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Old 13-08-2012, 11:59   #76
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Re: Lightning Strike Damage Details Needed

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There is typically a ground connection to most of the electrical on the mast head. Also, the Windex might be connected to the AL mast.
Also true, but nothing like the type of least resistive path to ground that has been discussed and installed, for e.g. in post #37. So my question is with regard to whether a rod can attract, etc., does it matter that the rod is part of an extensive, purpose-built grounding system to protect the boat from strikes?
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Old 13-08-2012, 12:19   #77
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Re: Lightning Strike Damage Details Needed

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Also true, but nothing like the type of least resistive path to ground that has been discussed and installed, for e.g. in post #37. So my question is with regard to whether a rod can attract, etc., does it matter that the rod is part of an extensive, purpose-built grounding system to protect the boat from strikes?
Obviously I can't really answer your question - not enough of an armchair expert..
Quote:
but nothing like the type of least resistive path to ground
actually they would be least resistive. They are direct connects with clean wire to the system ground. They just aren't large enough to carry the strike after it hits, so the strike has to go through some other path.
My last boat had a typical production boat bonding system. When I owned it I dismissed more elaborate lightening bonding systems, especially the bottle brush silliness. My current boat has an elaborate lightening bonding with BF bonding wires, an air terminal and large external bonding plate. Now I'm less dismissive of the lightening bonding systems. Funny how that works out.
If the boat didn't have the system already installed, I doubt I would go through the effort and cost to put it in. In the end having a basic bonding system and an insurance policy with low-deductible for electronics probably is sufficient.
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Old 13-08-2012, 12:49   #78
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Re: Lightning Strike Damage Details Needed

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Obviously I can't really answer your question - not enough of an armchair expert.. actually they would be least resistive. They are direct connects with clean wire to the system ground. They just aren't large enough to carry the strike after it hits, so the strike has to go through some other path.
My last boat had a typical production boat bonding system. When I owned it I dismissed more elaborate lightening bonding systems, especially the bottle brush silliness. My current boat has an elaborate lightening bonding with BF bonding wires, an air terminal and large external bonding plate. Now I'm less dismissive of the lightening bonding systems. Funny how that works out.
If the boat didn't have the system already installed, I doubt I would go through the effort and cost to put it in. In the end having a basic bonding system and an insurance policy with low-deductible for electronics probably is sufficient.
My boat has what also sounds like the more typical bonding system where all of the thru-hulls, tanks, chain plates, prop shaft, mast step, etc. are bonded together, but my understanding is that this has more to do with dissipating potential galvanic corrosion or electrolysis than for lightening protection. There seems to be one school of thought that thinks it may also help for lightening, but then there's another who says that it runs the risk of directing a strike to all of those critical components!

With regard to a dedicated rod/plate attracting a strike, there is a strong consensus of scientific opinion which discount this, but there is a minority scientific view that supports it, and obviously some anecdotal evidence as we have seen on this thread.

I, for one, am back to the Mt. Gay & low insurance deductible strategy that others have wisely suggested.

Dan
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Old 13-08-2012, 12:54   #79
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Re: Lightning Strike Damage Details Needed

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I, for one, am back to the Mt. Gay & low insurance deductible strategy that others have wisely suggested.
Yes, this is surely good policy, and the one thing you surely should have, but I can tell you from experience that there still is a lot of pain to go through following a strike. And not from the rum...

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Old 13-08-2012, 12:59   #80
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Re: Lightning Strike Damage Details Needed

BoatUS.com - Seaworthy Magazine
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You Can Run, But You Can’t Hide
Volumes have been written about methods to mitigate damage or even avert a lightning strike. Lightning, however, doesn’t seem to read them.
Nothing you can do will prevent a strike or damages.

anyway good reading
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Hull Damage
As hard as lightning is on electronics, it can be just as brutal to fiberglass. In the case of Priority, the lightning traveled down the mast as well as through the VHF coaxial cable. The cable had been disconnected and was resting against the hull inside the boat. When the strike exited the cable, it had no easy way to get to the water. After traveling a quarter of a mile through air, lightning has no trouble going through a fiberglass hull, and this is exactly what it did, blowing a three-inch hole on the way. Fortunately, the hole was above the waterline and the boat was saved from sinking. (Note: If you disconnect your VHF cable from your radio during lightning season, like some boaters do, be aware that anything near the connector, including you, can get zapped during a strike.) Other boats have not been so lucky.

Giving the lightning a low-resistance path to the water is a good idea, but if it’s not done right, the damage can be even worse. The owner of a 27-foot sailboat bonded his through hulls properly with heavy wire, but didn’t realize that underneath one of the seacocks, the through-hull fitting was made of Marelon—plastic. When the boat was struck, the lightning dutifully followed the wire, but instead of continuing to the water as it would have through a bronze fitting, it jumped across the plastic one, destroying it and partially sinking the boat.
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Old 13-08-2012, 13:43   #81
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Re: Lightning Strike Damage Details Needed

Ionized path?

I was two boat lengths away from a couple who received a direct lightening hit. This happened in Fly creek Marina in south alabama. Out of about 200 boats in the slips, we were probably the only people in their boats. The couple was cooking on a stove and my guess is that the heated plume of rising air from their stove was a contributing factor. It seems to be too much of a coincidence for this not to play. The couple was unharmed but they did look rather surprised as they arose from the cabin.
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Old 13-08-2012, 14:34   #82
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Re: Lightning Strike Damage Details Needed

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The couple was cooking on a stove and my guess is that the heated plume of rising air from their stove was a contributing factor. It seems to be too much of a coincidence for this not to play.
Did the lightning hit their stove?

It is unlikely that heated air caused lightning. If that was the case, lightning would be crashing down on asphalt parking lots and highways everywhere and forgoing all those rain and wind cooled masts and towers sticking up in the air.

Coincidence is not cause/effect. Even if 100 of the 200 boats were struck at the same time and only those boats cooking on their stove were struck, that would still be only coincidence and not cause/effect.

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Old 13-08-2012, 16:41   #83
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Re: Lightning Strike Damage Details Needed

so, out of a total of over 300 empty boats, lightning strikes the boat with two people cooking?

coincidence? maybe?

After witnessing this first hand, from now on, I'm going to play it safe and wait till the clouds pass over before I light my stove.
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Old 13-08-2012, 19:26   #84
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Re: Lightning Strike Damage Details Needed

Yes, otherwise it would not be coincidence.

A couple months ago, we were in an anchorage full of sailboats with one powerboat in the middle. Lightning struck the powerboat. Coincidence? Or are boats without tall metal masts more likely to be hit? Should we increase our mast height to be more safe?

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Old 13-08-2012, 19:55   #85
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Re: Lightning Strike Damage Details Needed

We shackle a chain to the sidestay and chuck it overboard. Tadah! Grounded..... Now, let's go sailing
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Old 14-08-2012, 13:20   #86
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Re: Lightning Strike Damage Details Needed

"Lightning strikes may be a significant danger to giraffes in environments that have few tall trees and are topographically or geologically predisposed to attract lightning." Death by lightning for giraffes, elephants, sheep and cows – Tetrapod Zoology

I guess the main reason that I wanted to mention the lightning strike possibly induced by a rising plume of air is that it is yet another example of how random lighting strikes may seem. In this instance, a grounded mast may not have made any difference at all. Obviously, lighting doesn't always trike the highest tree, but I believe it wise to be observant of probability trends.

Some may believe that if you wrap your head with aluminum foil and stand on one leg your fine.

My uncertainly regarding afternoon thunderstorm activity in south Alabama remains.
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Old 14-08-2012, 14:38   #87
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Re: Lightning Strike Damage Details Needed

"Lightning strikes may be a significant danger to giraffes in environments that have few tall trees and are topographically or geologically predisposed to attract lightning."

Correct me if I am wrong, but don't giraffes live in areas with tall trees? Is that not the reason they have such long necks? To get at those tasty leaves?

Giraffes aside I would like to know of strikes with people aboard versus injury or death. So far in this and other posts on lightning there has been no posts of people killed while on their boat, and let's face it that is the first and foremost consideration. Perhaps second is a strike sinking a boat whilst on passage followed then by all the electronic goodies getting fried. So at the risk of thread drift (none already in this thread) could you all provide stats on injuries or fatalities along with the damage that the OP requested..
Thanks
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Old 14-08-2012, 18:32   #88
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Re: Lightning Strike Damage Details Needed

We were on board when struck. While we were not hurt, I did ruin a good pair of shorts. Our boat was fine structurally and did not sink, but our electronics were severely damaged.

I can't provide any statistics, only our one-off experience.

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Old 14-08-2012, 18:36   #89
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Re: Lightning Strike Damage Details Needed

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Originally Posted by vientoman View Post
"Lightning strikes may be a significant danger to giraffes in environments that have few tall trees and are topographically or geologically predisposed to attract lightning." Death by lightning for giraffes, elephants, sheep and cows Tetrapod Zoology

I guess the main reason that I wanted to mention the lightning strike possibly induced by a rising plume of air is that it is yet another example of how random lighting strikes may seem. In this instance, a grounded mast may not have made any difference at all. Obviously, lighting doesn't always trike the highest tree, but I believe it wise to be observant of probability trends.

Some may believe that if you wrap your head with aluminum foil and stand on one leg your fine.

My uncertainly regarding afternoon thunderstorm activity in south Alabama remains.

I don't understand the giraffe reference.

I agree with you that lightning strikes are random - that was why I questioned your cooking hypothesis.

I also agree with you that a well-grounded mast will not make any difference as to which boat gets struck. The grounded mast will make a difference as to which boat suffers the most structural damage when struck.

When my head is covered in aluminum foil and I am standing on one leg, I lose my ability to believe anything...

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Old 14-08-2012, 18:56   #90
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Quote:
Originally Posted by colemj
We were on board when struck. While we were not hurt, I did ruin a good pair of shorts. Our boat was fine structurally and did not sink, but our electronics were severely damaged.

I can't provide any statistics, only our one-off experience.

Mark
Colemj,
LMAO but not at you. Just know I would have done the same.
And ty for correcting me I would rather have real reports versus skewed stats.
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