Lightning

[Sondor]

It seems to me there are two discussions going on:

1) Can lightning strikes upon the boat be prevented? Consensus - nope
2) IF you DO get struck, are there things one can do to mitigate potentially boat sinking consequences? Consensus - absolutely

[Ex-Calif]

Originally Posted by SaltyMonkey

so, the overarching question for me is how many sailors actually ground their mast?

Mine is deck stepped and grounded via the shrouds to an underwater (small) plate

Originally Posted by zeehag

you may diss me until cows come home, but bakatcha, as the stuff you spew is just as off as that which i believe,.

Bless your heart Zee but belief is not science. The science of lightning and boats is not complete but the science of conductors and electricity pretty much is.

It is preposterous to think lightning "chooses" a grounded boat, house, the tallest mast, the tallest person or anything else.

It might but the variation and randomness make any effort to be less or more attractive to a strike futile.

Originally Posted by colemj

A lightning ground and DC bonding should be separate. I wouldn't consider grounding lightning to a thruhull very safe.

I personally know of two boats struck without any lightning ground that blew multiple holes through their hulls and created a lot of damage (one was sinking, but they were near a lift and hauled). I know 3 boats struck with lightning grounds that had no hull or other structural damage. I know 2 boats on the hard (ie, not grounded) that were struck with resultant hull damage.

Mark

I watched a J24 sink in about 20 minutes after a lightning strike here. There was no path to ground and the charge clearly jumped out near the base of the mast and made 3 separate holes in the boat.

We've also discussed the futility of trying to dissipate the entire lighting charge via many ground path ideas. I don't think you can attach a conductor big enough to ensure all the charge goes harmlessly to water but hey, if I can get a large portion of it to ground that's gotta be good.

There are two ways equipment gets fried IMO. Direct current through say the ground system and EMP.

My house was struck a couple weeks ago. There are at least 4 lightning ground rods bonded to the electrical system of my house. 2 modems were the only casualty and the whole house breakers tripped.

[colemj]

Originally Posted by CarinaPDX

The problem is that your sample size is so small that it is anecdotal rather than statistically significant.

To clarify, I didn't intend those examples as a statistical argument. The anecdotal cases I described were only to make a point about, well, anecdotal stories - since they were opposite results of other anecdotal stories presented as evidence in this thread.

Mark

[DeepFrz]

My house was struck a couple weeks ago. There are at least 4 lightning ground rods bonded to the electrical system of my house.

See that. I guess Zee was right. You shunta ground yer house.

[Ex-Calif]

Originally Posted by DeepFrz

See that. I guess Zee was right. You shunta ground yer house.

And I should padded the ceilings. I came 4 feet outta my chair and landed in a pile of my own brown stuff.

Closest I've eve been to a strike and way to close for me. It's like the freakin' air buzzed and sizzled with the ions floating around.

[Snowpetrel]

Originally Posted by Arthur Garfield

Marine engineer Kasten,has an interesting read for lightning attenuation.A very good overview!
Lightning Attenuation Onboard

Very very interesting links here to some newer theorys on lightning disipation through the waterline being better than underwater. Thanks for this link Arthur. Seems like long external pointed chainplates like the old timers had might have been pretty effective, as arethe dolpin strikers. Interesting..

[DeepFrz]

Yep, been there done that while paddling an aluminum canoe on the Churchill River in northern Saskatchewan. Kind of catches your attention and the smell of ozone is all pervasive. When all you hear is a zip and a bang you know you are to close.

[HappyMdRSailor]

Originally Posted by Ex-Calif

And I should padded the ceilings. I came 4 feet outta my chair and landed in a pile of my own brown stuff.

Closest I've eve been to a strike and way to close for me. It's like the freakin' air buzzed and sizzled with the ions floating around.

Originally Posted by DeepFrz

Yep, been there done that while paddling an aluminum canoe on the Churchill River in northern Saskatchewan. Kind of catches your attention and the smell of ozone is all pervasive. When all you hear is a zip and a bang you know you are to close.

You guys forgot the tingly hair.... Oh man...