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Thread: Lightning protection for a wooden boat with dyneema standing rigging

  1. #1
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    Default Lightning protection for a wooden boat with dyneema standing rigging

    Dear forumites,

    as some of you may know my 34ft wooden cutter is taking shape slowly. Once again I am pondering over the question of lightning protection, seeming to be somewhat complicated as I would like to go with dyneema as material for the standing rigging, and therefore having no natural current conducting connection from the mast top to the chain plates or to the bowsprit via steel wired shrouds. As having an external conducter along the mast from top to the mast step is no option (main sail lacing) it seems I am left with 2 options only:

    1: Running a lightning rod / band from the mast top along 1 or 2 dyneema shrouds to the chain plates connected to the lead keel, or
    2: Running a lightning rod inside the wooden mast to the step and on to the lead keel.

    Am I missing an option here? If not: What is the right choice?
    Last edited by zauberberg; 07-11-2018 at 05:41 AM. Reason: Readability
    Thomas
    -----------------------------------
    panta rei

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    From what I've read, these are all bad ideas. Running your ground wire inside anything is hazardous. If you really feel you must use dyneema, then you're likely best off with the old fashioned rod to bronze sailtrack to mast step to with as little kink as possible a keel bolt that has contact with a plate in the water.

    Lead does not really do much as a ground.

    Be sure that everything on the mast - lights, radio antennae, et cetera - can be disconnected and seperated from the mast by a few feet. Or enjoy buying new stuff.

    That will not meet the modern standard that amounts to a gauss cage, but you might at least not sink.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Buy insurance for your boat that covers lightning and sinking, not much else will matter if you're hit.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Hi Thomas,

    We are in a similar situation, and what I have done is run a lightening conductor (2/0 AWG) inside a laminated mast. It's exits via solid copper - a rod on the top and a big tab to take a lug on the bottom. I did this for both our main and mizzen. It was a bit of work, but I feel more comfortable with a proper conductor over my head.

    Cheers,
    Mark

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Mark0 View Post
    Hi Thomas,

    We are in a similar situation, and what I have done is run a lightening conductor (2/0 AWG) inside a laminated mast. It's exits via solid copper - a rod on the top and a big tab to take a lug on the bottom. I did this for both our main and mizzen. It was a bit of work, but I feel more comfortable with a proper conductor over my head.

    Cheers,
    Mark
    I'm starting a small boat, but this is what I'll be doing too. A strike may damage the mast, it may even send it to splinters, but as long as the hit doesn't make my body part of the circuit I'm fine with making a new mast.

    An extensive study some years back found that a boat is not more or less likely to be hit if it has lightning protection, but the damage is almost always more severe without it.
    -Dave

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Lightning is a crap shoot.
    Like electrolysis, It's mostly theory that sometimes works differently in the actual world.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Mark0 View Post
    Hi Thomas,

    We are in a similar situation, and what I have done is run a lightening conductor (2/0 AWG) inside a laminated mast. It's exits via solid copper - a rod on the top and a big tab to take a lug on the bottom. I did this for both our main and mizzen. It was a bit of work, but I feel more comfortable with a proper conductor over my head.

    Cheers,
    Mark
    So its inside the mast, thank you, Mark and Dave. Most probably everything that is on top and inside of the mast then will be destroyed then in case of lightning. What are you doing to protect the rest of the systems on board? Do you disconnect as a routine all mast running lines in case of a thunderstorm on the boat or when leaving the boat?
    Thomas
    -----------------------------------
    panta rei

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    I would consider a wire fore stay, if your having hank on sails or a roller, both will come under a certain amount of chafe, and a length of chain going over the side. The idea of a conductor inside the mast i find quite frighting, can you imagine the kind of splinters being thrown in all directions from an exploding spar? No thanks. One stay from wire is a small price to pay, given the amount of work in the alternatives, and the risks,IMHO.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by skaraborgcraft View Post
    I would consider a wire fore stay, if your having hank on sails or a roller, both will come under a certain amount of chafe, and a length of chain going over the side. The idea of a conductor inside the mast i find quite frighting, can you imagine the kind of splinters being thrown in all directions from an exploding spar? No thanks. One stay from wire is a small price to pay, given the amount of work in the alternatives, and the risks,IMHO.
    This is a clever variant that didn't come to my mind, thank you very much. I indeed have a hanked on staysail, and the topic of chafe there to a dyneema stay already was another point of concern.

    So the implementation would consist of a lightnig "antenna" on the mast top, a mast external copper rod to the forstay mast band (no interference there to main sail lacing), and then probably a somehow clamped / screwed connection directly to the SS forestay. Hopefully the only one SS wire can do the job.

    The chain you are talking of probably is attached constantly to the forstay and thrown over board when leaving the boat or when under way and a thunderstorm is approaching? One could probably also connect the forstay to "boat earth", or would you expect the chain solution giving better protection to the on board systems?
    Thomas
    -----------------------------------
    panta rei

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Hi,

    I'm wondering why folks feel a mast would splinter with a lightening strike with a conductor inside ? There certainly won't be enough heating/expansion to cause such a violent result - in my case the 2/0 AWG is WAY over sized. Trees explode with the current flowing in the moisture and the higher resistance causing heating and expansion.

    I personally wouldn't want to be taking actions during a storm like dangling a chain overboard.

    Cheers,
    Mark
    Last edited by Mark0; 07-12-2018 at 03:33 AM.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by wizbang 13 View Post
    Lightning is a crap shoot.
    Like electrolysis, It's mostly theory that sometimes works differently in the actual world.
    No. It's a crap shoot if you get hit or not, but when you do get hit it's well understood and the risk can be mitigated.

    Cheers,
    Mark

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging


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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by zauberberg View Post
    This is a clever variant that didn't come to my mind, thank you very much. I indeed have a hanked on staysail, and the topic of chafe there to a dyneema stay already was another point of concern.

    So the implementation would consist of a lightnig "antenna" on the mast top, a mast external copper rod to the forstay mast band (no interference there to main sail lacing), and then probably a somehow clamped / screwed connection directly to the SS forestay. Hopefully the only one SS wire can do the job.

    The chain you are talking of probably is attached constantly to the forstay and thrown over board when leaving the boat or when under way and a thunderstorm is approaching? One could probably also connect the forstay to "boat earth", or would you expect the chain solution giving better protection to the on board systems?
    To be honest, i have only ever carried a length of 10ft chain to hook onto whatever shround or backstay is suitable at the time, and i never used it, generally because i had one of the smallest boats in at an anchorage or mooring and a far shorter mast than those around me. Only once between mainland Spain and Ibiza did i get surrounded by lighting storms, but never close enough for me to get the chain out.
    Maybe a 12-16% moisture content of a hollow spar is enough to avoid catastrophic explosion.....i dont know. I felt a chain over the side might have been better than having a bonded system, especially on a ferro-cement boat, i have heard stories of the armature being blown apart, but if true, i do not know. I have always had minimal electrics, so nothing to concern being "knocked out" in a possible strike. Certainly a subject worthy of looking into, but not one i have lost sleep over.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    The old theory of a run down the mast and straight through the keel to a discharge plate has been largely replaced by designs that are more like a Gauss cage.

    Since Meg has conventional ss rigging and external chainplates, I ran the chainplates for the main and mizzen uppers to a bit below the waterline and provided a horizontal discharge plate there. The lifelines make a ring connection completing the Gauss cage.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    This is the 2011 NFPA standard. There is a 2017 edition but I believe this section is unchanged.

    Chapter 10 Protection for Watercraft10.1 General.10.1.1 The intent of this chapter shall be to provide lightning protection requirements for watercraft while in water.

    http://gost-snip.su/download/nfpa_78..._lightning_pro

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Mark0 View Post
    No. It's a crap shoot if you get hit or not, but when you do get hit it's well understood and the risk can be mitigated.

    Cheers,
    Mark
    I don't think this is 100% true, the risk can be mitigated however what can go wrong will. 100,000 Volts can be unpredictable.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Ian McColgin View Post
    The old theory of a run down the mast and straight through the keel to a discharge plate has been largely replaced by designs that are more like a Gauss cage.

    Since Meg has conventional ss rigging and external chainplates, I ran the chainplates for the main and mizzen uppers to a bit below the waterline and provided a horizontal discharge plate there. The lifelines make a ring connection completing the Gauss cage.
    Interesting stuff. What does a horizontal discharge plate look like? Just a bit of steel flat bar?

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    From the Boat US article: "The grounding point should be a corrosion-resistant metal plate installed on the exterior of the hull below the waterline. The plate should be at least one square foot in size and at least 3/16 of an inch thick. Research shows that most of the electrical discharge occurs along the edges, so a long, narrow plate, especially one with grooves cut in it, will be most effective at dispersing the charge. A new major point of contention is where to install the grounding plate, or plates. Some research indicates that a location at or near the waterline is by far the most effective solution"

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    My boat has a copper water pipe running inside the laminated mast which is grounded to the lead keel. Shrouds or stays may not be very useful even if they are wire since most standing rigging is stainless, and stainless is not a very good conductor (relative to copper or aluminium)... but maybe better than nothing. Whatever you use for a ground, the bigger the surface area the better.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Mark0 View Post
    No. It's a crap shoot if you get hit or not, but when you do get hit it's well understood and the risk can be mitigated.

    Cheers,
    Mark
    As we see here,several experienced mariners concour on very little on this subject.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    "there has been strong disagreement between professionals about the best way to mitigate damage in a lightning strike and precious little data to support one point of view over another.*The sometimes-raucous debate surrounding certain unproven lightning- protection devices and such theories as "fuzzy" lightning dissipation terminals and early-streamer emission terminals, as well as unorthodox placement of grounding terminals (a.k.a. grounding plates), have sharply divided the recreational boating technical community, all of which makes consensus on lightning protection difficult, if not impossible."

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Would not a well set up lightning grounding plate attached to a rod at the top of the mast invite a lightning strike?

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Electrolytic damage to the wood under a grounding plate is a very real concern. I have seen boats that required several new planks due to severe deterioration under a copper plate. This gets worse when you mix stainless wire, aluminum spars, bronze fasteners, lead keels, copper connecting wire....

    I have cast iron ballast, and am loathe to connect heavy copper wire to my keel bolts. Perhaps a large knife switch that is closed only when on board and otherwise left open could isolate the system enough.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Geftb View Post
    Would not a well set up lightning grounding plate attached to a rod at the top of the mast invite a lightning strike?
    No. A survey of boats hit by lightning shows that a grounding system does not change the odds of being hit. But those not grounded had more severe damage, including sinking.
    -Dave

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by J.Madison View Post
    Electrolytic damage to the wood under a grounding plate is a very real concern. I have seen boats that required several new planks due to severe deterioration under a copper plate. This gets worse when you mix stainless wire, aluminum spars, bronze fasteners, lead keels, copper connecting wire....

    I have cast iron ballast, and am loathe to connect heavy copper wire to my keel bolts. Perhaps a large knife switch that is closed only when on board and otherwise left open could isolate the system enough.

    But what happens when the boat his hit when unattended? No one around to mitigate. Plus the risk of more extensive damage is real.
    -Dave

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by J.Madison View Post
    Electrolytic damage to the wood under a grounding plate is a very real concern. I have seen boats that required several new planks due to severe deterioration under a copper plate. This gets worse when you mix stainless wire, aluminum spars, bronze fasteners, lead keels, copper connecting wire....

    I have cast iron ballast, and am loathe to connect heavy copper wire to my keel bolts. Perhaps a large knife switch that is closed only when on board and otherwise left open could isolate the system enough.
    You could put in a gas discharge arrestor or other similar surge protection devices to isolate until a high voltage incident.

    Cheers,
    Mark

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by wizbang 13 View Post
    As we see here,several experienced mariners concour on very little on this subject.
    Nope. Just folks on a Wooden boat forum. There are bodies of scientists and engineers that have developed standards and best practices.
    How often do you hear of an aircraft taken out by a lightening strike ? I can't recall one in my lifetime. There are strict guidelines and testing required, and it works.

    Cheers,
    Mark

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    I saw a boat that had been hit , a diesel powered 40' fishing boat, off Bermuda, hit while actually fishing.
    5 dudes aboard were knocked unconscious for 5 to 10 minutes. Several had burns from the batteries that exploded and the plastic that melted off EVERY wire on the boat.
    The freakin diesel KEPT RUNNING!.
    About 4 holes were BLOWN out or the topside planking. Biggest was at the transom where the fuel tank was. All were above the waterline.
    Guys came back into St Georges , where they all got very drunk that night on Black Seal.
    Open my eyes to what a strike can do .

    Id be afraid of that grounding plate blowin a hole in the planking , yea , I know what it's SUPPOSED to do .

    ...And I've also seen some nasty business under those plates, mostly put on there for SSB radios.

    I do not have the answer , I barely have a strategy... Poop and Pray... has worked so far.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Woxbox View Post
    But what happens when the boat his hit when unattended? No one around to mitigate. Plus the risk of more extensive damage is real.
    Very, very unlikely in my area. In harbor, boats in the PNW are almost never hit. Sailing, way out in the middle of the straights or offshore seems like the only real risk to me.

    This part of the country doesn't really have much lightning.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Mark0 View Post
    Nope. Just folks on a Wooden boat forum. There are bodies of scientists and engineers that have developed standards and best practices.
    How often do you hear of an aircraft taken out by a lightening strike ? I can't recall one in my lifetime. There are strict guidelines and testing required, and it works.

    Cheers,
    Mark
    These scientists and engineers building and sailing wood boats? Apples and Oranges ...boats and planes .

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Woxbox View Post
    No. A survey of boats hit by lightning shows that a grounding system does not change the odds of being hit. But those not grounded had more severe damage, including sinking.
    There would have to be a thousand variables in such a survey.
    Poop and pray will do for me also. If my time ends with a lightning strike while sailing then that's not such a bad way to go.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Man, another thing to worry about......

    https://learn.weatherstem.com/module...ons/36/02.html
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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    Quote Originally Posted by Mark0 View Post
    Nope. Just folks on a Wooden boat forum. There are bodies of scientists and engineers that have developed standards and best practices.
    How often do you hear of an aircraft taken out by a lightening strike ? I can't recall one in my lifetime. There are strict guidelines and testing required, and it works.

    Cheers,
    Mark
    How many airplanes get hit? How does one ground an airplane? Show us some real numbers of airplane lightning strikes. You totally ignore the quote I posted btw.
    Last edited by navydog; 07-11-2018 at 08:33 PM.

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    When it comes to small boats and lightening protection there are many views and not much agreement. However, look to protection on buildings and we see lightening protection pretty much sorted. High rise buildings get hit often, and the occupants will not even be aware. So, I ignored all the small boat commentary, read all I could about systems used for buildings, then applied that information to my boat. In essence the message for buildings seems to be, really heavy duty conductor (eg. copper cable) and big ground (plate, or mesh buried in the soil), and at the skyward end is a spike or sphere (both seem to work fine).

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    Default Re: Lightning protection for a wooden boat with dyneema standing rigging

    My concern is having an aluminum mast and stainless rigging. The mast will be the conductor and there needs to be a path from the mast to the water that doesn't include a hole in the hull under the maststep.

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