On Thu, 26 Apr 2007 21:04:02 -0400, Peter Hendra
wrote:

On Thu, 26 Apr 2007 00:14:18 +0000, Larry wrote:


Oh, and what is an optimum length and diameter - covered in plastic or
bare? - I know, only a project manager would want precision such as
this.

Thanks for all of this Larry. I shall follow your advice.

By the way, I have been dutifully hoarding my softdrink/soda/pop
plastic bottles. I even have a large hanging laundry bag to store them
in after rinsing them. However, my favourite drinks here in Trinidad
are Lemon, Lime and Bitters sold by the Angostura company in small
glass bottles and cans of coconut and pineapple fizzy drink. Are you
aware of any techiques whereby I can put out "message in a can" or
"message in a small glass green bottle"? I have been drinking Coca
Cola but no longer wish to support that icon of American Imperialism
(openly at least). We called in to Assab a few years back, the large
and empty Eritrean port that had been captured back from the invading
Ethiopians. At the time, Eritrea was the second poorest nation and had
just won a war of independence against colonising Ethiopia with no
external aid despite both the US and Ruissians suppling their foes
with weapons at different times. The town had nothing but a single
main unpaved street, and apart from the port wharves and cranes was
largely unchanged since the Italians colonised it after the Great War.
There were a lot of little cafes making great, strong and flavoursome
(eat your heart out Vic) espresso coffee with beautifully maintained
polished brass and copper machines dating back to the 1920's. The only
other non-alcoholic drink was good old Coca-Cola kept cool with ice.
Expectedly, both tasted divine.

I only ask about the cans as I recognise the spirit of a lateral
thinking mind and you are wholely responsible for my collection
fetish/mania. I almost ate a half eaten hamburger from a rubbish bin
the other day - it looked delicious but some people I knew were
looking. Still, as my Zoology professor said - "The good germs fight
the bad germs and the good germs usually win".

Waiting for it...............
cheers
Peter the dumpster man


Larry,
A few questions from a dummy in this area.

What diameter should I make the floating ground for the aerial (4mm ?)

I did try trailing a chain and weight on the end of a cable from the
base of the port shroud as alightning ground but the damn thing was
bumping annoyingly against the hull. My back stay is split at the
masthead - one is the aerial for SSB and the other is entire. Could I
attach a cable to that and throwm it ovewr the stern? - or would two
attached to the capshrouds give better protection? I unashamdely admit
to being terrified of being struck again - not a personal fear but one
of having to shell out all those dollars again to replace it all.

I got sick of pulling all the plugs out from the instruments when
lightning hove in the distance - in our path, so I put the 13 wires to
the radar unit for example to a 15 pin plug that just pulls apart -
other instruments likewise. N o more hiolding a colured Visio
schematic and trying to figure colours in the dark.

I should have shaved my arms before antifouling - I am still picking
it off despite cleaning up and showering.

cheers
Peter
Don W wrote in news:vMwXh.19209
:

Also, it'd sure be great if lightning grounds were
this simple... But unfortunately...



Actually, they ARE that simple. Trail two more ground cables, during the
storms, attached to the port and starboard shrouds to trail off electrons
to the sea, right where it's SO easy to attach them at the
deck/chainplates. Don't be neat...use hefty stainless winch cable,
stranded gets the best ground. Find something to stow them in at the
base of the shrouds when not in lightning storms. Great grounds are easy
in the ocean....that don't HAVE to be through a hole in that leaky hull!

Just let the cable trail back on either side in the wake. It only
matters that they are submerged, not skipping along the surface. On our
ketch, at 6 knots, skipping along the surface would be a miracle...(c;

Larry

On Thu, 26 Apr 2007 21:41:17 -0400, Peter Hendra
wrote:


There were a lot of little cafes making great, strong and flavoursome
(eat your heart out Vic) espresso coffee with beautifully maintained
polished brass and copper machines dating back to the 1920's. The only
other non-alcoholic drink was good old Coca-Cola kept cool with ice.
Expectedly, both tasted divine.

I do miss the espressos I often had in coastal European towns when in
the Navy years ago. I suspect this is due to my youth at the time and
the ambience of the surroundings more than the coffee itself, or just
an entirely faulty memory. In any case, good espresso is available
nearby, but the experience would certainly not be Ethiopian.
Your Coke reference brings to mind some other experience that may be
useful to those in the tropics and not having ice available.
My boiler room was normally @ 110-120 degrees F. when steaming in the
daytime Caribbean.
We boilermen often stood near powered vents to gain comfort from the
cool 100 degree air forced in from the sunny outside decks.
I always (after my first cruise, that is) brought some cans of Coke on
cruises, kept in my boiler room locker, which would hold about 12
cans. They became quite valuable after a few weeks at sea, and I was
offered as much as $5 for a can.
My monthly salary was @ $90 then. Anyway, I never sold any, but did
give away a few.
Our method of cooling a can of soda in the boiler room was to wrap it
in a wet rag and place it in a vent. The strength of the air blowing
there was very strong. Maybe 30 knots. The rag was wetted as many
times as necessary to cool the soda. Repeated wetting only whetted
the appetite for the imminent treat.
Can't say exactly how cold it got the soda, but I'd estimate 70
degrees or less. Damn cold relatively speaking.
And in the case of cooling Coke in a Navy boiler room, I am a
relativist.
Whether this would work for tropical sailors I don't know.

--Vic

On Thu, 26 Apr 2007 22:46:54 -0500, Vic Smith
wrote:

Hi Vic,
Thanks for this tip that I had forgotten. I had expected an irate
outburst from you denying that you were a coffee philistine but you
ignored the bait.

Years ago when we used to go camping (tenting) as a young family at
our beach property we used this trick to keep fhe food cool. We had no
spare cash to buy a fridge and would hang such as milk bottles (are
you old enough to remember when milk came in bottles?) wrapped in a
wet rag from a shaded tree branch. The evaporation kept it cool. I
also had a couple of open sided large concrete building blocks (8
inches wide ones to give a 16 inch square) buried in the sandy ground
- 2 high with a concrete paving stone on top. It also was in the shade
and kept constantly damp. Both worked very well.

I taught science at highschool for a couple of years then and am
trying to remember the science of it. Something about the latent heat
of evaporation and the energy required to turn the water into a gas
and why methylated spirits or alcohol rubbed on the skin gives a
greater cooling feeling than does water. It turns into a gas at a
lower temperature. Memory is dim on this.

I understand your memories of having coffee at some of the places you
must have visited in the Med. My family being from Crete, I was raised
on the Greek/Turkish style of heating it on a sand brazier in a small
pot which I sometimes drink on the boat though I do prefer Italian
style espresso. Unfortunately I don't have the power for a decent
expresso machine onboard though I have one at home.

My best coffee memory is of rising at 5 am in the hotel in Cairo (I am
an early riser) and going to a 24 hour cafe to have coffee and a
shisha (huba buba water filtered smoking device) in the street with
other regulars on their way to and from work. Same as you, probably
the ambiance.

I agree. There is nothing quite like a cold coke when you are thirsty
and hot. Must be the caffiene hit and thus the resultant addiction.
Damned economic imperialism. It should be included in the war on
drugs.

Incidentally, as to our term 'philistine', it appears that it is a
misnomer and that it was the Israelites who were the unsophisticated
tribal barbarians who had migrated in from the desert and who were the
destroyers. The Israeli archeological department and academics have
recently excavated many Philistine cities and have expressed this view
themselves. They have shown that the Philistines were from Mycenean
Greece and were the kin of Agamemnon, Menelaus, Ulysses, and Achilles
(who was of course my direct ancestor on my mother's father's side of
the family). They had a very definite high level of sophisticated
manufacture of bronze, gold and pottery and also used traded goods
from all over the known world, being maritime merchants themselves
which is why these cities were founded along the coast.

Before I get castigated for being anti-Israeli (I'm not) by those who
make an overly simple connection, look it up on the web. I am
fascinated by the proven connection they have made with the many
references in historical literature throughout the Middle East to the
"sea peoples". It was always a mystery as to who they were and where
they came from.

If you are interested, also look up the 14th century BC bronze age
shipwreck that is now displayed in the museum at Bodrum castle in
Turkey. It contains items from all over the then known world and shows
the well developed trade links between nations. Bronze, wine and olive
oil were the base products for international commerce then, not
Coca-Cola.

Yes, I know that this is off topic, but this is why I 'cruise' - to
visit these places and see and experience in the first person. My
occupation is in modern technology but my passion is for history.

cheers
Peter

Our method of cooling a can of soda in the boiler room was to wrap it
in a wet rag and place it in a vent. The strength of the air blowing
there was very strong. Maybe 30 knots. The rag was wetted as many
times as necessary to cool the soda. Repeated wetting only whetted
the appetite for the imminent treat.
Can't say exactly how cold it got the soda, but I'd estimate 70
degrees or less. Damn cold relatively speaking.
And in the case of cooling Coke in a Navy boiler room, I am a
relativist.
Whether this would work for tropical sailors I don't know.

--Vic

On Fri, 27 Apr 2007 05:54:45 -0400, Peter Hendra
wrote:

On Thu, 26 Apr 2007 22:46:54 -0500, Vic Smith
wrote:

Hi Vic,
Thanks for this tip that I had forgotten. I had expected an irate
outburst from you denying that you were a coffee philistine but you
ignored the bait.

Ah. Then you are prone to making unfounded assumptions.
I must say I am disappointed at that (-:

Years ago when we used to go camping (tenting) as a young family at
our beach property we used this trick to keep fhe food cool. We had no
spare cash to buy a fridge and would hang such as milk bottles (are
you old enough to remember when milk came in bottles?)

Yes, and with cream floating on top too. And I remember scraping wax
with my fingernails from coated cardboard milk cartons as I ate
cereal, when that transition was made. They say more changes in the
way we live have occurred in the last 100 or so years than in all
times prior. I've seen many of those changes myself, recalling living
with an icebox, horse drawn vendor wagons in the streets of Chicago,
etc. But here's something pasted below that I noted in another group
a while ago. It was a thread about "most important innovations."
It puts technological progress in a perspective we normally don't - or
can't - imagine.
"An old farmer I saw on the Johnny Carson had his answer, which with I
agree, and from the response of the audience, they did too.
He was 100 years old, and Carson asked him if he was still working the
farm. He said he did a bit of work, but his son was doing the
seeding, plowing, etc. Carson asked him how old is your son, and
the farmer said 80. That got a laugh.
Then - this was very early '70s - Carson mentioned TV, man on the
moon, fast cars, etc, all the usual suspect innovations you might
imagine that a man born about 1870 and still alive had witnessed.
Then Carson asked the old guy what innovation had most impressed him
and changed his life during its long span.
The old man didn't bat an eye, but just said "Electricity."
The audience roared.
Nobody expected that answer, because they took that for granted.
But judging from Carson's and the audience's reaction, nobody
disagreed."

wrapped in a
wet rag from a shaded tree branch. The evaporation kept it cool. I
also had a couple of open sided large concrete building blocks (8
inches wide ones to give a 16 inch square) buried in the sandy ground
- 2 high with a concrete paving stone on top. It also was in the shade
and kept constantly damp. Both worked very well.

I taught science at highschool for a couple of years then and am
trying to remember the science of it. Something about the latent heat
of evaporation and the energy required to turn the water into a gas
and why methylated spirits or alcohol rubbed on the skin gives a
greater cooling feeling than does water. It turns into a gas at a
lower temperature. Memory is dim on this.

Sounds right enough. My steam training covered all this and I used to
hold in my head the BTU count for every stage of the water to steam
process. Vaporization is by far the most energetic piece, and did the
trick with a can of Coke.

I understand your memories of having coffee at some of the places you
must have visited in the Med. My family being from Crete, I was raised
on the Greek/Turkish style of heating it on a sand brazier in a small
pot which I sometimes drink on the boat though I do prefer Italian
style espresso. Unfortunately I don't have the power for a decent
expresso machine onboard though I have one at home.

Your family being from Crete perhaps gives you a special sensitivity
to words such as "philistine."
Actually, I haven't had an espresso coffee since Italy many years ago.
They were mostly con leche or con cognac.
I did learn a pidgin Italiano and those Spanish terms sufficed for my
infrequent coffee orders in Italy.
My habits are at least half a gallon on coffee daily and coffee is my
main source of liquids. Espresso would quickly do me in, all else
being equal.
I do occasionally make a very strong drip brew but it is weaker than
espresso. I am about to go out with my wife and am determined to stop
for an espresso to erase my current ignorance..

My best coffee memory is of rising at 5 am in the hotel in Cairo (I am
an early riser) and going to a 24 hour cafe to have coffee and a
shisha (huba buba water filtered smoking device) in the street with
other regulars on their way to and from work. Same as you, probably
the ambiance.

I agree. There is nothing quite like a cold coke when you are thirsty
and hot. Must be the caffiene hit and thus the resultant addiction.
Damned economic imperialism. It should be included in the war on
drugs.

Exactly right about thirsty and hot. That is really the main time I
drink it. And addiction. I was surprised when my otherwise food-
frugal wife got the habit of a Coke every day. She's originally a
farm girl from Poland and wasn't exposed to it there.
Better that than vodka, no doubt.

Incidentally, as to our term 'philistine', it appears that it is a
misnomer and that it was the Israelites who were the unsophisticated
tribal barbarians who had migrated in from the desert and who were the
destroyers. The Israeli archeological department and academics have
recently excavated many Philistine cities and have expressed this view
themselves. They have shown that the Philistines were from Mycenean
Greece and were the kin of Agamemnon, Menelaus, Ulysses, and Achilles
(who was of course my direct ancestor on my mother's father's side of
the family). They had a very definite high level of sophisticated
manufacture of bronze, gold and pottery and also used traded goods
from all over the known world, being maritime merchants themselves
which is why these cities were founded along the coast.

Before I get castigated for being anti-Israeli (I'm not) by those who
make an overly simple connection, look it up on the web. I am
fascinated by the proven connection they have made with the many
references in historical literature throughout the Middle East to the
"sea peoples". It was always a mystery as to who they were and where
they came from.

If you are interested, also look up the 14th century BC bronze age
shipwreck that is now displayed in the museum at Bodrum castle in
Turkey. It contains items from all over the then known world and shows
the well developed trade links between nations. Bronze, wine and olive
oil were the base products for international commerce then, not
Coca-Cola.

What a rich find that was! And it must have been a great loss to
merchants of the time when it sank. I wish I knew of this when
my destroyer was steaming about Cyprus in 1964 during that
so-called "crisis." It would have added some reflection to that
boring time, when we were at sea for more than 30 days.
I'm also interested in history and cultures, and sensing the place
in time of events can be an almost mystical experience.
In 1988 I took my family on a driving trip of the western U.S.
We mostly stayed off the interstate highways and tent camped
except every 5th day or so, when we would overnight in a motel.
We stopped at many historical sites, mostly related to the westward
settlement of America; wagon trails, sites of Indian ambushes, etc.
Most of these were very recent in the scope of time, circa mid-19th
century.
One day in a small Kansas town we stopped in the town museum.
I can't recall the name of the town.
I saw a metal helmet in a glass case, and upon reading the description
found it was discovered by a boy in a cave outside town in 1912 and
experts say it was left there by a member of Coronado's expedition of
1540! Since I have studied some history and literature I instantly
had a context for this as immediately predating Shakespeare and
the Elizabethan period. I stood in awe before that helmet, with
thoughts of the Spanish Conquests, gold, Coronado, Aztecs, native
American Indian cultures, Henry VIII, his wives, English law, the
Jamestown settlement 67 years in the future of this helmet's placement
in the lonely Kansas cave - all flying about in my head. It was one
of those subliminal experiences.
In writing this I did a net search to find the name of that Kansas
town and discovered the provenance of artifacts like this helmet
are somewhat in question, and it is likely I was simply a tourist rube
tricked by some slick Kansas chamber of commerce scheme.
Be that as it may, Coronado was close by in 1540 and that helmet
did the trick for me in putting this Kansas place in the vast sweep
of time. BTW, Dana's Two Years Before the Mast had a similar effect
on me when I read of that 1834 voyage knowing of other contemporary
events.
My history knowledge is lacking many specifics in many areas not
directly studied in college, largely due to my lack of travel. When I
traveled to Europe and the Caribbean as a youth I had more interest in
whorestory than history. But of course that was also something of a
cultural education and more fun to me at that time than stuffy
museums.

Yes, I know that this is off topic, but this is why I 'cruise' - to
visit these places and see and experience in the first person. My
occupation is in modern technology but my passion is for history.

Very good. Wish I were with you drinking coffee.

--Vic

On Fri, 27 Apr 2007 09:23:57 -0500, Vic Smith
wrote:

The old man didn't bat an eye, but just said "Electricity."
The audience roared.
Nobody expected that answer, because they took that for granted.
But judging from Carson's and the audience's reaction, nobody
disagreed."

Just spend a few days in your house without electricity and you will
rapidly agree. It changes your whole lifestyle, and not for the
better.

Peter Hendra wrote in
:

Oh, and what is an optimum length and diameter - covered in plastic or
bare? - I know, only a project manager would want precision such as
this.

Thanks for all of this Larry. I shall follow your advice.



Optimum length would be 5% longer than 1/4 wavelength of the frequency
you are operating on. 1/4 wavelength in meters is 75.7/frequency in Mhz.

So, if we are on 6 Mhz, for instance, we get 75.7/6 x 1.05 = 13.2 meters.

But, because the radiating element ISN'T a proper length and we are using
a tuner, just make it LONG and the tuner will tune out the reactance and
match it up...

--------------------------------------------------

On another issue you have brought up, you said you had two backstays in
parallel, one with insulators that is the antenna and one that is not and
is solidly connected to the mast, right??

If this is so, in close proximity to the radiating element, that second
backstay is simply absorbing a major part of your radiation from the real
antenna, greatly reducing your actual field strength at some remote
receiver. We can't stop induced, out of phase, RF currents in any of the
rigging, but you can reduce it, greatly, giving you a nicely stronger
signal.

If these backstays are as I think, please consider putting insulators at
equal distance in BOTH backstays,not just one. Then, run a jumper
between upper end of the bottom insulators, effectively paralleling them.
Feed the tuner into the CENTER of this jumper, which can also be two
equal-length wires from the HV output of the tuner to the two insulator
feedpoints. The effect of doing this is a radiator that is MUCH greater
in "virtual diameter", both radiating IN PHASE, which aids their field
strength. Instead of the second backstay absorbing the signal, it will
create more signal, in phase. If your tuner is below them, you can
either make a T to feed the two backstays or just Y them out of the
tuner, itself, with EQUAL LENGTH conductors to preserve their phase
relationship.

Larry
--
Antennas R Us
If it doesn't glow blue after dark, power output is down.....(c;

Thanks Larry,
You are making my simple mind spin.

Seriously though, I am truly appreciative of your advice in this and
all matters. What you say about backstay aerials makes sense and I
shall do as you suggest. What I would really like, as do most others,
is long range voice comms. If anything reasonable helps in any way, I
will do it. There is nothing quite so annoying as to not be able to
receive an interpretable weather fax because of poor reception.

I'll add the ground from my stays. By the way, I neglected to tell
that I have a painted box section wooden mast, deck stepped. Forestay,
backstays and capshrouds are electrically connected due to their
attachment at the head of the mast. There is an aluminium sailtrack
which has no connection. Should this be a factor for consideration?

My specific area of small expertise over the past few years has been
packet data and such as better compression algorithms, up and down
linking to comms satellites, and the problem of latency or delay in
resending packets - solved by a really neat way of transmitting two
packet streams, with a slight delay on the second. If one packet
address is missing or denatured in some way, "it" merely grabs its
copy from the second incoming stream without having to ask the
originator for a resend and the consequent latency or time delays
whilst waiting - speeds it up no end. Probably been invented before
somewhere else but that sort of thing happens all the time. The
tracking system can track all of our active patrol boats as well as
Indonesia's ( and give postion, direction, speed and a lot of other
data in sub minute real time as well as sending and receiving text
messages and orders. If we needed to, we could add engine revs,
temperature and a lot of other really uinnecessary stuff.

Even though mobile phones are just glorified two channel radios, So
far as radio propagation (and most of the rest of it) has failed to
lodge in my brain successfully.

Thanks again for being so helpful and for freely disseminating your
experienced advice to those such as me whom you will probably never
meet.

cheers
Peter

On Fri, 27 Apr 2007 16:33:31 +0000, Larry wrote:

Peter Hendra wrote in
:

Oh, and what is an optimum length and diameter - covered in plastic or
bare? - I know, only a project manager would want precision such as
this.

Thanks for all of this Larry. I shall follow your advice.



Optimum length would be 5% longer than 1/4 wavelength of the frequency
you are operating on. 1/4 wavelength in meters is 75.7/frequency in Mhz.

So, if we are on 6 Mhz, for instance, we get 75.7/6 x 1.05 = 13.2 meters.

But, because the radiating element ISN'T a proper length and we are using
a tuner, just make it LONG and the tuner will tune out the reactance and
match it up...

--------------------------------------------------

On another issue you have brought up, you said you had two backstays in
parallel, one with insulators that is the antenna and one that is not and
is solidly connected to the mast, right??

If this is so, in close proximity to the radiating element, that second
backstay is simply absorbing a major part of your radiation from the real
antenna, greatly reducing your actual field strength at some remote
receiver. We can't stop induced, out of phase, RF currents in any of the
rigging, but you can reduce it, greatly, giving you a nicely stronger
signal.

If these backstays are as I think, please consider putting insulators at
equal distance in BOTH backstays,not just one. Then, run a jumper
between upper end of the bottom insulators, effectively paralleling them.
Feed the tuner into the CENTER of this jumper, which can also be two
equal-length wires from the HV output of the tuner to the two insulator
feedpoints. The effect of doing this is a radiator that is MUCH greater
in "virtual diameter", both radiating IN PHASE, which aids their field
strength. Instead of the second backstay absorbing the signal, it will
create more signal, in phase. If your tuner is below them, you can
either make a T to feed the two backstays or just Y them out of the
tuner, itself, with EQUAL LENGTH conductors to preserve their phase
relationship.

Larry

Peter Hendra wrote in
:

Seriously though, I am truly appreciative of your advice in this and
all matters. What you say about backstay aerials makes sense and I
shall do as you suggest. What I would really like, as do most others,
is long range voice comms. If anything reasonable helps in any way, I
will do it. There is nothing quite so annoying as to not be able to
receive an interpretable weather fax because of poor reception.


Whatever else you can do to move as much of the suspended metal away from
the radiating antenna element is of most importance in creating more
field strength at the remote receiver.

When Geoffrey first got Lionheart, the mainmast backstay on the ketch
goes from the rear of the center cockpit right up in parallel with the
boom lift, which WAS a stainless steel cable attached to the mast. If
the boat were close hauled, that cable was only a couple of feet from the
radiating backstay and just sucked the signal the transmitter was putting
out right out of the air. We replaced it with a proper, non-conductive,
line and got rid of the mainsail problem. It matters not where the main
is sheeted to the transmission, now.

I also made the backstay antenna BIGGER, longer, with a capacitor hat
top, because I find we use the lower HF frequencies more often. The
triattic between the masts was insulated fore and aft making a flat top
insulated wire. I insisted on the highest voltage insulators because at
the top end of every HF antenna, no matter what frequency you are on,
there is no current, only very high voltage at the top. I then added a
small cable from the upper end of the insulated backstay antenna (below
the upper insulator, of course) to the center of the triattic right above
it, creating a longer antenna with a capacitor hat top.

http://www.cebik.com/gp/cp-th.html
Notice the radiation pattern graph on this webpage of a vertical dipole,
a 1/4 wave vertical against a ground plane (that ocean ground we want)
and how the radiation pattern is much more HORIZONTAL, out towards that
remote station we are trying to contact, with the addition of the
triattic capacitor hat. Anything we can do to lower the vertical's too-
high radiation angle will make our signal much stronger out over the
horizon as it will lower the angle of attack on the ionosphere.

I've been playing with antennas since I was 10. I've been burned playing
with antennas since I was 11....the day the first ham transmitter was
operated...(c; That was 1957...a great year for ham radio at the peak of
the sunspot cycle maximum.

Larry W4CSC - proof positive RF ISN'T hazardous to your health.
I'm still being burned playing with antennas...(c;
--

Peter Hendra wrote in
:

I'll add the ground from my stays. By the way, I neglected to tell
that I have a painted box section wooden mast, deck stepped. Forestay,
backstays and capshrouds are electrically connected due to their
attachment at the head of the mast. There is an aluminium sailtrack
which has no connection. Should this be a factor for consideration?


I'd feel better if you'd add a smooth metal cap at the top of the mast to
bleed off static buildup before it causes a strike.

We've learned a lot since the "lightning rod" days, one of the worst
things ever done to protect buildings from lightning. Remember those
sharp-pointed lightning rods that sprayed electrons into the air to
ionize it and GIVE the clouds a path to ground....right at the top of the
flammable barn roof? This was NOT the way to protect buildings!

Today, lightning systems use a grounded, smooth copper flashing that
distributes the electrons along a smooth, long surface to release them
over as wide an area as possible. A pointy grounded thingy ATTRACTS
lightning because there is a concentrated stream of electrons spraying
off the point, ionizing the air above the point...exactly what the cloud
is looking for.

If there's some kind of metal ring at the top of the mast that's grounded
by the various shrouds and stays, that's great. A metal cap that can
take a pretty good strike, might also keep a hit from boiling the sap in
the mast, creating a steam explosion and putting you out of the sailing
business. This alone makes a mast top bypass cap a good thing.

Larry
--

If there's some kind of metal ring at the top of the mast that's grounded
by the various shrouds and stays, that's great. A metal cap that can
take a pretty good strike, might also keep a hit from boiling the sap in
the mast, creating a steam explosion and putting you out of the sailing
business. This alone makes a mast top bypass cap a good thing.

Larry

yes, it is just as you describe, but this generates another question
(sorry). I had often thought of putting a pointed copper rod on top
grounded to the stays as per many books and articles on the matter. I
have never done so because I believed that it would act as an
attractant, rather like Benjamin Franklin's key on the kite string.

Also what got hit first during the lightning strike in Malaysia - the
day we went back into the water before setting out across the Indian
Ocean mind you - was the VHF aerial. the question is - does the damned
thing act as a lightning attractor as it is the highest thing there?

cheers
Peter