Lightning and Windsurfing
RJ Associates
I am concerned about lightning strikes when out on the water. We
typically have summer storms in the afternoon in Colorado, and they
often include thunder and lightening. I would like to minimize the risk
of being whacked by the lightening but still be able to enjoy the wind
as much as possible.
Has lightning been a problem for windsurfers? Does anybody know how far
lightning travels across water if, lets say, a strike occurs about 1
mile away. Any gear suggestions which could minimize the potential
impact of being struck? Other comments, war stories? I guess being
grounded is unrealistic :).
Rich
Cris Pavloff
>I am concerned about lightning strikes when out on the water. We
>typically have summer storms in the afternoon in Colorado, and they
>often include thunder and lightening. I would like to minimize the risk
>of being whacked by the lightening but still be able to enjoy the wind
>as much as possible.
Yeah, I sail in Colorado too. Aurora REs. WE ususally stop when the
lightning and thunder are closer than about 5 secs. BTW, the wind
does not stop when it starts raining as Mike aluded to.
>
>Has lightning been a problem for windsurfers? Does anybody know how far
>lightning travels across water if, lets say, a strike occurs about 1
>mile away. Any gear suggestions which could minimize the potential
>impact of being struck? Other comments, war stories? I guess being
>grounded is unrealistic :).
Your question about the lightning hitting the water has to be
addressed. Water is actually a very weak conducter. If for some
reason lightning struck plain water and you were a mile a way, I doubt
if you could feel even a tickle.
clive
I have a fibreglass mast (not very conductive as far as I know), but
considering one of the metal items I have on-board is my harness spreader
bar, I don't think standing in the middle of a lake in a lightning storm is
a good idea. Even though my spreader bar is located in a vulnerable
location (seat harness, use your imagination), I don't think anyone else
should push their luck by being out there, no matter what their equipment
is made of (carbon, alum, foam, etc..)
All I know is, when a storm is coming, chances are you could get to shore
quicker by sailing, so instead of swimming it in, sail it home.
>If I saw lightning 1 mile away I would be off the board and swimmng.
> Anyone have an opinion or experience about whether you are more of a
lightning
> magnet when towing a rig vs. swimming alone?
>
> Tom O'Brien - Chicago
NLW TFW NM
RE:"So in conclusion . . . The best thing to do if caught out in lightning
conditions is to sail in as fast as you can - vs dropping the rig and waiting
it out our swimming it in. If you're right, the chance of a direct hit on the
rig is less than the chance of a (semi-local) hit on the water which will
hard-boil a downed sailor in place."
That's about right, except that the problem in the water is more direct
electrocution rather than boiling. Ever cook a weiner for your hot dog by
plugging 110 volts across it? Doesn't take long!
BTW, my source is discussions with Dr. Thomas Moore, the head of a
nationally-known lightning research laboratory in NM. We've talked on a couple
of occasions specifically about lightning and windsurfing.
Mike \m/
Never Leave Wind To Find Wind
Gleshna
>
>Your question about the lightning hitting the water has to be
>addressed. Water is actually a very weak conducter. If for some
>reason lightning struck plain water and you were a mile a way, I doubt
>if you could feel even a tickle.
>
>
My $.02:
1. About seven years ago a kid playing baseball was killed by lightening in
the northwest Chicago metro area. The nearest cloud was a mile away. The
lightening shot ahead of the storm and nailed the kid. Source: speaker from
NWS. So a mile away is dangerous.
2. Around the same time, give or take a few years, , a woman dove off her boat
in Chicago. She did not know that a 220 line had fallen off the boat into the
water. She died. So electricity can travel in the water and kill you.
The distance from lightening in water and killing potential is an interesting
question. Anyone have facts as to the ratio of distance to decrease in
electrical power?
Bob
Gleshna
>If I saw lightning 1 mile away I would be off the board and swimmng.
>
>summer thermals) and dropped my rig and started swimming the whole thing in.
>Hate to do it when the wind is blowing, but you might not get a second chance
>on this one.
>
>Anyone have an opinion or experience about whether you are more of a
>lightning
>magnet when towing a rig vs. swimming alone?
>
>
This is not a direct answer. What we need is beach access to one of those
radars like on the Weather Channel. That way we will know when to come in
before the storm gets that close to us. I guess a second choice would have
someone by a tv call someone at the beach. This might work on storm potential
days.
Luck,
Bob
Walt
Last summer while sailing at Aurora res (Colorado) I was 'sort' of hit
by lightning while windsurfing. There was thunder nearby and I was
heading back in but having just a little too much fun to do it very
quickly (its not that often to be on a 4.6 m**2 during the summer). I
beleive the lightning struck the shore about 50 yards in front of me. At
the same moment the lightning struck, I got a pretty good shock from the
boom and I saw some sort of ark out of the corner of my eye - I beleive
it was on the boom.
Its odd that more windsurfers dont get hit by lightning given all the
deaths from lightning strikes and how far windsurfers typically push it
(at the time of my incedent, there were others out sailing and Im not
the last guy to get off the lake). It may be that a body of water which
is more conductive is 'sort of safe' to be on during a lightning storm
since the conductivity spreads charge making you less 'attractive or
visible' to a lightning bolt. On a fresh water lake, it may not be as
bad as standing out in a field holding a 16 foot conductor straight up,
but its still got to be real dangerous...
Finally are you safer sailing towards the beach or getting in the water?
The longer you are vulnerable, the more likely you are to get hit (so
sail to shore and get in a car?). However, if you are IN the water, you
probably are pretty invisible to the lightning (your body / equipement
doesnt disturb the electric field accross the water much) and most
likely wont take a direct hit. I guess if the sailing's good, at least
get that one last good reach in???? If I had to make a choice, Id
probably take my chances in the water (which of course, is not the
decision I made on the 'day' last summer). There was a guy in the water
when the lightning struck and he felt nothing.
Ice Flyer
http://rainbow.rmi.net/~ez2rem
Randall Rainey
To add a foot note to your observations...
I live in Annapolis Maryland, and it does take on a different aspect with being
close to the ocean. Storms in this area, even on clear days move in really fast.
If you have access to a weather band radio tune in and listen to the Marine
Forcast. It will tell of storms moving in and give boaters (ie.windsurfers etc.)
pretty good warning.
Cheers,
NLW TFW NM wrote:
> Rich --
> We've had two sailors hit directly by lightning on just one little lake between
> Albuquerque and Santa Fe, New Mexico, USA, so it can't be all that uncommon.
> One was pulled from the water unconscious by nearby sailors in time to avoid
> drowning, did some hospital time, and was still sore a week later. The other
> came to in time to save his own butt -- a good thing because rescuers were
> several minutes later. In both cases it appeared that the rig diverted the bolt
> (the million amps of electricity) away from the sailor. Good thing, because a
> few thousandths of one amp can be fatal.
>
> Sailing any time there's any lightning within many miles is stupid. I'm not
> saying I haven't done it; I'm just saying it's stupid. Lightning often strikes
> many miles away from the nearest cloud, with no warning. I was once driving to
> this same lake because there was a big T-storm many miles west of it in the
> mountains. I was amazed to see a huge bolt of lightning nail the ground near
> the lake from absolutely clear blue skies more than 5 miles away from the
> nearest cloud. I turned around and went home.
>
> I prefer to have some degree of control over my sports. On motorized toys I can
> always back off the throttle. Skiing, I could always just turn away from
> inherently dangerous stuff or slow down (I am just an intermediate skiier). And
> I can (and do) avoid 20-foot closed-out surf. I avoid sky-diving because my
> life there is in the hands of the weenie who packed my chute (and because being
> limited to a few minutes of fun a day doesn't float my boat). And, similarly, I
> very seldom place my life in the gun barrel as God plays Russian Roulette with
> 3 cartridges in the cylinder by sailing when there's a T-storm nearby.
>
> OTOH, the odds are slim. Lightning will deviate from its random path by only 10
> meters in search of a better conductor, so unless we sail within 10 meters of
> its intended path at the instant it strikes, we're pretty safe from direct
> hits. But that aluminum or carbon mast can certainly attract lightning that
> happens to be within that 10 meters.
>
> But if we're in the water when it strikes the lake, dangerous voltages can
> exist over a wide area of the lake. If that voltage finds a better conductor
> than the water (a metal or carbon part, your salty body, etc.), it will
> concentrate current in that better conductor. Thus if we get caught down in the
> water in a lightning storm, the safest posture is lying on the board in fresh
> water or in the water if in salt water. And get the metal and bare carbon away
> from you. If the lightning is not raining down like hail, get it up and get the
> hell to shore.
>
> Our odds of getting hit are very small. But they're increased a thousand times
> -- probably a million times -- by sailing in T-storm winds. The two people here
> are lucky to be alive. Had they been uphauling or waterstarting or just napping
> in the water when they got hit -- anything but sailing -- they'd both be dead.
>
> The only time I feel "safe" doing this is when the T-storms are so far away we
> can't even hear the thunder, but that was exactly the situation the day I saw
> lightning out of the clear blue. I've REALLY backed off my T-storm sailing,
> which means almost no sailing here between about early June and October.
>
> It's a personal choice if one has no family, and is sailing alone so no one is
> endangered in a rescue attempt. And if that sounds alarmist to people outside
> this part of the country or Florida, realize that we often see/hear many very
> close lightning strikes per minute in this part of the country (both mine and
> that of the poster). It's like a minefield some days.
>
> A word of warning: when you feel that first drop of rain, forget everything and
> get your raggedy ass to shore. That first little showery curtain of rain kills
> the wind and provides a path for the lightning. And that's meteorological
> science, not just wives' tales or mere observation.
>
> Mike \m/
> Never Leave Wind To Find Wind
--
Randy
May the wind be always @ your back! (:-))
My Email address is blue...@toad.net
My Webpage is http://www.toad.net/~bluefrog/
Francois Duboisl
Personally, I wouldn't stay on the water when a storm which has lightning
is around. But if that is the only time there is wind then don't get a
carbon mast as lightning really loves a nice conductor such as carbon.
Farewell !!!
Francois
RJ Associates <rjor...@ix.netcom.com> wrote in article
<34CCDD...@ix.netcom.com>...
> I am concerned about lightning strikes when out on the water. We
> typically have summer storms in the afternoon in Colorado, and they
> often include thunder and lightening. I would like to minimize the risk
> of being whacked by the lightening but still be able to enjoy the wind
> as much as possible.
>
> Has lightning been a problem for windsurfers? Does anybody know how far
> lightning travels across water if, lets say, a strike occurs about 1
> mile away. Any gear suggestions which could minimize the potential
> impact of being struck? Other comments, war stories? I guess being
> grounded is unrealistic :).
>
> Rich
>
Steve Williams
Last week we sailed Alsea Bay here on the Oregon Coast during a passing
cold front. Towards the end of the session the wind picked up, it started
pouring and hailing, and thunder and lightning flashes started going off
all over the place. We hooted and hollered, gritted our teeth, and kept
right on sailing. Must admit it was quite a rush, but probably not very
smart. Oh well, all your friends are doing it.................
NLW TFW NM
Lightning sensors are cheap commercially or easy to fabricate. They tell you
how strong the fields are getting and some register strikes in the area. But
that's not of a great deal of use, because lightning and T-storms just don't
behave that consistently. Chris has even seen some cases where the wind kept
blowing after the rain began, and that's not common IF the rain is from the
same T-storm that's causing the wind. Just shows how unpredictable they are.
TomBuckOb2
Anyone remember the high school physics experiment where you demonstrate that
distilled water is a very poor conductor but tap water is an excellent
conductor of electricity?
There must be some relationship of the composition of the water to its
conductivity - what about salt water vs. fresh?
TomBuckOb2
Here in Chicago the storms can come up fast, but they always come from the same
direction and if you can't spot the thunderheads rolling in, you aren't
looking. We wait for the storm to pass and then the wind fills in behind it -
from the opposite direction.
Benjamin Kaufman
In article <19980126200...@ladder02.ne ws.aol.com>, From
nlwt...@aol.com (NLW TFW NM), the following was written:
> OTOH, the odds are slim. Lightning will deviate from its random path
> by only 10 meters in search of a better conductor, so unless we sail
> within 10 meters of its intended path at the instant it strikes, we're
> pretty safe from direct hits. But that aluminum or carbon mast can
> certainly attract lightning that happens to be within that 10 meters.
Lightening's path is not random. It chooses the path with least
resistance. There are invisible events which occur in advance of the
strike. Anything wet sticking up 15 feet from a flat surface will
surely provide a better path for the feeder which precedes the strike.
Ben
--
Ben Kaufman
antispam: To Email me, change domain from spam_sync to pobox.
- 01/27/98
Benjamin Kaufman
In article <01bd2ac7$7cb5f540$a2f152ca@default> , From "Francois
Duboisl" <ge...@hkstar.com>, the following was written:
> Personally, I wouldn't stay on the water when a storm which has
> lightning is around. But if that is the only time there is wind then
> don't get a carbon mast as lightning really loves a nice conductor
Forget about the material which the mast is made of. It's wet, the sail
is wet and it's 15 feet closer than anything else.
NLW TFW NM
Re:"Lightening's path is not random. It chooses the path with least
resistance. There are invisible events which occur in advance of the
strike. Anything wet sticking up 15 feet from a flat surface will
surely provide a better path for the feeder which precedes the strike."
sudden turns. But at each of those jagged turns its options are very limited,
and it considers only about a 10-meter radius when picking its path of least
resistance. That's why the lightning expert we consulted advised us to sail
ashore ASAP rather than hiding in the water; the 15-foot mast is just not that
much of a target unless that bolt had us near its "crosshairs" already. He did
add that if we are down, get AWAY from conductors such as mast or boom.
I have little feel for how important a litte (key feature: "short") conductor
such as a spreader bar would be (one poster asked about that). It all has to do
with just how strong the electrical field is as the bolt dissipates through the
water. If the field is so strong that it induces enough current through a
1-foot bar to heat up that hefty bar enough for us to care, I'd guess the bar
is the least of our worries.
Re:"Forget about the material which the mast is made of. It's wet, the sail
is wet and it's 15 feet closer than anything else."
I suspect that's true and pertinent regarding the diversion of any bolt that
was going to strike 20 feet away anyway; that juicy target just might persuade
the bolt to change it's "mind" -- ar at least be an effective tie-breaker. But
If we're hit, it's nice to have a good conductor nearby to shunt the bolt's
power, and carbon or aluminum would probably be a better shunt than mylar and
fiberglass. It'e merely anecdotal, thus proves nothing, but of our two victims,
the one on a carbon mast went ashore and went for a few-mile run until the wind
cleaned up again (along with his shorts). The one on the fiberglass mast was
hospitalized and injured much worse. The rig on the glass mast was toast; I
believe (not sure) the rig on the carbon mast survived to some degree.
TomBuckOb2
So is this how the logic works??
1) Sailing with rig up presents a very small target for lightning - a strike
would be more of a random event than a result of attraction by the mast.
2) Lying down on board (or in water) you are also a target - subject to
approximately the same "random" chance of a direct hit or a strike (very)
nearby.
3) For a nearby strike, I don't think *degree* of water conductivity is going
to matter.
4) Therefore make yourself a target for a random lightning strike for as short
a time as possible - sail your butt in.
RJ Associates
I wonder: if a windsurfer was 50 meters from a tree which was the same
size as the mast ie, same size on the horizon, which would be the more
likely target? That is, is something on the water more or less likely
to be hit as opposed to land? Would the salinity of the water change
whether the sailer is hit as opposed to the tree?
I remember seeing a Discovery program about lightning once and most of
the direction of the strike is influenced by electrical fields between
the clouds and the earth. Once the two forces (the one up from the
earth and the one down from the friction of the clouds (?)) link up you
have a strike, but the last 50 meters is pretty variable and it goes to
the higher point, most attractive point, etc. I wonder though if that
would be the water or the land? In any case, I guess we should be more
conservative. better to sail another day.
Rich
NLW TFW NM
Re:"There must be some relationship of the composition of the water to its
conductivity - what about salt water vs. fresh?"
Salt water's a much better conductor than fresh (and than our bodies). That's
why we MAY BE safer in the water than lying in the board in the ocean. As the
path of greatest resistance in salt water, we may receive little current. I say
"MAY BE" because there is some tradeoff between bobbing at the top of a swell
and conceivably taking a direct hit versus being down in the water and just
getting hit by the leftovers.
But because we're talking millions of volts and millions of amps, and because
milliamps (thousandths of an amp) can kill, nuances and blind luck are still
big factors. That lightning bolt is an 800-pound gorilla. It's going to go
where physics tell it to, and it's not going to just stand there and be denied
just because the lake's a poor conductor. It's going SOMEWHERE, By God, and
FAST! After all, dry air is a lousy conductor, and that doesn't stop lightning
from travelling miles through the atmosphere.
NLW TFW NM
Re:"So is this how the logic works??
I'd say that's a good practical summary of it, with a few tweaks:
1. Unless a sailor took #1 so literally that he kept on shreddin'. It's not
THAT random.
2,3. I don't know how close it must be to be a threat, nor just how lightning
behaves in salt versus fresh water. I doubt the equations would affect #4 all
that much.
NLW TFW NM
Re:"most of the direction of the strike is influenced by electrical fields
between
the clouds and the earth."
As a charged cloud blows by overhead, its charge induces an opposite charge in
the ground beneath it. The ground charge races along beneath the cloud,
following the terrain sort of like your shadow does as you drive or fly along
watching your shadow. The ground charge surges towards the top of each hill/
person/ building/ tree/ mast/ etc it encounters, "trying" to push enough charge
high enough that the ratio of [VOLTAGE difference between cloud and ground
charges at that instant] to [DISTANCE from cloud to "ground" (including
objects) at each instant] is sufficient to overcome the air's extreme
resistance to electrical flow. When the "highest point" this ground charge is
"climbing up for a better look" is US, the ground charge makes our hair stand
up and maybe our skin tingle. That's time -- and reason -- for a major change
of shorts and a fast duck to a crouch. (As long as you're gonna do that in your
pants, ya may as well ASSUME THE POSITION.)
That VOLTS/METER number, the electrical field strength, varies by the
milli/micro-second and over mere meters as the humidity, terrain, objects,
charge configurations, conductivities, and karma (the unmeasurables and
nuances) change. Both cloud and ground charges send out "probes" of charge
("leaders"), trying to find a continuous path between cloud and ground charges.
(Sounds like two people in a bar trying to pick up some companionship for the
evening.) These leaders are paths of ionized air (including moisture) that are
better conductors than the surrounding air.
When ground and cloud leaders connect, that establishes a path for the cloud
and ground charges to discharge their pent-up energy, and all hell brakes
loose. It's just like laying a wrench across your car's battery terminals,
except a WHOLE LOT more dramatic.
There's much more to it, but we don't care. Tom's summary is of much more
immediate practicality and urgency.
Gleshna
>There must be some relationship of the composition of the water to its
>conductivity - what about salt water vs. fresh?
Also, if you sail fresh water near industry, there may be additional conductors
in the water.
Bob
Paul Fernquist
In article <09980027083421.OUI19.bsk@spam_sync.com>,
Benjamin Kaufman <bsk@spam_sync.com> wrote:
>In article <19980126200...@ladder02.ne ws.aol.com>, From
>nlwt...@aol.com (NLW TFW NM), the following was written:
>> OTOH, the odds are slim. Lightning will deviate from its random path
>> by only 10 meters in search of a better conductor, so unless we sail
>> within 10 meters of its intended path at the instant it strikes, we're
> > pretty safe from direct hits. But that aluminum or carbon mast can
>> certainly attract lightning that happens to be within that 10 meters.
>
>resistance. There are invisible events which occur in advance of the
>strike. Anything wet sticking up 15 feet from a flat surface will
>surely provide a better path for the feeder which precedes the strike.
>
>
Resistance is one component, but shape is another. The electric field is
concentrated at points. That's why lightning rods are pointed. It's an
art not a science determining where lightning will hit. A place near
where I used to work generates artificial lightning to test where
lightning would hit an object. They tested an airplane once and the
lightning hit the fuel cap!
Paul
Cris Pavloff
On 26 Jan 1998 23:48:57 GMT, gle...@aol.com (Gleshna) wrote:
>1. About seven years ago a kid playing baseball was killed by lightening in
>the northwest Chicago metro area. The nearest cloud was a mile away. The
>lightening shot ahead of the storm and nailed the kid. Source: speaker from
>NWS. So a mile away is dangerous.
Not what I am saying. I am saying that if lightning hits the water a
mile away from you (in fresh lake water) I doubt if that current can
travel that far through such a poor conductor as fresh water.
>2. Around the same time, give or take a few years, , a woman dove off her boat
>in Chicago. She did not know that a 220 line had fallen off the boat into the
>water. She died. So electricity can travel in the water and kill you.
I know it can kill you, but one mile with a 50-100 foot deep lake is
probably enough volume of water to disperse the current.
Bruce
> > There must be some relationship of the composition of the water to its
> > conductivity - what about salt water vs. fresh?
ions, it's all about ions. Salts in the water form ions which carry the
current, no ions, no conduction.
the lightning strike ionises the air, I vaguely remember reading somewhere
that the initial flow is from sky to land forming an ionised path, then the
major flow is back up. Anyway, the reason pointy objects are attractive to
lightning is because there is a charge build up around a point which
ionises the air in the region of the point.
There was a mistaken impression that lightning conductors were a safe place
to stand when this topic surfaced once before. Again, I think tehre is a
cone of about 45 degrees about the conductor which is protected, but the
not the conductor itself.
Theoretically the safest place to be might be near (but not touching)
someone else holding a carbon/Al mast ...
--
any opinions expressed are my own
work: br...@nzgo.govt.nz, http://www.govt.nz
play: br...@winzurf.co.nz, http://www.winzurf.co.nz
kevin
Once I was out waterskiing when a thunder storm hit.
Without much warning, the wind hit about 45mph.
All of the windsurfers got flattened.
I really thought our 16' boat would get sunk by the waves.
A few bolts of lightning hit and the storm passed.
Unfortunately, a woman loading a Hobbie Cat onto a trailer was killed.
If you sail in lots of lightning storms, may I suggest carbon fiber
booms and masts vs the aluminum counterparts. If I were caught in
a lightning storm, I would probably get in the water since harness
spreader bars have a hefty amount of metal. I wonder if proping up
the rig on the board would work as a lightning rod? Leaving the board
on it's own.
Last summer I got caught in a Colorado lightning storm on my motorcycle.
Scared the hell out of me.
Good luck,
Kevin
Bruce Spedding
http://www.winzurf.co.nz/windsurf/tech/bruce01.htm
check it out
p.s.
I spent several hours once sitting on watch in an 11 m yacht in the middle of
the Tasman Sea probably several 100km from anything else, Al mast etc. and
watched lightning coming down into the sea all around us non stop. The
phosphorescence in the water was going off like bombs with each strike.
Didn't feel a tickle
Bruce Spedding
Check out these sites ....
wiNZurf - Windsurfing and Surfing in NZ http://www.winzurf.co.nz
rec@nz - recreation guide and classifieds NZ http://www.winzurf.co.nz/recnz
NDTA - Non Destructive Testing Assn http://www.winzurf.co.nz/ndta
NZ Gateway to Government - http://www.govt.nz
TomBuckOb2
>If you sail in lots of lightning storms, may I suggest carbon fiber
>booms and masts vs the aluminum counterparts. If I were caught in
>a lightning storm, I would probably get in the water since harness
>spreader bars have a hefty amount of metal. I wonder if proping up
>the rig on the board would work as a lightning rod? Leaving the board
>on it's own.
If you sail in lots of lightning storms it is only a matter of time . . .
Carbon fiber booms and masts are excellent lightning conductors.
See earlier posts for info about being in the water VS. on the board and
sailing.
Benjamin Kaufman
In article <19980127164...@ladder02.news.aol.com>, From
tombu...@aol.com (TomBuckOb2), the following was written:
> So is this how the logic works??
>
> 1) Sailing with rig up presents a very small target for lightning - a
> strike would be more of a random event than a result of attraction
> by the mast.
>
To fully appreciate what happens requires a scientific explanation which
I think will put a lot of people to sleep as well as cost me more time
than I want to commit <g>.
So I will present my summary first.
SUMMARY: The mast can be a factor in triggering the strike as well as
being the target.
The area chosen for a strike on FLAT TERRAIN is a matter of being at the
right place at the right time. The TIME is when the electric field has
increased to a voltage which exceeds the dielectric (resistance) of air.
As the field strength reaches the critical level of air break down,
introducing a 15 foot mast not only provides a visibly shorter path, it
literally brings the ground 15 feet closer which further increases the
strength of the field between the mast and the sky because electric
fields increase as the charges are brought closer (with the square of
the distance for point charges and linear for plate charge models - of
which our real world example is more complicated).
Ben
--
Ben Kaufman
antispam: To Email me, change domain from spam_sync to pobox.
- 01/28/98
DTW
As you may have heard, B.Franklin conducted a few lighting experiments in
the Philly area. The record doesn't show that he was, in fact, on a
windsurfer at the time. Ben was trying to attract lightning to a key on a
kite string. After several unsuccessful attempts he put that away and took
off to a nearby lake. He sailed out into the center of the lake on a board
made of balsa wood that he had imported from Spain. He now had the key
strung to the mast and the rest is history!
You too could make some history, on a lake, in a thunderstorm!!!
RJ Associates wrote in message <34CCDD...@ix.netcom.com>...
Rob Wood
A few random points about lightening:
1. An AM radio tuned between stations makes a great lightening sensor.
2. Conductivity of water depends on its ion content, more disolved salts,
more conductivity. Thanks to our marine origins, a humans' salt
concentration is very close to that of seawater, which is why lightening
won't "see" you in the ocean, but you'll look like a hunk of copper in very
pure fresh water.
3. Being surrounded by things which conduct better than -or at least equal
to- you is the safest place to be. That's why being in a car is considered
safe (as long as you're not touching metal)- it's not the tires as many
folks think. So maybe having an aluminum or carbon boom, mast, or carbon
fibers in your board nearby isn't a bad thing as long as you're not hangin'
on it.
4. Consider that a lightening bolt is connecting a source and sink separated
by many miles, so it is unlikely that you will do much to fine-tune its path
within the last few feet.
rob
Cris Pavloff
Boy, what if the whole shark situation and this one collided. A
stormy day on the coast while sitting in shark-infested urine-sea-
water in front of a rivermouth. I think that that's about 500
violations of the Lightning Safety Handbook.
Conclusion: Don't pee in your wetsuit when there is lightning in the
area.
clive
> Conclusion: Don't pee in your wetsuit when there is
lightning in the
> area.
Taking a crap in it isn't good either...
Does anyone know if that attracts sharks too, or just
flies? :)
Clive
Randall Rainey
TomBuckOb2 wrote:
> Anyone remember the high school physics experiment where you demonstrate that
> distilled water is a very poor conductor but tap water is an excellent
> conductor of electricity?
Could this be a lesson in what kind of polutants (metals, chemicals, etc.) that
might conduct even better than salt...
This could be part of the big <BANG> theory...
Until then.... when the hair on your neck starts to rise Duck or get the He
double hockey sticks or 2 pc. carbon or fiber glass out of there.
>
>
> There must be some relationship of the composition of the water to its
> conductivity - what about salt water vs. fresh?
>
> Tom O'Brien - Chicago
--
Randy
May the wind be always @ your back! (:-))
My Email address is blue...@toad.net
My Webpage is http://www.toad.net/~bluefrog/
Randall Rainey
RJ Associates wrote:
> I wonder: if a windsurfer was 50 meters from a tree which was the same
> size as the mast ie, same size on the horizon, which would be the more
> likely target? That is, is something on the water more or less likely
> to be hit as opposed to land? Would the salinity of the water change
> whether the sailer is hit as opposed to the tree?
>
I live in Maryland, a few years ago a power boater, to avoid the lightning on the
Cheseapeake Bay, ran to shore @ Harte Miller Island near Baltimore. He stood under
a tree and was killed by the lightning He tried to avoid. So... the moral is watch
the sky, and if it even looks threatening, get the H E L L out of Dodge and
into your car, boat, or house.
> I remember seeing a Discovery program about lightning once and most of
> the direction of the strike is influenced by electrical fields between
> the clouds and the earth. Once the two forces (the one up from the
> earth and the one down from the friction of the clouds (?)) link up you
> have a strike, but the last 50 meters is pretty variable and it goes to
> the higher point, most attractive point, etc. I wonder though if that
> would be the water or the land? In any case, I guess we should be more
> conservative. better to sail another day.
>
> Rich
>
> TomBuckOb2 wrote:
> >
> > Anyone remember the high school physics experiment where you demonstrate that
> > distilled water is a very poor conductor but tap water is an excellent
> > conductor of electricity?
> >
NLW TFW NM
Hey, if I'm surrounded by sharks and lightning, the FIRST thing I'm likely to
do is pee.
Benjamin Kaufman
In article <34D0C7D4...@mcnc.org>, From Rob Wood
<rw...@mcnc.org>, the following was written:
> Being surrounded by things which conduct better than -or at least
> equal to- you is the safest place to be. That's why being in a car is
> considered safe (as long as you're not touching metal)- it's not
the > tires as many folks think. So maybe having an aluminum or carbon
> boom, mast, or carbon fibers in your board nearby isn't a bad thing
as > long as you're not hangin' on it.
Rob, it's not just that the car is made of metal but because it forms a
FARADAY CAGE around you. Note that it would have to be a hardtop, not a
convertible.
Ben
--
Ben Kaufman
antispam: To Email me, change domain from spam_sync to pobox.
- 02/01/98
Rob Wood
Benjamin Kaufman wrote:
> Rob, it's not just that the car is made of metal but because it forms a
> FARADAY CAGE around you. Note that it would have to be a hardtop, not a
> convertible.
>
> Ben
>
Ben- I think you're on to something here... We need a cage which will do
double duty as a Faraday Cage and a shark cage, voila, two major WS problems
solved! We'll install a latrine for Mike, and include an optional gun rack
for all those redneck sailors...
rob
Benjamin Kaufman
In article <34D5C81F...@mcnc.org>, From Rob Wood
> double duty as a Faraday Cage and a shark cage, voila, two major WS
> problems solved! We'll install a latrine for Mike, and include an
> optional gun rack for all those redneck sailors...
Rob,
They already have something very similar to that, it's called a
SAILBOAT.
Ben
--
Ben Kaufman
antispam: To Email me, change domain from spam_sync to pobox.
- 02/02/98