Federal Gov't. I worked with voltages up to 12 KV. Lighting is WAY higher than that. It is a whole other ball game. Don't stand near any trees and get as far away from the mast and shrouds as you can :) Walter MacArthur Tejana '70 Cal34 #301 Gerald Sobel wrote: Just my guess, but I'd bet a tree, with all its leaves and branches, and being a living organism with electrolyte, makes a good static dissipater. Therefore, one should always sit under a tree, or better yet, climb into a tree, during a lightening storm. So why is it that it isn't recommended to do so during a strom, and why does lightening frequently strike trees? I don't think lightening is very smart. I saw a video on lightning strikes, and one victim was a teller working in a bank in an office, at his desk, who was struck, even tho the storm clouds were miles away. The discharge came in through the metal frame of the outdoor teller window and followed electric cables through the office. The strike left him permanently disabled. Just a guess, but isn't grounding the mast make it more likely to attract a lightening strike, in the first place? Then grounding bronze through holes to the mast sounds like looking for trouble. If you must, leave the through holes ungrounded, and clamp a heavy electric cable, the thickest one you can find, to the mast and trail it overboard, away from where you're sitting Jerry

walter wrote: > > I have seen the aftermath of trees hit by lightning and they (at > least, the trees I have seen) look like and exploded pile of > toothpicks. Conductivity in trees is not good. So they cannot conduct > the energy efficiently to the ground. So the lighting often comes out > the sides of the trunk simply because it can't drain to the ground > quickly enough. > One problem with trees is that they have a higher resistance than, say, copper wire, so they heat up from carrying high lightning currents and the moisture boils and the wood explodes. I have a big cottonwood, the highest tree around, and it was struck last summer. I was not there. The noise was, according to neighbors, quite astonishing. There is a track down the trunk where the bark popped off, about 2-3" wide, and a furrow in the sapwood about an inch across and deep. Interestingly, the tree did not lose foliage after the strike except right at the point of contact, and seems to be OK. I've got my fingers crossed, both because I like the big tree and because it would cost a small fortune to have it cut down. Chris Campbell