Poey50
Well-known member
Yes, annoying that no references are given.
Lightning strikes
- Thread starter davierobb
- Start date
Yes, annoying that no references are given.
duncan99210
Well-known member
I‘ve been in a number of thunder storms in Greek waters over the past few years. Biggest problem I’ve encountered is the sudden loss of visibility with the intense downpour that usually occurs as the cell passes over. I don’t think it’d matter much if the boat took a significant strike where you were on board or what you were doing: it’s the luck of the draw as to what damage would be done to the crew.
What I have seen from folks who’ve sustained strikes is that it doesn’t matter much if kit is turned off or not: a strike will fry most or all of the electronics on board. I know of one boat ashore in Corfu which took a strike which reduced all of the one board kit to burnt rubbish along with all the bonded through hull fittings, which provided the earth path. The inside of the boat was also to trashed by the charing damage from metal fittings.
Equally, another boat in San Carles took a hit and looked perfectly normal but most of the electronics were fried along with some of the electrical circuits. Wasn’t until the switch panel was opened that you could actually see any physical damage.
What I‘ve always thought is that if caught in the storm, I put a phone and HH VHF into the oven on the ”I hope this works“ principle and then hope for the best.
Final note. My Bavaria comes with a hefty cable run from the mast foot to the forward keel bolt: Ive no idea if this offers any protection but it may offer a better path to earth than arcing from the chain plates?
What I have seen from folks who’ve sustained strikes is that it doesn’t matter much if kit is turned off or not: a strike will fry most or all of the electronics on board. I know of one boat ashore in Corfu which took a strike which reduced all of the one board kit to burnt rubbish along with all the bonded through hull fittings, which provided the earth path. The inside of the boat was also to trashed by the charing damage from metal fittings.
Equally, another boat in San Carles took a hit and looked perfectly normal but most of the electronics were fried along with some of the electrical circuits. Wasn’t until the switch panel was opened that you could actually see any physical damage.
What I‘ve always thought is that if caught in the storm, I put a phone and HH VHF into the oven on the ”I hope this works“ principle and then hope for the best.
Final note. My Bavaria comes with a hefty cable run from the mast foot to the forward keel bolt: Ive no idea if this offers any protection but it may offer a better path to earth than arcing from the chain plates?
coopec
N/A
How could this possibly be legit?
Sertec CMCE Marine – Lightning Protection System
The innovative CMCE Marine lightning protection system by Sertec prevents lightning from striking your vessel.
Sertec CMCE Marine - Lightning Protection System | ELCOME
Sertec CMCE Marine – Lightning Protection System
The innovative CMCE Marine lightning protection system by Sertec prevents lightning from striking your vessel.
Sertec CMCE Marine - Lightning Protection System | ELCOME
ProDave
Well-known member
From that link:
This picture is interesting
It tends to suggest on a typical yacht you are relatively safe?
Poey50
Well-known member
I read that as an ideal scenario assuming a very good grounding system. As the article says "it’s important to realise that the area [of protection] is by no means absolute." There seem to be a number of accounts where people who seemed to have a good protection system have sustained serious damage. So it's a probability game with no guarantees.
William_H
Well-known member
I am not sure that the rod on top of the mast is such a good idea. Yes it will impact the VHF performance especially in some directions. I am not sure it will protect the mast head instruments I think you will have to regard them as lost in a strike. There is one VHF antenna type (called a J antenna) (perhaps more) where the antenna itself is firmly connected to the base. The coax feed arrives above the base. vhf j antenna - Google Search
This should provide the conductor you want while operating as an antenna. Yes the VHF radio will probably still be smoked but then I think your idea for a parallel conductor will still see the VHF killed. Current on one conductor will induce by magnetic coupling a voltage into the other.
Re heavy cables mast base to keel... I think this has much merit in being easy practical and always ready. Corrosion of the different metals will be a problem to the condition of the mast but will not be a problem to lightning current. Indeed I might suggest thin insulating material between metals to stop galvanic corrosion which I suggest will not be a barrier to lightning voltage. ol'will
Just saw the diagram "Zone of protection" I would suggest more the zone of attracting lightning. Yes a person say in the water in that zone might be protected from a direct strike to the head but this at the sacrifice of the boat. The boat if struck will have a high current/voltage in the mast, any resistance in it's path to the water will still carry current but get very hot. (explode). Hence the concept of low resistance which will conduct the current without so much heating. How much current carrying capability is enough? Who knows. The current in the concuctor will generate a magnetic field which will induce voltage in any other conductors so probably fry electronics. Disconnect from any wiring will help but putting devices in a metal box will help even further.
Yes all this is theoretical as lighning seems to do it's own thing. Ignore the possibility (as most of us do) or do what seems like a fair thing to you. ol'will
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Poey50
Well-known member
While there are no guarantees and, as ever, people must make their own choices on the basis of fairly thin evidence - including the common choice to do nothing:
1. Research into incidence does not support the common view that lightning protection methods attract strikes.
2. I'm not planning a cable from mast to keel.
3. My proposed measures are temporary so corrosion is not a factor.
4. In the range of methods all recommend an air terminal a minimum of 15cm above anything else.
Edit. Just to show there is nothing new under the sun, I found this quote in a 2006 post from someone I think you know well.
"If you have real concerns at the time you could drop an additional conductive plate in the water connected by heavy wire to the mast. How heavy? Probably any size might be inadequate but starter or welding cable size would be a start."
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Poey50
Well-known member
Just for interest's sake I asked for a quote on the gold (smallest) version of this. It was $6,750 dollars although that does include international shipping. That's Christmas sorted...
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coopec
N/A
Maybe we should all carry a ;laser pointer on board our yachts?
Australian Scientists Aim to Tame Lightning to Prevent Bushfires
Scientists in Canberra are trying to tame the lightning bolts responsible for many Australian bushfires. The scientists believe the bolts’ path and direction could be controlled by small, portable laser pointers.
Lightning is generated when frozen raindrops collide in a storm cloud, creating an electric charge. Researchers have shown that thunderclouds could be "short-circuited" by using a laser to heat tiny particles in the air to trigger a lightning strike.
Australian Scientists Aim to Tame Lightning to Prevent Bushfires
Australian Scientists Aim to Tame Lightning to Prevent Bushfires
Scientists in Canberra are trying to tame the lightning bolts responsible for many Australian bushfires. The scientists believe the bolts’ path and direction could be controlled by small, portable laser pointers.
Lightning is generated when frozen raindrops collide in a storm cloud, creating an electric charge. Researchers have shown that thunderclouds could be "short-circuited" by using a laser to heat tiny particles in the air to trigger a lightning strike.
Australian Scientists Aim to Tame Lightning to Prevent Bushfires
PilotWolf
Well-known member
I seem to remember some research where a wire flexible brush type lightening conductor was the best option.
Bad description but not sure how else to describe it
W.
Bad description but not sure how else to describe it
W.
coopec
N/A
I know what you mean and I was going to install one until I found out the price and then I read they didn't work
Lightning Protection: The Truth About Dissipators
https://s30384.pcdn.co/wp-content/uploads/2019/10/p1cgh4oukck3dggm1r5kemm12sj6.jpg
PilotWolf
Well-known member
I seem to think they were firing them to antenna towers? It it was a long time ago.
Also remember one program where they were using the sand strikes as art.
W
Also remember one program where they were using the sand strikes as art.
W
GHA
Well-known member
Might have been the West marine catalogue you read that..
PilotWolf
Well-known member
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GHA
Well-known member
If it was actually real science (unlikely on tv) the insurance companies would love to hear about it......... they must pay out millions every year.
Google Scholar
coopec
N/A
pvb
Well-known member
coopec
N/A
A lightning strike will probably blow a hole in the bottom of your hull! (I wouldn't worry about it) ?
Lightning Attenuation Onboard
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William_H
Well-known member
Brush type dissipators have been used on aircraft for half a century. Almost all aircaft apart from slow SE have them on the trailing edges of wing and tail. The very fine points concentrate a charge so encouraging it to discharge (dissipate) at a lower tension.
The intent on aircraft is to reduce radio interference from high voltage discharges. Not specifically for averting lightning strike but may help. The actual dissipator can be a brush type or often a very sharp needle point of metal. Conceivably the dissipator could encourage discharge of static at a lower charge so reducing the chances of a high static voltage starting the leader to a strike. ol'will
The intent on aircraft is to reduce radio interference from high voltage discharges. Not specifically for averting lightning strike but may help. The actual dissipator can be a brush type or often a very sharp needle point of metal. Conceivably the dissipator could encourage discharge of static at a lower charge so reducing the chances of a high static voltage starting the leader to a strike. ol'will
coopec
N/A
I have a piece of copper rod which I intend to grind the tip to a sharp point and mount to the top of my mast.
