Does lightning strike cause delamination on fiberglass hulls?

[barnakiel]

I have heard of one case where it did. A direct hit on a properly grounded boat. Delamination under the grounding strap.

I have also talked to owners of another boat that took a direct hit and had no damage. This one had a deck stepped, not grounded, mast, though.

Hard to say if there is any relationship, these are just two cases.

b.

[Tortuga's Lie]

My boat was on the hard over the summer and a severe lightening storm went through. A boat not more than 60 feet away got a direct hit and it blew holes out through the hull near the jack stands, jumped to the jack stands and blew holes into the earth. Scary stuff. You could also see where the strike exited through a thru-hull fitting and spread across the surface of the copper bottom paint like rivulets until it could find ground at the jack stands. I won't mention the brand of boat, don't think it matters. I also thank my lucky stars: my mast is about 12 feet taller than the one that got struck.
Here's a carbon fiber fishing rod that got struck on a fishing boat:
https://www.google.com/search?q=carb...ybEzCaHBG7M%3A

[CHRIS V CLEMENT]

A friend of mine had a North Anerican 41 that was struck by lightning while on the hard.There was a spiderweb pattern on the bottom paint that concentrated at the steel jack stands.In order to confirm the structural integrity of the solid fiberglass hull, a number of 2" cores were cut in the bottom below the water line.In every case, the glass cloth was intact, but the resin had been turned to powder. The layers of cloth came apart like playing cards.The hull was totaled due to the loss of structural integrity.Do not take lightning strikes lightly !!!

[a64pilot]

I think there are a lot more used boats for sale that have been struck than we realize, be suspicious of the boat that the owner decided to replace all the electronics just prior to deciding to sell it.
Who does that?

[westwinds]

If the boom was replaced, it would appear that the lightening came down the mast and then into the boom. The boom could have been an exit point so I would check the hull wherever the boom would have been. Also, how was the end of the boom secured when in the harbor. That could have been the most likely point of exit from the boom.

[reed1v]

Originally Posted by Paul L

No, that would not be a reasonable assumption. It could affect the hull but usually doesn't.

Yes that would be a reasonable assumption. Direct lighting strikes can pinhole a fiberglass hull easily. Being struck by a side flash probably will not. So depends on how you are struck. A full on leader flowing down your mast at thousands of degrees heat will do a lot of damage, pinholing the hull included; if not blasting a hole in it. Seen it on several boats down in Jacksonville FL

[barnakiel]

Originally Posted by Tortuga's Lie

Here's a carbon fiber fishing rod that got struck on a fishing boat:
https://www.google.com/search?q=carb...ybEzCaHBG7M%3A

Awesome!

THX for sharing!

b.

[reed1v]

Originally Posted by barnakiel

Awesome!

THX for sharing!

b.

Yup, carbon fiber basically fries when hit by lightning, same with a carbon fiber hull. Carbon fiber does not belong out on the open seas.

[UNCIVILIZED]

You can get some good, professional grade, information on this topic via Professional Boat Builder magazine www.Proboat.com As they routinely do updated articles on the topic, to add to the knowledge disseminated via older issues. And commonly the articles are 3-5x as long as most magazine articles, sometimes spanning a dozen pages. With good reference links/info & bibliographical data right in the magazine.

Also, lightning doing making multiple small holes at the waterline is pretty common. It happened to a friend of mine, twice, IIRC. Blew a bunch of cigarette size ones around the perimeter of the boat. One boat was a woody.
They just leaned over the windward side, patched things with Duct Tape, & continued on. Kinda' had to, due to being offshore in a gale.

[nautitrix]

I have had two episodes the most enlivening was when I was in the water between the strike and the dock. The electronics were all engaged with the bonding system which fortunately was very well done. After we replaced all the fuses, much of it came back to life over time. There was no damage to the hull and the rigging suffered some scorching where the stainless came in contact with the aluminum. This was in fresh water on the great lakes and this may make a big difference as salt water is an electrolyte whereas freshwater offers more resistance than the bonding straps.
Some powerboat hulls were made with embedded metal salts to fire-proof the fibreglass. These salts can have a high reaction to salt water as an electrolyte and these hulls are famous for their blistering. I would suppose that an electrically active hull could easily see de-lamination in a lightning strike.
Best advice is have a very good survey of the hull, the thru-hulls, and all the fittings, especially at any connections of dissimilar metals.

[CharlesV]

what are the precautions against lightning damage?

[reed1v]

Originally Posted by CharlesV

what are the precautions against lightning damage?

Direct path for lightning to take, not that it will, but may help. We used big alligator clips fused to thick 10' copper wire that was also attached to a big block of zinc. Clip onto shroud just above lifeline, drop the rest into the water. Never got to see if it worked or not. Same method used on maxi yachts when in ports with a lot of stray currents.

Otherwise, the recommendations are all over the place. The science is almost nil, and experiences vary wildly.

[CharlesV]

Originally Posted by reed1v

Direct path for lightning to take, not that it will, but may help. We used big alligator clips fused to thick 10' copper wire that was also attached to a big block of zinc. Clip onto shroud just above lifeline, drop the rest into the water. Never got to see if it worked or not. Same method used on maxi yachts when in ports with a lot of stray currents.

Otherwise, the recommendations are all over the place. The science is almost nil, and experiences vary wildly.

I think I dont know enough to speak but yes, lightning needs a path --and into earth or a receptacle capable of absorbing what, 250,000 volts? But the boat being in the water and water conducting electricity how can a path to water not affect the boat? What if a lightning rod was pathed into a bucket of dirt on the deck? Work or not?

[tkeithlu]

Not. We're talking about megaamps and megavolts. In the most frequent cases, we're also not talking about a single path, but to network of paths described in some of the posts above. A well grounded mast means a whooping connection to the water, not a piece of wire, and even then parts of the bolt may go wandering through standing rigging, antennas, fishing rods (!), your grounded electronics, and your plumbing. When it doesn't find an easier set of routes, it may go through your fiberglass as well. I think the central problems in people's thinking on this topic are first, that the point of contact does not have to be a conductor, since it's a static charge, and second that the magnitude of the electricity conducted once contact is made is so far outside our everyday experience with electricity. We think of an ordinary conductor to ground, but we're dealing with a strike that can do all the things described above and more. There is not a single reliable solution that will protect a boat, although supplying a clear route to ground may improve your chances for minimum damage,

[CharlesV]

Whats needed to hide from lightning the things on the boat that are attracting it in the first place? What defines a sort of purposeful umbrella? Or a parabolic dish to deflect it back into the sky?

Im not deliberately trying to be stupid.