This is a question I've asked a few people but never got a solid answer to. If caught in a thunderstorm, is your sailboat just a big lighting rod? I'm just curious, how dangerous is to be in a sailboat in a lighting storm? Or, what if I was just hanging out on my boat at the dock, and a thunderstorm approached, would that be dangerous? Thanks, Don
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JAck T Greer
Lightning
Don of NJ I think being out on a sailboat in a electrical storm is about as frightening as seeing White over Red an Green running light at night and hearing the sounds of an engine or being below deaks and hearing five blast on a ship horn. They all make the hair the back of your neck stand up. I live here on the Chesapeake Bay in Virginia where in the summer time there are frequent thunderstorms and electrical storms. I ground my boat by attaching anchor chain to my shrouds putting it overboard. If I have sea room hove to and go below to ride storm out. If I must stay above deck and Helm the boat I stay clear of all metal. Jack
Don of NJ I think being out on a sailboat in a electrical storm is about as frightening as seeing White over Red an Green running light at night and hearing the sounds of an engine or being below deaks and hearing five blast on a ship horn. They all make the hair the back of your neck stand up. I live here on the Chesapeake Bay in Virginia where in the summer time there are frequent thunderstorms and electrical storms. I ground my boat by attaching anchor chain to my shrouds putting it overboard. If I have sea room hove to and go below to ride storm out. If I must stay above deck and Helm the boat I stay clear of all metal. Jack
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MArk
Lightning-proof, NOT!
Don, You can't prevent lightning from striking but you can do things to help you (and your boat) survive. The links below have good information. This one even mentions the effect of water ballast (I hadn't thought of that). Look under the 'trailerable sailboats' link: http://www.marinelightning.com/science.htm More information is on the related link below. Also check the ABYC recommendations. / Happy sails _/), MArk
Don, You can't prevent lightning from striking but you can do things to help you (and your boat) survive. The links below have good information. This one even mentions the effect of water ballast (I hadn't thought of that). Look under the 'trailerable sailboats' link: http://www.marinelightning.com/science.htm More information is on the related link below. Also check the ABYC recommendations. / Happy sails _/), MArk
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Bob
Lightning strike
My buddy Steve took a lightning hit or near-hit in the Chesapeake Bay about 5 years ago in his 28 Columbia. He said just before it happened everything got real quiet and he could feel what seemed to be lots of static electricity in the air. He did not remember its making any sound, which I find amazing, but it fried every piece of electrical equipment on board - replacement/repair costs were about $2500. His insurance paid with no hassle. No other physical damage to the boat occurred, though. I've seen boats that were holed above and below the waterlines (fiberglass) by lightning strikes. Rule of thumb: park next to someone with a taller mast.
My buddy Steve took a lightning hit or near-hit in the Chesapeake Bay about 5 years ago in his 28 Columbia. He said just before it happened everything got real quiet and he could feel what seemed to be lots of static electricity in the air. He did not remember its making any sound, which I find amazing, but it fried every piece of electrical equipment on board - replacement/repair costs were about $2500. His insurance paid with no hassle. No other physical damage to the boat occurred, though. I've seen boats that were holed above and below the waterlines (fiberglass) by lightning strikes. Rule of thumb: park next to someone with a taller mast.
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Tom
You are probably much safer on a sailboat than a
motorboat. Especially if your mast is properly grounded. A properly grounded mast provides a "cone of protection". (Reminds me of the "cone of silence with Get Smart"...LOL) I posted a good link on Lightning and Boats to get you started, If you have Calders book (aka The Bible) on Boat Maintenance it also has a section on it. So basically a properly grounded mast is MUCH safer than standing on the dock (ala Cone Of protection) And the jury is out whether a properly grounded mast or one that isn't grounded attracts more lightening strikes. But there is no doubt that properly grounded mast is safer for you AND the boat if you get struck. I would have to think that NO mast (think row boat in the water) is going to attract much less lightning strikes than a sailboat. BUT if you get hit in that rowboat, you are as good as dead. In the sailboat, most of the people survive . Sort of like the reason buildings have lightning rods on their buildings/houses, etc. Also look here http://www.cdc.gov/nasd/docs/d000001-d000100/d000007/d000007.html
motorboat. Especially if your mast is properly grounded. A properly grounded mast provides a "cone of protection". (Reminds me of the "cone of silence with Get Smart"...LOL) I posted a good link on Lightning and Boats to get you started, If you have Calders book (aka The Bible) on Boat Maintenance it also has a section on it. So basically a properly grounded mast is MUCH safer than standing on the dock (ala Cone Of protection) And the jury is out whether a properly grounded mast or one that isn't grounded attracts more lightening strikes. But there is no doubt that properly grounded mast is safer for you AND the boat if you get struck. I would have to think that NO mast (think row boat in the water) is going to attract much less lightning strikes than a sailboat. BUT if you get hit in that rowboat, you are as good as dead. In the sailboat, most of the people survive . Sort of like the reason buildings have lightning rods on their buildings/houses, etc. Also look here http://www.cdc.gov/nasd/docs/d000001-d000100/d000007/d000007.html
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Bill O'Donovan
Lightning deflector
I have at home a flier from a company that makes a heavy steel clamp that attaches to the mast with two heavy trailing lines to throw in the water. They insist that will deflect the strike into the water and save one's electronics. If you're interested, email me at bodonovan@vagazette.com and I'll dig it out.
I have at home a flier from a company that makes a heavy steel clamp that attaches to the mast with two heavy trailing lines to throw in the water. They insist that will deflect the strike into the water and save one's electronics. If you're interested, email me at bodonovan@vagazette.com and I'll dig it out.
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Dale I
Attract or Disapate...that is the question....
Yup....and I really don't get it either. Its about as confusing as whether to electrically bond every piece of metal in sight as well. Been to the archives regarding both bonding AND lightning....with no resolution it seems. The Hunter that I chartered in St. Pete, (lightning capitol of Florida), had this splayed-out-wire-brush thing at the top of the mast which I took at the time for a sea gull deterant...found out later that it was intended to dissipate the static charge and provide this 'cone of protection'....and the next thing I read is to put up a singular pointed lightning rod to attract it to the boat and somehow steer it to ground with 8" radius' bends in a ground wire.... It would seem logical to me that if 12 sq" was required for a grounding plate that a prudent person would ground every thru-hull AND the keel to a 'static charge defuser' and keep up the zincs just to be on the safe side. Any hard evidence or studies either way? I haven't seen it... (P.S. The boat that I currently own was struck....on the hard in the Cape Canaveral marina yard prior to my purchase...blew a hole out the bottom.... Several others within a 100 yard radius were also rumored to be struck in the yard within a year or so previous...so don't think you're immune just being close in).
Yup....and I really don't get it either. Its about as confusing as whether to electrically bond every piece of metal in sight as well. Been to the archives regarding both bonding AND lightning....with no resolution it seems. The Hunter that I chartered in St. Pete, (lightning capitol of Florida), had this splayed-out-wire-brush thing at the top of the mast which I took at the time for a sea gull deterant...found out later that it was intended to dissipate the static charge and provide this 'cone of protection'....and the next thing I read is to put up a singular pointed lightning rod to attract it to the boat and somehow steer it to ground with 8" radius' bends in a ground wire.... It would seem logical to me that if 12 sq" was required for a grounding plate that a prudent person would ground every thru-hull AND the keel to a 'static charge defuser' and keep up the zincs just to be on the safe side. Any hard evidence or studies either way? I haven't seen it... (P.S. The boat that I currently own was struck....on the hard in the Cape Canaveral marina yard prior to my purchase...blew a hole out the bottom.... Several others within a 100 yard radius were also rumored to be struck in the yard within a year or so previous...so don't think you're immune just being close in).
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MArk
Deflect
Hi again, After reading the related link and the pdf file on the 'technical literature' connected link, two things are apparent: 1. You can't prevent lightning from hitting your boat so your only alternative is to dissipate to reduce the chances of a strike and deflect the ones that do hit into the water with minimal damage to your crew, boat and electronics. 2. A one square foot grounding plate is not sufficient to prevent side flashes in fresh water. MArk
Hi again, After reading the related link and the pdf file on the 'technical literature' connected link, two things are apparent: 1. You can't prevent lightning from hitting your boat so your only alternative is to dissipate to reduce the chances of a strike and deflect the ones that do hit into the water with minimal damage to your crew, boat and electronics. 2. A one square foot grounding plate is not sufficient to prevent side flashes in fresh water. MArk
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Tom S.
Mark, you basically got it. (Long & informative)
Bill O, the deflector you described from that company sounds like it could work. But I have a question. What is at the end of those two heavy trailing lines to you throw in the water? It better be a large area of metal (like a 2 square feet of copper), if its just the ends of the copper cable it is not helping as much as it could. As for the statement that "they insist that will deflect the strike into the water and save one's electronics." Well that happens to be a pretty bold statement for something that is not physically capable of doing, and I'll explain why below. If they make a statement such as that, do they back it up with money or an insurance policy? Will they pay for the electronics that "blow" when using their product? I bet they don't. ---------------------------------------------------------------------------- Well it works something like this (I will over simplify it ....so any engineers need not get too crazy if not 100% accurate --- yeah yeah...Amperes Law...Maxwells equation, et.al.).... When the lightning current travels down the mast (or whatever) It creates a HUGE electromagnetic field (typically at right angles to the current)........That HUGE electromagnetic field is then picked up *THROUGH THE AIR" by all different sorts of wiring or metal throughout your boat. Thus that induced HUGE Electromagnetic field is then turned into current again in the (supposedly) completely isolated wiring of your delicate electronic circuits........Yes all those tiny little circuit boards and electronics are picking up that HUGE magnetic field and converting it to current in those tiny little circuits AND typically it is WAY more current than the electronic circuits can handle. (This is the same general principal in how alternators/generators work----current in induced into parallel windings of wire......they are not touching it just is induced across the air gap) So why do some electronics blow and not others....Well there are many factors but I will list 2 variables. 1) Strength of Lightning -- Obviously the stronger the strike--- the more the current ---- which means stronger EMF (Electromagnetic Field) induced. 2) Orientation of Lightning Path to delicate wiring in Electronics. More current will be induced across when these two conductors are parallel. (The source lightning path and the pickup electronic wiring...internal & external wiring) I really don't think you have any say in this...the orientation and wiring are in all sorts of different axis and I think its just luck how it might end up . Though in a "perfect" world a wire perpendicular to the conductor for lightning will pick up little to no EMF thus very little current) That is why some things blow and some things *appear* to be still working..... PLEASE NOTE: Just because something *seems* to work does not mean it is 100%. The Induced lightning could have caused some slight damage to the instrument that does not "completely knock it out"...There is a very good chance of premature failure being induced. So this explains why Electronics can blow : A) EVEN IF your Boat was not struck but the one a slip or two away got the direct hit. A) EVEN IF your Boat in *completely* bonded and set up to take a lightning strike B) EVEN IF your VHF Antenna is not connected C) EVEN IF your electronics are disconnected at the time of the strike C) EVEN IF your electronics are 20 feet away from the apparent strike....(obviously the further away the less induction of current) The only way to *really* protect anything in lightning strike is to put the whole device into what people call a "faraday shield"....(Basically a completely enclosed metal box), this way the EMF "rolls" around the outside surface of the box and does not induce current on the inside. Respectfully yours Tom S. Stamford, CT (BTW --- this was once the desired way to start a nuclear strike.....Drop a Nuclear bomb over the area about a mile up and it would create such an EMF that it would knock out all the electronics and telecom in the area to create havoc......then they would drop the next one....Boom!...........They also made this EMF happen in Vegas to temporarily knock out the lights in that new movie "Oceans 11" with George Clooney and Brad Pitt...etc....cool movie....lol) Take a look at the link below
Bill O, the deflector you described from that company sounds like it could work. But I have a question. What is at the end of those two heavy trailing lines to you throw in the water? It better be a large area of metal (like a 2 square feet of copper), if its just the ends of the copper cable it is not helping as much as it could. As for the statement that "they insist that will deflect the strike into the water and save one's electronics." Well that happens to be a pretty bold statement for something that is not physically capable of doing, and I'll explain why below. If they make a statement such as that, do they back it up with money or an insurance policy? Will they pay for the electronics that "blow" when using their product? I bet they don't. ---------------------------------------------------------------------------- Well it works something like this (I will over simplify it ....so any engineers need not get too crazy if not 100% accurate --- yeah yeah...Amperes Law...Maxwells equation, et.al.).... When the lightning current travels down the mast (or whatever) It creates a HUGE electromagnetic field (typically at right angles to the current)........That HUGE electromagnetic field is then picked up *THROUGH THE AIR" by all different sorts of wiring or metal throughout your boat. Thus that induced HUGE Electromagnetic field is then turned into current again in the (supposedly) completely isolated wiring of your delicate electronic circuits........Yes all those tiny little circuit boards and electronics are picking up that HUGE magnetic field and converting it to current in those tiny little circuits AND typically it is WAY more current than the electronic circuits can handle. (This is the same general principal in how alternators/generators work----current in induced into parallel windings of wire......they are not touching it just is induced across the air gap) So why do some electronics blow and not others....Well there are many factors but I will list 2 variables. 1) Strength of Lightning -- Obviously the stronger the strike--- the more the current ---- which means stronger EMF (Electromagnetic Field) induced. 2) Orientation of Lightning Path to delicate wiring in Electronics. More current will be induced across when these two conductors are parallel. (The source lightning path and the pickup electronic wiring...internal & external wiring) I really don't think you have any say in this...the orientation and wiring are in all sorts of different axis and I think its just luck how it might end up . Though in a "perfect" world a wire perpendicular to the conductor for lightning will pick up little to no EMF thus very little current) That is why some things blow and some things *appear* to be still working..... PLEASE NOTE: Just because something *seems* to work does not mean it is 100%. The Induced lightning could have caused some slight damage to the instrument that does not "completely knock it out"...There is a very good chance of premature failure being induced. So this explains why Electronics can blow : A) EVEN IF your Boat was not struck but the one a slip or two away got the direct hit. A) EVEN IF your Boat in *completely* bonded and set up to take a lightning strike B) EVEN IF your VHF Antenna is not connected C) EVEN IF your electronics are disconnected at the time of the strike C) EVEN IF your electronics are 20 feet away from the apparent strike....(obviously the further away the less induction of current) The only way to *really* protect anything in lightning strike is to put the whole device into what people call a "faraday shield"....(Basically a completely enclosed metal box), this way the EMF "rolls" around the outside surface of the box and does not induce current on the inside. Respectfully yours Tom S. Stamford, CT (BTW --- this was once the desired way to start a nuclear strike.....Drop a Nuclear bomb over the area about a mile up and it would create such an EMF that it would knock out all the electronics and telecom in the area to create havoc......then they would drop the next one....Boom!...........They also made this EMF happen in Vegas to temporarily knock out the lights in that new movie "Oceans 11" with George Clooney and Brad Pitt...etc....cool movie....lol) Take a look at the link below
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