Gizmo’s halo, hello Lightning Electrotechnologies
We’ve had a run of interesting new products this week, but this may be the topper. That cast-aluminum “wheel” — wrapped with I’m not sure what and threaded for a stainless steel masthead mount that’s grounded to a Dynaplate — is a new lightning protection technology called a Streamer Inhibitor from a new company called Lightning Electrotechnologies. I’ve posed it with the Lightning Master Static Dissipater which generated a fair bit of skeptical commentary when I took it off Gizmo’s masthead last summer. The Inhibitor seems to be related to the Dissipater, but different. Understanding lightning and how you might avoid it is very challenging, and I have yet to form strong opinions one way or another…
What I’m hoping is that some of the scientists, engineers, and all-round geeks out there study what Lightning Electrotechnologies is up to and give us all some feedback. The best starting point, I think, is the company’s Inhibitor brochure PDF, downloadable here. A little more fun is the testing video shot at an amazing High Voltage Laboratory in Quebec. There are more L. E. technical publications here, and do check out the impressive credentials of chief scientist Dr. Farouk Rizk.
Now I get a kick out of trying to wrap my head around concepts like Glow-Mode Corona (see the brochure), but I’m most taken by Lightning Electrotechnologies’ analysis of what the 35cm Inhibitor will do for Gizmo, which I’ll paraphrase to some degree:
The attractive radius of your mast without any protection is 69.68m. This means that essentially there is an imaginary cylinder around your mast that has a radius of about 70m and any lightning that falls within that cylinder will attach to the boat. Assuming of course that there are no other boats or masts within that 70m radius. With an Inhibitor installed the attractive radius of your mast is reduced to 23m.
…{Given a generous Maine lightning activity level of 4 strikes per square kilometer per year} without an Inhibitor you can expect your boat to receive 1 strike every 11 years; with an Inhibitor the expectation becomes 1 strike every 99 years. If you find yourself in South Florida…your uninhibited boat could expect one strike every 2.7 years…with inhibitor every 25 years.
Those are attractive numbers, if true, and Gizmo is apparently not ideal for an Inhibitor because her mast is somewhat short relative to her length. In fact, LE may replace the 35cm version with a 60cm ring. Full production has not yet begun, by the way, but these inhibitors are expected to sell for a few hundred dollars. So what do you all think…wasted money or interesting new protective device?
Incidentally, LE tells me that the radio interference purportedly generated by brush-style lightning dissipaters during stormy conditions does not occur with the Inhibitor. But if I understand Glow-Mode Corona correctly, the halo effect might be something to see.
I find this stuff extremely hard to evaluate, most especially because I’ve never seen a credible boat-specific study that compares various lightning protection techniques in the real world.
Of the information available online, I find the explanations of Marine Lightning Protection Inc. most persuasive, but that’s perhaps because they are simply the best at explaining their point of view and contextualizing the evidence that supports it.
MLP are particularly negative on lightning dissipators — at least the “bottle brush” type, noting:
“Perhaps the reason why these devices are still popular is the rave reviews they get from the telecommunications industry. When a dissipator is at the top of a telecommunications tower on a mountain it does appear to lower the incidence of lightning strikes that originate at the tower, that is, upward lightning. Unfortunately, this is only applicable to this type of lightning, which is not the type that predominantly strikes boats, or other structures on a flat earth.”
I have no connection to MLP. http://www.marinelightning.com/
/afb
We (Lightning Electrotechnologies) are very familiar with the work of Dr. Ewen Thompson and Marine Lightning Protection. In fact we first discussed the use of this new technology on boat masts with Dr. Thomson before anyone else in the industry, perhaps as long ago as two years. I don’t want to speak on his behalf but in my personal discussions with Dr. Thomson, he did have a favourable reaction to this new technology and I hope to collaborate with him on future projects. I have sent Dr. Thomson a link to this article and invited him to personally join the discussion.
thanks
It would be great to have both LE and MLP involved in this discussion. Thanks!
/afb
The percentages sound incorrect to me.
Are in fact 11% of the friends you know with boats in Maine getting struck every year? Is it even 1% every couple of years?
Also I’d be asking how many of those 4 strikes/sq km/year are even hitting the ground or water, vs cloud to cloud strikes. The design concept and electrical performance and performance against simulated lightning may or may not be good but I think it has to be better calibrated against ground truth.
Firstly, the concept of a ground flash density simply means that within a square km in a certain region there is a historical probability of a certain number of lightning flashes to ground per year, this is excluding cloud to cloud flashes. So that could be strikes to man-made structures, boats, the ground itself, the water, a person… anything that lies within that square km. These figures are tabulated based upon observation over time and they vary from region to region . Southern Florida being one of the regions with the highest flashes to ground in the US (google the concept). The figure we chose of 4 flashes /sq-km per year was high for the coast of Maine, which is where Gizmo is usually located.
Details about the calculations below but please note that we qualified our figures with the note that those calculations are made with the assumption that there are no other masts nearby (please see quote in article). It is an assumption that leads to the highest of safety margins. But the reality is that boats are often stationed in groups, in marinas and such particularly during storms and so even when you have very high rates of lighting incidence, the fact that you don’t actually have a single boat alone within each square km changes the numbers and therefore they don’t coincide perfectly with the stats as per your example. However if you check the statistics on insurance claims for boats in Florida I suspect you will be surprised as to the amount of damage. I imagine that sometimes when one boat is hit, ones that are very nearby can also suffer damage, particularly to the electronics.
For more information on the basis of our calculations, (which incidentally are the recommended lightning strike distance equations for power transmission towers and power lines as per the Electric Power Research Institute EPRI as well as inclusion in IEEE Standard 1243) I invite you to our website: http://www.lightningelectrotechnologies.com, there you will find a number of peer reviewed publications in reputable scientific journals (IEEE Transactions on Power Delivery and Transactions on ElectroMagnetic Compatibility) that are the basis of our calculations. Essentially they are based on the height of the mast with due consideration to any shielding provided by the body of the craft and the perspective return stroke current of an impending flash.
thanks.
I have a Hinkley Halo (TV antenna). This hoop would make the birds very happy as they have two levels to sit, chat, and poop on the deck :^)
Seriously, I have the fuzzy static disapator. I’m not sure it would really work better or worse.
So far (knock on teak) I haven’t be struck by anything that is noticable. We are based in the Chesapeake.
Although we didn’t give the leisure preferences of birds any consideration in the design of these electrodes, I can assure you that our Inhibitor electrode would indeed work much better than the fuzzy dissipators. The fuzzy dissipators are prone to the production of streamer discharges (St. Elmo’s Fire) just as much as any antenna or any other object would be prone to the production of those discharges when placed at the top of a tall mast under thunderstorm conditions. In fact some proponents of these dissipator device will actually show you laboratory demonstrations wherein these devices are producing visible, audible onset streamer discharges (St. Elmo’s Fire). These discharges are the precursor to an upward connecting leader from the mast, which then attaches to the descending stepped lightning leader and results in a direct lightning strike. As I hope you can see from the demonstration video referenced above, the Inhibitor, unlike the control test object or absolutely anything else, including fuzzy dissipators, is not prone to the production streamer discharges, it in fact suppresses them, no audible, visible discharges. Furthermore it raises the leader inception voltage of the mast, meaning that it increases the voltage required to breakdown the laboratory gap. These are things that no fuzzy, dissipator brush device could ever do.
Since the fuzzy static dissipators are prone to the production of streamer discharges, they can’t be expected to reliably suppress them and thus they do little to nothing to affect the probability of the mast from launching an upward connecting leader. Although under certain conditions, i.e. an extremely high ambient ground field (slow varying field due to cloud charges before appearance of descending lightning leader), under such circumstances prolonged streamer discharges from the fuzzy dissipator and other things at the top of the mast during that first stage of the slow varying field, immediately prior to the appearance of the descending lightning leader, such conditions can cause the upward connecting leader to start from the side of the mast, somewhere below the top, or from something very close by to the dissipator at the top of the mast like an antenna.
thanks.
Our 40′ sailboat was hit last July in Miami, took a direct hit either to the Lightning Master Static Dissipater and or the VHF “Digital” antenna. The antenna was blown off the mast, the Static Dissipater was “Charred” some of the brush was melted. All electronics were damaged, even those handheld battery powered devices not wired into to the boat and we had a lot of electronics installed. Many other boats in the marina sail and power suffered damaged electronics, but not total wipe out as we did. Insurance coverage took care replacing all the items… I did put back a new Static Dissipater for all that it did or did not do in this particular storm.
You really need to mount some old throttle levers up alongside this
thing : )
Thanks for this info. From your account I would guess that it was the antenna that took the direct hit. Had the dissipater taken that strike those brush wires would have surely vaporized or splattered as molten metal. The fact that only some of the brush was melted suggests that currents that ran through it were not from the return stroke current (direct hit) but were of the induced type. Especially considering the damage caused to nearby boats, it must have been a big strike with a large current.
Another important distinction between those types of dissipators and our Inhibitors is the capability of our device to take a strike. Inhibitors do not eliminate the probability of a lightning strike, they merely reduce the chances by reducing the masts attractive radius and so logically the support structure is specifically designed to sustain lightning currents and meets all international standards as a Class II lightning Air Terminal. Also the Inhibitor coil is exactly that, a coil, and so it has an inductance and since the lightning return stroke current is a high frequency current, it does not pass through the coil and is carried almost entirely by the robust support toroid (wheel).
If you send us some photos and info on the dimensions your craft we’d be happy to quote you on an Inhibitor.
I know that “lightning doesn’t strike twice” is a myth…but what about the famous “It’s been pre-disastered!” theory expressed in Life According to Garp? Here’s the scene from the movie:
http://www.youtube.com/watch?v=DBSAeqdcZAM
we have a 40′ sailboat with 50′ tall mast what product would be recommended? Contact me off list at: [email protected]
I’ve no connection with this site or this guy, but there’s an interesting (but perhaps not definitive) podcast about lightening here:
http://furledsails.com/article.php3?article=676
I have no illusions about the fuzzy dissipator changing the inexorable result of a huge thunderstorm’s and the sea/land’s edge charge differentials being blocked by man’s intervention.
However, I believe (as contrasted to know) that the benefit comes form the reduction of micro discharges which would otherwise cause problems to masthead devices and the boat’s systems in general.
I have less faith, but more hope, that the dissipator will reduce the likelihood of minor strike.
I’m waiting for a product that doesn’t have to explain its failures.
Lightning is sentient. It makes decisions to resolve it’s difficulties. It has no rules, but it does seem to resent the presumtions we have about it.
What I have learned from the Discovery Channel is that a model rocket trailing a thin copper wire can initiate a discharge of the potential threat; once done there is no threat from that Cloud or crowd of clouds,and _that_ is a solution in my mind. How many rockets can I buy for the price of one lightning strike in the wrong place?
That was hilarious!
However I don’t subscribe to the philosophy. The probability that a structure will be hit by lightning is strongly related to physical parameters, like height and where its located and the structure’s likelihood of launching upward connecting leaders. The fact that a structure has been hit before is probably just in an indictions of its vulnerability and it is in no way a safety measure. You know the CN tower in Toronto gets hit 70 to 80 times per year. And I’m sure that there are some really tall TV towers in Florida and other places around the world that get hit even more then that.
So in the context of the movie clip, I think Robin Williams should have first checked to see if the backyard of that house was at the end of an airport runway before he made his calculation!
On the other hand, if the probability of some event is extremely remote, then once it happens, I guess it is true that the probability of two such events happening in succession is even more remote. So I suppose that once a particular canoe, in a crowded marina full of super yachts, gets hit by lightning, you can be pretty sure that won’t happen again. although i’d be suspicious if any such canoe actually did get hit in first place, it might be haunted. lol
Indeed there is nothing we can do can alter the thunder storm, nor can we do anything to influence where and when a descending leader will make its appearance. However, the grounded object, the boat mast in this case, does play a role in an individual strike. It launches an upward connecting leader to meet the descending leader, this is what determines what specifically gets hit. Although it has no influence on whether there will be a strike in the area or not. We see the boat as an electrode and we are altering its discharge performance characteristics
Rocket triggered lightning is almost always an example of an upward flash, the lightning originates from the wire that trailed the rocket and rises up to meet a center of charge in the clouds. Much like the type of lightning that is generated by very tall towers, and so it would offer much the same type of protection.
thanks.
I just can’t bring myself to look at the pdf.
Look at that thing. How badly would that interfere with the accuracy of our wind vane’s or ultrasonic wind sensoros, obscuring VHF antenna’s, obscuring masthead lights, etc. Even if I figured out how to make it all play nice together, I wouldn’t be so fond of the additional weight on the top of the masthead impacting sail performance.
The percentages also sound incorrect to me, as someone wrote above. “Are in fact 11% of the friends you know with boats in Maine getting struck every year? Is it even 1% every couple of years?”
I have commented on and explained the quoted percentages above and we stand by them. As to the compatibility with other equipment at the top of the mast, our primary consideration here was to affect the mast’s electrical performance and interaction with lightning, surely there will be trade-offs. However, the devices are made from anodized aluminum and they don’t weigh that much, just a few pounds. And surely the very best in lightning protection is not for everyone and not for every vessel.
Lightening protection is a hideously complex subject, that is complicated by nature’s vagaries. I live in south Florida, and I find, via my repair requests, that the split between sailboats being struck, and power boats is about 50/50. I know it is counter intuitive, but this is my experience. In large marinas, one vessel can be struck, and adjacent vessels can sustain damage greater than the struck vessel. Lightening that gets on the marina’s ground system, can be devastating also, and a large number of lightening claims are caused by collateral damage from another vessel being struck. Size doesn’t seem to matter, I have repaired damage on 75 footers, and Boston Whalers, and on average I do about 3 boats per year. I have also repaired boats that had the “bottle brush” thingy properly installed. Entry points for the lightening is almost always on something pointed, ie VHF antennas, and they seem to be favorites. With regards to lightening protection, the best insurance, is good boat insurance. I have never had an insurer balk at a repair bill, and for many owners this means brand new state of the art electronics. I think lightening strikes boats because it can, and for the same reason, tornado’s seem to like mobile home parks. I did a little piece last year on a boat that was in an electron avalanche if you are interested. http://themarineinstallersrant.blogspot.com/2009/12/oh-watch-out-for-that-electron.html
Fascinating article, I had only ever heard the term “electron avalanche” used to refer to a process that happens at the molecular/atomic level. When electrons begin to be ripped from neutral air molecules, in groups or clusters (avalanches) leaving behind ions…. More specifically, a “critical electron avalanche” is the start of a streamer discharge.
The fact that there was a storm nearby suggests that the boat could have been exposed to high ambient electric fields. But the fields required to produce those symptoms would, as you correctly point out, typically be associated with lightning activity, ongoing and very nearby. a very strange case.
As to your personal experience, I’m particularly interested in you observation about actual attachment points or entry points in your repair jobs.
You say its almost always something pointed i.e. VHF antenna, just how pointed are these things, are they sharp or rounded at the top, how thick are they? Also, are they hit at the very top of the antenna or somewhere below the top, even just a few inches below the top. Its important to know how high off the water they were in the particular cases you are describing, height of mast if possible.
You say its 50/50 between power boats and sailboats, what is the sample population, are there generally 50/50 sailboats and power boats in marinas? I would expect that things that are taller not necessarily bigger are getting hit more.
I am very interested in your experience and may have more questions, please reply directly to [email protected],
thanks
Amir, thank you for the comments, and I am apologizing for the Lightening typo, I guess I was inadvertently trying to “lighten” the conversation. My observations are strictly empirical in nature. VHF antennas are very pointed, and most are sheathed in fiberglass with the antenna wire going all the way to the top. I think that coronal discharges, ie St Elmo fire/electron avalanche activities favor streaming off of pointed objects, for reasons I am not clear about, and hence become the target for the strike when the circuit is completed. I have never seen a strike directly on a boats deck, or hardtop. That doesn’t mean it can’t happen, but have not seen it.
A few of the recent boats I have repaired are:
Carver Marquis/Searay
60′ sailboat to starboard of the Carver was struck with the entry point being a Shakespeare 4200 3′ SS mast mounted antenna. damage on the sail boat was minor, in relative terms, and damage was confined to air conditioning control boards, and a Raymarine E120 system. Exit point was the fiberglass sheathed keel (blew a hole about quarter sized out) Current jumped onto a Carver Marquis, and did about $70K worth of damage. (4 E120’s, sounder module, network switch inverter/charger, two additional battery chargers et al). The boat to the starboard of the sailboat, a 39′ Searay had the Caterpillar digital displays destroyed, and some minor additional damage. The marina lighting system was damaged indicating current also got onto the marina shore power system, and there may have been additional damage I am not aware of. I understand from observers present it made quite the bang.
Boston Whaler 305 Conquest
During a thunder storm, owner and family anchored in Sarasota Bay, and went below (very smart move by the way). Engines were idling (2 Verado’s), and generator was running. Lightning struck the VHF antenna (Shakespeare 5225 XT) and blew the top half off. Exit point was the port Verado lower unit. Owner and family survived unscathed, but it took some time to get over the event. Vessel was towed in after a cell phone call for help. All electronics on the boat were destroyed, including engines, Nav systems, generator, AC system. The fuse panel had exploded, and there was wire harness damage. Repair cost was $65K
Cruisesr 35
Entry point was the VHF antenna, no exit point was found, although the marina ground system was suspected. The basin had smaller boats, and most were not plugged in. Damaged limited to nav instruments, air conditioning controller, refrigerator, stereo, and TV’s.
Amir, I am not an expert, but more like the paramedic who shows up after the accident. When you keep seeing T-boned cars, at the same intersection, you start to get a sense of what is happening.
Pointiest, highest, best grounded, or combinations of all of them, I don’t have the expertise to tell.
My best guess is that sailboats are about 20% of the vessels in the area, and I actually do less sailboats, than power boats. There seems to be a random factor here. I think a good subject to think about might be a lightning tower protection system for marinas, where most boats seem to live together. It may be better to provide a first class target for lightning in a marina,or basin and protect a lot boats at once. A large number of lightning repairs also come from local strikes (ground waves) getting onto the marina’s shore power systems. I will forward via E-mail a report I wrote for the local marina regarding the electron avalanche incident. Tnx Bill
A ham radio operator who worked for the state power company once told me that the trick to lightening protection was grounding. All of their towers were well grounded by, among other things, pouring salt into the holes in the ground they were mounted. But rather than passing an actual strike to ground, the towers, being well grounded, tended to suck free electrons from the surrounding air. With the air close to the tower having fewer electrons and thus more electrical resistance to ground than other surrounding air, lightening tended to take the path of least resistance and not hit the tower. In essence the grounded tower created an electrical vacuum. In his view, there was no way to safely carry the current of a strike, only to avoid it happening.
However, for this to work, there must be a very good ground. And that is very hard to achieve on a boat, particularly as, I’m told, lightening can act like RF, which likes copper strips rather than round wires.
I really think the only way to protect against a strike is to disconnect the antennas and put your electronics, including batteries, in a Faraday cage.
Good grounding is indeed essential to good lightning protection, for a number of reasons. The most obvious being that the current associated with a particular lightning strike is a predetermined characteristic of that particular strike. So the resistance of the lightning protection system will determine the voltage that appears on the system. The lower the resistance, the lower the voltage. But the problem in the case of a boat with a mast (in addition to the inherent grounding problems on water, especially fresh water) is that even when such a system works perfectly and it conducts the lightning current to ground, although you’ve likely avoided any damage to the body of the craft, the fact that such a large current was “safely” conducted down a single conductor in the center of the vessel, this will create huge electromagnetic fields that can destroy electronics. This is why boats that are merely near ones that were struck directly can be damaged.
So the Inhibitor, which must be properly grounded, can receive and safely conduct the lightning current to ground (The Inhibitor is designed to meet all international standards as a lightning air terminal), but in addition to this it tries to limit the number of strikes by reducing the masts ability to launch an upward connecting leader. Please see our brochures and our web site for more on the details of the physics of a lightning strike.
Improving the grounding for a reasonably well grounded tall communication tower should not have any influence on its ability to ionize the air around it under under intense electric fields nor should it influence the tower’s probability of being hit, however and depending on the sensitivity of the installed electronics, it may make most lightning strikes to those towers seem practically unnoticeable. Do they have some sort of lightning strike detection system installed or is it just that no damage has been registered?
You are correct about lightning’s preference for “strips” rather than “round wires”. But our understanding is that things that produce cylindrically shaped electric fields, like the ones you’d find around long wires or conductors are, under the same conditions, less prone to producing leader discharges (please see our web site) than are things that have spherical electric fields, like the electric fields produced at the top of a mast or a rod or tower.
correct again, where ever possible the Farady cage is the only 100% solution, in this case since you are in a conducting cage and all the current is carried around you instead of next to you, you are shielded from the intense electric fields and the current is also safely conducted to ground.
thanks
What about metal boats? I have a 40ft steel trawler with a 24ft steel mast. I’ve never been hit. I understand that grounding is important. Am I correct in the assumption that the entire boat is a giant, grounded, electrical conductor?
I can understand the need for grounding strips, etc. on fiberglass vessels because they act as insulators , but do the same rules apply to steel vessels?
If the body of the boat is made of steel and it is well bonded to a steel mast then yes, you can’t really get much better than that as far as grounding is concerned. However, if stuck by lightning although the structural integrity of the boat itself is quite safe, the electronics and any people on board may still not enjoy the experience.
thanks
When I worked for BellSouth in their cellular division they put the dissapators on all of their cell towers in Florida. At one point they swore by them. Not sure if there was any empirical data behind this decision. Just another data point.
There is a scientific basis as to why point discharge devices (brush dissipators) can have an influence on very tall structures. However this mechanism is sporadic and hard to control. We go into some detail about this in our brochures and web site. See the term “lightning rod self-protection” in our brochures and the IEEE peer reviewed publication “Lightning Exposure of Sharp and Blunt Rods”. The performance of an Inhibitor in the same conditions will be superior and more consistent.
I’d really appreciate it if you could give me some contact info of anyone at BellSouth who is involved in Lightning protection. Please email me personally [email protected].
Thanks.
PS Meant to note that I used that tall picture above because it shows off Gizmo’s new Fortress FX-55 anchor. While anchoring is certainly better understood than lightning, there’s still lots of argument about which ones are best. When Panbot Allan Seymour told me he was trying to get rid of the Fortress (at a super reasonable price), I checked it out pretty carefully. My best sources gave the design a big thumb’s up, and this one is certainly sized for serious second anchor situations. The shank is almost 4 feet long, though the total weight is still 32 pounds. Thank you, Allan!
Adam,
Unfortunately I don’t think MLP/ Dr. Thomson will be joining our discussions, not for any technical reasons but rather more for marketing/commercial reasons. However if you want an Inhibitor installed on your boat, MPL will do that for you but they will not install any brush type dissipators. Hopefully that will give you some indication as to their relative scientific credibility.
thanks
Bill,
About ten years ago we took a hit aboard our Tashiba 40 in Oyster Bay, Long Island. If I remember correctly one sailboat was the target and had blackened and burned masthead. The cluster of boats around him showed less damage. One J-24 had dozens of very small holes in the hull. Our boat showed no damage at first, however, once we got underway for a sail I found the GPS, laptop, and instruments not working. It looked to me like our damage came in through Ground and not from the mast head.
As a result I installed the expensive mast mounted brush thing and lightening suppressors on the coax cable for whatever good it might do. “IF” it works – Great! And, I do believe lightening can strike the same place twice.
Ben – we were in contact with Amir Rizk, V.P. Lightning Electrotechnologies more than a year ago to represent a similar product here in South Florida. Lighting is certainly an issues here and my own boat was in fact hit a few years back. But what we found is that boat owners would not want to spend the amount of money it would cost to purchase and have our professional team of Marine Electronics Techs install it correctly. Also sailors did not want to add the weight to the top of the mast. It is for these reasons we did not distribute the product nor have any installations. The science may support this but the pocketbook does not. Now if it was required by insurance that would change drastically.
Jeffrey Schwartz, Director of our Marine Division at JS Consruction 2 Miami.