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Lightning Anyone?

11K views 32 replies 18 participants last post by  Hudsonian 
#1 ·
Ahoy,
Anyone here ever been in a boat while it was struck by lightning? I plan to live a board next year and always wondered if this is something for me to worry about. All information is valuable.
thanks!
 
#2 ·
Holy Cow!

I lived aboard for what, something like 15 years and sailed through some nasty squalls. Getting struck by lightning was on the list of things I needed to worry about, but it was way the kryst down on that list! You''ll see what I mean.
 
#29 ·
Lightning Protection Systems & Strikeshield system product

See "Lightning & Sailboats" by Ewen M. Thompson.
Sea Grant Project #R/MI-10
Lots of other good web sources are searchable.
Bottom line: BOND EVERYTHING.
Good Luck
Gord
-------------
The link to the Florida University & the lightning research that was created still exists and is really, really helpful to read. (its brief & non technical).

I also just completed a US Power Squadron course on marine electronics which had one brief, but informative, chapter on lightning PROTECTION SYSTEMS. You can't stop a lightning strike but you CAN install a 'system' that provides 99% protection under a "cone." Its a three part system.... all really simple to understand... that works in conjunction with a fourth part called grounding which runs horizontal bow to stern.

The "strikeshield lightning protection system" is a commercial retail after market product that is attached to one's sailboat. I was doing some reading on it. The problem is: it seems to contradict the information from the US Power Squadron text. That is, the conductor running down the mast isn't supposed to jut sideways out over the deck. Lightning wants to do directly downward to ground and if you don't provide a low resistance path, it simply archs or jumps off the path to the path it wants to follow. Right angle turns of the after market system don't seem to be as safe as they imply.

Anyone know of any lightning strikes upon boats using that after market system? I'd bet its better than nothing, but I'm not yet convinced.
 
#5 ·
I can tell you from experience that bonding will not stop a strike and there is no proof that it mitigates the damage.

When a few million volts hits you, there''s not much you can do. Sometimes the damage is minor, sometimes it blows a thru-hull out.

Worrying about it is like worrying about a meteor striking you - there''s not much point.
 
#6 ·
I''d lived in CLearwater, FL for 20 years and seemed like lightning struck everything down there. Power transformers, homes, even Stop signs.. but I''d never heard anyone speak of it hitting a mast or whatever. I do know that some lightning bolts have enough energy to run the city of Chicago for 24 hours so it seems like if you do get hit, you''re out of luck. Anyone else?
--jeff
 
#7 ·
Fourknots, when he says bonding I think he means bonding the mast (and shrouds) to the keel if you have an external lead/iron keel and not necesarily the thru-hulls.

Seperately, the reason you might want to bond the thru-hulls is to prevent their deterioation due to electrolysis or galvanic corrosion, but like you said that has nothing to do with lightning strikes.

BUT, if you were on a boat and your boat got hit with lightning, you (or your loved ones) have a MUCH better chance of not getting hit by the lightning or side-flashes if your mast/shrouds are bonded/grounded.

If you are on a boat, especially a deck stepped one, and the lightning comes down the mast or shrouds and then has nowhere to go (since you didn''t bont it to the keel) then you are just as good a conduit of that electricity as the air is (maybe better!).

To me, that is the best reason to ground/bond the Mast/Shrouds to the keel. (I wouldn''t bond to the thru hulls).

I think the website/article he refernces alludes to that also. Its more for safety IF you do get hit.
 
#8 ·
Protection against lightning is basically to stay neutrally charged. If your mast is aluminum and highly conductive, not a problem as long as it does not emit a "leader" or positive electrostatic charge up into a negatively charged storm cloud. There are two things you do about this: firstly ground out your mast to something substantial and conductive in the water. If the keel is encased in an insulating (electrically speaking) material, grounding to it may not be the best. Note that a lightning strike with poor ground will overcharge all metal in contact and disperse everywhere: this is how the chainplate bolts get popped out of sidestays. The point of contact gets very hot very fast, something sacrificial above the masthead is advised, but not copper or aluminum, they melt easily: try painted ferrous iron. The second part of this is to arrange the boat to have as little static charge as possible: main offender here is going to be wind ripping past sailcloth just before the rains come, creating an ionic charge that is often stored in the mast and boom. Take down all sails when a lightning storm is apparent and check your electrial grounds. The boat should then be close to neutral as the surrounds--or at least as good as it gets. Unplug things electric and sit away from metallic objects. A strike will be proportionate to the attraction of the mast and the negativity of the stormcloud. The strike needs a route from the masthead to saltwater in the shortest path with the least resistance.
 
#9 ·
A point of information...Been sailing offshore many years....been in many lightning storms....some where the night becomes day as the lightning lights up everything like daytime seeing the ocean around you for miles...more severe is when the lightning gets closer (the front)& more intense....instead of just lighting up everything it intensifies so you get a white out...meaning the lightning at first lights up everything...seeing colors of your deck, winches, etc...and then grows in intensity til all color & images are washed out & everything is just super bright white no depth to anything...which at this point you involuntary close and cover your eyes. All of this happens in a matter of 1-3 seconds, which feels like a long time....On one trip from Bermuda to N. Carolina, we encounted a major lightning storm, lightning shooting down everywhere 2, 3, 4, 8 strikes to the water at once over a wide area ...you could see the front (cloud line)on the horizon(north to south,as far as you could see) & coming toward us..it''s amazing how fast it moves. I had a deck stepped mast and decided to disconnect the batteries at the terminals & disconnect all wiring going up the mast..I was thinking if I don''t make any electrical fields, I would not attract the lightning..I had no mast grounding system......as the front got closer the nite turned into day as the lightning strikes lit up the ocean & sky. Again as we merged the white outs began. You could feel the pressure changes on your body as the strikes got closer..the thunder was deafening to a point where it seemed to hurt...the helmsman had rubber gloves on..but not touching the helm..only when needed.(no autopilot w/batteries disconnected)me at the winches port side with storm jib up...We had on our foul weather gear with only our faces showing...at times the wind & pressure came straight down on us..other times being sucked up violently around us...one strike, to this day we don''t know how close...hit fast & hard..causing an immediate white out & the rain on our faces to get so warm we had to wipe the water off our face....As we went thru the front things eased off quickly where we could start breathing again...BUT NO STRIKE!!!....I feel because the mast was not ground the lightning would have to find the mast like in a fog....where a grounded one would have attracted possibly many strikes....Being 200 miles from any landfall I was just glad we didn''t get hit...
 
#11 ·
Ahoy, Me Mateys in all my years I never got struck on a boat or on the water. Then I moved to SW Florida. within thirty days I personally shook hands wit God almighty in a glorious flash of pure white light so beautiful and peacefull I thought at the beginning that, gee thats a strange kind of light? DUH ... The Two wenches sharing me bed at the time came running and although I could see thier mouths moving I couldn''t hear a thing. In fact for those wonderfull moments when I was talking to God.. ohh and by the way he looks more like Albert Einstien than George Burns , .. uhh oh yeah Time stood still . It''s a good thing cause he''s a little slow witted when it come to practical problem solving so it took me a while to answer all his questions,,.. uhh Anyway I wasn''t on the boat and though Me wenches thought me smoking hair and stunned look on me face meant I was dead I didn''t feel nothing. Felt fine in a couple of minutes when the hearing returned and all been well wit me since. De point I suppose youse slow witted mortals may need to hear is this . When God dials your number its best to answer and tell him I said Hello. Pirate of Pine Island. Deckstepped Mast grounded to water by large cables directly over the side to the water. Ugly but effective.
 
#12 ·
Loved your most technical and informative response, I quote you as saying "A strike will be proportionate to the attraction of the mast and the negativity of the stormcloud. The strike needs a route from the masthead to saltwater in the shortest path with the least resistance."
SOUNDS GREAT IN THEORY... however the unexpected can also happen. We were struck by lightning on the stern of our boat while anchored out. We were sitting in the cockpit at the time (no, I wasn''t holding a mast in my hands)... when it struck I dove down the open companionway just as my husband grabbed me by the strap of my bra... to keep me from falling on my head! We laugh about it now... and I think he actually wasn''t trying to help ME as much as he was trying to get me out of HIS WAY to safety! BOTTOM LINE: Be prepared for anything, it can and will happen. Sometime, somewhere. We weren''t injured and the boat was fine... but I''ll never forget that sound and the light show on our stern, it was something like right out of the Twilight Zone!
 
#14 ·
I spent the better part of a year studying static electricity and lightning strikes related to protecting metal buildings and steel towers, back in the mid-80''s, so the memory''s fading a bit--but there were a few things that stick in my mind. Firstly the the flukey and erratic, unpredictable nature of a strike: it does not always strike the highest point. It strikes the most charged point. It needs a "leader" from the object up into the charged atmosphere for the discharge to occur: sometimes in a video you see this, a faint leader reaching upwards before the strike downwards. the leader comes from an electrostatic charge or a source. Remove or reduce these and the strike chances are less. I remember at the time that I was doing all this industrial building protection there was a belief that if you ground out something too well, and put up too many lightning rods on a building, you may end up attracting lightning instead of reducing it. That went resolved. Glad no one got hurt. Wish there was a guaranteed recipe for protection. Does anyone try battery jumper cables overboard and clipped to the shrouds? If so, are they alive to tell the tale?
 
#15 ·
maxcontax,

I have dropped a chain over the side that was attached to a side shroud while I was sailing on my old boat (deck stepped and encapsulated keel). I''m still here, even a few times when in the middle of a storm. I think its just luck....

But forget about attracting or not. I think the REAL good reason for grounding is not about attraction or less attraction, but rather, when it hits the odds are "MUCH" more in your favor of not getting a person on board bZAPPED if you boat/mast is grounded.....THAT is the reason for it IMHO.
 
#17 ·
I have been reading the thread on lightning protection with great interest and am amazed at the amount of misconceptions about the whole thing. Especially the information on lightning "prevention" systems or static dissipaters.
I think that it is safe to say that the information is wide ranging and confusing.
A few things are sure however, and need to be reiterated for the benefit of people wondering.
First of all there is no such thing as attracting a strike. Some individuals think that because they have the tallest mast in a marina that they are more susceptible to a strike or that installing a ground to the mast will increase the likelyhood of a strike. That is simply not true.
Secondly, there is no such thing as preventing a strike. Static dissipaters have been scientificially questioned by the IEEE and there are several papers written by scientific authorities documenting this. Two that are worth reading are:

http://www.strikeshield.com/Lightning%20info/mousaIEEEDissipators.pdf
This first paper was written as a result of a comprehensive study done for British Columbia Hydro on the effectiveness of static dissipaters. Dr. Moussa relied heavily on US data from NASA, the FAA and other scientific authorities.
and
http://www.thomson.ece.ufl.edu/lightning/IEEE.pdf
This paper written by the eminent Dr. Ewan Thomson of the university of Florida basically criticized the ABYC for recommending "seriously inadequate" measures for lightning protection.

All of the lightning authorities agree that there is only one solution to this problem and that is to properly ground ANY structure that is susceptible to a lightning strike and this includes boats. The problem for sailors is that most boat manufacturers DO NOT abide by the ABYC standards which recommend the installation of properly sized conductors to ground lightning energy from the mast to the water.
What are we left with ? Unprotected boats, improperly jury-rigged grounding devices such as chains and booster cables and complete confusion as to what to do.

A few important areas require attention of one is to create a lightning protection system;
Material selection and assembly procedures are quintessential to the success of such systems.
I shudder when I hear of people clamping booster cables to the stays of their sailboats. This is so dangerous !
The cable connectors are improperly sized and offer little contact surface. The result is an exploding vaporized copper clamp.
Using chains wrapped around masts is equally dangerous. The links are highly resistive and can overheat and melt the roof or set it on fire.
This has happened time and time again and yet people still believe that this is an acceptable solution. It is not.

Conductors must be properly sized. Nothing less than a 1/0 multi-stranded tinned copper marine shipboard cable should be used.
Wires must be connected using proper lugs that should be swaged onto the wire with an industrial hydraulic press. The connections should be tinned and then protected with a heat shrink. These methodologies and assembly techniques are used in the power industry. There are UL, ISO, ASTM and IEEE standards with respect to the use of cables for conducting power and they are the result of extensive testing and experience.These methods are the only acceptable methods of building such a system. Hardware store household No.4 wire saddle clamps are inadequate for marine applications.
Electrical connection to the mast must be made through a large contact area. Small clamps and screws or bolts are inadequate for sustaining multiple strikes. Copper parts and components should be tinned for corrosion resistance and to prevent galvanic reactions.
All parts used in the creation of such a system MUST be copper. Not Monel, Not Bronze, Not Stainless Steel or any other less conductive metal. Choosing materials other than copper only adds resistivity to the ground circuit which will cause this material to overheat. This principle is used in electric stoves. Steel wires with high current running through them turn red hot. Same thing will happen to these resistive metals if lightning energy comes through them.
Bonding Bronze Throughulls to the lightning ground is another good method of ensuring the boat sinks in the event of a strike. If the throughulls have lightning energy running through them, the current passing through will heat them up to the point where they may melt the surrounding fiberglass and pop out. Then you will have much more serious problems.
Finally the dissipation electrode in contact with water must be copper (tinned) and offer a large amount of edges as electrical energy will contact with water much more freely through edges than flat areas.

Chris L.
Strikeshield
 
#18 ·
I have been reading the thread on lightning protection with great interest and am amazed at the amount of misconceptions about the whole thing. Especially the information on lightning "prevention" systems or static dissipaters.
I think that it is safe to say that the information is wide ranging and confusing.
A few things are sure however, and need to be reiterated for the benefit of people wondering.
First of all there is no such thing as attracting a strike. Some individuals think that because they have the tallest mast in a marina that they are more susceptible to a strike or that installing a ground to the mast will increase the likelyhood of a strike. That is simply not true.
Secondly, there is no such thing as preventing a strike. Static dissipaters have been scientificially questioned by the IEEE and there are several papers written by scientific authorities documenting this. Two that are worth reading are:

http://www.strikeshield.com/Lightning%20info/mousaIEEEDissipators.pdf
This first paper was written as a result of a comprehensive study done for British Columbia Hydro on the effectiveness of static dissipaters. Dr. Moussa relied heavily on US data from NASA, the FAA and other scientific authorities.
and
http://www.thomson.ece.ufl.edu/lightning/IEEE.pdf
This paper written by the eminent Dr. Ewan Thomson of the university of Florida basically criticized the ABYC for recommending "seriously inadequate" measures for lightning protection.

All of the lightning authorities agree that there is only one solution to this problem and that is to properly ground ANY structure that is susceptible to a lightning strike and this includes boats. The problem for sailors is that most boat manufacturers DO NOT abide by the ABYC standards which recommend the installation of properly sized conductors to ground lightning energy from the mast to the water.
What are we left with ? Unprotected boats, improperly jury-rigged grounding devices such as chains and booster cables and complete confusion as to what to do.

A few important areas require attention of one is to create a lightning protection system;
Material selection and assembly procedures are quintessential to the success of such systems.
I shudder when I hear of people clamping booster cables to the stays of their sailboats. This is so dangerous !
The cable connectors are improperly sized and offer little contact surface. The result is an exploding vaporized copper clamp.
Using chains wrapped around masts is equally dangerous. The links are highly resistive and can overheat and melt the roof or set it on fire.
This has happened time and time again and yet people still believe that this is an acceptable solution. It is not.

Conductors must be properly sized. Nothing less than a 1/0 multi-stranded tinned copper marine shipboard cable should be used.
Wires must be connected using proper lugs that should be swaged onto the wire with an industrial hydraulic press. The connections should be tinned and then protected with a heat shrink. These methodologies and assembly techniques are used in the power industry. There are UL, ISO, ASTM and IEEE standards with respect to the use of cables for conducting power and they are the result of extensive testing and experience.These methods are the only acceptable methods of building such a system. Hardware store household No.4 wire saddle clamps are inadequate for marine applications.
Electrical connection to the mast must be made through a large contact area. Small clamps and screws or bolts are inadequate for sustaining multiple strikes. Copper parts and components should be tinned for corrosion resistance and to prevent galvanic reactions.
All parts used in the creation of such a system MUST be copper. Not Monel, Not Bronze, Not Stainless Steel or any other less conductive metal. Choosing materials other than copper only adds resistivity to the ground circuit which will cause this material to overheat. This principle is used in electric stoves. Steel wires with high current running through them turn red hot. Same thing will happen to these resistive metals if lightning energy comes through them.
Bonding Bronze Throughulls to the lightning ground is another good method of ensuring the boat sinks in the event of a strike. If the throughulls have lightning energy running through them, the current passing through will heat them up to the point where they may melt the surrounding fiberglass and pop out. Then you will have much more serious problems.
Finally the dissipation electrode in contact with water must be copper (tinned) and offer a large amount of edges as electrical energy will contact with water much more freely through edges than flat areas.

Chris L.
Strikeshield
 
#20 ·
in your message you refer to tinned copper as the only substance to take a lightning strike without failure, but what I ask is how is lightning diferent than a spark in a sparkplug and why could you not concider a material with as little resistance as carbon fiber ( the conductor in spark plug wires) if the bonding were to use a carbon fiber conductor you wouldn''t have a problem with excesive voltage heating up the conductor, but your worry would be only the conecton to the mast/rigging and to the grounding plate. please share your thoughts
joey
 
#21 ·
In the summer of 2004 we were in St Pete Florida the capitol of lightning strikes. I had pulled into the Municipal Harbor to the cleanout station and a squal had come in. I was at the wheel and just stood off the dock waiting for the rain and wind to pass. KABOOOOM! my wife was looking out of the companion way at me when it hit. I had just at the exact second turned and without thinking grabbed the back stay to steady myself.It struck a boat shed about twenty yards astern but the branches must have jumped off and hit us. It burned my bare feet and the palm of my hand which was on the backstay. I was not sure if I had ahold of the wheel to or not as I was just sitting at idle.The burns were very minor,the electronics was fried. Every thing on the boat with a printed circuit was zapped and dead or only worked part way. Clock radio had no display but the radio worked. Tv zapped all wind insterments,depth speed ect zapped. Some of the stuff was not plugged in and was still fried.The only possible reason that I was not killed may have been this.We had been in the anchorage and when we pulled the hook a plow it came up with a big wad of mud. Since we were only going agout a mile arount the Pier at St Pete we left the anchor hanging down with maybe six feet of chain from the chock to the shank so the mud would wash off. That could have disipated some of the charge off.I talked to some Navy electronic survalance guys and ask about this and they said that they had hung plates in the water attached to ship masts from chains to take the charge away from the ship. I am thinking about some stainless chain and a couple of round plates so I can just use a d rind to attach them to the stays on both sides of the mast. I am thinking a circle of about 18inches across on a piece of chain long enouhg to get the plate at the same depth as the led or cast iron keel. a piece of thin wall clear plastic tube to keep the chain off the hull. This may or may not help but it makes it a little more grounded.Boats in salt water get hit less than boats in fresh water was something I found out. I don''t know how much being plugged into shore power helps if at all. I worked on a three story house in Colorado quite a few years back as a plumbing contractor. The lightning had struck th roof above the peoples daughters bed. It blew a three foot hole through the roof through the bed went through the floor lifting the hard wood about three inches hit the copper plumbing and blew the fixtures off the wall in two bathrooms ruptured the hotwater tank in the garage and set the place on fire. No one was home luckey for them becaause the daughter spent allot of time sitting on the bed yacking to her gitlfriends on the phone that was melted on a night stand.
 
#23 ·
My 02.
I''ve lived in Florida 56 yrs and on sailboats 10+ along the ICW. Seen many boats struck and talked to people who were onboard or near during the strike. Boats I''ve looked at have had their aluminun masts melted and fiberglass hulls blown to pieces and sunk. Others were everything else from standing rigging bolts punched out to St Elmo''s Fire and no damage. The ones with "grounding wires" hanging into the water from a stay survived way better than those without...always.

When you get hit and it only takes out electronics it is a "feeder" strike. Study the numbers and you will see nothing survives a strike by the main bolt. It blows or melts everything from too much pressure or heat. The is no practical way to conduct that much juice to prevent damage.

The only thing you can do is bleed static charge away and prevent attraction. The highest point will be struck if charged more than the surrounding areas. I put a handheld miliamp meter on an aluminum mast. Everytime the wind gusted the needle pegged showing static charge. The static bled off faster with a grounding wire clamped to the stay and dropped in the water compared to nothing in the water. Anyone can do this test on their own boat to see. An old electrical contractor/sailor showed me this. He did mostly high voltage and lightning protection for buildings and farms.
 
#24 ·
The real reasons to bond the mast, stays, shrouds, and chainplates is to: 1)provide a protective cage for the crew to stay inside; 2) help prevent side flashes, where the current from the lightning bolt jumps laterally between to large metal components and injures or kills anyone standing in the way.

The DC grounding and bonding system for the electronics and through hulls should be separate from the lightning grounding system.
 
#25 ·
shocking.experience

sorry.for.the.periods.again.no.spacebar.
yes.I.was.struck.by.lightning.off.of.chicago.about.2.years.ago.
we.came.through.a.squall.trying.to.get.in.and.were.faced.with.a.horizon.that.was.black.as.coal.
I.sent.everyone.down.below.and.put.on.my.foul.weather.gear.
I.think.we.were.lucky.that.the.boat.was.wet.as.it.spread.the.hit.over.a.larger.space.
It.basically.blasted.my.hands.off.the.wheel.:eek:and.when.I.could.hear.again.I.was.so.glad.to.hear.my.atomic.4.engine.still.running.
We.lost.all.the.electronics.and.anything.plugged.into.the.shore.power.110.system.
At.first.I.thought.it.was.a.near.miss.as.I.saw.the.flash.about.20.yards.off.the.starboard.beam.
I.later.learned.that.the.masthead.was.struck.and.the.bolt.travelled.down.the.starboard.topshroud.and.when.it.got.to.the.imbedded.
chainplate.spat.out.the.hull.leaving.about.a.5.inch.circle.of.delamination.and.a.pellet.sized.hole.out.the.hull.of.the.boat.
Since.then.I.have.read.up.some.and.asked.some.questions.
1...you.need.a.good.ground.from.your.standing.rigging.and.your.mast.and.the.water.whether.it.is.a.plate.on.the.hull.a.direct.connection.
to.an.external.keel.or.(in.my.case).4.10.foot.lengths.of.1/4.inch.chain.and.a.quicklink.which.I.hang.off.of.the.shrouds.on.both.sides.so.if.I.am.
under.sail.I.have.4.points.of.ground.into.the.water.on.both.tacks.
it.deploys.quickly.you.can.have.it.set.up.within.5.minutes.of.spotting.foul.weather.
2...as.for.the.electronics.good.luck.I.have.installed.inline.fuses.on.a.lot.of.stuff.and.set.up.two.separate.fuse.blocks.for.everything.but.
as.I.understand.it.with.lightning.it.can.jump.right.across.the.fuse.block.without.even.noticing.it.has.blown.the.fuse.
I.know.in.my.case.the.old.style.socket.fuseholders.on.my.boat.were.blown.into.the.engine.compartment.like.little.22.bullet.
I.highly.recommend.a.hand.held.vhf.on.board.as.it.may.be.the.only.communication.you.have.after.a.strike.

""lightning.never.strikes.the.same.place.twice....too.bad.I.moved.my.boat""
Eric.Branson
"Zarathustra"
Islander.37
Chicago.Il.
 
#26 ·
While waiting for a squal to pass up in St pete I was at the pump out at the City Marina. I stood at the wheel raining like hell and boom. We were struck it stunned me burned my hand that I had used to grab the back staw to steady myself as I turned to look over my sholder to see where the boat shed behind me was.We lost all our electronics and some things that were sitting on the shelf and were not plugged in. Well the good thing is I am alive. We had our anchor hanging on about five feet of chain to wash the mud off which may have taken some of the current away.
 
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