Don't flame Billy. As it turns out Lightening is a legit word with many definitions including possibly the origin to the word lightning as we use it today.
Lightning
- Thread starter EmeraldBay
- Start date
Lightning (corrected sp)
Also I want to stress I am by no means an expert in the subject of marine lightning protection. I just wanted to get some science from the wireless industry in front of the group.
In the mid 80s the cellular and public safety wireless industry developed. The number of towers and wireless base stations increased exponentially. Polyphaser labs built an artificial lightning machine (thanks to Mr Tesla) and started testing everything in the industry. They were actually able to determine under labaratory conditions what worked and what didn't. This is how modern lightning protection practices were developed for the wireless industry. These experiments cost millions of dollars and were driven by the need to save money by reducing lightning damage to the many thousands of radio sites across the country. This research was driven by money, which is how things normally get done. From my observations the yachting industry has not made the significant investment needed to do the research needed to determine what really works to protect your boat and what really doesn't. It appears to me the information gathered so far in studying marine lightning strikes is anecdotal at best and from insurance claims.
I hope that someone out there in the boating industry commits to studying lightning strike management in a laboratory setting and can come up with some science to guide the industry. Strides can really be made if enough resources (Money and brainpower) are committed to the research. We will then know exactly what everyone needs to do to make their boat safe and boat builders can incorporate these findings into their manufacturing processes.
Also I want to stress even after 30 years of study there is still very little science on lightning strike avoidance and that largely remains a dark art.
Please remember this is land based knowledge and should not be blindly applied to marine applications.
Two long posts in one night. I need a scotch.
Absolutely Correct. Lightning behaves as RF and not regular AC or DC. A sharp bend in the ground cable will be seen as a "spot impedance" and cause the energy to want to seek an easier path to ground (or water). Think of it as a tidal wave that needs to be channeled. A wide path with easy turns will carry it away. A sharp turn will make it overflow and wreak havoc.
Also I want to stress I am by no means an expert in the subject of marine lightning protection. I just wanted to get some science from the wireless industry in front of the group.
In the mid 80s the cellular and public safety wireless industry developed. The number of towers and wireless base stations increased exponentially. Polyphaser labs built an artificial lightning machine (thanks to Mr Tesla) and started testing everything in the industry. They were actually able to determine under labaratory conditions what worked and what didn't. This is how modern lightning protection practices were developed for the wireless industry. These experiments cost millions of dollars and were driven by the need to save money by reducing lightning damage to the many thousands of radio sites across the country. This research was driven by money, which is how things normally get done. From my observations the yachting industry has not made the significant investment needed to do the research needed to determine what really works to protect your boat and what really doesn't. It appears to me the information gathered so far in studying marine lightning strikes is anecdotal at best and from insurance claims.
I hope that someone out there in the boating industry commits to studying lightning strike management in a laboratory setting and can come up with some science to guide the industry. Strides can really be made if enough resources (Money and brainpower) are committed to the research. We will then know exactly what everyone needs to do to make their boat safe and boat builders can incorporate these findings into their manufacturing processes.
Also I want to stress even after 30 years of study there is still very little science on lightning strike avoidance and that largely remains a dark art.
Please remember this is land based knowledge and should not be blindly applied to marine applications.
Two long posts in one night. I need a scotch.
Re: Lightening
I am in the generator business and grounding is a big part of what we encounter. The above post about keeping the potential the same is the key.
We had a house that was hit. It came from the service lines. Went through the house only to find its way to a pan on the stove. It ruined the stove eye, the pan and nothing else. The stove eye switch was turned off. I quit trying to predict it at that point.
I am in the generator business and grounding is a big part of what we encounter. The above post about keeping the potential the same is the key.
We had a house that was hit. It came from the service lines. Went through the house only to find its way to a pan on the stove. It ruined the stove eye, the pan and nothing else. The stove eye switch was turned off. I quit trying to predict it at that point.
Thanks
BoatUS has done, IIRC, quite a bit of research, since it affects their insurance business and is specifically aimed (pi!
) at boats.
I don't recall their "conclusions & recommendations" and am sure they are available on their website.
Thanks again.
Steve, thanks for the great information and your clarity in presenting it.
BoatUS has done, IIRC, quite a bit of research, since it affects their insurance business and is specifically aimed (pi!
) at boats. I don't recall their "conclusions & recommendations" and am sure they are available on their website.
Thanks again.
Em,
I can tell you this pal, I looked into lightning protection about 15 years ago.
The more I read the more questions I had.
The USCG has an article on a protective cone for sailboats. The more I read, the less I believed.
Case in point, there were two modern top-shelf luxury yachts at a dock. They had the latest in bonding & electrical grounding protection. Both boats were hit & both yachts had bilge water instantly vaporize causing a pressure buildup that blew the thru hull fittings out of the hull. Both boats sank. These were million dollar boats but, with all the well-intentioned protection, they sank.
Do I believe in lightning protection & bonding...........NO.
I have NO bonding in my boat nor, do I have lightning grounding protection.
When the shiz hits the fan, I just turn off my VHF, my GPS & FM radio when lightning strikes are all around me. Lightning starts from the ground up not from the sky down. So, I don't give lightning a chance to create a path to my boat. I was hit once as a bounce lightning strike years ago since then, I decided to isolate me from a ground to sky circuit, I've never had a problem since but, others having wired protection have.
Their bonding wires to their aluminum tanks & aluminum binnacle caused electrolysis. The tanks pitted holes & the aluminum flaked off the binnacle powdercoating. My friend had new tanks made & hooked up the same bonding wires. Within a year & a half, the same holes pitted his tanks. I said, "Luther, cut these wires man." He's never had a problem since.
It's a bit different for boats running voltages 24/7 but if this is not you, it's a simple fix. I have a ground wire to my fuel tank to stop static electricity buildup when fueling. I disconnected this wire & added an alligator clip. When I fuel up, I clip this to a tang on my tank. Fueling finished, I remove the alligator clip, my tank is now isolated.
Here are some links for you to read & decide what's best for you & remember, I live in the lightning capital of the USA so, I deal with lightning seven months a year.
Read the links, and decide for yourself man.
ps: bonding can/will cause less noble metals to corrode.
http://www.bing.com/images/search?q...at+cone+of+protection+for+lightning&FORM=IGRE
http://www.lightningsafety.com/nlsi_pls/cone-of-protection-myth.html
CR
I can tell you this pal, I looked into lightning protection about 15 years ago.
The more I read the more questions I had.
The USCG has an article on a protective cone for sailboats. The more I read, the less I believed.
Case in point, there were two modern top-shelf luxury yachts at a dock. They had the latest in bonding & electrical grounding protection. Both boats were hit & both yachts had bilge water instantly vaporize causing a pressure buildup that blew the thru hull fittings out of the hull. Both boats sank. These were million dollar boats but, with all the well-intentioned protection, they sank.
Do I believe in lightning protection & bonding...........NO.
I have NO bonding in my boat nor, do I have lightning grounding protection.
When the shiz hits the fan, I just turn off my VHF, my GPS & FM radio when lightning strikes are all around me. Lightning starts from the ground up not from the sky down. So, I don't give lightning a chance to create a path to my boat. I was hit once as a bounce lightning strike years ago since then, I decided to isolate me from a ground to sky circuit, I've never had a problem since but, others having wired protection have.
Their bonding wires to their aluminum tanks & aluminum binnacle caused electrolysis. The tanks pitted holes & the aluminum flaked off the binnacle powdercoating. My friend had new tanks made & hooked up the same bonding wires. Within a year & a half, the same holes pitted his tanks. I said, "Luther, cut these wires man." He's never had a problem since.
It's a bit different for boats running voltages 24/7 but if this is not you, it's a simple fix. I have a ground wire to my fuel tank to stop static electricity buildup when fueling. I disconnected this wire & added an alligator clip. When I fuel up, I clip this to a tang on my tank. Fueling finished, I remove the alligator clip, my tank is now isolated.
Here are some links for you to read & decide what's best for you & remember, I live in the lightning capital of the USA so, I deal with lightning seven months a year.
Read the links, and decide for yourself man.
ps: bonding can/will cause less noble metals to corrode.
http://www.bing.com/images/search?q...at+cone+of+protection+for+lightning&FORM=IGRE
http://www.lightningsafety.com/nlsi_pls/cone-of-protection-myth.html
CR
Guys,
The only good data set we have thus far is from Dr. Ewen Thompson and the Florida Sea Grant study. Beth Leonard is also compiling data from Boat US but she is not done yet. I began talking with her about this over two years ago.
Dr. Ewen Thompson is the foremost authority/expert on marine lightning:
"there is no support for the argument presented by some sailors that they should not ground their sailboat since it will increase chances of being struck by lightning."
Dr. Ewen Thompson NO SUPPORT for not grounding!!!
"Data obtained from sailors whose boats have been struck by lightning are consistent with the above scenario: boats that do not have a protection system do indeed suffer more damage."
My own data set (real world multiple hit boats):
I do lightning surveys and repair the electrical and electronics damage to these boats. I act as an intermediary between the insurance company and owner so the owner gets his estimate of damage done correctly and he gets a fair hand from the insurer.. My data pool very much mirrors Dr. Thompson's data.
*Boats with lightning grounds are hit less.
*Boats with lightning grounds suffer less hull damage & very often no hull damage.
I get more boats hit without lightning bonding systems in place than I do that get hit with lightning grounds in place. I see more hull damage on boats with no bonding system than I do with boats that do... While my sample size is smaller than Dr. Thompson's it is running very much in-line with the Sea Grant data. I reached out to Beth to see how my data compared with Boat US. I think her summation and investigation will be published later this year.
Last summer was a light one, only six boats hit:
4 with no lightning bonding, three of those with hull damage
2 with lightning grounds neither had any hull damage
Almost all of the boats lost most of the sensitive electronics one boat lost a main sail, sail cover and dodger due to embers from the decimated VHF whip.....
P.S. the idea that you don't have a "ground path" or are ungrounded just because you'd not used large gauge wire from the spar to keel is entirely flawed just follow your VHF whip..........
The only good data set we have thus far is from Dr. Ewen Thompson and the Florida Sea Grant study. Beth Leonard is also compiling data from Boat US but she is not done yet. I began talking with her about this over two years ago.
Dr. Ewen Thompson is the foremost authority/expert on marine lightning:
"there is no support for the argument presented by some sailors that they should not ground their sailboat since it will increase chances of being struck by lightning."
Dr. Ewen Thompson NO SUPPORT for not grounding!!!
"Data obtained from sailors whose boats have been struck by lightning are consistent with the above scenario: boats that do not have a protection system do indeed suffer more damage."
My own data set (real world multiple hit boats):
I do lightning surveys and repair the electrical and electronics damage to these boats. I act as an intermediary between the insurance company and owner so the owner gets his estimate of damage done correctly and he gets a fair hand from the insurer.. My data pool very much mirrors Dr. Thompson's data.
*Boats with lightning grounds are hit less.
*Boats with lightning grounds suffer less hull damage & very often no hull damage.
I get more boats hit without lightning bonding systems in place than I do that get hit with lightning grounds in place. I see more hull damage on boats with no bonding system than I do with boats that do... While my sample size is smaller than Dr. Thompson's it is running very much in-line with the Sea Grant data. I reached out to Beth to see how my data compared with Boat US. I think her summation and investigation will be published later this year.
Last summer was a light one, only six boats hit:
4 with no lightning bonding, three of those with hull damage
2 with lightning grounds neither had any hull damage
Almost all of the boats lost most of the sensitive electronics one boat lost a main sail, sail cover and dodger due to embers from the decimated VHF whip.....
P.S. the idea that you don't have a "ground path" or are ungrounded just because you'd not used large gauge wire from the spar to keel is entirely flawed just follow your VHF whip..........