Does it Make any Sense to Install a "Lightning Dissipator"?

From what I've read, lightning dissipation systems are ineffective at preventing a lightning strike. The amount of charge dissipated is insignificant compared to the charge in the lightning bolt.

If it's going to hit, your best bet is to give it a harmless path to ground.

http://stormhighway.com/protection.php

http://lightningsafety.com/nlsi_lhm/charge_transfer.html

Lightning dissipation systems do work. They can be very expensive systems to properly design, let alone implement. It all depends on your local terrain and soil conditions. Very often the deep rooting tree line (i.e. oak) above your roof elevation will make a roof lightning rod a waste of money. Then there are structures so prone to a direct lightning strike that a system with plasma ball exhaust vents must be added to prevent or limit what needs to be repaired.

"... cause I wanted to had lightning rod/s installed only places roof. " Please read: ON MY PLACE´S ROOF

In good sail boats the mast is grounded (to the water) with a wide copper strip to the (massive steel) keel, just to make it easy(ier) to get rid of the energy. It is better than letting a lightning strike find its way through (more or less conductive) other parts (your personal yourself included when you are in the boat).

We are talking about 12 cm wide and 1 mm thick, bolted to the bolts that hold the keel.

10 pieces M16 (stainless steel)

A proper grounding system is necessary on boats, both external and internal protection is required....Although a trawler is at less risk of being struck than a sailboat, there still is a risk, also depends on type of electronics you have....

http://www.trawlerforum.com/forums/#maintenance-systems

http://www.trawlercrawler.net/viewtopic.php?f=8&t=327

https://shearmadness72.com/about/lightning-strike/

http://www.yachtingmagazine.com/fire-sky

Yes but even on Jack-Ups drilling [with legs bonded to hull] a strike near would take out some electronics, especially the CCTV systems. Installed dissipators and filters, helped maybe.

Just re-read your post and there are some issues I would like to discuss: The metal (steel) mast is painted with good quality 2 components polyurethane paint, being fixed to the keelson by means of a latch pin. The only truly exposed parts are the SS stays... but conductivity of these components is not good because of the paint acting as an isolator. Should I link the mast to the deck by means of a copper cable?

In the event of a lightning strike, the current will run trough the hull, and from there to the water trough the 2" propeller shafs and propellers, as these structures are grounded. So, what sense would it make to put additional chains into the water, considering that the anchor is already linking the boat to the riverbed by means of a 1/2" chain?

It might be a good idea to improve the conductivity between your mast and sea. You have a misunderstanding about the goal of a dissipator. A dissipator is trying to prevent a local lightning strike from happening. A dissipator will not help at all if a local strike still happens.

Hi, no misunderstanding at all. I have decided NOT to install a dissipator... but was wondering if the mast should be well connected to the hull "just in case". I understand that entire structure of the boat will act as a Faraday cage; and that it is very likely that all the electronics get toasted in that event.

The best form of lightning protection is a KrisDel Certificate of electrical compliance.
Lightning bolts will see the certificate if it is prominently positioned and turn tail and run immediately
Del

(This idiocy is based on a story in our local press where some idiot blamed lighting damage on the fact that the house electrics hadn't been certified by a qualified electrician!)

<...lighting damage on the fact that the house electrics hadn't been certified by a qualified electrician...> That is understandable, however it is up to the home owner to engage the correct individual to install the lighting and to obtain certification.

<...blamed...>

When the finger of blame points away from the body, look at where the other three are pointing.

Any lightning installation is intended to provide a preferred path for the discharge so as to offer a measure of protection to non-preferred paths. A boat's mast is a prominent electrode pointing upwards and in the expanse of a large body of water forms a preferred path for the discharge as it is closer to a charged cloud than the water. It makes sense to ensure protection by providing a reliable conductive path so as to provide a measure of protection for the non-preferred paths, which include the rest of the boat and the people on it, which can also be considered cloud-pointing electrodes.

Nuff said?

I have been around experts that had proof that lightning dissipators do work. I have been around experts that had proof that lightning dissipators do not work. Most of these experts had a financial interest in supporting their position. I don't have a clue to the real truth but the scale of the cloud is so huge that I have a hard time seeing how an economical collection of one or more dissipators will be effectively different than a single point on a lightning rod. Just my guess, I don't know.

I have never heard an expert state that lightning rods weren't highly effective (best not to assume 100.0000% perfect). As Brave Sir Robin pointed out, the 100,000 ++/-- amps of current flowing through the lightning rod system creates huge E & H fields. Just because the lightning rod "works" doesn't mean that any of your electronics will work.

Lightning is a bit like a firearm. When it comes to human safety, take safety precautions and then conduct yourself in the storm as if no safety precautions have been taken.

My parents' motor ketch got hit many years ago when they were aboard at anchor. It vaporized the VHF antenna at the mast head. That was the only visible damage to the boat. However, every bit of electronics, whether it was plugged in or not was non-operational, including battery operated electronics. If there was even a remote chance of lightning, my dad would put chains in the water from the stays when at anchor even though the masts were bonded to the keel.

Haven't heard from you in awhile. How is your project boat coming along? Were you able to get away this past summer?

I have seen the items on some Amateur Radio towers, LILCO (Long Island Lighting COmpany) had some on several of their towers in the late 90's. I have never seen them on a corporate owned TV or commercial tower like cell phones use.

My understanding is if your system (boat) is well grounded the charge will dissipate before reaching flashover potential. However, I've seen more than one sky to ocean lightning strike.

Back in the old days before steel belted tires, static caused by static electricity was annoying on the AM radios. A ball was affixed to the end of the antenna to dissipate the buildup. It worked for the relatively low voltage static charge, I see no reason why it wouldn't work in a larger form. As strikes are quite rare, I doubt there is any valid empirical evidence.

Hi, thanks for your interest! :-) This project started 2 years and 3 months ago (my wife counted each second, and it is a miracle she has´t left me so far!). The boat is ALMOST ready (yes, I know boats are NEVER 100% ready) to get into the water... but as it is in a large commercial wharf and currently cornered by large barges I have to wait until the repairs in one of them (Propellers and shafts) are finished. This may take 3 more weeks (or months!)... so I left my anxiety aside and decided to enjoy my stay doing stuff I could have done in the water ... or not have done at all!

"A ball was affixed to the end of the antenna to dissipate the buildup."

This is counter-intuitive to the physics I know! Sharp points dissipate charge, while balls (either conductive or non-conductive) reduce the dissipation until a greater voltage differential has built up and then the resulting discharge has much greater current, and therefore can do more damage.

Charges on a conductive ball will distribute themselves until they are uniformly spaced, leaving a maximum distance and therefore minimum repulsion between charges. On a sharp point, the charges are forced close together, where the mutual repulsion is greatly increased, so some of the charges are forced out into space, loosing some of the charge.

Placing a non-conductive ball on the sharp point will prevent the discharge until the breakdown voltage of the ball has been exceeded, again resulting in a larger, more dangerous discharge when it does occur.

I once had a personal experience with this. While standing on the very top of a pointed mountain, I observed St. Elmo's fire (charge being dissipated) off the tip of an extended finger, but NOT off the closed fist. I didn't stick around long enough to see how big a spark would eventually be emitted by the fist. I left quickly, and around five minutes later, lightning did indeed strike the spot where I had been standing.

To the OP: The bottom line of this is to have a sharp conductive point on the tip of your mast. Such a sharp tip can spray considerable neutralizing charge into the air above the boat. In some cases this can reduce the atmospheric potential difference sufficiently to prevent a lightning strike. In the worst case, it will have reduced the charge in the region near your boat, and thus reduced the current when lightning does strike. As others have said, make sure the mast is well grounded to the keel/hull.

AFAIK The goal of a ball on the end of an antenna is to improve the S/N ratio of demodulated AM reception. Frequent tiny discharges in close proximity to the antenna will effect a broad spectrum of amplitudes, including the carrier frequency.

Two different things going on in #13. In the described application the balls could have been very effective. As extrapolated out dkwarner has a valid point and the balls on the antenna would go against the new goal.

In a previous life I had to use whip antennas in high electric field environments. We commonly had corona bursts at a rate of about 2-3 a second. This was causing major problems for our receivers. I took ping pong balls, filled them with foam insulation from a can and then glued them to the top of the whip antenna. In terms of static electricity they got rid of the point and were very effective at eliminating corona. (Not somewhat effective, they were VERY effective)

In the provided example the car and the rotating tires where basically just a Van De Graaff generator. The car was the big ball on the top of the Van De Graaff generator and the sharp point of the whip antenna would leak corona and cause problems with the AM radio. The balls would soften the point and stop the corona. Been there, done that, I'll call it true and sound science.

Then we change gears dramatically to trying to prevent lightning. This is a major change of gears. Just in case you missed it I'll point out that it is a major change of gears.

Lightning likes to strike trees, towers and tall buildings because they are more "pointy" than the area around them. Because they are "more pointy" they leak corona charge up, a leader stroke comes down, a return strike goes up and BOOM.

The theory of the dissipators is that they prevent lightning by either 1) leaking enough corona into the air to discharge the cloud (hard to believe) or 2) leak enough corona into the air to create a "smooth" region of charge and effectively eliminate the "pointey" features of what they are protecting. There are experts that have proof that they work. There are experts that have proof that they don't work.

As for me:
1) I am not an expert
2) I don't know if they work
3) Even if there is a dissipator overhead I will stay inside during the storm.

I once had very bad precipitation static on a mobile radio setup; the radio's built-in gas tube would conduct when the voltage rose, but there was a characteristic zap.....zap.....zap!.....zap!.....zap!.....zap!...zap!...zap!..zap!..zap!..zap!.zap!.zap!zap!zap!zap!zap!ZZZZZZZZZZZZZZZZZZZZZZPOW!.

This responded very well to a shunt inductive match at the low end of the spectrum used.

Cortland, ka5s

This has some relevance to the controversy; at least one paper I skimmed through suggests that "dissipators" do one thing well, and that is to protect connected equipment from damage due to built up electrostatic CHARGE.

I worked for a number of years at the firm that made digital loop equipment - bridging the last half-mile from the local telco cabinet to subscriber equipment. One of the calls I got was that lightning protectors on dwellings and in our equipment were failing without cause. I didn't get the time to find out; the company was starting to lay people off and I was one of them…

However, the cause was visible all along. The location was Texas, a place where severe thunderstorms are very common, and a lot of highly charged clouds pass overhead without rain reaching the ground - or lightning. These are charged objects, and as they pass over the thousands of miles of wire on poles, they can induce a considerable charge in the wires.

I never got to test my theory, but I'm convinced that the protectors, designed to survive quite a few very high transients from induced currents, were burning out carrying a much lower, longer current as the charge induced in wires by clouds passing by was shunted to ground.

My mobile station responded to putting a low impedance path to ground for induced charges; it's possible a dissipator would've done the same thing - but wouldn't have helped reception at all.

Something to think about.

Thank you for sharing your Knowledge / opinions! so far I have the feeling I will not install the dissipator on my boat, cause I have the feeling that a "non efficient" installation may do more harm than good. Although climate has been changing a lot down here in Buenos Aires over the recent years (much milder winters and more extreme summers) where thunderstorms are frequent, reports of vessels hit by a lightning are extremely rare. I only recall 2 cases in the last 20 or 30 years: both boats had FRP (Fibre Reinforced Polyester) hulls. One almost sunk at a marina, while the other one belongs to a friend of mine who was at anchor living aboard his ketch. He told having seen a intense light immediately followed by a big explosion. As skies were blue, he thought the onboard propane bottle had exploded. Besides all the electronics (even those unplugged like a laptop inside a bag) and part of the regular 12V installation were gone, no other damages to the structure of the boat were seen. About ½ hour later that area got hit by massive summer storm. Later that day a witness told him he saw a lightning hitting the top of the mast. Having said this, if getting into a thunderstorm, I will say a prayer to the memory of Mr. Faraday, lock me in.... and hope for the best...

There is apparently no good correlation between installation of "static dissipaters" and a reduction in lightning strikes to objects they're mounted on; a web page I came across noted that on one mountain-top antenna site, neither dissipater-protected nor conventional pointed-rod-protected (Franklin rod) antennas were struck, while a number of blunter antenna installations were hit.

There is a Yahoo Group on lightning protection headlined with a "Beware of Fraud Rods" article, and a quick search of the message base ("join" to see messages) lead me to a dispassionate evaluation of these devices:.
https://groups.yahoo.com/neo/groups/LightningProtection/conversations/messages/453

Also see slides 47-49 of http://pserc.wisc.edu/documents/general_information/presentations/pserc_seminars/pserc_seminars0/sen_2001.pdf

Thanks for the info!!! I wil read it asap

Found a very interesting paper: http://www.jpier.org/PIER/pier113/19.10111302.pdf

Your boat is steel. The major concern you need to address is making sure the mast is well bonded to the hull. Except for the electronics, there isn't a need for a lightning protection system. Damage to boats is caused by the Lightning going to ground through materials which have insulating properties and the resistance results in heat, blowing small and large holes in the hull as well as creating streamers within the hull. Steel hulls will not create substantial resistance. Lightning does not need to strike your vessel to cause damage to the electronics which can be significantly damaged by the pulse event of a nearby strike. Protection can be had but requires disconnecting antennas, wiring and commas networks from the unit and placing them in a metal container. Microwaves and ovens are popular Faraday cages on storage challenged vessels. As for the dissipator, the brush must be over one thousand feet of elevation to work properly.

My next door neighbour's house was hit this Thursday. It blew the sockets out of the wall and a paving slab was broken in the garden piercing the ground some metres away . Although we were on a different phase our fuses blew and electronics were fried, and especially the power supplies made in China all blew (fuses hidden, if any ?)

This was the first hit in 40 years, but is it a coincidence that several trees that were at the front have been removed recently, or could they have been acting as dissipators ?

I'm not suggesting that you should tie a tree to the mast, or am I ?

What type of trees should do you suggest to tie to the mast????

Obviously a lightning tree.

In the event of a lightning storm, should me an my crew also wear those yellow suits? or is this one better https://www.google.com.ar/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj34fbm2ZXMAhWBI5AKHah1DZAQjRwIBw&url=http%3A%2F%2Fmetro.co.uk%2F2013%2F06%2F28%2Fguitarist-creates-lightning-storm-during-gigs-by-standing-on-tesla-coil-3860321%2F&bvm=bv.119745492,d.Y2I&psig=AFQjCNF8xi6HpsK7IwIg8tTQqVJgF5nPoQ&ust=1460982259206616

Sorry !Don´t know wow to paste images using Mac´s Safari

Use Firefox. It has a tool bar for CR4 that makes everything that is a pain on Safari (including posting JPEGs and links) easy. I've been using it for essentially all of the nearly 10 years I've been on CR4, and always on a Mac.

I understand that Chrome works too, but I've had no reason to change

Here's the link to your Tesla coil artists: http://metro.co.uk/2013/06/28/guitarist-creates-lightning-storm-during-gigs-by-standing-on-tesla-coil-3860321/

YES !!!!!! This is IT! Probably most Mac user will hate me, but I finally decided to get rid of Safari! It got replaced by Chrome (I tried Firefox some years ago, and did not like the interface then, so I went for what i use at work) Thanks DK !

¡De nada! ¡Que rápido!

You don't have to get rid of Safari. I still use it occasionally, but never on CR4.

Muchas gracias again!