Lightning strike scare???

[Currie]

I agree with you Moe. In terms of being more attractive to a lightning strike, - it's similar to saying that you are protected in a car by its rubber tires. When lightning intends to make an arc across a mile of air, it really couldn't care less about a few inches of rubber. IMO, any benefit - or drawback - to grounding is probably minimal, with respect to the boat getting hit.

~Bob

[Hamin' X]

Moe, Can you post a link to "Ewen Thomas's research", I can find nothing useful when I Google him.

Also, much of the misunderstanding of lightning behavior is due to people equating grounding, negative and earth and the confusion between ions and electrons. More later, Ive got to get ready for work.

Rich

[Chip Hindes]

Moe, Can you post a link to "Ewen Thomas's research", I can find nothing useful when I Google him.

The name is Ewen Thomson, and some of the stuff can be foundhere. Note the UF recommends contacting him by email. Also the cautions that the study is over ten years old (actually now over 15) and "may be dated".

There was a major discussion on this subject on the Board a few years ago and this study was cited by a number of contributors.

Don't know if you'll be able to find the study, but my personal opinion is that you'll not find much useful either way. I've read and reread that study, and I believe the conclusions arrived at by the lightning "expert" were not supported by the statistics he presented. Maybe I'm just naturally cynical. It's possible that it was completley above board that his conclusions just happened to enhance the sale of the lightning protection products he was plugging on the side.

IMO, didn't pass the sniff test.

I decided some time ago that a lightning protection system of even marginal effectiveness would so severely comporomise the utility of a trailerable CB boat that it simply wasn't worth the expense or effort for the rather dubious return.

There are well over 5000 Macs on the water and the number of reports of lightning strikes are somewhere between few and none.

[kmclemore]

This is the lightning protection company that Ewen Thomson runs now:
http://www.marinelightning.com/

... and his résumé (CV) can be found here:
http://www.marinelightning.com/consulting.htm

... and what would appear to be his latest treatise is here:
http://www.marinelightning.com/science.htm

[tangentair]

There are well over 5000 Macs on the water and the number of reports of lightning strikes are somewhere between few and none.

And the number of posts about the rigging taking a charge are relatively few on the board compared to the number of posters, so I wonder if it is a configuration, sailing area, willingness to sail in marginal weather, or other reason - or everyone has experienced it and just not noticed - it never happened on any of our family's keel boats to the best of my knowledge - but the mast and rigging was probably grounded through the engine and keel.

[Frank C]

... There was a major discussion on this subject on the Board a few years ago and this study was cited by a number of contributors...

Some of the earlier discussions dropped from the archives, but this one was pretty thorough ...

Lightning protection options

[Moe]

Sorry about the misspelling of his name, and thanks for the correction, Chip. I think I may've also pointed out his vested interest before. Nevertheless, the insurance claim data didn't support grounding increasing the probability of a strike.

At one time I believed the unlimited supply of electrons theory (the previous thread Frank links to), but having thought about it more, it seems to be the opposite.

--
Moe