I have a new Catalina 315. I understand it has no built-in lightning protection. I'm considering adding a heavy #1 or #2 wire running from the metal mast compression post to a keel boat. I understand this is no guarantee of safety, but I'm thinking it's better than nothing. Am I missing anything?
Lightning Protection
- Thread starter asalotto
- Start date
You might find this thread helpful including first tread' post #2's and the second thread recommendation on wire size.
Lightning always seeks the path of least resistance, there is a school of thought that claims that providing a path of lesser resistance promotes lightning strikes. Another School of thought indicates that the boat is under a cone of protection which extends from a point at the top of the mast to a circle down in the water with a diameter of the same length as the mast. Observation and recording of strikes on boats reveals that the majority of strikes occur next to land. Is it because land attracts them or because at any given time there are more boats in or near land? The last thought is that lightning strikes at pure random. That the force is so great that nothing we can do will deviate it and that it will strike where it may. But there is a positive aspect and that is that we do not often by far hear of any lighting strikes on sailboats where people have died. I personally subscribe to getting away from land and rest under the Cone of Protection. For many years I sailed out of Tampa (Indian word for firestick) , lightning Capital of North America, and sailed through numerous electrical storms, seldom on purpose but always felt the odds were with me. If anyone claims they have a proven solution, do not believe them. Don't know if there is a trade off in possibly attracting a strike while at the same time minimizing damage that may occur. My only answer is do what will make you feel more secure.
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No solution, but we don't have an epidemic of Water Tower destruction by lightning strikes.
The reason is a well grounded tower with a Lightning Rod.
By grounding your mast to your keel, you will have the best protection.
The size of the wire is not to pass high voltage, but to allow your standing rigging to flow electrons and to reduce electron build up.
What is key is to make your boat appear like flat ground/water [electrically] around your boat.
That will minimize your chances that you get a direct hit.
Jim...
PS: This is the science, a Faraday Cage.
PSS: Guess what a sailboat's Lightning Rod is?
If your boat was built since 1995, it should meet ABYC standards for lightning avoidance already.
Jim...
PS: Check out my post #5 on this link.
newbie lightning protection?
Awww gee I still like you a lot!
_______
Bonding electrically, if your boat has it, may help protect your electronics on an nearby strike.
Plus lets your shaft/prop be another grounding source. [#10 yellow/green stripe wire]
Jim...
A St. Someone or other statue? Patron saint of sailors, or patron saint of expensive electronics. The bolt that hits you has traveled a mile or so? Overcoming quite a lot of air resistance, I don't know how much fooling around with the last 50 ft of its journey is going to matter that much at least in terms of avoidance. It would seem that hardening your boat to withstand the strike without blowing up or sinking is the way to go.
Actaully...
You have to consider electric and magnetic fields with lighting. How do you get electric fields? Initially there is a bunch of negative charge in a cloud which induces positive charge in the ground. Those charges separated create a voltage difference between the charges (coulombs law). So we have a voltage potential separated by a distance and this creates an electric field or volts per distance. Electric field is what's important for lightning. Ionization and corona currents in air require a sufficiently high electric field. For example, if we have a million volts but the separation is a million miles, a million volts sounds like a lot but the electric field is only 1 volt per mile.. Ie, pretty much nothing. However, if that same million volts in separated by only one mile, now we have 1 million volts per mile.
Why is this important.. because air doesnt ionize until you have a field of around 3 million volts per meter. If have enough charge to generate three million volts, separate that charge by 2 meters, nothing happens. Separate that charge by half a meter and the air ionizes and zap..
Before and in the process of strike, there is a strong electric field created. If a mast is grounded to the water, the top of the mast will be at ground potential. Since the vertical mast is in a vertical electric field created by the lightning charge, the field at the top of the mast is CONCENTRATED and INCREASED compared to an ungrounded mast.
So.. grounding a mast does make it the same potential as ground. But grounding a mast also will increase the electric field at the top of the mast.. in fact it will be double the field compared to an ungrounded electrically floating mast. That higher electric field at the top of the mast will affect both corona currents and leader generation. Its incorrect to think grounding makes you "invisible".
But if you didnt read any of that.. no problem to ground a mast, it would not seem to matter that much for getting struck but it has other benefits.
You have to consider electric and magnetic fields with lighting. How do you get electric fields? Initially there is a bunch of negative charge in a cloud which induces positive charge in the ground. Those charges separated create a voltage difference between the charges (coulombs law). So we have a voltage potential separated by a distance and this creates an electric field or volts per distance. Electric field is what's important for lightning. Ionization and corona currents in air require a sufficiently high electric field. For example, if we have a million volts but the separation is a million miles, a million volts sounds like a lot but the electric field is only 1 volt per mile.. Ie, pretty much nothing. However, if that same million volts in separated by only one mile, now we have 1 million volts per mile.
Why is this important.. because air doesnt ionize until you have a field of around 3 million volts per meter. If have enough charge to generate three million volts, separate that charge by 2 meters, nothing happens. Separate that charge by half a meter and the air ionizes and zap..
Before and in the process of strike, there is a strong electric field created. If a mast is grounded to the water, the top of the mast will be at ground potential. Since the vertical mast is in a vertical electric field created by the lightning charge, the field at the top of the mast is CONCENTRATED and INCREASED compared to an ungrounded mast.
So.. grounding a mast does make it the same potential as ground. But grounding a mast also will increase the electric field at the top of the mast.. in fact it will be double the field compared to an ungrounded electrically floating mast. That higher electric field at the top of the mast will affect both corona currents and leader generation. Its incorrect to think grounding makes you "invisible".
But if you didnt read any of that.. no problem to ground a mast, it would not seem to matter that much for getting struck but it has other benefits.
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If you want to read more of @walt comments and a full thread on subject refer to
newbie lightning protection?
I still like ABYC E4 standards the best.
Jim...
PS: There are electron mast dissipaters available, shown in that link.
Well take a good picture of the HOLE in your fiberglass boat when the insurance company hauls it out of the water.
Direct strike = hole in your boat.
Side bolt strike...
Bye bye electronics and wiring.
Jim...
How much electric field do you need to get a lighting bolt going? 1000 meter long 3 billion volts? How important is the e field of the last 10 meters? I do bet that a grounded mask presents a more attractive target than a floating mast if the bolt of lightning was going to hit within say 10 meters of you anyway. But with the grounded mast you should survive the strike, with an ungrounded mast don't you end up blowing holes in the bottom of your boat? Ungrounded mast is still more attractive than air it is already conductive.
My .02 on that..
Some electric field must trigger a bolt of lighting to start traveling in the cloud.. (maybe google will have some insight on that) but as the bolt of lighting travels, the electric field will be highest at the end points of the ionized column.. and why the strike mostly keeps going in the direction it was traveling.
Before the strike and when the charge may have be separated by a mile, the electric field is strong enough to charge the water surface and create corona currents from things that concentrate fields like a mast.
But once the bolt starts and heads down towards the surface, now all that charge has a shorter and shorter distance as it travels. Same voltage and shorter distance equal higher electric field. Note that electric field travels at the speed of light which is much faster than the bolt of lightning travels. So to some extent, the bolt of lightning can "see" best gradients as it travels downward. As the bolt gets closer to ground, the electric field increases rapidly and usually a leader from the ground will reach up and connect with the downward bolt.
Before the strike, the charge in the sky "sees" the ground charge but something like a mast would be like picking out a mast from an airliner.. Ie, that detail is in the noise. But when the bolt gets near the ground, something like a mast either grounded or not grounded would be better at generating an upwards leader as the mast (grounded or ungrounded) is good at concentrating electric fields in its vicinity.
However.. if you look at cone of protection geometry, that is also on the order of the distance a mast will influence where a strike connects. Ie, its only when the strike would have stuck close anyhow does the mast make a difference.. But.. a good grounded mast that will definitely take the strike and safely dissipate the charge into the water is WAY better than that same charge picking the top of your head. And of course how the cone of protection works.. the mast will take the strike instead of anything in the protected area.
Some electric field must trigger a bolt of lighting to start traveling in the cloud.. (maybe google will have some insight on that) but as the bolt of lighting travels, the electric field will be highest at the end points of the ionized column.. and why the strike mostly keeps going in the direction it was traveling.
Before the strike and when the charge may have be separated by a mile, the electric field is strong enough to charge the water surface and create corona currents from things that concentrate fields like a mast.
But once the bolt starts and heads down towards the surface, now all that charge has a shorter and shorter distance as it travels. Same voltage and shorter distance equal higher electric field. Note that electric field travels at the speed of light which is much faster than the bolt of lightning travels. So to some extent, the bolt of lightning can "see" best gradients as it travels downward. As the bolt gets closer to ground, the electric field increases rapidly and usually a leader from the ground will reach up and connect with the downward bolt.
Before the strike, the charge in the sky "sees" the ground charge but something like a mast would be like picking out a mast from an airliner.. Ie, that detail is in the noise. But when the bolt gets near the ground, something like a mast either grounded or not grounded would be better at generating an upwards leader as the mast (grounded or ungrounded) is good at concentrating electric fields in its vicinity.
However.. if you look at cone of protection geometry, that is also on the order of the distance a mast will influence where a strike connects. Ie, its only when the strike would have stuck close anyhow does the mast make a difference.. But.. a good grounded mast that will definitely take the strike and safely dissipate the charge into the water is WAY better than that same charge picking the top of your head. And of course how the cone of protection works.. the mast will take the strike instead of anything in the protected area.
Also my .02 on grounded vs not grounded mast.
Before the strike begins to travel, there is an electric field that is strong enough to charge the water surface and create corona currents in metal objects that can concentrate fields such as a vertical mast (why you can get shocked on a mast and sometimes hear a buzzing sound). Because of corona currents, an ungrounded mast will take on the vertical electric potential of its mid point. A grounded mast will of course have the potential of ground. So the top of the grounded mast in the vertical electric field will have a higher field concentration than the ungrounded mast. The higher fields at the top of the grounded mast are better at generating corona current..
But corona current is really overall very small. When the bolt of lightning gets near the mast, the electric field is increasing so rapidly that the field magnitude completely swamps out any difference between grounded or ungrounded before the strike. Corona currents are way to small to react in time to how fast the fields are changing. At the very high fields when the strike gets near the mast, no problem to ionize the air or whatever between an ungrounded mast and water. I think that very rapidly increasing field just before getting to the mast is why grounded or ungrounded really doesnt matter much in your odds of getting struck.
Could be wrong...
Before the strike begins to travel, there is an electric field that is strong enough to charge the water surface and create corona currents in metal objects that can concentrate fields such as a vertical mast (why you can get shocked on a mast and sometimes hear a buzzing sound). Because of corona currents, an ungrounded mast will take on the vertical electric potential of its mid point. A grounded mast will of course have the potential of ground. So the top of the grounded mast in the vertical electric field will have a higher field concentration than the ungrounded mast. The higher fields at the top of the grounded mast are better at generating corona current..
But corona current is really overall very small. When the bolt of lightning gets near the mast, the electric field is increasing so rapidly that the field magnitude completely swamps out any difference between grounded or ungrounded before the strike. Corona currents are way to small to react in time to how fast the fields are changing. At the very high fields when the strike gets near the mast, no problem to ionize the air or whatever between an ungrounded mast and water. I think that very rapidly increasing field just before getting to the mast is why grounded or ungrounded really doesnt matter much in your odds of getting struck.
Could be wrong...
Most of my reading suggests that grounding the mast (or not grounding it) has no impact on getting struck or not. But, I'm thinking there is a potential to avoid a hole in the hull with a grounded mast. As a grounded mast likely doesn't increase the odds of getting struck, but maybe decreases the odds of sinking, why not ground the mast? A few bucks is all I can see as a downside.
What if you ground your mast through your anchor rode (chain)... and if you do, what is the best anchor to use? If you did get struck by lighting, what is the best bottom paint to have to enhance the grounding of your hull?
If you did get struck by lighting, what is the best bottom paint to have to enhance the grounding of your hull?
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My last comment on this thread...
The strike charge depends on the Cloud Charge at time of strike.
Sometimes clouds are positive charged and sometimes negative.
Positive charged clouds... the electrons flow is upwards.
There is some studies that show, only the surface of waters are charged [negative] and not deeper.
I will depend on my keel grounding per ABYC...
So far, so good...
Most damages are not from direct strike, but back flow voltage thru shore power on a land strike nearby.
Hoping all a Good Avoidance...
Jim...
The strike charge depends on the Cloud Charge at time of strike.
Sometimes clouds are positive charged and sometimes negative.
Positive charged clouds... the electrons flow is upwards.
There is some studies that show, only the surface of waters are charged [negative] and not deeper.
I will depend on my keel grounding per ABYC...
So far, so good...
Most damages are not from direct strike, but back flow voltage thru shore power on a land strike nearby.
Hoping all a Good Avoidance...
Jim...
I once considered the use of static wicks but ruled them out for a boat. Like I said, the only sure thing is the fact that reports of deaths due to lightning strikes in sailboats are nil. For the boat and electronics nothing is as effective as good insurance coverage. Do what will make you personally feel more comfortable.
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For your viewing pleasure...
Forespar Lightning Master Static Dissipator
Read the footnotes too.
Also a good read for the doubters...
Understanding Boat Corrosion, Lightning Protection & Interference
Jim...
Forespar Lightning Master Static Dissipator
Read the footnotes too.
Also a good read for the doubters...
Understanding Boat Corrosion, Lightning Protection & Interference
Jim...