RE: [bolger] Re: Lightning protection
On Wed, 7 Jun 2000, Foster Price wrote:
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
> What do you make of that !!!That most people survive being hit by lightning. Most boats, too.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
Okay I can't resist any longer - I have to tell you about a person I saw
struck by lightning many years ago.
It was my Dad, and he was in those days a farmer. One evening he was
shutting his dogs into their runs (made of galvanised pipe covered in steel
mesh). Thre was a thunderstorm taking place and it was raining. My Dad
always used an umbrella in the rain (not normal for a farmer I know but he
didn't care!). So my Mum and I are looking out of the window at him as he
completed his chores before dinner, rather pleased that we weren't outside
in the rough weather. Just as he went to put the last dog in he got a
direct hit by a lightning bolt. The lightning seemed to arc down the
umbrella and onto the steel dog cage - both glowed with a blueish tinge. We
were horrified and rushed out but he was OK, and infact oblivious to what
had happened. The dogs were ok but the umbrella was a write-off, all the
metal joints were fused together as though spot-welded, and the fabric was
sort of chared where it touched the metal frame.
What do you make of that !!!
Regards - Foster
struck by lightning many years ago.
It was my Dad, and he was in those days a farmer. One evening he was
shutting his dogs into their runs (made of galvanised pipe covered in steel
mesh). Thre was a thunderstorm taking place and it was raining. My Dad
always used an umbrella in the rain (not normal for a farmer I know but he
didn't care!). So my Mum and I are looking out of the window at him as he
completed his chores before dinner, rather pleased that we weren't outside
in the rough weather. Just as he went to put the last dog in he got a
direct hit by a lightning bolt. The lightning seemed to arc down the
umbrella and onto the steel dog cage - both glowed with a blueish tinge. We
were horrified and rushed out but he was OK, and infact oblivious to what
had happened. The dogs were ok but the umbrella was a write-off, all the
metal joints were fused together as though spot-welded, and the fabric was
sort of chared where it touched the metal frame.
What do you make of that !!!
Regards - Foster
> -----Original Message-----
> From: Paul A. Lefebvre, Jr. [mailto:paul@...]
> Sent: Wednesday, 7 June 2000 10:16
> To:bolger@egroups.com
> Subject: RE: [bolger] Re: Lightning protection
>
>
> > -----Original Message-----
> > From: Roger Dewhurst [mailto:dewhurst@...]
> >
> > If your feet are too close together how do you kiss your
> arse goodbye?
>
> Guess you'd have to be pretty flexible! You probably wouldn't
> have time
> anyway!
>
> I'll add my 2 cents on what has turned out to be a very
> interesting thread -
> I think there's alot to this hold-the-ankles bit. I've got a
> fascination
> with lightning, and work alot with electricity. I've heard that fatal
> electric shocks occur when the current goes through the
> torso, and that
> occurs when one hand gets the jolt while the other is
> grounded, or even more
> likely when your feet are grounded and you take the charge
> from somewhere in
> your upper body - like the golfers you hear about every
> summer, caught on
> open ground with their graphite or metal clubs high in the
> air and their
> feet in a wide stance, in steel-spiked shoes, well grounded in
> over-irrigated turf! When this happens, the current
> essentially has to pass
> through your heart to get to ground. If you've got your feet
> close together,
> there is a smaller area in which your body may have happened
> upon a good
> ground, and if you're holding your ankles with your hands as
> was recommended
> earlier (I wouldn't want to be discovered this way, all crispy, but
> anyway....) you're lower and less likely to attract a bolt,
> your arms are
> not out there so you'd have to get hit in the head or the
> arse, whichever is
> higher, and even then it may go out your arms or legs to your
> feet and not
> kill you. Still wouldn't be a pleasant experience but maybe
> you'd live to
> tell about it.
>
> keep your heads down!
>
> Paul Lefebvre
>paul@...
>
>
>
>
> --------------------------------------------------------------
> ----------
> Accurate impartial advice on everything from laptops to table saws.
>http://click.egroups.com/1/4634/10/_/3457/_/960329305/
> --------------------------------------------------------------
> ----------
>
>
In a message dated 6/6/00 12:26:31 PM Central Daylight Time,
crandall@...writes:
<< And, of course, you've probably been using e-glass with your epoxy, and
e-glass stands for "electrical", and you know what that means.
In short, catastrophic failure. >>
I didn't notice any "smiley face" (":)") after this. Is this a joke I almost
understood?
Bill in MN
crandall@...writes:
<< And, of course, you've probably been using e-glass with your epoxy, and
e-glass stands for "electrical", and you know what that means.
In short, catastrophic failure. >>
I didn't notice any "smiley face" (":)") after this. Is this a joke I almost
understood?
Bill in MN
> -----Original Message-----Guess you'd have to be pretty flexible! You probably wouldn't have time
> From: Roger Dewhurst [mailto:dewhurst@...]
>
> If your feet are too close together how do you kiss your arse goodbye?
anyway!
I'll add my 2 cents on what has turned out to be a very interesting thread -
I think there's alot to this hold-the-ankles bit. I've got a fascination
with lightning, and work alot with electricity. I've heard that fatal
electric shocks occur when the current goes through the torso, and that
occurs when one hand gets the jolt while the other is grounded, or even more
likely when your feet are grounded and you take the charge from somewhere in
your upper body - like the golfers you hear about every summer, caught on
open ground with their graphite or metal clubs high in the air and their
feet in a wide stance, in steel-spiked shoes, well grounded in
over-irrigated turf! When this happens, the current essentially has to pass
through your heart to get to ground. If you've got your feet close together,
there is a smaller area in which your body may have happened upon a good
ground, and if you're holding your ankles with your hands as was recommended
earlier (I wouldn't want to be discovered this way, all crispy, but
anyway....) you're lower and less likely to attract a bolt, your arms are
not out there so you'd have to get hit in the head or the arse, whichever is
higher, and even then it may go out your arms or legs to your feet and not
kill you. Still wouldn't be a pleasant experience but maybe you'd live to
tell about it.
keep your heads down!
Paul Lefebvre
paul@...
>If you are fishing and your line starts floating up in the air it is time toIf your feet are too close together how do you kiss your arse goodbye?
>get the Hell out of there and get to land. If you are caught in the open
>squat down wiht your feet as close togeather as you can and grab
>your ankles. In case of a near strike you want as little area as possible
>to build up a charge and you want your feet close togeather so the voltage
>flowing through the ground will have the least difference between one foot
>and the other. I suppose the same would be true if you were caught in
>a boat. If you are caught in a boat stay as far away as you can from
>metal.
> A lead keel would make a good grounding plate.Yes, and well, no.
The lead keel will not *absorb* the charge.
It still needs to escape, and an encapsulated keel (such as a Micro),
would need a pathway to the water (which is a good grounding "plate").
This means the charge would find a way to jump from the lead to the
water, and it would probably make a hole through the plywood, fiberglass,
and epoxy to do it.
And, of course, you've probably been using e-glass with your epoxy, and
e-glass stands for "electrical", and you know what that means.
In short, catastrophic failure.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
From: "Stan Muller" <smuller@...>
It goes from the ground up most of the time. But it goes the other
way as well particulary near the most intense part of the storm.
Very good advise.
If you are fishing and your line starts floating up in the air it is time to
get the Hell out of there and get to land. If you are caught in the open
squat down wiht your feet as close togeather as you can and grab
your ankles. In case of a near strike you want as little area as possible
to build up a charge and you want your feet close togeather so the voltage
flowing through the ground will have the least difference between one foot
and the other. I suppose the same would be true if you were caught in
a boat. If you are caught in a boat stay as far away as you can from
metal.
And good luck
Gordon
Gordon Cougergcouger@...
Stillwater, OK www.couger.com/gcouger
405 624-2855 GMT -6:00
> Preface; I'm Not an expert in this field! But for the sake of=====
> the thread, I can pass along what I have been lead to understand.
> 1) Lightning discharges from the ground up, not from the sky down.
It goes from the ground up most of the time. But it goes the other
way as well particulary near the most intense part of the storm.
> 2) The best protection is not to give it a path to follow, no launch--------
> point, i.e. a wooden mast, with no stays, track, or wiring.
> 3) Rain water is a poor conductor, and it you wax the mast so the water
> beads up, it is even a poorer conductor.
> 4) So, unless you are planing to mount a copper plate under the boat, At
> about 10sqft, for salt water, and about 20sqft for fresh water, and then
> run copper wire the size of your thumb down each mast to a grid covering
> the boat, then to connected at several points to the underwater copper
> plate, it is better to do nothing. As has been said previously, to do
> anything less, will have you blowing holes in the bottom of your boat.
> Postscript; I'm Not an expert in this field! But this is what I
> have been told by the experts, and from my experiences of installing
> lightning protection on commercial buildings, I see no reason not to
> believe this to be true. This is for your information only, do what you
> think is best and make your up your own mind as what to do. Me, when
> faced with a storm, I drop any antennas and go ashore!
> Regards, Stan, Micro Tugger, Snow Goose
Very good advise.
If you are fishing and your line starts floating up in the air it is time to
get the Hell out of there and get to land. If you are caught in the open
squat down wiht your feet as close togeather as you can and grab
your ankles. In case of a near strike you want as little area as possible
to build up a charge and you want your feet close togeather so the voltage
flowing through the ground will have the least difference between one foot
and the other. I suppose the same would be true if you were caught in
a boat. If you are caught in a boat stay as far away as you can from
metal.
And good luck
Gordon
Gordon Cougergcouger@...
Stillwater, OK www.couger.com/gcouger
405 624-2855 GMT -6:00
Richard wrote, > Lots of trees get hit.
the tree apart by the rapid boiling of the super heated sap. The sap is
the conductor. Case in point, has anyone any first hand knowledge of a
dead tree being hit by lightning?
There is two kinds of damage from lightning. Static surge, this is
what commonly damages our electronics equipment. For this we use surge
protectors. At sea, in the days of old, it was called St. Elmos fire,
and for all intents and purposes, relatively harmless. The other
lightning damage is direct strike, This with it's millions of amperes,
does the blow up, tear apart and burn type damage. The only to protect
against this is to go to materials that can handle it, and they are
massive. On a regular farm house with its lightning rods, you will find
a copper wire about 5/8 inch diameter, connecting all the rods together,
and a drop of the same heavy wire from each rod to its own driven ground
rod.
A little hard to duplicate on a boat.
For what it's worth, Stan, M.T.,S.G.
>This is true, the lightning follows the sap, in fact many times blows
the tree apart by the rapid boiling of the super heated sap. The sap is
the conductor. Case in point, has anyone any first hand knowledge of a
dead tree being hit by lightning?
There is two kinds of damage from lightning. Static surge, this is
what commonly damages our electronics equipment. For this we use surge
protectors. At sea, in the days of old, it was called St. Elmos fire,
and for all intents and purposes, relatively harmless. The other
lightning damage is direct strike, This with it's millions of amperes,
does the blow up, tear apart and burn type damage. The only to protect
against this is to go to materials that can handle it, and they are
massive. On a regular farm house with its lightning rods, you will find
a copper wire about 5/8 inch diameter, connecting all the rods together,
and a drop of the same heavy wire from each rod to its own driven ground
rod.
A little hard to duplicate on a boat.
For what it's worth, Stan, M.T.,S.G.
Preface; I'm Not an expert in this field! But for the sake of
the thread, I can pass along what I have been lead to understand.
1) Lightning discharges from the ground up, not from the sky down.
2) The best protection is not to give it a path to follow, no launch
point, i.e. a wooden mast, with no stays, track, or wiring.
3) Rain water is a poor conductor, and it you wax the mast so the water
beads up, it is even a poorer conductor.
4) So, unless you are planing to mount a copper plate under the boat, At
about 10sqft, for salt water, and about 20sqft for fresh water, and then
run copper wire the size of your thumb down each mast to a grid covering
the boat, then to connected at several points to the underwater copper
plate, it is better to do nothing. As has been said previously, to do
anything less, will have you blowing holes in the bottom of your boat.
Postscript; I'm Not an expert in this field! But this is what I
have been told by the experts, and from my experiences of installing
lightning protection on commercial buildings, I see no reason not to
believe this to be true. This is for your information only, do what you
think is best and make your up your own mind as what to do. Me, when
faced with a storm, I drop any antennas and go ashore!
Regards, Stan, Micro Tugger, Snow Goose
the thread, I can pass along what I have been lead to understand.
1) Lightning discharges from the ground up, not from the sky down.
2) The best protection is not to give it a path to follow, no launch
point, i.e. a wooden mast, with no stays, track, or wiring.
3) Rain water is a poor conductor, and it you wax the mast so the water
beads up, it is even a poorer conductor.
4) So, unless you are planing to mount a copper plate under the boat, At
about 10sqft, for salt water, and about 20sqft for fresh water, and then
run copper wire the size of your thumb down each mast to a grid covering
the boat, then to connected at several points to the underwater copper
plate, it is better to do nothing. As has been said previously, to do
anything less, will have you blowing holes in the bottom of your boat.
Postscript; I'm Not an expert in this field! But this is what I
have been told by the experts, and from my experiences of installing
lightning protection on commercial buildings, I see no reason not to
believe this to be true. This is for your information only, do what you
think is best and make your up your own mind as what to do. Me, when
faced with a storm, I drop any antennas and go ashore!
Regards, Stan, Micro Tugger, Snow Goose
----- Original Message -----
From: "Lincoln Ross" <lincolnr@...>
To: <bolger@egroups.com>
Sent: Monday, June 05, 2000 6:53 PM
Subject: [bolger] Re: Lightning protection
> You don't say anything about a nice, direct cable from the mast to
> the
> motor, and if there was one it might set off the gasoline in the
> motor. The point is to provide a conductive path capable of carrying
> high currents without causing damage. Just "grounding" the boat won't
> work unless your hull, and mast are conductive. If not, you need a
> cable, a thick one without sharp turns or loops, connecting the high
> point with the ground. I am not an expert but I understand a little
> bit about electricity. Other significant metal objects might have to
> be connected as well, but the specifics of that are beyond my
> knowledge.
>
> BTW, I don't know but I'd guess that a lead keel would make a very
> good grounding plate.
>
> I recall that many years ago there was an article in "SAIL" magazine
> detailing how to protect your boat from lightning.
>
A lead keel would make a good grounding plate.
Copper flashing an 1/8 inch thick and 4 to 6 inches wide make a very
good conductor to bond other metal to the keel. It can be glued to the
hull and can be very much out of the way. Your gounds need to be in
a star arangement where each ground wired goes to the ground plate
not 'Y"s or loops. It would be a good idea for the power wires to be very
close to the ground wire/strap so you don't build up a charge on the
positive wiring.
It would be reasonable to use 1.5 or 2 inch rigid copper pipe as a ground
strap and a conduit for the rest of the wiring. If you used the lead or
steel
keel as ground the common tie point should be as near the engine and
battery as possible. Run your copper ground/conduit to each of the end
points from there. The ones that come to mind are the controls, mast, fore
and aft lighting. By creative routing you should be able to cover the
lighting
for the cabin with the conduit going to the fore lights.
This would also keep electrical noise low.
Gordon
Gordon Cougergcouger@...
Stillwater, OK www.couger.com/gcouger
405 624-2855 GMT -6:00
You don't say anything about a nice, direct cable from the mast to
the
motor, and if there was one it might set off the gasoline in the
motor. The point is to provide a conductive path capable of carrying
high currents without causing damage. Just "grounding" the boat won't
work unless your hull, and mast are conductive. If not, you need a
cable, a thick one without sharp turns or loops, connecting the high
point with the ground. I am not an expert but I understand a little
bit about electricity. Other significant metal objects might have to
be connected as well, but the specifics of that are beyond my
knowledge.
BTW, I don't know but I'd guess that a lead keel would make a very
good grounding plate.
I recall that many years ago there was an article in "SAIL" magazine
detailing how to protect your boat from lightning.
the
motor, and if there was one it might set off the gasoline in the
motor. The point is to provide a conductive path capable of carrying
high currents without causing damage. Just "grounding" the boat won't
work unless your hull, and mast are conductive. If not, you need a
cable, a thick one without sharp turns or loops, connecting the high
point with the ground. I am not an expert but I understand a little
bit about electricity. Other significant metal objects might have to
be connected as well, but the specifics of that are beyond my
knowledge.
BTW, I don't know but I'd guess that a lead keel would make a very
good grounding plate.
I recall that many years ago there was an article in "SAIL" magazine
detailing how to protect your boat from lightning.
--- Inbolger@egroups.com, "Vance Cowan" <vcgraphics@t...> wrote:
>
> > Lightning is unpredictable.
>
> There are almost 5000 "hits" on this site, we are not very good at
> keeping threads untangled, and the search engine seems to be
> the little engine that couldn't. So the following is from memory.
>
> One of the early messages was from someone who had a very
> bad lightning experience with his Micro. As I recollect it was
> moored with the masts up, and the outboard lower end just
> touching the water. Lightning struck, and his Micro burned to the
> waterline.
>
> Would a grounding plate have helped? The boat was grounded
> by the motor. The more I hear about lightning protection the less
> I seem to know.
>
> Vance
The engineer's study referred to earlier made a conclusion about
lightning rods that is NOT the same as conventional, i.e., Ben
Franklin, wisdom. He found that the sharp pointy rods used for
protection are not hit because they do not provide the protection
which one expects. In other words, with a pointy lightning rod for
protection, IF hit, it is LESS LIKELY to be on the rod! The more
effective "arrestors" in his experiments proved to be rods with
rounded, not pointy ends. Rounded end arrestors were more effective
in directing the lightning charge to ground and minimizing or
eliminating damage. Pointy arrestors were ineffective at directing
most of the charge to ground because they did not "collect" the
charges AIMED at them, therefor, "not hit as frequently."
BOTTOM LINE: contrary to convention, a rounded end lightning arrestor
is a far more effective provider of protection, WHEN YOU ARE HIT,
than a pointy end arrestor.
MY CHOICE: when hit by lightning, any combustible will burn, anything
containing moisture will explode, any noncombustible will get hot as
hell; I'm installing lightning protection with a rounded end arrestor.
lightning rods that is NOT the same as conventional, i.e., Ben
Franklin, wisdom. He found that the sharp pointy rods used for
protection are not hit because they do not provide the protection
which one expects. In other words, with a pointy lightning rod for
protection, IF hit, it is LESS LIKELY to be on the rod! The more
effective "arrestors" in his experiments proved to be rods with
rounded, not pointy ends. Rounded end arrestors were more effective
in directing the lightning charge to ground and minimizing or
eliminating damage. Pointy arrestors were ineffective at directing
most of the charge to ground because they did not "collect" the
charges AIMED at them, therefor, "not hit as frequently."
BOTTOM LINE: contrary to convention, a rounded end lightning arrestor
is a far more effective provider of protection, WHEN YOU ARE HIT,
than a pointy end arrestor.
MY CHOICE: when hit by lightning, any combustible will burn, anything
containing moisture will explode, any noncombustible will get hot as
hell; I'm installing lightning protection with a rounded end arrestor.
--- Inbolger@egroups.com, "Vance Cowan" <vcgraphics@t...> wrote:
and dangle them overboard attached to your stays. The idea is to
provide a path to ground. The problem is that the the chain probably
won't have the recommended wetted area, which is a couple of square
feet, as I remember.
And it is also not a solution for the original problem which was an
unstayed wooded mast.
Peter
>An old idea about lightning protection is to carry lengths of chain
> > Lightning is unpredictable.
>
and dangle them overboard attached to your stays. The idea is to
provide a path to ground. The problem is that the the chain probably
won't have the recommended wetted area, which is a couple of square
feet, as I remember.
And it is also not a solution for the original problem which was an
unstayed wooded mast.
Peter
> Lightning is unpredictable.There are almost 5000 "hits" on this site, we are not very good at
keeping threads untangled, and the search engine seems to be
the little engine that couldn't. So the following is from memory.
One of the early messages was from someone who had a very
bad lightning experience with his Micro. As I recollect it was
moored with the masts up, and the outboard lower end just
touching the water. Lightning struck, and his Micro burned to the
waterline.
Would a grounding plate have helped? The boat was grounded
by the motor. The more I hear about lightning protection the less
I seem to know.
Vance
On Mon, 5 Jun 2000, Orr, Jamie wrote:
through the nice big metal mast.
Hole made by lightning tend to be surprisingly small.
About 1 cm is the cutoff between a small lightning hole
and a big lightning hole.
small, on any given lightning storm. I've been out sailing in several,
never got hit. (Didn't want to be there, but in Florida, sometimes
there's no choice and no place to hide.)
Had some friends anchored off of Cumberland Island, first island north of
Florida (where JFK Jr got married). They spend two hours in the storm,
and the 6 boats that were anchored together (the Gulf-Atlantic Yacht Club
overnight outing) were never hit. Lightning was seen to hit the water
quite close to them.
Lightning is unpredictable.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
> If a mast has wire shrouds and stays, does it matter what the mast isStays will carry a current, yes, but the juice would prefer to follow down
> made of -- assuming it does with no shrouds and stays?
through the nice big metal mast.
> To discharge a lightning strike, how big and heavy does the copperMy expert says "jumper cable size" (and not those mini-ones).
> wire/rod have to be?
> it practical to have any protection -- would the weight in the mast beNot all that big, esp. if there's a plate down there.
> significant? Also (still on the same question) it appears that it
> would take a large ground in the hull to pass the charge without
> putting a large hole in the hull -- how big does it need to be?
Hole made by lightning tend to be surprisingly small.
About 1 cm is the cutoff between a small lightning hole
and a big lightning hole.
> Finally, if a small boat is hit, it seems to me its going to beYes, it does. However, the probability of being hit is surprisingly
> severely damaged whether protected or not, so the important question
> would be, does protection improve the chances of survival for the
> occupants, once hit?
small, on any given lightning storm. I've been out sailing in several,
never got hit. (Didn't want to be there, but in Florida, sometimes
there's no choice and no place to hide.)
Had some friends anchored off of Cumberland Island, first island north of
Florida (where JFK Jr got married). They spend two hours in the storm,
and the 6 boats that were anchored together (the Gulf-Atlantic Yacht Club
overnight outing) were never hit. Lightning was seen to hit the water
quite close to them.
Lightning is unpredictable.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
On Mon, 5 Jun 2000, Richard Spelling wrote:
:-)
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
> I'm sure these pages answer those questions:You don't suppose they'll end up suggesting you buy their product, do you?
>http://www.lightningrods.com/
:-)
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
I'm sure these pages answer those questions:
http://www.lightningrods.com/
http://www.lightningrods.com/
----- Original Message -----
From: "Orr, Jamie" <jorr@...>
To: <bolger@egroups.com>
Sent: Monday, June 05, 2000 3:56 PM
Subject: RE: [bolger] Re: Lightning protection
> Thought I'd jump in with some questions.
>
> If a mast has wire shrouds and stays, does it matter what the mast is made
> of -- assuming it does with no shrouds and stays?
>
> To discharge a lightning strike, how big and heavy does the copper
wire/rod
> have to be? I'm wondering how big a boat has to be to make it practical
to
> have any protection -- would the weight in the mast be significant? Also
> (still on the same question) it appears that it would take a large ground
in
> the hull to pass the charge without putting a large hole in the hull --
how
> big does it need to be?
>
> Finally, if a small boat is hit, it seems to me its going to be severely
> damaged whether protected or not, so the important question would be, does
> protection improve the chances of survival for the occupants, once hit?
>
> Yours in ignorance,
>
> Jamie Orr
>
> -----Original Message-----
> From: Sakari Aaltonen [mailto:sakaria@...]
> Sent: None
> To:bolger@egroups.com
> Subject: Re: [bolger] Re: Lightning protection
>
>
> Richard Spelling wrote
> >
> > Actualy, the way I understand it, charge difference is between the
> > ground/water and the clouds. It is concentrated on nice tall pointy
things
> > regardless of whether they are metal or wood.
>
> OK, let's picture a marina with 21 sailboats. 20 wooden masts, one
> metal one. All 21 masts are equally tall and equally pointy.
>
> Lightning strikes and hits one of the masts.
>
> Which one?
>
>
> Sakari Aaltonen
>
> ------------------------------------------------------------------------
> Failed tests, classes skipped, forgotten locker combinations.
> Remember the good 'ol days
>http://click.egroups.com/1/4053/10/_/3457/_/960237248/
> ------------------------------------------------------------------------
>
>
> ------------------------------------------------------------------------
> Failed tests, classes skipped, forgotten locker combinations.
> Remember the good 'ol days
>http://click.egroups.com/1/4053/10/_/3457/_/960238739/
> ------------------------------------------------------------------------
>
>
Don't you love the internet?
http://wvlightning.com/myths.html
"For instance, if there are two posts of the same height in a field, one
wood and one steel, if they are far enough apart they are both equally
vulnerable to a lightning strike. Only if they are close enough together
will the lightning be more likely to strike the steel post. "
So, Bill should park his boat next to taller boats with metal masts. Or,
have a lighning system for when he's the tallest one around...
http://wvlightning.com/myths.html
"For instance, if there are two posts of the same height in a field, one
wood and one steel, if they are far enough apart they are both equally
vulnerable to a lightning strike. Only if they are close enough together
will the lightning be more likely to strike the steel post. "
So, Bill should park his boat next to taller boats with metal masts. Or,
have a lighning system for when he's the tallest one around...
----- Original Message -----
From: "Richard Spelling" <richard@...>
To: <bolger@egroups.com>
Sent: Monday, June 05, 2000 4:11 PM
Subject: Re: [bolger] Re: Lightning protection
> interesting
>
> It is concentrated on tall things, and discharged into the air on the
pointy
> parts?
>
> So, Bill, you should have a lightning system that has pointy rods on your
> WDJ then!
> (note obligatory Bolger boat reference)
>
> ----- Original Message -----
> From: "Chris Crandall" <crandall@...>
> To: <bolger@egroups.com>
> Sent: Monday, June 05, 2000 3:48 PM
> Subject: Re: [bolger] Re: Lightning protection
>
>
> > On Mon, 5 Jun 2000, Richard Spelling wrote:
> > > If the rod had a really sharp point, it might discharge some via
> > > corona discharge.
> > and
> > > It is concentrated on nice tall pointy things regardless of whether
> > > they are metal or wood.
> >
> > I heard on the radio yesterday, a engineer doing some research on
> > lightning found that sharp pointy lightning rods rec'd far fewer strikes
> > than dull, roundy tipped ones. In fact, in his research, although the
> > round ones got lots of strikes, the pointy ones in the same area got
zero
> > strikes.
> >
> > Chris Crandallcrandall@...(785) 864-4131
> > Department of Psychology University of Kansas Lawrence, KS 66045
> > I have data convincingly disconfirming the Duhem-Quine hypothesis.
> >
> >
> >
> > ------------------------------------------------------------------------
> > Failed tests, classes skipped, forgotten locker combinations.
> > Remember the good 'ol days
> >http://click.egroups.com/1/4053/10/_/3457/_/960238844/
> > ------------------------------------------------------------------------
> >
> >
>
>
> ------------------------------------------------------------------------
> Bids starting at $7 for thousands of products - uBid.com
>http://click.egroups.com/1/3027/10/_/3457/_/960239555/
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>
>
interesting
It is concentrated on tall things, and discharged into the air on the pointy
parts?
So, Bill, you should have a lightning system that has pointy rods on your
WDJ then!
(note obligatory Bolger boat reference)
It is concentrated on tall things, and discharged into the air on the pointy
parts?
So, Bill, you should have a lightning system that has pointy rods on your
WDJ then!
(note obligatory Bolger boat reference)
----- Original Message -----
From: "Chris Crandall" <crandall@...>
To: <bolger@egroups.com>
Sent: Monday, June 05, 2000 3:48 PM
Subject: Re: [bolger] Re: Lightning protection
> On Mon, 5 Jun 2000, Richard Spelling wrote:
> > If the rod had a really sharp point, it might discharge some via
> > corona discharge.
> and
> > It is concentrated on nice tall pointy things regardless of whether
> > they are metal or wood.
>
> I heard on the radio yesterday, a engineer doing some research on
> lightning found that sharp pointy lightning rods rec'd far fewer strikes
> than dull, roundy tipped ones. In fact, in his research, although the
> round ones got lots of strikes, the pointy ones in the same area got zero
> strikes.
>
> Chris Crandallcrandall@...(785) 864-4131
> Department of Psychology University of Kansas Lawrence, KS 66045
> I have data convincingly disconfirming the Duhem-Quine hypothesis.
>
>
>
> ------------------------------------------------------------------------
> Failed tests, classes skipped, forgotten locker combinations.
> Remember the good 'ol days
>http://click.egroups.com/1/4053/10/_/3457/_/960238844/
> ------------------------------------------------------------------------
>
>
Thought I'd jump in with some questions.
If a mast has wire shrouds and stays, does it matter what the mast is made
of -- assuming it does with no shrouds and stays?
To discharge a lightning strike, how big and heavy does the copper wire/rod
have to be? I'm wondering how big a boat has to be to make it practical to
have any protection -- would the weight in the mast be significant? Also
(still on the same question) it appears that it would take a large ground in
the hull to pass the charge without putting a large hole in the hull -- how
big does it need to be?
Finally, if a small boat is hit, it seems to me its going to be severely
damaged whether protected or not, so the important question would be, does
protection improve the chances of survival for the occupants, once hit?
Yours in ignorance,
Jamie Orr
-----Original Message-----
From: Sakari Aaltonen [mailto:sakaria@...]
Sent: None
To:bolger@egroups.com
Subject: Re: [bolger] Re: Lightning protection
Richard Spelling wrote
metal one. All 21 masts are equally tall and equally pointy.
Lightning strikes and hits one of the masts.
Which one?
Sakari Aaltonen
------------------------------------------------------------------------
Failed tests, classes skipped, forgotten locker combinations.
Remember the good 'ol days
http://click.egroups.com/1/4053/10/_/3457/_/960237248/
------------------------------------------------------------------------
If a mast has wire shrouds and stays, does it matter what the mast is made
of -- assuming it does with no shrouds and stays?
To discharge a lightning strike, how big and heavy does the copper wire/rod
have to be? I'm wondering how big a boat has to be to make it practical to
have any protection -- would the weight in the mast be significant? Also
(still on the same question) it appears that it would take a large ground in
the hull to pass the charge without putting a large hole in the hull -- how
big does it need to be?
Finally, if a small boat is hit, it seems to me its going to be severely
damaged whether protected or not, so the important question would be, does
protection improve the chances of survival for the occupants, once hit?
Yours in ignorance,
Jamie Orr
-----Original Message-----
From: Sakari Aaltonen [mailto:sakaria@...]
Sent: None
To:bolger@egroups.com
Subject: Re: [bolger] Re: Lightning protection
Richard Spelling wrote
>OK, let's picture a marina with 21 sailboats. 20 wooden masts, one
> Actualy, the way I understand it, charge difference is between the
> ground/water and the clouds. It is concentrated on nice tall pointy things
> regardless of whether they are metal or wood.
metal one. All 21 masts are equally tall and equally pointy.
Lightning strikes and hits one of the masts.
Which one?
Sakari Aaltonen
------------------------------------------------------------------------
Failed tests, classes skipped, forgotten locker combinations.
Remember the good 'ol days
http://click.egroups.com/1/4053/10/_/3457/_/960237248/
------------------------------------------------------------------------
On Mon, 5 Jun 2000, Sakari Aaltonen wrote:
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
> OK, let's picture a marina with 21 sailboats. 20 wooden masts, oneNobody knows. Lightning is not predictable like that.
> metal one. All 21 masts are equally tall and equally pointy.
> Lightning strikes and hits one of the masts.
> Which one?
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
Excluding edge effects (more chance to hit on the sides and corners),
effectivly random.
I could certainly be wrong, I'm not a lightning specialist.
Unlike the static charge you get from rubbing your socks on the carpet, the
voltages in lightning is enough to jump thousands of feet of air and ground
out through hundreds of feet of non-conductive tree.
At these voltages, air, normaly a very good insulator (better than wood), is
carrying current. I would guess (IMHO) that considering that, there is
little effective difference between wood and metal as far as lightning
strikes.
I'm sure someone has done a study on this, we should look it up.
effectivly random.
I could certainly be wrong, I'm not a lightning specialist.
Unlike the static charge you get from rubbing your socks on the carpet, the
voltages in lightning is enough to jump thousands of feet of air and ground
out through hundreds of feet of non-conductive tree.
At these voltages, air, normaly a very good insulator (better than wood), is
carrying current. I would guess (IMHO) that considering that, there is
little effective difference between wood and metal as far as lightning
strikes.
I'm sure someone has done a study on this, we should look it up.
----- Original Message -----
From: "Sakari Aaltonen" <sakaria@...>
To: <bolger@egroups.com>
Sent: Monday, June 05, 2000 3:34 PM
Subject: Re: [bolger] Re: Lightning protection
> Richard Spelling wrote
> >
> > Actualy, the way I understand it, charge difference is between the
> > ground/water and the clouds. It is concentrated on nice tall pointy
things
> > regardless of whether they are metal or wood.
>
> OK, let's picture a marina with 21 sailboats. 20 wooden masts, one
> metal one. All 21 masts are equally tall and equally pointy.
>
> Lightning strikes and hits one of the masts.
>
> Which one?
>
>
> Sakari Aaltonen
>
> ------------------------------------------------------------------------
> Failed tests, classes skipped, forgotten locker combinations.
> Remember the good 'ol days
>http://click.egroups.com/1/4053/10/_/3457/_/960237248/
> ------------------------------------------------------------------------
>
>
On Mon, 5 Jun 2000, Richard Spelling wrote:
lightning found that sharp pointy lightning rods rec'd far fewer strikes
than dull, roundy tipped ones. In fact, in his research, although the
round ones got lots of strikes, the pointy ones in the same area got zero
strikes.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
> If the rod had a really sharp point, it might discharge some viaand
> corona discharge.
> It is concentrated on nice tall pointy things regardless of whetherI heard on the radio yesterday, a engineer doing some research on
> they are metal or wood.
lightning found that sharp pointy lightning rods rec'd far fewer strikes
than dull, roundy tipped ones. In fact, in his research, although the
round ones got lots of strikes, the pointy ones in the same area got zero
strikes.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
Richard Spelling wrote
metal one. All 21 masts are equally tall and equally pointy.
Lightning strikes and hits one of the masts.
Which one?
Sakari Aaltonen
>OK, let's picture a marina with 21 sailboats. 20 wooden masts, one
> Actualy, the way I understand it, charge difference is between the
> ground/water and the clouds. It is concentrated on nice tall pointy things
> regardless of whether they are metal or wood.
metal one. All 21 masts are equally tall and equally pointy.
Lightning strikes and hits one of the masts.
Which one?
Sakari Aaltonen
> Richard Spelling wrotecan
> > The static
> > charge is what attracts the lightning, not the conductivity, and wood
> > hold just as much static charge as metal.I always thought that the point of the lightning conductors was to discharge
> >
>
> But isn't the very point of metal lightning conductors that they
> discharge into ground, immediately, any charge that comes their way?
> Hou would they build up a lightning-attracting static charge?
>
>
the strike into the ground and not the boat/house/etc. If the rod had a
really sharp point, it might discharge some via corona discharge. But if the
purpose is to discharge the static buildup from the structure, it should be
attached to the structure and not the ground.
Actualy, the way I understand it, charge difference is between the
ground/water and the clouds. It is concentrated on nice tall pointy things
regardless of whether they are metal or wood.
> > I would put in the lightning system to discharge the current from astrike,
> > I don't think it would make one any more likely.Yes, that would be foolish. As would be carrying a plastic or wood pole of
>
> Let's say I'm walking along a road in a thunderstorm carrying
> a metal pole of some length that points up. I'm not being
> foolish? It doesn't make any difference?
>
equal length. Or walking on the road with no trees around in a storm...
Generaly, you don't want to be the tallest thing around, but if you are, you
want a nice thick wire leading to the ground to conduct the current when you
get struck...
(What I've always wondered is how those people with wireless cable get away
with putting a 30 ft metal pole on the top of their house, and connecting it
to the most expensive electronics in the house... they must be charmed)
>
> Sakari Aaltonen
>
>
> ------------------------------------------------------------------------
> Failed tests, classes skipped, forgotten locker combinations.
> Remember the good 'ol days
>http://click.egroups.com/1/4053/10/_/3457/_/960230102/
> ------------------------------------------------------------------------
>
>
Richard Spelling wrote
discharge into ground, immediately, any charge that comes their way?
Hou would they build up a lightning-attracting static charge?
a metal pole of some length that points up. I'm not being
foolish? It doesn't make any difference?
Sakari Aaltonen
> The staticBut isn't the very point of metal lightning conductors that they
> charge is what attracts the lightning, not the conductivity, and wood can
> hold just as much static charge as metal.
>
discharge into ground, immediately, any charge that comes their way?
Hou would they build up a lightning-attracting static charge?
> I would put in the lightning system to discharge the current from a strike,Let's say I'm walking along a road in a thunderstorm carrying
> I don't think it would make one any more likely.
a metal pole of some length that points up. I'm not being
foolish? It doesn't make any difference?
Sakari Aaltonen
If you want my 2 cents, at the voltages we are talking about, a wooden mast
is almost as good a conductor of (static) electricity as a metal one. If you
are the only boat in the middle of the storm, and lightning is likely, then
you will get struck just as easily as one with a metal mast. The static
charge is what attracts the lightning, not the conductivity, and wood can
hold just as much static charge as metal.
The difference being that the a metal mast would not explode from the
current caused by the actual strike.
Lots of trees get hit.
I would put in the lightning system to discharge the current from a strike,
I don't think it would make one any more likely.
is almost as good a conductor of (static) electricity as a metal one. If you
are the only boat in the middle of the storm, and lightning is likely, then
you will get struck just as easily as one with a metal mast. The static
charge is what attracts the lightning, not the conductivity, and wood can
hold just as much static charge as metal.
The difference being that the a metal mast would not explode from the
current caused by the actual strike.
Lots of trees get hit.
I would put in the lightning system to discharge the current from a strike,
I don't think it would make one any more likely.
----- Original Message -----
From: "William D> Jochems" <wjochems@...>
To: <bolger@egroups.com>
Sent: Monday, June 05, 2000 11:04 AM
Subject: Re: [bolger] Re: Lightning protection
> In reply to Chris Crandall, I asked originally if a wooden boat, with an
> unstayed wooden mast, should be equipped with lightning protection. Isn't
> such a boat, without protection, less likely to attract lightning than a
> boat with a metal mast and wire stays and also without protection?
> So, by adding the protection to the wooden mast are you really increasing
> the risk?
> Bill
> -----Original Message-----
> From: Chris Crandall <crandall@...>
> To:bolger@egroups.com<bolger@egroups.com>
> Date: Monday, June 05, 2000 8:43 AM
> Subject: Re: [bolger] Re: Lightning protection
>
>
> >On Sun, 4 Jun 2000, lm2 wrote:
> >> ...or how to repair the big hole in your bottom if you decide not to
> >> put in the lightning protection.
> >
> >WHile living in Gainesville, Florida (the lightning capital of the
world),
> >I was fortunate enough to hear a presentation by an engineer who talked
> >about lightning and sailboats--he had a major Sea Grant to do this
> >research, and I later learned he is one of the acknolwedged top experts
in
> >that area.
> >
> >At the end of his talk, we talked pragmatics. It seems that lightning
> >protection increases the safety of one's boat *if* you are hit.
> >Unfortunately, lightning protection increases the probability that you
> >will get hit.
> >
> >He really did not make a recommendation--I can assure you that he was
> >quite knowledgeable about just about everything in this area.
> >
> >By the way, the safest place in a lightning storm is in the cabin, near
> >the middle, abaft the mast, and away from anything metal.
> >
> > Chris Crandallcrandall@...(785) 864-4131
> > Department of Psychology University of Kansas Lawrence, KS 66045
> > I have data convincingly disconfirming the Duhem-Quine hypothesis.
> >
> >
> >
> >------------------------------------------------------------------------
> >Failed tests, classes skipped, forgotten locker combinations.
> >Remember the good 'ol days
> >http://click.egroups.com/1/4053/10/_/3457/_/960216201/
> >------------------------------------------------------------------------
> >
> >
> >
>
>
> ------------------------------------------------------------------------
> Porsche Boxter. You and a friend. Nine dream days from
> Napa Valley to Beverly Hills. Provided by CarsDirect.com.
> Click to enter.
>http://click.egroups.com/1/4882/10/_/3457/_/960221361/
> ------------------------------------------------------------------------
>
>
In reply to Chris Crandall, I asked originally if a wooden boat, with an
unstayed wooden mast, should be equipped with lightning protection. Isn't
such a boat, without protection, less likely to attract lightning than a
boat with a metal mast and wire stays and also without protection?
So, by adding the protection to the wooden mast are you really increasing
the risk?
Bill
-----Original Message-----
From: Chris Crandall <crandall@...>
To:bolger@egroups.com<bolger@egroups.com>
Date: Monday, June 05, 2000 8:43 AM
Subject: Re: [bolger] Re: Lightning protection
unstayed wooden mast, should be equipped with lightning protection. Isn't
such a boat, without protection, less likely to attract lightning than a
boat with a metal mast and wire stays and also without protection?
So, by adding the protection to the wooden mast are you really increasing
the risk?
Bill
-----Original Message-----
From: Chris Crandall <crandall@...>
To:bolger@egroups.com<bolger@egroups.com>
Date: Monday, June 05, 2000 8:43 AM
Subject: Re: [bolger] Re: Lightning protection
>On Sun, 4 Jun 2000, lm2 wrote:
>> ...or how to repair the big hole in your bottom if you decide not to
>> put in the lightning protection.
>
>WHile living in Gainesville, Florida (the lightning capital of the world),
>I was fortunate enough to hear a presentation by an engineer who talked
>about lightning and sailboats--he had a major Sea Grant to do this
>research, and I later learned he is one of the acknolwedged top experts in
>that area.
>
>At the end of his talk, we talked pragmatics. It seems that lightning
>protection increases the safety of one's boat *if* you are hit.
>Unfortunately, lightning protection increases the probability that you
>will get hit.
>
>He really did not make a recommendation--I can assure you that he was
>quite knowledgeable about just about everything in this area.
>
>By the way, the safest place in a lightning storm is in the cabin, near
>the middle, abaft the mast, and away from anything metal.
>
> Chris Crandallcrandall@...(785) 864-4131
> Department of Psychology University of Kansas Lawrence, KS 66045
> I have data convincingly disconfirming the Duhem-Quine hypothesis.
>
>
>
>------------------------------------------------------------------------
>Failed tests, classes skipped, forgotten locker combinations.
>Remember the good 'ol days
>http://click.egroups.com/1/4053/10/_/3457/_/960216201/
>------------------------------------------------------------------------
>
>
>
On Sun, 4 Jun 2000, lm2 wrote:
I was fortunate enough to hear a presentation by an engineer who talked
about lightning and sailboats--he had a major Sea Grant to do this
research, and I later learned he is one of the acknolwedged top experts in
that area.
At the end of his talk, we talked pragmatics. It seems that lightning
protection increases the safety of one's boat *if* you are hit.
Unfortunately, lightning protection increases the probability that you
will get hit.
He really did not make a recommendation--I can assure you that he was
quite knowledgeable about just about everything in this area.
By the way, the safest place in a lightning storm is in the cabin, near
the middle, abaft the mast, and away from anything metal.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
> ...or how to repair the big hole in your bottom if you decide not toWHile living in Gainesville, Florida (the lightning capital of the world),
> put in the lightning protection.
I was fortunate enough to hear a presentation by an engineer who talked
about lightning and sailboats--he had a major Sea Grant to do this
research, and I later learned he is one of the acknolwedged top experts in
that area.
At the end of his talk, we talked pragmatics. It seems that lightning
protection increases the safety of one's boat *if* you are hit.
Unfortunately, lightning protection increases the probability that you
will get hit.
He really did not make a recommendation--I can assure you that he was
quite knowledgeable about just about everything in this area.
By the way, the safest place in a lightning storm is in the cabin, near
the middle, abaft the mast, and away from anything metal.
Chris Crandallcrandall@...(785) 864-4131
Department of Psychology University of Kansas Lawrence, KS 66045
I have data convincingly disconfirming the Duhem-Quine hypothesis.
Take a look at Parkers' "The New Cold Molded Boatbuilding" as he has a great
section on protecting a boat with wood masts and no rigging...
...or how to repair the big hole in your bottom if you decide not to put in
the lightning protection.
Bob & Sheila
section on protecting a boat with wood masts and no rigging...
...or how to repair the big hole in your bottom if you decide not to put in
the lightning protection.
Bob & Sheila
From: "Peter Vanderwaart" <pvanderw@...>
hull and 2 inch solid copper rod through the hull connected directly
to the alumimum mast. If you had a wooden mast I would put as big
a copper pipe as I could inside the mast.
The connection from the mast to the copper though hull should have
as little curve in it as possible and should be made with a very large
wire. The Idea situation would be for the mast to go right through the
hull and connect to the copper sheets.
You also need some way to seal the hole that the lighting makes in the
hull.
Chain plate and any where a guy wire is attached need to be bonded
to the copper sheet that make up the ground system. Large copper
flashing works well for that.
A complete copper bottom would be the ideal ground.
Any wires should be inside the metal mast or copper pipe or high voltage
and current will be induced in any wire the runs along the outside of the
metal mast. Some will probably be induced on the wire inside but it will
be a lot less. You can proably right off ever electrical appliance that is
connected to the wiring system. This includes radios, GPS, electronic
ignition and fuel injection, generators, alternators and posibly the
battries.
Disconnecting radios and what have you will protect them from both direct
and close lighting strikes.
When in dock try to tie up to a ship with a taller mast so his cone of
protection
covers you.
>I would think a large copper plate attached to the outside of the
> 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.
hull and 2 inch solid copper rod through the hull connected directly
to the alumimum mast. If you had a wooden mast I would put as big
a copper pipe as I could inside the mast.
The connection from the mast to the copper though hull should have
as little curve in it as possible and should be made with a very large
wire. The Idea situation would be for the mast to go right through the
hull and connect to the copper sheets.
You also need some way to seal the hole that the lighting makes in the
hull.
Chain plate and any where a guy wire is attached need to be bonded
to the copper sheet that make up the ground system. Large copper
flashing works well for that.
A complete copper bottom would be the ideal ground.
Any wires should be inside the metal mast or copper pipe or high voltage
and current will be induced in any wire the runs along the outside of the
metal mast. Some will probably be induced on the wire inside but it will
be a lot less. You can proably right off ever electrical appliance that is
connected to the wiring system. This includes radios, GPS, electronic
ignition and fuel injection, generators, alternators and posibly the
battries.
Disconnecting radios and what have you will protect them from both direct
and close lighting strikes.
When in dock try to tie up to a ship with a taller mast so his cone of
protection
covers you.