Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.

they don't begin to get struck 1 time in 20 storms. not even close.

Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.

if I thought I had a 5% chance (1 in 20) of any given storm hitting
me!!! OUCH, Paul


Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.

(JAXAshby) wrote in message ...
they don't begin to get struck 1 time in 20 storms. not even close.

Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.







you need to pay attention to the assumptions I made. I assume a LONE
sailboat underneath a thunderstorm. This happens fairly rarely for
most of us, even those of us who live in the lightning capital of the
world. If there are other objects within the effective area of a
sailboat, then the probability of being struck is divided between
them. Furthermore, most of us avoid being directly under a well
developed thunderstorm or we minimize our time under such a storm.
Next, the cloud to ground strike rate may be less for some storms.
The thunderstorms I have seen up north are not REAL thunderstorms by
my perspective but are often fairly wimpy compared to those driven by
very warm water or very warm plains. If you ever get in such a REAL
thunderstorm, you will see why some of us make such extreme efforts to
avoid them.

(JAXAshby) wrote in message ...
they don't begin to get struck 1 time in 20 storms. not even close.

Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


As I write, a weak thunderstorm is passing over the bldg. lightning
rate seems low, less than once/minute and most are prob NOT cloud to
ground. However, I estimate wind at 40 kts.

Based on a few storms I have seen on Apalachee bay, I think the 5.8%
probability for those intense storms to be reasonable and I seriously
avoid them.

Strongest storms cover a larger area with greater wind. I have never
been in one of those but have watched them. The sky doesnt just get
dark, but turns a strange color. Intense strike rate for a few
minutes followed by a sudden increase in rain rate followed by a taper
off in wind and strike rate.

I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.

dum dum, a 1 chance in 20 means a long oak tree standing on a hill, or a
telephone pole on the roadway would be splintered to toothpicks in a couple
seasons.

they don't begin to get struck 1 time in 20 storms. not even close.

Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


As I write, a weak thunderstorm is passing over the bldg. lightning
rate seems low, less than once/minute and most are prob NOT cloud to
ground. However, I estimate wind at 40 kts.

Based on a few storms I have seen on Apalachee bay, I think the 5.8%
probability for those intense storms to be reasonable and I seriously
avoid them.

Strongest storms cover a larger area with greater wind. I have never
been in one of those but have watched them. The sky doesnt just get
dark, but turns a strange color. Intense strike rate for a few
minutes followed by a sudden increase in rain rate followed by a taper
off in wind and strike rate.

I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.

How do you define "effective" area?
Your equation assumes that any lightning within the effective area of your
boat will strike your boat. If that were the case I'd be very afraid.

"Parallax" wrote in message
om...
Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

....

(Parallax) wrote in message . com...
(JAXAshby) wrote in message ...
they don't begin to get struck 1 time in 20 storms. not even close.

Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


As I write, a weak thunderstorm is passing over the bldg. lightning
rate seems low, less than once/minute and most are prob NOT cloud to
ground. However, I estimate wind at 40 kts.

Based on a few storms I have seen on Apalachee bay, I think the 5.8%
probability for those intense storms to be reasonable and I seriously
avoid them.

Strongest storms cover a larger area with greater wind. I have never
been in one of those but have watched them. The sky doesnt just get
dark, but turns a strange color. Intense strike rate for a few
minutes followed by a sudden increase in rain rate followed by a taper
off in wind and strike rate.

I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.








OK, OK, I take back anything I said about wimpy thunderstorms up north
after viewing a series of websites with supercell storms over the
great plains states and all the way up to MN.

parray, you take back everything you ever said about anything.

Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

Assume LONE sailboat, Flat conducting ocean, assume the mast is well
grounded, assume lightning equally distributed over the thunderstorm
area.

Now, I have forgotten how to do this calculation (this used to be my
speciality) but I vaguely remember that a spike type conductor above a
grounded plane produces minimal effects more than 3X its length away.
This means that a mast produces an EFFECTIVE AREA (a) of pi*9*l^2
where l = mast length.

BTW, I work in meters.


As I write, a weak thunderstorm is passing over the bldg. lightning
rate seems low, less than once/minute and most are prob NOT cloud to
ground. However, I estimate wind at 40 kts.

Based on a few storms I have seen on Apalachee bay, I think the 5.8%
probability for those intense storms to be reasonable and I seriously
avoid them.

Strongest storms cover a larger area with greater wind. I have never
been in one of those but have watched them. The sky doesnt just get
dark, but turns a strange color. Intense strike rate for a few
minutes followed by a sudden increase in rain rate followed by a taper
off in wind and strike rate.

I assume a thunderstorm diameter of 4 km based on driving through one
two days ago for a total storm area of 12X10^6 m^2. I assume the
lightning strike rate is about 3/minute and the storm lasts for 40
minutes for a total number of strikes/storm (n) to be 120.

SO...the probability of getting hit is: P=n*a/A *L (L is your "luck
factor", 0L1 means you are either optimistic or lucky, L=1 means you
do not believe in Luck, L1 means you are pessimistic or unlucky, L=0
means you dont really sail). Top of my mast is 17 m above water for
an effective area of 7803 m^2.

So, P= 120*7803/16X10^6 *(L) = 585225X10^-6 * (L)= .058 * (L) or 5.8%
* (L).

Based on limited experience with games of chance, I estimate my L = 3
so my strike probability is 17.4%.

Seriously, the 5.8% chance shows why sailboats do not get struck more
often although they are the tallest things around.








OK, OK, I take back anything I said about wimpy thunderstorms up north
after viewing a series of websites with supercell storms over the
great plains states and all the way up to MN.

"rnh17" wrote in message ...
How do you define "effective" area?
Your equation assumes that any lightning within the effective area of your
boat will strike your boat. If that were the case I'd be very afraid.

"Parallax" wrote in message
om...
Out of curiosity, I did a quick back of the envelope estimate of the
probability of a lone sailboat getting hit by lightning in a
thunderstorm.

...


As I said, effective area is defined as pi*9*(mast height squared).
This is comes from the distance over which a conductor over a flat
conducting plane (3* mast height) has minimal effect on the electric
field distribution(you know, the area of a circle being pies are
squared.

Telephone poles have conductors attached to them and normally have a
ground wire. Trees on the top of a tall hill all alone would not last
long if active thunderstorms passed over them often enough. Around
here, tall pines get hit and die while many other trees survive
strikes. Look at pines with vertical slashes on them running waaaay
up the tree, this is often caused by lightning strikes.

If you do not believe my 1 in 20 chance, consider the number of
golfers who get hit each year here in FL playing during thunderstorms.
Furthermore, find something wrong with my reasoning. Since the math
is correct, the only possibility is that the cloud to ground strike
rate is too high but I watched such strikes during a storm to get this
rate.

I believe my analysis is correct, and until I did this simple
calculation based on area, my experience with electrostatics had
caused me to think the probability should be MUCH higher with this set
of assumptions.