SailNet Community banner

1 - 20 of 38 Posts

·
Registered
Joined
·
137 Posts
Discussion Starter #1
Would like to hear from any sailors who have had direct experience with lightning strikes and lightning dissipaters. I understand the theory but do they really work?
 

·
Registered
Joined
·
1,000 Posts
I have no personal experience beyond near misses in a couple of different marinas.

But.....there is a sailboat a couple of docks away from us that was hit by lightning. It had/has one of those lightning dissipaters on it. I do not know which one is on the boat, but it didn''t seem to work to well.
 

·
Registered
Joined
·
3 Posts
When lightning travels 20 miles, a wire bottle brush is not going to stop it.
I plan on grounding, as I will be the tallest sail boat under the lightning when I''m hit.
I hope my message got through as this is a poor excuse for a BBS.
Carl T. Knox
Sailing weekends on Superior.
 

·
Registered
Joined
·
3 Posts
Well Carl T. Knox if this is such a poor excuse of a BBS, may I ask why do you waste your time reading and/or posting messages on it? Probably most of the people that do read and or post messages here and enjoy doing so would prefer NOT to read your messages anyway. Gees, what a guy.
 

·
Registered
Joined
·
1,000 Posts
Lightning

Sailor Friend Lost Several Thousand Dollars Of Electrical Gear On A 65 Loa Cutter. Installed Dissipator For Approx $80.00, His Insurance Agent Told Him That He Had Never Received A Claim From Anyone Using This Device. Some Insurance Companies Are Giving Discounts For Boats Using This Device, In The Past There Was No Discounts Given For Their Use. They Operate On The Premise That A Object That Has No Static Electricity Has Less Chance Of Strike Than Object With Static Electricity. There Is Another Forum At Sailboatowners With Some More Input Concerning The Ionic Dissipators Some Favorable, Some Not So Favorable. Interesting Topic.
 

·
Registered
Joined
·
314 Posts
We came a bit too close on the passage from Bali to Malaysia last year. The waters around Singapore is probably the most thunder 'infected' in the world. Not a direct hit, but close enough to knock out most of the electronic. In number I would say that there are probably not many direct hits where damages may be reduced or prevented by use of diffeent devices. Most of the damages in numbers are caused by what I would call 'too close', and there is probably nothing sensible equipment awailable at the market to prevent it. It is one of the hazards of sailing.
You are welcome to browse our web page:
http://www.geocities.com/haffiman37
for more.
I think the electronic dealers in Singapore must be the most experienced in lightening damages in the world, both on yachs and commercial vessels. If you want more statistic material I suggest You contact them.
 

·
Registered
Joined
·
562 Posts
I've been hit twice. Once ont he hard whcih did minimal damage - a burned spot on my upper shroud that did need replacing as one of the strands was burned through.

Time 2 was in my slip. I was not aboard. Lightening blew my battery charger apart scattering its pieces throughout the bilge. All my electronics were fried and I had to replace all my bronze thru hulls.

I view dissipators with suspicion. One company offers a guarentee. They will pay your insurance deductable if you get hit. What a scam. I think their dissipater costs around $300. Insurance companies figure .1% of boats get struck. Do the math. That company sells thier disapater for $300 each - it cannot cost them even $100 to make it but give that to them. They sell 1000 at $200 profit = $200,000. One of those boats gets hit (insurance figures) and they pay out the $500 deductable. A $199,500 profit per 1000 units. Someone hit on a great idea.
 

·
Registered
Joined
·
314 Posts
Irwin 32:
Interesting post. The first hit and damage pattern I find normal, the second one raises a few questions.
Was your boat actually hit or was it a hit somewhere in the shore power lines that went through to your battery charger?
Were your main switches on or off at the time?
Are your throug hulls grounded to the same grounding piont as your shore power system?
If the rigging is grounded it should have been some traces on that too where the lightening hit?
 

·
Registered
Joined
·
6 Posts
If you want to protect yourself against a stroke of lightning get a metal made boot and shelter inside the faraday's cage. But if you can not avoid the situation and are in the bad case to be on one of this electrifying "plastic made vessels" the only thing you can do is to discharge any electrical potential which could induce a "Preflash To Heaven"! If your boot gets hit and it didn't frie you the same instant you might have been hiding in an aluminum case ore you just have met your protectif angel.
A lightning flash will most probably go strait from the masttop to the botom to the keel and the sideflashes unpredictable any possible way along riggings, wires etc.
So, just take your chances!
Good Luck.
Elena
 

·
Registered
Joined
·
1,000 Posts
" Installed Dissipator For Approx $80.00, His Insurance Agent Told Him That He Had Never Received A Claim From Anyone Using This Device. " His insurance could have just said "I don't know anything about these." yes, they make good claims, but elsewhere I'd read from someone who DID use one, DID get hit, DID try to claim the warranty coverage for it, and couldn't get anywhere with the maker. Apparently the concept behind the device (multiple sharp tips to dissipate a static charge) works in theory, to LESSEN the risk and diffuse the charge. But the warranty is worthless and the devices are not "absolute" protection any more than anything else.

If you've ever heard static discharge literally crackling off an antenna or lightning rod, you'll understand that a static discharge is real.
 

·
Registered
Joined
·
562 Posts
Haffiman

Strike # 12 is indeed strange. It was at least 15 years ago, so the details are no longer fresh in my memory. All I can say is that when i checked the rig, which was up all winter, I found a burned spot above the spreader. There were no power lines in the boat yard so that is not an option.

I cannot say that the spot was not there at the time of winter layup - I can just say that I check the rig every spring and it was not there in the spring a year earlier.

It seemed to me, that unless some vandal went up my mast with a torch and put that burn mark there - enough to cut through one or two of the SS strands in the upper shroud above the spreader - lightning was the only resonable explanation.
 

·
Registered
Joined
·
1,000 Posts
Irwin 32 !! my boat was hit by lightning this year and my battery charger exploded and all my electronics were fried . My outboard engine was ruined also . Boats on either side of me were untouched . Lightning does not read the rule books , so try anything you think will help and hope for the best . I think the lightning hit the dock and followed the power cord into my boat . Ken
 

·
Registered
Joined
·
24 Posts
This seems to be a recurring thread about lightning. My take on the "brushes" is that they can help and I have never had anyone suggest that they can do harm. First of all, they are not "lightning dissipators" and anyone reading this thread should realize that they are not intended to protect you from a lightning strike, as far as I know there is nothing on the market yet that can do that. What they are purported to do is bleed of ions from the boat and lessen the likelyhood of a lightning strike. They dissipate potential. Personally I hope it does this well as I have one installed on a full keel fiberglass boat that is not bonded. The statistics I have read on the internet state that a bonded boat is twice as likely to be struck by lightning as a boat that is not. The sad inverse of the statistic is that an unbonded boat is twice as likely to have catastrophic damage- as in a big hole in the hull and dead sailors. I have some things to overcome in order to effectively bond my boat because of the encapsulated full keel in the way of the "direct path to ground"
 

·
Telstar 28
Joined
·
1,000 Posts
From what I understand of the way the "brushes" work, they won't do much of anything unless they are properly grounded.
 

·
Telstar 28
Joined
·
1,000 Posts
No, a dynaplate, which is generally made up of sintered bronze spheres, gives a lot of surface area but is not a proper ground for a lightning system and can actually be detrimental in the case of a lightning strike...as the water that is trapped within the porous nature of the plate can superheat and vaporize and essentially detonate the plate into tiny bronze shrapnel.

A proper ground for a lightning system is a heavy copper plate, preferably tinned, that has at least four linear feet of edge, as it is the edges that tend to dissapate lightning, not mere surface area. A long strip that is two inches wide, and three feet long is better than a plate that is one foot square, and often easier to incorporate into the hull.
 

·
Registered
Joined
·
1,000 Posts
SD et all,

Physics was never my favorite subject, but it seems logical to me that for a disspator to work properly, the boat would need to be grounded. I put a large one on my last boat and lived in Fort Myers, where there are very severe lightning storms every day. I was never struck, other boats around me were. My mast was the tallest. Did the dissipator save me??? Only God knows that.

Not to dig up an old thread about grounding versus not grounding, but if you ground your boat and do not think you are seriously increasing your chances of getting struck, I think you are kidding yourself. However, if you don't... better be prepared for the consequences if you do get bit.

I have heard the static popping on the mast. Eerie. A disspator is not going to save, just reduce the odds that you get hit and instead smack your neighbor (and maybe curve back around and hit you). I guess my thought is: Why not? For the small cost involved, why not put on a dissipator? You can't even buy a decent hand held GPS for the cost of one.

If you want to ground your boat, it still seems logical to me that you can use some South Island Ingenuity and just wrap your chain around the shrounds and toss the anchor over. If there is tension on it, it would seem a better conductor than plastic.

Just some thoughts.
 

·
yacht broker
Joined
·
251 Posts
About the charge dissipators, by reducing the charge they reduce the probability of being hit. It is known that when a lightning cloud (also know as cumulus-boomulus) passes over land it induces a positive charge on the land below. Then the lightning is attracted to where the charge accumulates. Photographs have been taken of the precursor charged paths that go somewhat upwards from the ground the instant before the strike. The dissipator helps reduce that induced charge and any potential strike path.

This summer a friend's boat a few piers away was hit in the slip and most electronics got fried. He had a charge dissipator at the time. I talked to my dad who is a retired electrical engineer with experience with protecting large tracking antennas. He explained that in a marina with many boats close together, the charge dissapitor won't help much unless almost every boat has one. The entire marina with all of those sailboat masts has a high induced charge and becomes attractive to the strike and it's a crap shoot where it actually hits. So it doesn't matter much in the marina whether or not you have a dissipator. He then explained that when you really need the dissipator is when you are in an anchorage where vessels are spaced apart or you are just out underway. Then you are the only or one of the few tall masts around. That's when you want to try to look smaller to the cloud.

Many years ago I was in central Florida on a somewhat threatening stormy day. I remember how chilling it was to see my wife's freshly dried hair start raising straight up on it's own as she walked toward me in my car in an open field under a fast moving dark cloud. Fortunately there was not a strike but it did leave quite an impression with us. If that happened again I would tell her to get down.

From what I've read on this the metal boat solution is true. The US Navy has metal boats of many sizes which are taking quite a few strikes out there. The Navy has studied the lightning issue to the point of attracting strikes and photographing the direct strike. The Navy's findings are the rarely do those strikes on metal boats cause significant electrical damage or personnel injuries. That is not the case on fiberglass boats. The Faraday cage works.
 

·
Telstar 28
Joined
·
1,000 Posts
BTW, getting down is generally bad advice. It leaves you more exposed than crouching does. The best position is to be indoors, but if you must be outdoors during a lightning storm, crouching is probably your best bet, as it minimizes your exposure to both direct and indirect lightning strikes.
 

·
Full time cruiser
Joined
·
542 Posts
I have one and last year went though two sever thunderstorms in the Bahamas - the first we were at sea and had all the sails down, as we saw it coming, and tried to get out of the way but is rolled right over the top of us and the electronics flickered but all came back on - there was lightening everywhere -
we then went into chub cay and just after dropping the hook and settling down for dinner a huge thunderstorm rolled through and while we did not get a direct it it was close enough that we lost all and i mean all electronics - everything from the reefer to all insturments to windlass to you name it - two surveyors and the electrician that repaired it said that the dissapator probably kept us from getting a direct hit - are they right - who knows - but i do know we had one boat in our marina that is 15 slips away from mine and does not have one got hit in the slip and was the only boat to get hit and one of the few that does not have one -- he does now.
chuck and soulmates
 
1 - 20 of 38 Posts
Top