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Old 03-05-2021, 07:40   #61
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Re: So my boat lacks a lightning ground.

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Argument by aphorism, as usual, isn’t very effective. While doing something, anything, might be better than doing nothing, that isn’t always the case. Sometimes just doing something makes me feel better, without necessarily actually changing the course of the universe.

Some ovens can be quite effective as a faraday shield. Others are virtually useless. Putting your GPS in either might make you feel better. Is that the "good" that we should accept over the "perfect?"
Almost all ovens are sheet steel to my knowledge and better than a true Faraday cage.

In this article they tested Faraday cages and found solid sheet steel to provide far better protection. Now if you have a glass door that is another matter. However, even the glass door on an oven usually has a metal coating that would provide some protection.

https://physicsworld.com/a/are-farad...ously-thought/

Article about coatings on glass that provide protection

https://www.pilkington.com/en-gb/uk/...etic-shielding
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Old 03-05-2021, 07:44   #62
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Re: So my boat lacks a lightning ground.

I've never had an insurance company offering a reduced rate for a lightening protection system. Nor even ask about it on the application.

These companies have all the data on every claim - and aren't stupid. If any form of lightening protection would substantially reduce their payout - they would require it.
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Old 03-05-2021, 08:02   #63
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Re: So my boat lacks a lightning ground.

I did a check regarding the fact I saw my fluorescent lights glow in my pilot house after lightning strikes nearby.

I found this discussion.

However, a strong enough EMF field can excite the gases inside the tube and cause it to produce light. The initial EMF field created by a lightning strike can light a tube several meters away, which explains this phenomenon. You can also try standing under a high voltage transmission line (115kV or greater) with a fluorescent tube and the field generated by the line will cause the tube to light. Or use a plasma globe and hold the tube within 6″ of the ball. The tube will light without physically contacting it!

Therefore, I double confirm, to myself at least, that lightning struck several times close enough to my vessel that it still failed to hit the mast despite being a very tall point and made of aluminum. Of course the blinding flash, large noise, as well as the jolt I felt in my hands while holding the helm were additional confirmations.

Had my mast been grounded, I am quite certain it would have struck the mast.

There are hundreds of people reading this thread. I would be very curious is we total up all of those who had damaging lightning strikes and see how many of them had grounded masts.

Further I want to know how many had a large antennae on top of the mast. The mast might not be grounded but the antennae might be, and the path is right into the control panel.
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Old 03-05-2021, 08:15   #64
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Re: So my boat lacks a lightning ground.

Thanks to Pbmaise for some actual science.

In my case, the propane oven is sheet steel with a non-conductive silicone gasket around the formed steel door, with a 5” x 12” glass opening. I can’t see any reason why they would put a metallic coating on a thermal oven door. There’s certainly nothing there to complete a putative electrical connection between the glass and the door.

The microwave oven has a cavity formed of sheet steel, but the door is completely made of plastic, presumably with a metallic coating or additive, and a choke joint.

Neither one of them will provide reasonable protection from lightning.

Yours might perform better than mine, but maybe not.

CarlF has had the same experience as I’ve had: no insurance company since 1976 has ever even mentioned a lightning "protection" system. Even after my two strikes.
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Old 03-05-2021, 08:36   #65
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Re: So my boat lacks a lightning ground.

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Thanks to Pbmaise for some actual science.

In my case, the propane oven is sheet steel with a non-conductive silicone gasket around the formed steel door, with a 5” x 12” glass opening. I can’t see any reason why they would put a metallic coating on a thermal oven door. There’s certainly nothing there to complete a putative electrical connection between the glass and the door.

The microwave oven has a cavity formed of sheet steel, but the door is completely made of plastic, presumably with a metallic coating or additive, and a choke joint.

Neither one of them will provide reasonable protection from lightning.

Yours might perform better than mine, but maybe not.

CarlF has had the same experience as I’ve had: no insurance company since 1976 has ever even mentioned a lightning "protection" system. Even after my two strikes.
But there is a coating of metal on almost every single glass door on any oven made in the past 25 years. That low-e coating is metal.

Low-E, meaning "low emissivity," is an extremely thin layer of metallic particles, or more commonly, several layers, applied to the glass that, in simple terms, allows the glass to act like a sieve. Long wavelengths, or heat, are filtered out, while short wavelengths (the visible light spectrum) are allowed to pass through. However, today Low-E is is much more than that. By changing the types of materials used in the "stack" or layers of Low-E, or by increasing or decreasing the number of layers, we can now get more specific in choosing glass that will meet our exact project needs. Need high visible light but low U-values? There’s a Low-E for that. Need greater protection from fading? There’s a Low-E for that. And it gets even more specific than that. Adding argon gas to the captive air space, as we all know, will improve insulating value. Adding various tinting agents to the glass itself will allow for even further refinement of the glass’s performance.



But if you can see through low-e glass won't the EMP get in too?

The answer is NO.

Cardinal glass studied this exact question. See
https://www.cardinalcorp.com/source/...08_02-2019.pdf

"Silver, found in Cardinal Low-E coatings, is very
effective at attenuating electromagnetic energy.
Typically, the more silver in a Low-E coating, the
more UHF is shielded. Our coatings made with three
layers of silver (LoE3 366 & LoE3 340), will attenuate
the most, followed by our two silver layer products
(LoE2 270 & LoE2 272), then our single silver layer
product (LoE 180)."
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Old 03-05-2021, 08:50   #66
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Re: So my boat lacks a lightning ground.

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" There is no evidence that lightning has significant, damaging power at the gigahertz ranges."

Absolutely true. The energy in lightning ranges from (almost) DC to 300-500 MHz.

Thus it seems reasonable to think that a choke joint, carefully designed to block 2450 MHz
(the specific frequency of a microwave oven) is likely to be of NO USE at all in stopping lightning energy.

An oven which uses a silicone gasket to retain heat is also not going to be very effective as a faraday cage.

Some ovens (microwave or otherwise) have a conductive gasket and can be quite effective as a faraday cage. But many other, for example the ones that I just happen to have, do not.

So, itís not always a good idea to just put things in the oven to protect them from lightning. In some cases, itís no better than leaving them on the galley counter.

One has to follow the science, not just do what makes them feel good.
And how does the hole size change as you increase the frequency? You need very small hole sized screen to protect from ghz frequencies, but as you go down to the lower frequencies even large holes still protect as a Faraday cage.
It is not reasonable for cruisers to be able to test their oven or microwave against lightning energy to see what level of Faraday cage protection they have. It is reasonable and prudent to use the oven or microwave to store some backup nav gear while in lightning country. Aphorism or not.
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Old 03-05-2021, 09:35   #67
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Re: So my boat lacks a lightning ground.

So, the theory has now become "You canít test it, you canít prove it, but itís 'prudent' to do something because it might work under some conditions." That seems less than scientific to me.

Thereís no good reason why one SHOULDN'T put one's electronics in the oven. But one shouldnít put a lot of faith in it either. Just like the fuzzy brushes on the top of the mast or the various solutions for grounding this or that with a plethora of different ground plates. Sometimes they work and sometimes they donít.

Once, when cruising from Mexico to El Salvador, I sailed through a really nasty lightning storm. Confirming the old aphorism about a lack of atheists in foxholes, I prayed. I wasnít struck. But Iím not going to advocate prayer as a generic solution to lightning.

Do what makes you comfortable, but donít try and call it science.
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Old 03-05-2021, 09:59   #68
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Re: So my boat lacks a lightning ground.

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Originally Posted by Bycrick View Post
So, the theory has now become "You can’t test it, you can’t prove it, but it’s 'prudent' to do something because it might work under some conditions." That seems less than scientific to me.

There’s no good reason why one SHOULDN'T put one's electronics in the oven. But one shouldn’t put a lot of faith in it either. Just like the fuzzy brushes on the top of the mast or the various solutions for grounding this or that with a plethora of different ground plates. Sometimes they work and sometimes they don’t.

Once, when cruising from Mexico to El Salvador, I sailed through a really nasty lightning storm. Confirming the old aphorism about a lack of atheists in foxholes, I prayed. I wasn’t struck. But I’m not going to advocate prayer as a generic solution to lightning.

Do what makes you comfortable, but don’t try and call it science.
Hmm. Isn't science based upon observed facts?

Certainly there are many observers.

"Boat U.S. gathered insurance claim data from a 10-year period and found that the odds of being struck are about one in 1,000 in any given year. Location, however, matters a great deal. Florida accounted for 33 percent of all claims, and the Chesapeake Bay area accounted for 29 percent.Boating Magazine"


Hence wouldn't you agree that by now thousands of people have experimented and observed the consequences of their experiment?

There certainly were plenty of these people who suffered damage to their electronics. I personally know of three boat owners who suffered near total electronic failure.

Surely there are many of these who kept backup electronics like cell phones with mapping systems in their oven.

So far I have yet to here from a single person who:

#1 Suffered a major lightning strike that wiped out their electronics, and
#2 suffered damaged their electronics stored in the oven.

Anyone???

Perhaps we may find out that 99% of the time that people with backup electronics in their ovens were protected. Does that mean nobody should be doing that?
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Old 03-05-2021, 11:24   #69
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Re: So my boat lacks a lightning ground.

I’ll look forward to hearing anecdotal evidence about the number of people who "saved" their electronics from lightning strikes by keeping them in the oven. But at the very least, you should also ask about the number of people who had a lightning strike that DIDN'T damage hand-held electronics.

I can speak. to three cases, one my own, where the boat was directly struck by lightning. Damage to installed electrical equipment amounted to as much as $50k.
Case 1. The handheld GPS, VHF radio and the laptop computer on the saloon table at the base of the mast survived just fine.
Case 2. Every piece of electronics in the nav station was wrecked except for the auto stereo system and the two cell phones on the nav table.
Case 3. All the cellphones and handheld devices worked just fine after the strike.

Science is based on proof. It’s a fact that almost all of the people that die ate carrots, but correlation isn’t causation.Hard science used to be based on making a hypotheses and then seeing if it could make predictions that could be experimentally tested, repeatedly. That’s hard to do with lightning.

If you can point to a serious scientific study, that under a controlled set of circumstances shows that an oven (microwave or not) results in less damage, I’m certainly willing to listen. Otherwise, it’s just bar stories not science.
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Old 03-05-2021, 12:24   #70
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Re: So my boat lacks a lightning ground.

Lots of talk of ďscienceĒ and some mentions of experiments and observations. Let us remember many scientific fields progress without experiments. Everyone goes googaly eyed at astrophysicists or cosmologists. But that field almost totally lacks experimentsÖ some people would even call those fields soft or fluffy. Ouch. ĎStill good science even if almost totally observational. Only experiments show causation and experiments are the gold standard. I think the only way you could inform this discussion with experiments is rocket lighting studies but who would fund that given how infrequent it is.
https://en.wikipedia.org/wiki/Lightning_rocket
One could scale down the questions in to components and assume the total is the sum of the parts. I think many have done so because lighting physics research facilities do exist. (but I highly doubt they care much about boats)
There is still value in observational studies or even theorizing. Most fields function with both. I am an environmental chemist / toxicologist / ecologist. We have extensive experimental knowledge of the components of an oil spill for example. Experiments at the biochemical up to the organismal level. But never will I be allowed to monitor 60 estuaries and dump crude oil in half of them and that is the real world, ecological level. Just as we can never ďproveĒ climate change because we only have one earth, no control treatment, no replication. But we still have immense evidence or inference. Donít even get me started on the assumptions of engineers (razzing my applied brethren).
Having a PhD, MS, BS and BS in the sciences (plus a 3rd BS in a social science) and as a licensed science educator, I ask you to not let the lack of experiments be a reason to not discuss lighting safety
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Old 03-05-2021, 12:38   #71
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Re: So my boat lacks a lightning ground.

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Do you not have these? http://www.ftp.tognews.com/Projects/.../rudder003.jpg
Some Ty37 owners added ground straps. Look at Projects on the TOG news site
I was unable to find this, can you please link to it.
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Old 03-05-2021, 12:46   #72
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Re: So my boat lacks a lightning ground.

Our little Rhodes 22 1984 hull does not have a grounding plate, or a ground to the metal centerboard. Our lightning protection consists of having a shorter mast than the boats nearby. Deck stepped mast with 11 shrouds and stays; I figure if it gets hit it'll leap from the external chain plates the 2 or 3 feet down to the water. I hope.
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Old 03-05-2021, 13:12   #73
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Re: So my boat lacks a lightning ground.

While I might argue about Cadmus assertion that cosmology and astrophysics lack experimental confirmation, I do agree with the thought behind it. Sure, some of the esoteric string theories and super particle ideas currently lack experimental confirmation. But nobody has said "Just take this theory on faith."

There’s lots of soft science, and where the line is drawn between that and hard science is the realm of the "science philosophers."

But philosophy aside, the insurance companies don’t seem to find a compelling case for the installation of any kind of lightning system. So, if one is of the opinion that merely counting observed occurrences "proves" something, then they haven’t found yet what it might prove. That doesn’t mean that we shouldn’t "discuss" lightning protection. But, to me, it does mean that the pious assertions that one should, or must, or ought to do this or that or the other isn’t founded on science.

Like the arguments about faraday cages. Even after 100 years, according to an attachment above, there are still questions to be answered. Even if one assumes that it’s possible to design and build an oven which also acts as an effective faraday cage, that is certainly not the same thing as assuming that a random steel box with an opening door, designed with the purpose of cooking food, just accidentally happens to protect against lightning. Maybe it does work sometimes, but that doesn’t constitute a general proof.
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Old 03-05-2021, 13:34   #74
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Re: So my boat lacks a lightning ground.

The potential varies in the clouds and sea. So if you are in negatively charged water with positive clouds above (or vice versa) is the greatest danger. In this case putting a plate in the water will make it more likely to get struck, however the strike will be directed in a way less damaging and dangerous.


Often you can feel the charge in your body a split second before a near strike. A simple circuit can sense this, know the charge direction and then using a high voltage generator, charge the mast relative to sea to repel the strike from hitting the boat. Such a system could make you (almost) invincible to lightning strikes, however, it would need to be very powerful to block the strongest strikes. This system would need a plate in the water as well as connection to the mast, but they would be actively charged from the battery as needed. Synthetic rigging would be preferred to reduce capacitance of rig.



Also I wonder if synthetic rigging will melt in a strike? Does anyone know about synthetic rigging in lightning strike?
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Old 03-05-2021, 14:09   #75
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Re: So my boat lacks a lightning ground.

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The potential varies in the clouds and sea. So if you are in negatively charged water with positive clouds above (or vice versa) is the greatest danger. In this case putting a plate in the water will make it more likely to get struck, however the strike will be directed in a way less damaging and dangerous.


Often you can feel the charge in your body a split second before a near strike. A simple circuit can sense this, know the charge direction and then using a high voltage generator, charge the mast relative to sea to repel the strike from hitting the boat. Such a system could make you (almost) invincible to lightning strikes, however, it would need to be very powerful to block the strongest strikes. This system would need a plate in the water as well as connection to the mast, but they would be actively charged from the battery as needed. Synthetic rigging would be preferred to reduce capacitance of rig.



Also I wonder if synthetic rigging will melt in a strike? Does anyone know about synthetic rigging in lightning strike?
Well - Again anecdotal evidence...My rigging for the 11 years I owned my vessel was Dyneema. And yes the thought occurred to me that it would indeed melt if lightning traveled down its length. However, why would it? Even wet rigging is an extremely poor conductor compared to an aluminum mast.

I think we would be hard pressed to locate any evidence of any lightning damage to synthetic rigging.

However, it is possible to find damage to wire rope.

https://www.sciencedirect.com/scienc...50630718315632


In this paper we investigate the effects of a lightning strike occurred to the carrying rope of a high altitude aerial cableway (Pejo 3000), installed on the Italian side of the Alps. During a periodic visual inspection, an important localized damage in the rope produced by lightning was observed. After an initial attempt to repair it, the rope was dismantled. The damaged section was cut and the wires were subjected to microstructural analysis, static mechanical characterization and finally fractographic observation.

But I wouldn't let that potential scare you off from wire rigging. I was unable to find anything on Google that lightning strikes damaged wire rigging to the point that it was attributed to a demasting.
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