The "Real" Story on Lightening
- Thread starter Trev
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Think man think!
if a mystery was revealed about lightening ... a product would be developed and everyone would be wearing it on their head!
if a mystery was revealed about lightening ... a product would be developed and everyone would be wearing it on their head!
Try this article
This is the most definitive article on lightning and sailboats I know of. The academic argument makes sense. I do know of several boats that have been struck by lightning and it always seems to blow all the electronics. I do not know anyone who has been on a boat when it was struck. Lots of theories abound and not a lot of facts on this subject. Even when you think you have done everything to be ready, it is still frightening to be out there 50 to 60 miles offshore in the midst of an electrical storm!
This is the most definitive article on lightning and sailboats I know of. The academic argument makes sense. I do know of several boats that have been struck by lightning and it always seems to blow all the electronics. I do not know anyone who has been on a boat when it was struck. Lots of theories abound and not a lot of facts on this subject. Even when you think you have done everything to be ready, it is still frightening to be out there 50 to 60 miles offshore in the midst of an electrical storm!
I have been in a few thunder storms,,,,
What you do depends on how bad the storm is. First, avoid the storm. Second, it that is not possible, put the auto - pilot and get the sails down. If you going through a huge thunder head, sails and canvas down, auto - pilot on and wait it out below. The main thing is to get the sails and canvas down. Wind sheer is the big problem. The lighting may hit you but you can count on the wind sheer.
What you do depends on how bad the storm is. First, avoid the storm. Second, it that is not possible, put the auto - pilot and get the sails down. If you going through a huge thunder head, sails and canvas down, auto - pilot on and wait it out below. The main thing is to get the sails and canvas down. Wind sheer is the big problem. The lighting may hit you but you can count on the wind sheer.
My neighbour was hit yesterday by lightening.
Our yacht club's annual Turkey Race was held yesterday. Bronte Harbour to Hamilton and back - 20km. We didn't go out because of the weather forecasts, but many did, including my neighbour and his wife on their 30' Bayfield. Just off Burlington they saw that all hell was going to break loose, so they dropped their sails, started the engine, put on the autohelm, and sent the crew below. A few moments later, they were hit by a lightening strike. It blew out all their electronics, blew a few holes in their mainsail (which was sitting on the boom), melted their masthead instruments but thankfully didn't blow any through hulls or engine parts. Insurance is coming down first of the week to tally the damage. Higgs - your old buddy Ole was supposed to be on that boat, but he got smart when he saw the forecast and decided not to go.
Our yacht club's annual Turkey Race was held yesterday. Bronte Harbour to Hamilton and back - 20km. We didn't go out because of the weather forecasts, but many did, including my neighbour and his wife on their 30' Bayfield. Just off Burlington they saw that all hell was going to break loose, so they dropped their sails, started the engine, put on the autohelm, and sent the crew below. A few moments later, they were hit by a lightening strike. It blew out all their electronics, blew a few holes in their mainsail (which was sitting on the boom), melted their masthead instruments but thankfully didn't blow any through hulls or engine parts. Insurance is coming down first of the week to tally the damage. Higgs - your old buddy Ole was supposed to be on that boat, but he got smart when he saw the forecast and decided not to go.
Actually
on the boat is a good place to be. The lightning will just hit the mast. The mast is like a dome of silence and probably will not strike anying in that area... besides the mast. Stay down below and don't go anywhere near the mast. Stay away from the wheel; rigging; chainplates. Hopefully if lightning does hit your boat... it won't melt a thru hull fitting.
on the boat is a good place to be. The lightning will just hit the mast. The mast is like a dome of silence and probably will not strike anying in that area... besides the mast. Stay down below and don't go anywhere near the mast. Stay away from the wheel; rigging; chainplates. Hopefully if lightning does hit your boat... it won't melt a thru hull fitting.
Saturday Thunderstorm on Lake Ontario
Jim, I got caught out in the thunderstorm on Saturday. The sky turned a very interesting colour -sort of eggplant- and I furled the sails, got the engine cranking and headed in. Unfortunately, with the amount of traffic on the harbour, airport exclusion zone etc. couldn't go below. Got soaked to the skin in about 30 seconds and did not get hit by lightening, but saw a neat strike about half a mile away on Hanlons Point. I should have listened to the forecast.
Jim, I got caught out in the thunderstorm on Saturday. The sky turned a very interesting colour -sort of eggplant- and I furled the sails, got the engine cranking and headed in. Unfortunately, with the amount of traffic on the harbour, airport exclusion zone etc. couldn't go below. Got soaked to the skin in about 30 seconds and did not get hit by lightening, but saw a neat strike about half a mile away on Hanlons Point. I should have listened to the forecast.
Chains
I have heard that a good thing to do is to hook heavy chains to shrouds and drag them through the water. This gives the lightning an easy way to get to ground. Heard of using heavy battery cable clamps, like on jump start cables, hooked to heavy chain. Worth Having?
I have heard that a good thing to do is to hook heavy chains to shrouds and drag them through the water. This gives the lightning an easy way to get to ground. Heard of using heavy battery cable clamps, like on jump start cables, hooked to heavy chain. Worth Having?
I wouldnt trust chain
It's like having a piece of wire with a cut and twist connection every 2 inches, and expecting it to be a good conductor...but i might be wrong?
It's like having a piece of wire with a cut and twist connection every 2 inches, and expecting it to be a good conductor...but i might be wrong?
All you can do is make sure your boat is grounded.
There are standards. Check the archives and look around at various boats. The grounding is vital. My boat was struck while underway. And the bolt came out of the blue. Only one bolt came out of the squall that we were passing through. Pow. Blew out nearly everything. That was after being in dozens of lightning storms and having bolts strike within 100 feet. I hit the books to find out why. Turns out that my keel was the ground. I had just sealed it up with polyurethane to prevent rust. That prevented it from grounding the 'return path' aka St Elmo's Fire. I put a ground plate on the boat within a month of the strike and repaired the thousand holes that were now in the keel coating. Drat! But I've never been hit again. Been in some doosies too. And if you are on a sailboat that gets hit, you're safe. The only people who have been killed are power boaters. The mast provides, what is referred to, as the cone of protection.
There are standards. Check the archives and look around at various boats. The grounding is vital. My boat was struck while underway. And the bolt came out of the blue. Only one bolt came out of the squall that we were passing through. Pow. Blew out nearly everything. That was after being in dozens of lightning storms and having bolts strike within 100 feet. I hit the books to find out why. Turns out that my keel was the ground. I had just sealed it up with polyurethane to prevent rust. That prevented it from grounding the 'return path' aka St Elmo's Fire. I put a ground plate on the boat within a month of the strike and repaired the thousand holes that were now in the keel coating. Drat! But I've never been hit again. Been in some doosies too. And if you are on a sailboat that gets hit, you're safe. The only people who have been killed are power boaters. The mast provides, what is referred to, as the cone of protection.
The only way to beat lightening is to....
..make the boat invisable to lightening. The requires rendering the boats electrical state the same as the water it sits on. That required a very careful and thourough bonding of all metal and electrical equipment thru a grounding plate on the hull below the waterline. Chains might make you feel better but they do little for anything else.
..make the boat invisable to lightening. The requires rendering the boats electrical state the same as the water it sits on. That required a very careful and thourough bonding of all metal and electrical equipment thru a grounding plate on the hull below the waterline. Chains might make you feel better but they do little for anything else.
for the sake of another internet discussion
Lots of opinions about lightning, you have to pick your "expert" (there are several good links given in this thread). Im not an expert but here is my take.. Grounding with a chain over the side is likely NOT effective. I have tried to measure the impedance of a stainless steel chain and it was very poor. Also inductance (inductance is the impedance for "changing" currents such as occurs with lightning) on a chain is also poor. You need both low impedance and low inductance to effectively ground. Battery cable - could possibly help but it needs to be on the mast and not just on the shrouds. Lightning is most likely to hit the mast and because of inductance of the shroud, grounding the shroud only is not likely to prevent side flashing from the bottom of the mast. Good grounding from the bottom of the mast to a metal keel likely does improve safety. The connection must be both low impedance and low inductance. Several of the post here of boats being struck likely had good connections between the mast and the keel. Electronics were likely blown but also likely no major damage to the boat or personal injuries. In my opinion, the keel can have a electrically insulating coating (such as paint) and still be effective. The lighting strike just traveled 2 miles through the air, the gap between the keel and water through a thin layer of paint is "way in the noise". Dangerous areas in a boat are between the bottom of the mast, bottom of shrouds, ect and the closest water to these structures as this is where you are likely to get side flashes. One easy thing to do is to simply mark places inside the boat which are either dangerous in a storm (such as near the mast or shrouds) or places which are safer. For example, you may have green tape to note safer areas inside a boat and its easier and less confusing to tell for example kids or guests who dont know what a shroud is to go below and only sit under the green tape. The lightning dissipators mounted at the top of a mast will likely affect the charge state of an ungrounded mast - but this also likely has very little influence on your chances of recieving a strike. I doubt that lighting disipators do anything at all on a already grounded mast. Electronics.. This is probably going past what is reasonable to do but putting "transorbs" on all the power inputs will likely help. To some extent, this needs to be designed and implemented inside the box. The manufacutures more than likely already put this internal to the electronics but you dont know. I work in consumer electronics and we test our product with lightning simulators to some specificaiton but the spec is simply based on the econonics of the cost of the protection to warrenty returns. In my opinion, this is a good place to have things insured.. Can you make your boat invisible to lightning by such things as grounding or dissipators.. I dont think so... we can argue this further?
Lots of opinions about lightning, you have to pick your "expert" (there are several good links given in this thread). Im not an expert but here is my take.. Grounding with a chain over the side is likely NOT effective. I have tried to measure the impedance of a stainless steel chain and it was very poor. Also inductance (inductance is the impedance for "changing" currents such as occurs with lightning) on a chain is also poor. You need both low impedance and low inductance to effectively ground. Battery cable - could possibly help but it needs to be on the mast and not just on the shrouds. Lightning is most likely to hit the mast and because of inductance of the shroud, grounding the shroud only is not likely to prevent side flashing from the bottom of the mast. Good grounding from the bottom of the mast to a metal keel likely does improve safety. The connection must be both low impedance and low inductance. Several of the post here of boats being struck likely had good connections between the mast and the keel. Electronics were likely blown but also likely no major damage to the boat or personal injuries. In my opinion, the keel can have a electrically insulating coating (such as paint) and still be effective. The lighting strike just traveled 2 miles through the air, the gap between the keel and water through a thin layer of paint is "way in the noise". Dangerous areas in a boat are between the bottom of the mast, bottom of shrouds, ect and the closest water to these structures as this is where you are likely to get side flashes. One easy thing to do is to simply mark places inside the boat which are either dangerous in a storm (such as near the mast or shrouds) or places which are safer. For example, you may have green tape to note safer areas inside a boat and its easier and less confusing to tell for example kids or guests who dont know what a shroud is to go below and only sit under the green tape. The lightning dissipators mounted at the top of a mast will likely affect the charge state of an ungrounded mast - but this also likely has very little influence on your chances of recieving a strike. I doubt that lighting disipators do anything at all on a already grounded mast. Electronics.. This is probably going past what is reasonable to do but putting "transorbs" on all the power inputs will likely help. To some extent, this needs to be designed and implemented inside the box. The manufacutures more than likely already put this internal to the electronics but you dont know. I work in consumer electronics and we test our product with lightning simulators to some specificaiton but the spec is simply based on the econonics of the cost of the protection to warrenty returns. In my opinion, this is a good place to have things insured.. Can you make your boat invisible to lightning by such things as grounding or dissipators.. I dont think so... we can argue this further?
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