Wayne.B wrote:
On Sat, 17 Mar 2007 06:17:03 GMT, "barry lawson"
wrote:


In Australia anyway, the main thing is to not play golf, as this is where
the statistics say you are most likely to be killed by lightening, even
worse than shark attack.


Same thing here in south Florida. We usually have several fatal golf
course incidents every year.

So golfing is bad, good thing since my game is terrible anyway.

Regarding the boat, a well grounded mast, shrouds and stays seems to
be the consensus and jibes with my experience. If caught out, staying
away from metalic objects as much as possible seems prudent.

Err, metal like on my boat, the metal column and wheel of the helm? Yikes!!!

Stephen

"Sal's Dad" wrote

Any thoughts?

Make it a tall mast with a sharp point on top. There are also some special
electrodes that are supposed to be better than a sharp point but I have no
idea how valid their claims are.

--
Roger Long

"Roger Long" wrote in message
...

"Sal's Dad" wrote

Any thoughts?

Make it a tall mast with a sharp point on top. There are also some
special electrodes that are supposed to be better than a sharp point
but I have no idea how valid their claims are.



Better yet, fly a kite made out of aluminum foil and use a wire leader!

Are you trying to get the man killed?

Wilbur Hubbard

Any thoughts?

Make it a tall mast with a sharp point on top. There are also some
special electrodes that are supposed to be better than a sharp point but
I have no idea how valid their claims are.



Better yet, fly a kite made out of aluminum foil and use a wire leader!

Are you trying to get the man killed?

I was thinking along the lines of the "cone of protection" approach:
http://www.mdsg.umd.edu/CB/lightning.html
http://www.cdc.gov/nasd/docs/d000001...7/d000007.html
http://www.cgauxa.org/beacon/Summer06BEACON.pdf

or a Faraday Cage created from the framework of a bimini or dodger.

Or maybe a combination of both?

Sal's Dad

"Sal's Dad" wrote

I was thinking along the lines of the "cone of protection" approach:
or a Faraday Cage created from the framework of a bimini or dodger.

Exactly. I don't know if the accusation of trying to get you killed was
directed at me but the boathook originally referred to, doesn't produce much
of a cone unless it is an unusually long one. Headstays, backstays, and
shrouds outght to produce something of a Faraday Cage effect on a metal
boat.

--
Roger Long

"barry lawson" wrote in news:zJLKh.12288
:

we were protected from the lightening by our cloth bimini top

Fantastic stories! Thank you!

I was on watch during a very violent thunderstorm while out on Charleston
(SC, USA) Harbor on a Saturday afternoon. Cap'n Geoffrey had guests
aboard the Endeavour 35 who were not sailors, so I suggested, instead of
everyone getting drenched to the bone, that he take his guests down into
the cabin and I'd handle the helm until it stopped. I put her on a nice
tack in not-too-much wind (in spite of the storm), and was soon racing
against a Catalina 27 in the storm headed in the same direction.

Drowned to the bone by the deluge and having a ball, I soon felt the
hackles on my neck start tickling for no reason. I was leaning back
against the ungrounded backstay, without thinking about it, and holding
THE OCEAN in my hands, the metal wheel firmly attached by stainless
cables to the big aluminum rudder underwater! St Elmo's fire was
creeping up my arm to discharge that rigging.

I decided this was NOT the path to glory it said in the books, so moved
away from the backstay to stand on the upwind side of the wheel, steering
it from its side a little forward of the pedestal. There were two POPS
that jumped, one after the other, from the backstay to the wheel in my
hands about 5-10 minutes after I moved! It wasn't a lightning hit, it
was static discharging the rigging to that overhead black cloud. It
looked like the thin discharge from a Van Degraff static generator back
in high school physics class. They didn't hear it in the cabin.

I've often wondered how close we were to a major strike to the ungrounded
mainmast that lead down to the step in the bilge. Cap'n Geoffrey popped
his head up opening the hatch to see if I needed anything a few minutes
after. I didn't say anything, but I needed a change of pants....hee hee.

Larry
--
Roll up to the long checkout line....
Yell, "ICE RAID!"
It's your turn to load the grocery belt...(c;

Wayne.B wrote in
:

Every once in a while you hear about someone with a plastic thru hull
transducer getting blown out by lightning.



http://edis.ifas.ufl.edu/SG071
Great webpage. The professor of EE is also a sailor.

Enter:

Sailboat lightning grounding

into the Google search engine. There's lots of pages so you can do it
right.

NEVER MAKE A NEAT RIGHT ANGLE TURN ON A LIGHTNING GROUND! If you gotta
be "pretty", don't bother with it at all. ALL turns in ALL lightning
grounds MUST be made gradually over a large diameter, not those
"nautical" perfect looking turns the bilge pump wires have. This
reduceds series INDUCTANCE. Series inductance on the very-fast pulse of
a lightning hit is what destroys it....

http://www.copper.org/applications/e...kgbi_station_A
6082.html

http://www.space.com/businesstechnol...ket_lightning_
030130.html
Very interesting.....Xrays!


Larry
--
Roll up to the long checkout line....
Yell, "ICE RAID!"
It's your turn to load the grocery belt...(c;

Here's my list of lightning protection links. Probably more than you
ever wanted to know. I have a lightning rod on my mast, connected with
a large cable to a copper plate that I drop overboard when not
underway. Nothing will guarantee protection, but it's better than
nothing. At least it makes me feel better! :-)

http://www.kastenmarine.com/Lightning.htm
http://marinelightning.com/
http://www.thomson.ece.ufl.edu/lightning/
http://www.cdc.gov/nasd/docs/d000001...7/d000007.html
http://www.lightningsafety.com/
http://www.lightningsafety.com/nlsi_...od_recent.html -
specific info. on lightning rods
http://powerquality.com/ar/power_pre...tning_strikes/
http://www.lightningmaster.com/Structural.htm