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Discussion Starter · #1 ·

After a pleasant afternoon of club racing off Cape Canaveral yesterday I was exiting the Canaveral Locks in the early evening and took a direct lightning hit to the top of the mast.

There is now a small burn mark on my cockpit sole a foot in front of where I was standing (something hot landed there), and the only piece of the VHF antenna we could find was about 3/8" long and smoke black. The rest of it disappeared.

After the strike I saw a long plume of black smoke coming from the top of the mast. The powerboats trailing behind me suddenly gave me extra space.

All aboard are fine, as I had just moments before sent the two crew below because the weather was so crummy. They described the scene in the cabin as being equivalent to a dozen halogen lights flashing on at once.

I am scheduling a meeting with the insurance surveyor now and wondered if anyone has some advice on what I need to consider when I do the inspection. The boat will be pulled ASAP to check for damage underwater, I want a full rig and electronics inspection, in addition to a stem to stern look, but what in particular needs to be carefully examined? The boat is pretty well bonded, and the seacocks are all Marelon
 

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Richard--

Some friends of ours went through the same thing with their Beneteau First 42, Ocean Angel, last year in Bradenton. If you will PM me with your email address we can put you in touch with the owner--a NAMS surveyor and Public Insurance Adjuster--who, I'm sure, will be willing to provide some information and advice.

Also, for the sake of discussion, did you happen to have a lightening arrestor on your masthead?

s/v HyLyte
 

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Discussion Starter · #3 ·
All that's on the top of the mast is a windex, a tricolor light, and, until last night a whip VHF antenna. I've read mixed reviews on the various lightning devices, but I'm open to putting one on. There is certainly plenty of opportunity for another strike in Central Florida, which supposedly gets more lightning every year than any other place in the continental U.S.
 

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I found out today that a magazine article I had written on my lightning experiences has just been published in Outlook By The Bay Magazine ("for Bay Boomers and Beyond ..."). If you'd like to read the whole scenario surrounding my "Shocking Experience", click here and jump to page 22 of the .pdf document (which is page 20 of the magazine.)

Larry
 

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Richard, pretend that your nemesis has just called you and told you that he hid ten grams of coke on your boat and the DEA is on the way to find them.

Now, you've got a job ahead of you pretty much the same as doing a strip-search of the boat looking for any small packet that shouldn't be there.

Lightning damage can affect ANYTHING on the boat. Got keelbolts? Got an internal ballast? Doesn't matter, there may be pinholes below the water line anyplace that metal was close to the hull. Any Marelon fittings that had metal or metal-reinforced hose running to them, may be partly meleted, you'll need to work each one and eyeball it.

Engine, charging, starting systems may all have taken damage, internal or external. Every foot of every wire and fuse and breaker on the boat needs to be examined, as does the steering gear and everything beneath the cockpit. Every light bulb needs to be tested, along with every instrument for every function.

And of course, a full rigging inspection to see if anything got welded or vaporized--including the masthead sheaves.

Lightning is funny stuff, sometimes it comes and goes and leaves no trace. Other times, a month later you'll find things simply welded--or missing--where it snuck in and blew them away.

Odds are your insurance surveyor will NOT want to spend the time getting that intimate with your boat, so don't be in a rush to sign off ay 'final' claims.

Oh, and your VHF? Even if it still works--the finals could be blown, after the new antenna and cable are installed (replace the entire cable run) do an actual test to make sure it still works at full power transmit.
 

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I found out today that a magazine article I had written on my lightning experiences has just been published in Outlook By The Bay Magazine ("for Bay Boomers and Beyond ..."). If you'd like to read the whole scenario surrounding my "Shocking Experience", click here and jump to page 22 of the .pdf document (which is page 20 of the magazine.)

Larry
Nice article. Glad you didn't panic and let the lightning strike ruin the day. Reading this makes me hope it never happens to me, but reinforces that a lighting strike is not the end of the world. Thanks.
 

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I've read mixed reviews on the various lightning devices, but I'm open to putting one on. There is certainly plenty of opportunity for another strike in Central Florida, which supposedly gets more lightning every year than any other place in the continental U.S.
I have read the same reviews. We have had a bottle brush on our masthead since we arrived in Florida (in '92) and thus far have been spared while, during the interval, several yachts around us have been struck. I was convinced of the worth of the devices by an engineer from FP&L that used to have his boat moored near us. When asked about the device his response was that he couldn't say for sure but that after adding them to their poles, they did see a major reduction in strikes. Given that the devices are relatively inexpensive, they can't hurt and might help, which is good enough for me.

Regards,

s/v HyLyte
 

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Richard,
You know where the lightning hit but you need to determine the place(s) it exited. There will be holes and melting where it did. Plus all your electronics need to be thoroughly checked. Even if they weren't slagged the proximity of that much current can change the properties of the boards, connections, in fact any part of the beasties could be vulnerable. Also your light bulbs, especially the tricolor at the top of the mast might be damaged. Moving metal parts may no longer move.
That being said, lightning is unpredictable. I had lightning strike down the companionway of a boat I used to own and all it did was set the floorboards on fire. A friends of my took a strike while underway which slagged $20k worth of electronics.
You never know
 

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I've seen the effects up close and they are indeed unpredictable and the damage can be hidden. A brand-new Hunter 42 took a strike at a mooring at our club a few years back and our wife and I happened to see it. The top of the mast was pretty well vaporized to judge by the eight-foot dark-brown plume left hanging in the area, and several coin-sized holes at the starboard bow, linked by spidery black scorch marks, showed where the lightning left for the water.

And yet the boat started right away, and no electrics were damaged...just the hull. The boat had the holes literally taped shut and went back to the factory for reglassing.
 

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Good information on minimizing lightning damage. From University of Florida

Jack
 

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Lightning loves Sailboats......

We are building a Boat House in the back yard for all of our sail boat supplies and parts and such... mostly storage - partly work space. Have the H37C, several Macgregors, and such up and are working on them... In the center of the group - there is a 40' Pine Tree... Texas Storms being what they are, it was hit by lightning in the middle of one of these fast moving, turbulent events... Blew the bark off the tree on one side - top to bottom of the tree...

I wonder what would have happened it the masts were up... glad they were down...

The Tree will have to come down, I suspect... before it falls down...

I am convinced that Lightning loves Sailboats...

--jr
 

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In theory the bottle brushes work, by providing lots of "point discharge" from the wire ends which will allow the ground charge to bleed off into the air more efficiently. There's no doubt about that--in theory.

But at least one bottle brush maker supposedly was warrantying their product against strikes and strike damage and last I heard, no one could get them to pay up any warranty claims. So if you believe in the theory, fine. Just don't expect any warranty to be worth the paper it was printed on.
 

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Wow, you were very lucky. A boat was hit in our marina 2 years ago. Most of the interior burned out of it, and the thru hull transducers were blown out. Quick action by one of our club members kept the boat from sinking. There were lightning traces all over the bottom of the boat, but especially on the keel. The shockwave in the hull caused the hull to crack midway between the rail and the water line, about 12 inches long.

I would hate to have been inside the boat when that one hit.
 

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In 2003 we were caught in a pressure burst, a very violent little storm that lasted only 20 minutes. We were in a "harbour" in a place called Beira on the coast of Mozambique ("harbour" in parenthasis because it's actually just a river with a wharf).

We had real ships and wrecked ships (on the beach) all around us that offered lightning a good and proper earth but the lightning struck the water around our boat several times sometimes as close as 50 metres away. Huge founts of water shooting into the sky, noisy like hell, pretty damned scary with four of us huddled in the middle of the cockpit in torrential rain trying not to touch anything that would earth us.

We still have found no credible reason why the lightning never struck our boat. Don't know if anyone here has had that experience?
 

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You're really going to need a very thorough survey, since lightning can do a lot of damage in many areas of the boat. Pinholes through the hull, damage to the rigging, blown electronics, are just the beginning...
 

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I've been thinking about the lightning protection on my boat and I'm not sure what I am doing is a good idea. I have a keel-stepped mast that is not grounded and an ecapsulated keel. The other metal items on the boat are bonded. I live in an area that is not particularly susceptable to lightning, but I have witnessed two boats being struck within 50 yards of me!

When I believe I am in danger of a lightning strike I fasten 8' chains from the upper stays and the backstay and drop them overboard into the water. I always figured this would make a pretty good Fariday cage. However I've recently read that this practice is actually "dangerous" though the article did not explain why. Given that I can't easily install a proper grounding plate mid-season. Should I continue or discontinue this practice?
 

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h-
Considering that lightning will do what it pleases and no one has gotten that down to a 100% predictable science yet...

Chains and stuff dropped in the water are known to be questionable. Lightning likes to take straight paths, so what you may find is that it comes stright down your ungrounded mast and then, unable to find a convenient ground, it continues straight down blowing a thousand little holes in your keel encapsulation. Someone who took exactly this kind of damage said that it looked like someone took a shotgun to his keel after they hauled it.

Your best bet is probably to sister up cables--not chain--with multiple bulldog clamps, so that they are tightly bound in parallel with your rigging and offer a good diversion over the side into the water. Until you can get something similar from your mast into a proper lightning grounding plate.

Bonding the thruhulls is great to prevent electrolysis, but in the event of a lightning strike it might only ensure they all blow out together. There are lots of split opinions on that--but it isn't for lightning protection.

AFAIK a Faraday Cage is literally, and only, when you physically surround something with metal or at leaast dense metal screening. The "zone of protection" from you mast and shrouds isn't quite the same at all. Stick your boat inside a big metal shed--and then you'll have a Faraday Cage around it. (Which really would help, but you could still expect some holes in the shed when strikes burned it on contact. The top of the Empire State Building, full of transmitters, antennas, and a very professional ground system, takes hundreds of pinholes from strikes every year.)
 

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Ditto on the electronics. I had a number of electronics that failed do to a lightning strike. The probelm is they worked fine right afterwards. They were not claimed on the insurance. They failed over the next 2 years and all where related to the lightning strike.
 
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