Re: [bolger] Lightning protection
----- Original Message -----
From: "lm2" <lm2@...>
To: <bolger@egroups.com>
Sent: Tuesday, June 06, 2000 9:15 AM
Subject: Re: [bolger] Lightning protection
> > So. Would Bob of the Loose Moose please give us an account of his
> lightning
> > encounter?
>
> I can tell you what the aftermath was like as I was not on the boat when
it
> happened...
>
> The mast had exploded (!!!) and when examined the pieces we could find the
> interior of the mast was charred...the energy apparently followed the
> antennea cable into the electrical system and exited out the battery bank
> blowing a 3' by 3' hole in the bottom ( just below the compaionway)...The
> energy also seems to have used our mooring chain ( 3/8 inch high test) as
> well as the link that was at water level was melted into a blob of very
> shiny metal (which set us loose) from our mooring.
>
> Loose Moose then found itself blown on to the rocks just in front of our
> Senate building here in St Thomas in six to eight feet of surf. Within 24
> hours Loose Moose had broken in two a total loss...
>
> When we built the boat I was very worried about lighting having been hit
> once on a transpacific delivery ( which fried everything electrical on the
> boat) of a boat with complete bonding and lighting rod...I talked to quite
a
> few experts on the subject and the consensus was that bonding and using a
> rod made one 20,000 times more likely to be hit by lightning and not
bonding
> made one 20,000 times less likely to be hit but if hit it would be VERY
> serious. Taking the laws of averages into account not bonding seemed to be
> the way to go and boy was I wrong!
>
> Bob
The antenna system provided a very poor bond to ground winding it's
way thourght the antenna, radio battery and anchor chain. Some of the
paths may have been a spark gap.
Gordon
Gordon Cougergcouger@...
Stillwater, OK www.couger.com/gcouger
405 624-2855 GMT -6:00
> I talked to quite aI don't think you were wrong. Roughly speaking, shaving with an
> few experts on the subject and the consensus was that bonding and using a
> rod made one 20,000 times more likely to be hit by lightning and not bonding
> made one 20,000 times less likely to be hit but if hit it would be VERY
> serious. Taking the laws of averages into account not bonding seemed to be
> the way to go and boy was I wrong!
>
> Bob
electric razor might make it 20,000 times more likely that you
will be electrocuted in your bathroom (there might be water in the
sink, and the razor might fall into it with you holding onto it).
Yet, I wouldn't say anybody using an electric razor is a stupid fool
just tempting fate.
The probability of being hit by a lightning is, I think, exceedingly
small, somewhat like the probability of being hit by a car while
crossing a street on green. I was once hit by a car while crossing
on green. Was I wrong to cross?
Sakari Aaltonen
>I talked to quite ausing a
> few experts on the subject and the consensus was that bonding and
> rod made one 20,000 times more likely to be hit by lightning andnot bonding
> made one 20,000 times less likely to be hit but if hit it would beVERY
> serious.A member of our yacht club studied lightening as a meteorologist, and
had the experience of having his brand-new Schock 25 struck by
lightening. He had connected the mast and rigging to the keel by
heavy copper wire. The lightening blew a substantial amount of
fairing material and paint off the keel. I don't recall what damage
there was topside, but they sailed home uninjured, which probably
counts for a victory under the circumstances.
Here is my understanding of the situation, mostly from watching the
Discovery Channel. As a large charge builds in the clouds, it causes
a large opposite charge to build in the earth below, like a
capacitor. Eventually, the charge in the clouds (which is negative
and represents excess electrons) starts down. As it approaches the
earth, the approach of the huge charge draws tiny trails of positive
ions upward. When the bolt is some tens of feet from the earth, it
intersects one of these, and follows its path back to earth, because
the ionized path is the lower reistance than burning a new route
through the air.
So, if your mast in grounded, then it provides a good starting point
for one of these upward trails, and increases your chance of being
hit, but provides a downward path that doesn't run through the body
of any crew members and possibly allows the bolt to pass through the
bottom of the boat without making a big hole. Hopefully, without
making any whole at all.
I think the theory of the lightning rod is to dissipate the charge
from the earth in the immediate region, so the bolt is drawn to a
more highly charged place nearby. The idea of a pointed lightning rod
goes back to Ben Franklin. The newer research which favors a more
rounded point suggests that the blunter tip is more successful at
ejecting ions, thus dissapating the charge to a greater extent.
Peter
> So. Would Bob of the Loose Moose please give us an account of hislightning
> encounter?I can tell you what the aftermath was like as I was not on the boat when it
happened...
The mast had exploded (!!!) and when examined the pieces we could find the
interior of the mast was charred...the energy apparently followed the
antennea cable into the electrical system and exited out the battery bank
blowing a 3' by 3' hole in the bottom ( just below the compaionway)...The
energy also seems to have used our mooring chain ( 3/8 inch high test) as
well as the link that was at water level was melted into a blob of very
shiny metal (which set us loose) from our mooring.
Loose Moose then found itself blown on to the rocks just in front of our
Senate building here in St Thomas in six to eight feet of surf. Within 24
hours Loose Moose had broken in two a total loss...
When we built the boat I was very worried about lighting having been hit
once on a transpacific delivery ( which fried everything electrical on the
boat) of a boat with complete bonding and lighting rod...I talked to quite a
few experts on the subject and the consensus was that bonding and using a
rod made one 20,000 times more likely to be hit by lightning and not bonding
made one 20,000 times less likely to be hit but if hit it would be VERY
serious. Taking the laws of averages into account not bonding seemed to be
the way to go and boy was I wrong!
Bob
My Freedom was hit by lightning in Florida just before we bought her - all
new electronics. It's completely bonded, from masts (about 8-10 ga. copper
wire) to through-hulls and a ssb external grounding plate. No hull damage
although you hear of hulls pierced by juice trying to get in or out of the
hull.
A whole marina was hit a month or two ago up on the lake in Oklahoma -
everything from burned shore power plugs to dead chargers, instruments, and
electronics - all up and down the dock. No doubt the whole dock was
shocked, but without grounding I would think you've got a chance.
Gregg Carlson
new electronics. It's completely bonded, from masts (about 8-10 ga. copper
wire) to through-hulls and a ssb external grounding plate. No hull damage
although you hear of hulls pierced by juice trying to get in or out of the
hull.
A whole marina was hit a month or two ago up on the lake in Oklahoma -
everything from burned shore power plugs to dead chargers, instruments, and
electronics - all up and down the dock. No doubt the whole dock was
shocked, but without grounding I would think you've got a chance.
Gregg Carlson
>Meanwhile, I cannot help but notice that in marinas with forests of masts,
>in bays full of anchored boats, lightning loss is minimal & lightning
>protection also seems to be. Sort of in the category of iceberg protection.
>
>In my experience, I have not been hit but have seen countless near misses. I
>know of no one else who has been hit except a small powerboat apparently
>going full throttle. I have never seen a boat that has been damaged by
>lightning. I don't recall Herman Melville, Alan Villiers, Captain Voss,
>Joshua Slocum, or Larry Pardey complain much about the stuff in their pages.
>Hiscock, who ponders all possibilities at sea, concedes the chances are
>small of being struck, and in the event the greatest danger is to electrical
>equipment, not to hull and rig integrity. He does not say he did a thing to
>protect his own boat.
>
>So. Would Bob of the Loose Moose please give us an account of his lightning
>encounter?
>
>And would Tim please tell us where the heck he is next time he gives us a
>climate history. This is a most frustrating tendency among all you
>Bolgeristas. For the record, I am in eastern Virginia, berthed on the
>Rappahannock River, an area of intense lightning activity.
Bill,
Re lightning striking boats: Years ago I got ready to write a magazine
article on the subject. I sent inquiries to several boat people, including
Bolger, and nearly all replies were "Not in my experience, but precautions
might be helpful. Who knows?" Who knows indeed! Bolger's reply was to the
effect that he had no knowledge but the subject was worth pursuing. Next I
looked up all I could find about preventive measures. These proved
impossibly (for me) elaborate and expensive. I was left wondering if, with
all those grounds and through-hulls, I might not be attracting lightning.
Despairing of hard knowledge, I abandoned writing the article.
Meanwhile, I cannot help but notice that in marinas with forests of masts,
in bays full of anchored boats, lightning loss is minimal & lightning
protection also seems to be. Sort of in the category of iceberg protection.
In my experience, I have not been hit but have seen countless near misses. I
know of no one else who has been hit except a small powerboat apparently
going full throttle. I have never seen a boat that has been damaged by
lightning. I don't recall Herman Melville, Alan Villiers, Captain Voss,
Joshua Slocum, or Larry Pardey complain much about the stuff in their pages.
Hiscock, who ponders all possibilities at sea, concedes the chances are
small of being struck, and in the event the greatest danger is to electrical
equipment, not to hull and rig integrity. He does not say he did a thing to
protect his own boat.
So. Would Bob of the Loose Moose please give us an account of his lightning
encounter?
And would Tim please tell us where the heck he is next time he gives us a
climate history. This is a most frustrating tendency among all you
Bolgeristas. For the record, I am in eastern Virginia, berthed on the
Rappahannock River, an area of intense lightning activity.
Get Your Private, Free E-mail from MSN Hotmail athttp://www.hotmail.com
Re lightning striking boats: Years ago I got ready to write a magazine
article on the subject. I sent inquiries to several boat people, including
Bolger, and nearly all replies were "Not in my experience, but precautions
might be helpful. Who knows?" Who knows indeed! Bolger's reply was to the
effect that he had no knowledge but the subject was worth pursuing. Next I
looked up all I could find about preventive measures. These proved
impossibly (for me) elaborate and expensive. I was left wondering if, with
all those grounds and through-hulls, I might not be attracting lightning.
Despairing of hard knowledge, I abandoned writing the article.
Meanwhile, I cannot help but notice that in marinas with forests of masts,
in bays full of anchored boats, lightning loss is minimal & lightning
protection also seems to be. Sort of in the category of iceberg protection.
In my experience, I have not been hit but have seen countless near misses. I
know of no one else who has been hit except a small powerboat apparently
going full throttle. I have never seen a boat that has been damaged by
lightning. I don't recall Herman Melville, Alan Villiers, Captain Voss,
Joshua Slocum, or Larry Pardey complain much about the stuff in their pages.
Hiscock, who ponders all possibilities at sea, concedes the chances are
small of being struck, and in the event the greatest danger is to electrical
equipment, not to hull and rig integrity. He does not say he did a thing to
protect his own boat.
So. Would Bob of the Loose Moose please give us an account of his lightning
encounter?
And would Tim please tell us where the heck he is next time he gives us a
climate history. This is a most frustrating tendency among all you
Bolgeristas. For the record, I am in eastern Virginia, berthed on the
Rappahannock River, an area of intense lightning activity.
>From: "William D> Jochems" <wjochems@...>________________________________________________________________________
>Reply-To:bolger@egroups.com
>To: "Bolger" <bolger@egroups.com>
>Subject: [bolger] Lightning protection
>Date: Sat, 3 Jun 2000 21:32:47 -0600
>
>Estimado grupo Bolger,
> Should a wooden boat, with a wooden mast and no wire rigging, be
>equipped with lightning protection before sailing into a region where
>thunder storms are prevalent?
>Bill Jochems
Get Your Private, Free E-mail from MSN Hotmail athttp://www.hotmail.com
When my father described the lightning protection that he put on his
Hunter 30, he said that in the development of Punta Gorda Isles, an
average of two boats per year were destroyed by lightning.
His system involved a lightning rod and a ground. The ground was a
large plate (shaped like a fish!) that hung off the back while the
boat was at its mooring.
I have this observation, which is frightening or comforting,
depending on your point of view. Around a mast, there is supposed to
be a "cone of protection" where lightening won't strike because it
will strike the mast instead. Looking at this backward, if the
natural place for the bolt to hit is outside the cone of protection
of your mast, then your mast won't attract it.
From a practical point of view, the question to answer is: once the
bolt hits your mast and travels down to the natural end of that
electrical path, where is it and where is it going to go? In many
small boats (including mine), there is no clear, preferred path to
water, and the bolt could flash most anywhere and through most
anything. So, it pays to think about providing a safe path from mast
to ground.
Peter
Hunter 30, he said that in the development of Punta Gorda Isles, an
average of two boats per year were destroyed by lightning.
His system involved a lightning rod and a ground. The ground was a
large plate (shaped like a fish!) that hung off the back while the
boat was at its mooring.
I have this observation, which is frightening or comforting,
depending on your point of view. Around a mast, there is supposed to
be a "cone of protection" where lightening won't strike because it
will strike the mast instead. Looking at this backward, if the
natural place for the bolt to hit is outside the cone of protection
of your mast, then your mast won't attract it.
From a practical point of view, the question to answer is: once the
bolt hits your mast and travels down to the natural end of that
electrical path, where is it and where is it going to go? In many
small boats (including mine), there is no clear, preferred path to
water, and the bolt could flash most anywhere and through most
anything. So, it pays to think about providing a safe path from mast
to ground.
Peter
--- Inbolger@egroups.com, "lm2" <lm2@v...> wrote:
Or possibly not? This topic is under discussion at the moment in
alt.sailing.asa For those Bolgeristi with strong stomachs, thick
hides and a good grasp on sanity, it's probably worth sifting through
the moveable bar-room brawl and psychopolitical maelstrom that
usually
constitutes the newsgroup, because in the midst of the flames there
is appearing useful information. The argument is evenly divided
between "the jury is still out" on lightning protection to "you're
marginally better off with it". Ignore posters on that ng with an
obvious incomprehension of physics!
LM2s fate worries me, I must admit, because while we're not badly
thunderstorm prone, we do get some doozies in front of summer
changes,
the cool air from the Southern Ocean and Antarctica fighting the
oven-like blasts from the hot arid interior. My current solution for
the AS29 is to park alongside something taller, or if I'm in the
middle of the lake, drop the masts and anchor!
The problem appears to be the necessity for an unbroken, high
capacity
wire feed from a ground in permanent contact with the water, to the
top of a (swinging!) mast; and that if the protection doesn't diffuse
the charge and one is struck anyway, one still ends up with a
blown-up
mast and a large hole in the bottom of the boat. Better perhaps than
losing the whole thing...
Tim & Flying Tadpole
> YES! Loose Moose 2 was lost due to a lightning hit...as they sayhindsight is 20/20
>-----
> Bob
Or possibly not? This topic is under discussion at the moment in
alt.sailing.asa For those Bolgeristi with strong stomachs, thick
hides and a good grasp on sanity, it's probably worth sifting through
the moveable bar-room brawl and psychopolitical maelstrom that
usually
constitutes the newsgroup, because in the midst of the flames there
is appearing useful information. The argument is evenly divided
between "the jury is still out" on lightning protection to "you're
marginally better off with it". Ignore posters on that ng with an
obvious incomprehension of physics!
LM2s fate worries me, I must admit, because while we're not badly
thunderstorm prone, we do get some doozies in front of summer
changes,
the cool air from the Southern Ocean and Antarctica fighting the
oven-like blasts from the hot arid interior. My current solution for
the AS29 is to park alongside something taller, or if I'm in the
middle of the lake, drop the masts and anchor!
The problem appears to be the necessity for an unbroken, high
capacity
wire feed from a ground in permanent contact with the water, to the
top of a (swinging!) mast; and that if the protection doesn't diffuse
the charge and one is struck anyway, one still ends up with a
blown-up
mast and a large hole in the bottom of the boat. Better perhaps than
losing the whole thing...
Tim & Flying Tadpole
YES! Loose Moose 2 was lost due to a lightning
hit...as they say hindsight is 20/20
Bob
----- Original Message -----From:William D> JochemsTo:BolgerSent:Saturday, June 03, 2000 10:32 PMSubject:[bolger] Lightning protectionEstimado grupo Bolger,Should a wooden boat, with a wooden mast and no wire rigging, be equipped with lightning protection before sailing into a region where thunder storms are prevalent?Bill Jochems
In a message dated 00-06-03 23:37:03 EDT, you write:
<< Should a wooden boat, with a wooden mast and no wire rigging, be equipped
with lightning protection before sailing into a region where thunder storms
are prevalent?
Writing in "Sea Sense", Richard Henderson says "...some form of
protection is needed except perhaps in certain cases when the boat has a
metal hull." Apparently part of the reason for this is to "prevent a
build-up of static electricity...which might encourage a lightning strike."
This is an early version of the book, but probably the same principles still
apply. Also, I would guess the boat would be vulnerable just by being the
highest point around. He recommends the ABYC standards for a protection
system.
Regards, Warren
<< Should a wooden boat, with a wooden mast and no wire rigging, be equipped
with lightning protection before sailing into a region where thunder storms
are prevalent?
>>To William and all:
Writing in "Sea Sense", Richard Henderson says "...some form of
protection is needed except perhaps in certain cases when the boat has a
metal hull." Apparently part of the reason for this is to "prevent a
build-up of static electricity...which might encourage a lightning strike."
This is an early version of the book, but probably the same principles still
apply. Also, I would guess the boat would be vulnerable just by being the
highest point around. He recommends the ABYC standards for a protection
system.
Regards, Warren