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byron
RIP
Re: Lightning Strike
<font color=blue>I think, the EPIRB being a seperate item from the vessel's circuitry will be OK. Having said that if it attached to say a guard rail... then I really don't know.
An interesting question Fatipa and one I shall look forward to seeing a definate answer to.
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<font color=blue>I think, the EPIRB being a seperate item from the vessel's circuitry will be OK. Having said that if it attached to say a guard rail... then I really don't know.
An interesting question Fatipa and one I shall look forward to seeing a definate answer to.
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Roberto
Well-known member
Re: Lightening Strike
Electronics can be fried by the current passing through them or their components be ruined by the electromagnetic field created by the sudden change in current.
At least in theory, if you disconnect them (antennas too) and keep the wires sufficiently away, plus you put the instrument in a grounded metal box there should be a slightly higher probability of saving them. All of this is often not practical to do though.. Epirb? if it is sufficiently away from all internal cabling carrying the em field, it might be saved, but I think with lightning stuff there is hardly any certainty apart danger.
I have been struck once, the first things I saw after being blinded by the light were bits of plastic on fire falling from the masthead, two neverending seconds of panic before realising the mast was still in one piece and just the antenna was gone..
The vhf was fried, we could smell a smokey flavour in the cabin too, the compass kept turning round for a few minutes before stabilising again, a portable radio (with its own batteries, and switched off) was gone too. We had no gps at the time so can comment on it.
The boat had a cable connection from the mast base to a keel bolt, the insulation near the crimp had melted so I suppose it helped in some way.
Two people were sleeping on sailbags on the floor, not far from the mast, they answered ok when we called them from outside.
What I have now is a double connection from the mast base to the keel, no grounding of stays or shrouds. Maybe it has no other effect than on my peace of mind..
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Electronics can be fried by the current passing through them or their components be ruined by the electromagnetic field created by the sudden change in current.
At least in theory, if you disconnect them (antennas too) and keep the wires sufficiently away, plus you put the instrument in a grounded metal box there should be a slightly higher probability of saving them. All of this is often not practical to do though.. Epirb? if it is sufficiently away from all internal cabling carrying the em field, it might be saved, but I think with lightning stuff there is hardly any certainty apart danger.
I have been struck once, the first things I saw after being blinded by the light were bits of plastic on fire falling from the masthead, two neverending seconds of panic before realising the mast was still in one piece and just the antenna was gone..
The vhf was fried, we could smell a smokey flavour in the cabin too, the compass kept turning round for a few minutes before stabilising again, a portable radio (with its own batteries, and switched off) was gone too. We had no gps at the time so can comment on it.
The boat had a cable connection from the mast base to a keel bolt, the insulation near the crimp had melted so I suppose it helped in some way.
Two people were sleeping on sailbags on the floor, not far from the mast, they answered ok when we called them from outside.
What I have now is a double connection from the mast base to the keel, no grounding of stays or shrouds. Maybe it has no other effect than on my peace of mind..
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tome
New member
Re: Lightening Strike
Most likely the masthead gear will fry together with connected equipment (VHF, wind instruments etc). It's highly unlikely that rail mounted gear (GPS, Navtex etc) will be hit and almost impossible for a standalone EPIRB or handheld VHF to suffer.
All IMHO, haven't any direct experience...
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Most likely the masthead gear will fry together with connected equipment (VHF, wind instruments etc). It's highly unlikely that rail mounted gear (GPS, Navtex etc) will be hit and almost impossible for a standalone EPIRB or handheld VHF to suffer.
All IMHO, haven't any direct experience...
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Gunfleet
New member
Re: Lightening Strike
Keep handheld vhf and spare gps in a tin box and it will work as a Faraday cage. Army ammo boxes should work a treat. There will be quite a few available soon, I think.
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Keep handheld vhf and spare gps in a tin box and it will work as a Faraday cage. Army ammo boxes should work a treat. There will be quite a few available soon, I think.
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wayneA
New member
Re: Lightening Strike
<blockquote><font size=1>In reply to:</font><hr>
Being in the middle of a lightening storm really is about the only part of sailing which makes me wish I wasn't out there so any other stories/comments on lightening strikes welcome.
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Sorry, not much info on the EPIRB, but this site <A target="_blank" HREF=http://www.thomson.ece.ufl.edu/lightning/>http://www.thomson.ece.ufl.edu/lightning/</A> has to be one of the best sources of info on lightening protection for boats.
Hope it helps
Wayne
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<blockquote><font size=1>In reply to:</font><hr>
Being in the middle of a lightening storm really is about the only part of sailing which makes me wish I wasn't out there so any other stories/comments on lightening strikes welcome.
<hr></blockquote>
Sorry, not much info on the EPIRB, but this site <A target="_blank" HREF=http://www.thomson.ece.ufl.edu/lightning/>http://www.thomson.ece.ufl.edu/lightning/</A> has to be one of the best sources of info on lightening protection for boats.
Hope it helps
Wayne
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poggy
New member
Re: Lightening Strike
Hi,
It will largely depend on how new the equipment is and how your boat is laid out. Lightning will find the shortest route to ground and if it can't find a direct route then it will try and jump any insulator. Modern electronics need to meet CE marking which as long as they are not directly connected to the source of lightning (i.e aerial) means they have to withstand a certain amount of EM inteference. As far as sticking things in metal boxes, this may not always work as a faraday cage has a earth point to provide a very easy route for the energy, which you won't really have on a boat, this makes it slightly weaker and also the item would have to be insulated within the box to work (i.e not metal touching of the item touching the box).
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Hi,
It will largely depend on how new the equipment is and how your boat is laid out. Lightning will find the shortest route to ground and if it can't find a direct route then it will try and jump any insulator. Modern electronics need to meet CE marking which as long as they are not directly connected to the source of lightning (i.e aerial) means they have to withstand a certain amount of EM inteference. As far as sticking things in metal boxes, this may not always work as a faraday cage has a earth point to provide a very easy route for the energy, which you won't really have on a boat, this makes it slightly weaker and also the item would have to be insulated within the box to work (i.e not metal touching of the item touching the box).
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oldharry
Well-known member
Re: Lightening Strike
I'm no expert Poggy, but I remember BBCs Tomorrows World demonstrating how a car works as a faraday cage when struck by lightning. They managed to persuade some bloke to drive a car around under a high voltage source which flashed over to the car every time it drove beneath it! The driver was completely unharmed, but eventually the discharges fried the cars electronic ignition module.
My point is that: a) it didnt save the electronics, and b) the driver was entirely safe because of the faraday cage effect, although it was not earthed being on rubber tyres.
I also remember reading of a Panda Car being struck by lightning a few years ago. 2 Young bobbies scared witless but OK, but the car tyres all burst - presumably from the heat of the flashover as the charge jumped from the wheel rims.
I guess theres not an awful lot can be done to preserve electronics in a ligthning strike situation - theyre just too vulnerable.
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I'm no expert Poggy, but I remember BBCs Tomorrows World demonstrating how a car works as a faraday cage when struck by lightning. They managed to persuade some bloke to drive a car around under a high voltage source which flashed over to the car every time it drove beneath it! The driver was completely unharmed, but eventually the discharges fried the cars electronic ignition module.
My point is that: a) it didnt save the electronics, and b) the driver was entirely safe because of the faraday cage effect, although it was not earthed being on rubber tyres.
I also remember reading of a Panda Car being struck by lightning a few years ago. 2 Young bobbies scared witless but OK, but the car tyres all burst - presumably from the heat of the flashover as the charge jumped from the wheel rims.
I guess theres not an awful lot can be done to preserve electronics in a ligthning strike situation - theyre just too vulnerable.
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poggy
New member
Re: Lightening Strike
Hi,
Your quite right, a car will be quite safe in lightning. I think the reason for this is that a car is one big metal structure which can transfer the energy to the wheels quite easily and then to ground by arcing across the tyres.
The problem with a boat is that it will have a huge amount of water around it (with a contact to earth) and if it is GRP not a lot of conductors apart from the metal bits. This is likely to cause a number of paths through the metal parts as it tries to dissipate the energy, including the electronics.
A plane will not suffer much from lightning as there is no way for the current to route to earth, much like birds sitting on high tension lines or the special suits that the electrical workers wear.
It would be interesting to know what would happen if a boat is in salt free water with a very low general mineral content as the electrical conductivity would be much less and therefore maybe the lightning would not find an earth to travel to.
I worked at a Philips advanced development labs in Holland for a year with a Faraday cage and a huge generator to induce inductive lighting it metal halide lamps. The metal halide lights were placed in between huge plates insulated from the cage but connected to the generator to create a filed.
One day I was using a insulated probe through the cage to measure the light and I slipped slightly causing an arc to the cage. There was a huge explosion as the lamp blew apart as it received the full amount of energy. Never made the mistake again, but it me a while to get my hearing back.
Poggy
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Hi,
Your quite right, a car will be quite safe in lightning. I think the reason for this is that a car is one big metal structure which can transfer the energy to the wheels quite easily and then to ground by arcing across the tyres.
The problem with a boat is that it will have a huge amount of water around it (with a contact to earth) and if it is GRP not a lot of conductors apart from the metal bits. This is likely to cause a number of paths through the metal parts as it tries to dissipate the energy, including the electronics.
A plane will not suffer much from lightning as there is no way for the current to route to earth, much like birds sitting on high tension lines or the special suits that the electrical workers wear.
It would be interesting to know what would happen if a boat is in salt free water with a very low general mineral content as the electrical conductivity would be much less and therefore maybe the lightning would not find an earth to travel to.
I worked at a Philips advanced development labs in Holland for a year with a Faraday cage and a huge generator to induce inductive lighting it metal halide lamps. The metal halide lights were placed in between huge plates insulated from the cage but connected to the generator to create a filed.
One day I was using a insulated probe through the cage to measure the light and I slipped slightly causing an arc to the cage. There was a huge explosion as the lamp blew apart as it received the full amount of energy. Never made the mistake again, but it me a while to get my hearing back.
Poggy
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oldharry
Well-known member
Re: Lightening Strike
I do love these posts on lightning strikes in boats - they appear regularly on these forums (forae?), and some of the remdies proposed are - shall we say - unusual!
My favourite was from a guy who had suffered a ligtning strike of the American E coast, and having himself and crew received quite severe shocks from metal fittings, suggested that we should protect all our extremities with rubber - wellies rubber gloves, wellies, and for the gentlemen a certain other rubber item.....
This lead to the proposal that we fit wellies over our mastheads to reduce the possibility of lightning strike. which inevitably led us to wondering whether messrs Durex made a mast head sized one !!!
My own preparations for sever thunder conditions are stay at home, or if its too late put at least six feet of anchor chain over the side, in the (probably folorn) hope that by providing a nice straight direct path down the forestay into the water, the main charge will follow that, and not try to blast its way through the hull.
At least it makes me feel better that I have done SOMETHING...
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I do love these posts on lightning strikes in boats - they appear regularly on these forums (forae?), and some of the remdies proposed are - shall we say - unusual!
My favourite was from a guy who had suffered a ligtning strike of the American E coast, and having himself and crew received quite severe shocks from metal fittings, suggested that we should protect all our extremities with rubber - wellies rubber gloves, wellies, and for the gentlemen a certain other rubber item.....
This lead to the proposal that we fit wellies over our mastheads to reduce the possibility of lightning strike. which inevitably led us to wondering whether messrs Durex made a mast head sized one !!!
My own preparations for sever thunder conditions are stay at home, or if its too late put at least six feet of anchor chain over the side, in the (probably folorn) hope that by providing a nice straight direct path down the forestay into the water, the main charge will follow that, and not try to blast its way through the hull.
At least it makes me feel better that I have done SOMETHING...
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poggy
New member
Re: Lightening Strike
You would need a very large welly to fit all down the mast and it would need to be a deluxe version with really thick rubber. I think the best option is to stay at home as you say or connect a huge lead from the mast base over the side into the water and watch the fish float to the surface ready to eat.
I suppose it would charge the batteries pretty quick though.
Poggy
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You would need a very large welly to fit all down the mast and it would need to be a deluxe version with really thick rubber. I think the best option is to stay at home as you say or connect a huge lead from the mast base over the side into the water and watch the fish float to the surface ready to eat.
I suppose it would charge the batteries pretty quick though.
Poggy
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J_Priedkalns
New member
Re: Lightening Strike
I have had a "near" strike whilst on board; the dock my boat was attached to was vapourised, but no damage to my boat or myself, electrics or electronics. The noise and the horrendous flash was ubelievable! A friend in Florida was on the hard in a marina doing maintenance when he got struck whilst he was still in the boat below decks. He was not injured but his boat had several holes punched where the metal tripod support pads had been located. It doesnt matter what the coductivity of the fresh/salt water is; if your boat is not grounded you will end up with holes in your hull. A couple of production boats at our yacht club on the Great Lakes were hit at their docks, the manufacturer had installed proper grounding wires but had not connected them to the lead keel. The boats sank due to a large number of small holes made by lightening at the waterline!
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I have had a "near" strike whilst on board; the dock my boat was attached to was vapourised, but no damage to my boat or myself, electrics or electronics. The noise and the horrendous flash was ubelievable! A friend in Florida was on the hard in a marina doing maintenance when he got struck whilst he was still in the boat below decks. He was not injured but his boat had several holes punched where the metal tripod support pads had been located. It doesnt matter what the coductivity of the fresh/salt water is; if your boat is not grounded you will end up with holes in your hull. A couple of production boats at our yacht club on the Great Lakes were hit at their docks, the manufacturer had installed proper grounding wires but had not connected them to the lead keel. The boats sank due to a large number of small holes made by lightening at the waterline!
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J_Priedkalns
New member
Re: Lightening Strike
We had a "near" strike whilst sleeping onboard our boat; the finger dock that our boat was tied to was vapourised! No injuries to ourselves, boat, electrics or electronics. The noise and light show was horrendous! A friend of ours in Florida was struck whilst being on the hard for some maintenance. He was aboard at the time and was not injured. His boat suffered some damage in the areas of the hull where the tripod pads were supporting the boat. There were several small holes at each pad and on the concrete on which the boat was standing. The boat remained upright and with some electrical damage. It doesn't matter if the boat is in fresh/salt water it will get damaged if it is not grounded. We had two boats at our yacht club struck by lightening whilst being secured at the dock. The boats were properly wired for grounding, but the manufacturer forgot to attach the grounding wire to the lead keels. The boats sank due to thousands of little holes punched through along the entire length of the waterline. On our boat we had installed a grounding system which connected every major metal item such as rigging, tanks, engine, pulpit, pushpit, stanchions, windlass, winches etc to one major point in the keel below the mast support and through the hull to a large bronze plate. The size of the copper wire used was 6AWG.
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We had a "near" strike whilst sleeping onboard our boat; the finger dock that our boat was tied to was vapourised! No injuries to ourselves, boat, electrics or electronics. The noise and light show was horrendous! A friend of ours in Florida was struck whilst being on the hard for some maintenance. He was aboard at the time and was not injured. His boat suffered some damage in the areas of the hull where the tripod pads were supporting the boat. There were several small holes at each pad and on the concrete on which the boat was standing. The boat remained upright and with some electrical damage. It doesn't matter if the boat is in fresh/salt water it will get damaged if it is not grounded. We had two boats at our yacht club struck by lightening whilst being secured at the dock. The boats were properly wired for grounding, but the manufacturer forgot to attach the grounding wire to the lead keels. The boats sank due to thousands of little holes punched through along the entire length of the waterline. On our boat we had installed a grounding system which connected every major metal item such as rigging, tanks, engine, pulpit, pushpit, stanchions, windlass, winches etc to one major point in the keel below the mast support and through the hull to a large bronze plate. The size of the copper wire used was 6AWG.
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G
Guest
Guest
Re: Lightening Strike
It usually helps to reduce weight, or does fatipa refer to lightning?
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It usually helps to reduce weight, or does fatipa refer to lightning?
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richardandtracy
New member
Lightening Strike on Steel
Are there any steel boat owners who've had a strike? I'd be particularly interested if you've got a metal mast.
Regards
Richard
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Are there any steel boat owners who've had a strike? I'd be particularly interested if you've got a metal mast.
Regards
Richard
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tonyleigh
New member
Re: Lightening Strike
Yacht next to me on trots in Chausee hit last summer. Experience as you suggest. Radar, radio, lights and all mast linked gear frazzled. GPS (pushpit aerial) unaffected. Crew, sleeping inches from deck stepped mast woken up (!!!) but unharmed. Most chilling was to disconnect wires and have powder run out and no sign of wire itself! Sorry, no epirb carried.
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Yacht next to me on trots in Chausee hit last summer. Experience as you suggest. Radar, radio, lights and all mast linked gear frazzled. GPS (pushpit aerial) unaffected. Crew, sleeping inches from deck stepped mast woken up (!!!) but unharmed. Most chilling was to disconnect wires and have powder run out and no sign of wire itself! Sorry, no epirb carried.
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