Wayne.B wrote:
Larry wrote:

Wayne.B wrote:

The trouble with WM is that they have become so ubiquitous

That's ok as long as they don't become omnipotent...(c;

I believe the last person to claim ubiquitous omnipotence was struck
by lightening...

Funny that no one mentioned lightening as a sailing hazzard. I know
of at least half a dozen boats that have been hit, one twice in one
day, and another one or two sunk at the dock due to vaporized thru
hull fittings.

Is this preventable by installing a lightning prevention system ?
Tayana offers this as an option for $1000 but I don't know how
well it works.

On Sun, 18 Dec 2005 21:58:39 GMT, wrote:



Is this preventable by installing a lightning prevention system ?
Tayana offers this as an option for $1000 but I don't know how
well it works.

It is not preventable. Grounding systems provide protection by
creating a more attractive route to the lightning so that it does not
travel through the hull, woodwork or the crew.

Check out http://www.thomson.ece.ufl.edu/lightning/ for a good
discussion of lightning and boats.


Jack

_________________________________________
Jack Dale
ISPA Yachtmaster Offshore Instructor
CYA Advanced Cruising Instructor
http://www.swiftsuresailing.com
_________________________________________

wrote in news:jYkpf.3745$mj1.1632
@newsread3.news.pas.earthlink.net:

Is this preventable by installing a lightning prevention system ?
Tayana offers this as an option for $1000 but I don't know how
well it works.




Get that offer in writing so you can sue their asses in court when
lightning holes the hull.....(c;

NO lightning prevention system can prevent lightning from destroying the
boat....and still have a boat the waterline is below the toerail.
Lightning is hundreds of thousands of amps at billions of volts rising
from 0 in microseconds, creating an amazing electro-magnetic pulse,
which is what destroys all your electronic stuff. It only has to be
"close" to just blast it all to hell....

Most boats aren't really hit. A direct hit of this magnitude will melt a
metal mast, vaporizing a lot or all of it instantly. A direct hit
doesn't follow any grounding straps that are also vaporized instantly.
It came 10 MILES to that unfortunate mast and goes straight out the
bottom of what's left of it, straight through the hull, no matter what
material it's made of, and will create a hole around 4' across in wood,
fiberglass, plastic, shingled roof, etc. Your little boat is
insignificant to it all. We're talking Megajoules of energy in
microseconds.

What the grounding system will bypass is the static buildup or "St Elmo's
Fire" to the overhead cloud that may spark off the mast creating
electronic havoc aboard. It's pretty good doing that as long as there's
no SHARP, NEAT CORNERS the beautiful people love to put in everything so
it looks wonderful.

Here's some great pictures and movies for you to ponder from the
broadcast and power industry....
http://wvlightning.com/tower.shtml
http://sky-fire.tv/index.cgi/lightning.html
http://www.jampro.com/tech/NARTE.pdf

On Sun, 18 Dec 2005 19:28:11 -0500, Larry wrote:

///
NO lightning prevention system can prevent lightning from destroying the
boat....and still have a boat the waterline is below the toerail.
Lightning is hundreds of thousands of amps at billions of volts rising
from 0 in microseconds, creating an amazing electro-magnetic pulse,
which is what destroys all your electronic stuff. It only has to be
"close" to just blast it all to hell....
///

Not strictly comparable to boat strikes are airliner strikes. The
usual result of these is a pin hole or two going in and leaving the
skin. That's aluminum skin planes. Glass planes need more careful
design.....

Brian Whatcott Altus OK

Larry wrote:
wrote in news:jYkpf.3745$mj1.1632
@newsread3.news.pas.earthlink.net:


Is this preventable by installing a lightning prevention system ?
Tayana offers this as an option for $1000 but I don't know how
well it works.





Get that offer in writing so you can sue their asses in court when
lightning holes the hull.....(c;

NO lightning prevention system can prevent lightning from destroying the
boat....and still have a boat the waterline is below the toerail.
Lightning is hundreds of thousands of amps at billions of volts rising
from 0 in microseconds, creating an amazing electro-magnetic pulse,
which is what destroys all your electronic stuff. It only has to be
"close" to just blast it all to hell....

Most boats aren't really hit. A direct hit of this magnitude will melt a
metal mast, vaporizing a lot or all of it instantly. A direct hit
doesn't follow any grounding straps that are also vaporized instantly.
It came 10 MILES to that unfortunate mast and goes straight out the
bottom of what's left of it, straight through the hull, no matter what
material it's made of, and will create a hole around 4' across in wood,
fiberglass, plastic, shingled roof, etc. Your little boat is
insignificant to it all. We're talking Megajoules of energy in
microseconds.

What the grounding system will bypass is the static buildup or "St Elmo's
Fire" to the overhead cloud that may spark off the mast creating
electronic havoc aboard. It's pretty good doing that as long as there's
no SHARP, NEAT CORNERS the beautiful people love to put in everything so
it looks wonderful.

Here's some great pictures and movies for you to ponder from the
broadcast and power industry....
http://wvlightning.com/tower.shtml
http://sky-fire.tv/index.cgi/lightning.html
http://www.jampro.com/tech/NARTE.pdf

Not quite right. The 4' hole is possible but not a sure thing. My Dad
was in a 505 dinghy when it got hit by lightening. Nasty but they
survived and the boat was repairable.

Gaz

Brian Whatcott wrote in
:

Not strictly comparable to boat strikes are airliner strikes. The
usual result of these is a pin hole or two going in and leaving the
skin. That's aluminum skin planes. Glass planes need more careful
design.....



Airplane strikes aren't the intensity of one that hits the MASSIVE electron
supply of Mother Earth. Ground strikes can make the top of a big broadcast
tower simply vaporize from the intense current supplied by the electrons in
the ground.

I don't think I've ever seen the results of a ground strike hitting an
airplane on the tarmac. That might prove more interesting.

Gary wrote in news:tbppf.135388$ki.120635@pd7tw2no:

Not quite right. The 4' hole is possible but not a sure thing. My Dad
was in a 505 dinghy when it got hit by lightening. Nasty but they
survived and the boat was repairable.

Gaz


Static discharge. Lightning would have destroyed the dinghy and everyone
aboard.

On Mon, 19 Dec 2005 00:51:08 GMT, Brian Whatcott
wrote:

Not strictly comparable to boat strikes are airliner strikes. The
usual result of these is a pin hole or two going in and leaving the
skin. That's aluminum skin planes. Glass planes need more careful
design.....
====================================

I was in a large commercial jet that got hit by lightening at around
20,000 feet. It was an awsome experience. After several seconds of
totally stunned silence, everyone started looking around to see if we
were still alive. It took the pilot several minutes to get on the PA
system to announce the obvious and reassure us that all was OK. We
didn't know if he had been doing safety checks or just cleaning
himself up.

Larry wrote:
Gary wrote in news:tbppf.135388$ki.120635@pd7tw2no:


Not quite right. The 4' hole is possible but not a sure thing. My Dad
was in a 505 dinghy when it got hit by lightening. Nasty but they
survived and the boat was repairable.

Gaz



Static discharge. Lightning would have destroyed the dinghy and everyone
aboard.

Take another guess.

Gary wrote:
Larry wrote:
Gary wrote in
news:tbppf.135388$ki.120635@pd7tw2no:


Not quite right. The 4' hole is possible but not a sure thing. My
Dad was in a 505 dinghy when it got hit by lightening. Nasty but
they survived and the boat was repairable.

Gaz



Static discharge. Lightning would have destroyed the dinghy and
everyone aboard.

Take another guess.

Bet he didn't need to use hair curlers any more!