Like the vast majority of fiberglass boat owners, I'm sailing around in a
boat with next to no lightning protection. I have run a heavy copper
grounding wire from a chain plate to a couple of through hulls directly
below. That will help bleed off some charge and slightly reduce the chance
of being struck. If I am hit however, I imagine it will make the results
worse.

This is on my "someday" list and would be on the "already done" list if I
sailed more to the south. I nearly 40 years of sailing in this part of the
world, I've only once been in a situation that I was huddled below trying to
figure out the best place to be when the bolt hit. That was long ago enough
that I haven't gotten as worked up about the issues as I should.

I don't know as much about the subject as I should since I've spent my
professional life working with boats that have metal masts welded on top of
metal superstructures welded to metal hulls. So, I throw out this idea for
comment as a suggestion for either an interim solution or for cruising
grounds where energetic storms are too infrequent to justify a major
retrofit.

How about a couple of plastic coated battery cables with a snap shackle on
one end and a length of chain on the other. If it looks like you are going
to get caught right in the path of an energetic storm, the kind where you'll
want to either anchor or drift while you seek the safest place in the boat,
just clip them to the shrouds and drop over the side. Nearly straight run
down from the stays (at least if chain plates are not too far inboard), lots
of surface area in the chain, plastic coated wire to protect the topsides.
You wouldn't want to cruise around with this rig but it seems like it might
at least keep a strike from sinking the boat by blowing a hole in it.

--

Roger Long

Roger,

I like that idea but we need to work on the snap shackle because there would
be an increased resistance right there.

Ansley Sawyer

The resistance profile may reveal that the shroud becomes the main
dissapative element in the discharge path. It may well vaporize, and
you at sea with sails in a squall?

Every earth bond will include a weak link, which will burn out first,
causing x-metal vapour arc to be temporarily included in an
established hi current stroke discharge, if the bolt be juicy enough.

I would not want it to be a shroud which parts, possibly leaving me a
pedestrian.

Ground the base of the mast as directly as possible to a bare keel or
clean plate, keeping in mind you must plan a fusible weak point
somewhere, but hopefully not where it will cause the mistress to burn
her bum.

My weak point is the four smallish bolts penetrating the overhead at
the tabernacle.

My backup is that the shrouds should position the mast heel adequately
should all four bolts get burned off.

My proof is 25 holes burned in the old mast, repetitively struck by a
biggie. The path presented it's main resistance effect in two distinct
areas: The burn craters in the mast surface, strangely all at the
same point of curvature on the mast surface, and the keel bolt, which
cracked the fiberglass around it's bedding, to the tune of a new leak,
about one drop every five minutes. The bolt is fatter stainless than
the copper ground wire.

I would not want to be making connections grounding equipment once the
storm gets close enough to make it seem an urgent neccessity, I would
likely better be employed reefing or something. Then, I'll go below
and sit under a grounded umbrella, hugging the rum bottle and
whistling for a taxi.

I would have disconnected the VHF AE, but then the steaming lamp would
not work, besides I wasn't there at the time and had not thought to do
so when I left the boat at the dock.

No need, I suspect because the VHF survived the lightning stike.

Terry K

Charlie Morgan wrote:

On Thu, 15 Mar 2007 15:34:33 -0400, "Roger Long" wrote:


Like the vast majority of fiberglass boat owners, I'm sailing around in a
boat with next to no lightning protection. I have run a heavy copper
grounding wire from a chain plate to a couple of through hulls directly
below. That will help bleed off some charge and slightly reduce the chance
of being struck. If I am hit however, I imagine it will make the results
worse.

This is on my "someday" list and would be on the "already done" list if I
sailed more to the south. I nearly 40 years of sailing in this part of the
world, I've only once been in a situation that I was huddled below trying to
figure out the best place to be when the bolt hit. That was long ago enough
that I haven't gotten as worked up about the issues as I should.

I don't know as much about the subject as I should since I've spent my
professional life working with boats that have metal masts welded on top of
metal superstructures welded to metal hulls. So, I throw out this idea for
comment as a suggestion for either an interim solution or for cruising
grounds where energetic storms are too infrequent to justify a major
retrofit.

How about a couple of plastic coated battery cables with a snap shackle on
one end and a length of chain on the other. If it looks like you are going
to get caught right in the path of an energetic storm, the kind where you'll
want to either anchor or drift while you seek the safest place in the boat,
just clip them to the shrouds and drop over the side. Nearly straight run
down from the stays (at least if chain plates are not too far inboard), lots
of surface area in the chain, plastic coated wire to protect the topsides.
You wouldn't want to cruise around with this rig but it seems like it might
at least keep a strike from sinking the boat by blowing a hole in it.


Honestly? There is absolutely nothing you can do to a 30 or 40 foot boat to
protect it in the slightest. It may make you feel better, but there's truly no
way you are going to harness and direct a lightning strike that hits your mast.
Lightning will vaporize (literally) your battery cables. POOF!

The only thing that MAY help you is to always anchor with boats that have much
taller masts than yours.

How about a heavy wire connecting keel bolts to mast bolts, less than a
foot apart in my bilge?

Stephen

On Mar 15, 3:34 pm, "Roger Long" wrote:
Like the vast majority of fiberglass boat owners, I'm sailing around in a
boat with next to no lightning protection. I have run a heavy copper
grounding wire from a chain plate to a couple of through hulls directly
below. That will help bleed off some charge and slightly reduce the chance
of being struck. If I am hit however, I imagine it will make the results
worse.

This is on my "someday" list and would be on the "already done" list if I
sailed more to the south. I nearly 40 years of sailing in this part of the
world, I've only once been in a situation that I was huddled below trying to
figure out the best place to be when the bolt hit. That was long ago enough
that I haven't gotten as worked up about the issues as I should.

I don't know as much about the subject as I should since I've spent my
professional life working with boats that have metal masts welded on top of
metal superstructures welded to metal hulls. So, I throw out this idea for
comment as a suggestion for either an interim solution or for cruising
grounds where energetic storms are too infrequent to justify a major
retrofit.

How about a couple of plastic coated battery cables with a snap shackle on
one end and a length of chain on the other. If it looks like you are going
to get caught right in the path of an energetic storm, the kind where you'll
want to either anchor or drift while you seek the safest place in the boat,
just clip them to the shrouds and drop over the side. Nearly straight run
down from the stays (at least if chain plates are not too far inboard), lots
of surface area in the chain, plastic coated wire to protect the topsides.
You wouldn't want to cruise around with this rig but it seems like it might
at least keep a strike from sinking the boat by blowing a hole in it.

--

Roger Long

Check out the following website: http://www.marinelightning.com/

And the interview of the proprietor (Dr. Ewen Thomson) at:
http://furledsails.com/article.php3?article=676

The Furled Sails interview was quite interesting and the inventor
discussed both the product and his thinking behind it in detail, as
well as Boat U.S. insurance stats on the frequency of lightening
strikes. The web site has a variety of information as well. As for
the odds of being hit, the odds are greater if you are in Florida or
own a catamaran, and Charlie's advice about mooring near taller
targets is apt, as boats in marinas / crowded harbors, have lower risk
as well.

Steve Hayes

On Thu, 15 Mar 2007 15:34:33 -0400, "Roger Long"
wrote:

How about a couple of plastic coated battery cables with a snap shackle on
one end and a length of chain on the other. If it looks like you are going
to get caught right in the path of an energetic storm, the kind where you'll
want to either anchor or drift while you seek the safest place in the boat,
just clip them to the shrouds and drop over the side.

Most really large sailboats use zinc fish with an attached wire and
alligator clip. You can buy these at West Marine and other
chandleries. One on each upper shroud is a good start, and you can
also put one on the headstay and backstay (assuming it isn't
insulated.

I use one on each side of my trawler mast when docked, or at anchor in
threatening weather. In the end it's all luck however, lightning is
very capricious stuff.

http://tinyurl.com/zttlk

On Thu, 15 Mar 2007 14:22:13 -0700, Stephen Trapani
wrote:

How about a heavy wire connecting keel bolts to mast bolts, less than a
foot apart in my bilge?

That's about as good as it gets, better to use heavy copper braid
however. That also makes an excellent ground for your SSB radio.

"Terry K" wrote in message
oups.com...
The resistance profile may reveal that the shroud becomes the main
dissapative element in the discharge path. It may well vaporize, and
you at sea with sails in a squall?

Every earth bond will include a weak link, which will burn out first,
causing x-metal vapour arc to be temporarily included in an
established hi current stroke discharge, if the bolt be juicy enough.

I would not want it to be a shroud which parts, possibly leaving me a
pedestrian.

Ground the base of the mast as directly as possible to a bare keel or
clean plate, keeping in mind you must plan a fusible weak point
somewhere, but hopefully not where it will cause the mistress to burn
her bum.

My weak point is the four smallish bolts penetrating the overhead at
the tabernacle.

My backup is that the shrouds should position the mast heel adequately
should all four bolts get burned off.

My proof is 25 holes burned in the old mast, repetitively struck by a
biggie. The path presented it's main resistance effect in two distinct
areas: The burn craters in the mast surface, strangely all at the
same point of curvature on the mast surface, and the keel bolt, which
cracked the fiberglass around it's bedding, to the tune of a new leak,
about one drop every five minutes. The bolt is fatter stainless than
the copper ground wire.

I would not want to be making connections grounding equipment once the
storm gets close enough to make it seem an urgent neccessity, I would
likely better be employed reefing or something. Then, I'll go below
and sit under a grounded umbrella, hugging the rum bottle and
whistling for a taxi.

I would have disconnected the VHF AE, but then the steaming lamp would
not work, besides I wasn't there at the time and had not thought to do
so when I left the boat at the dock.

No need, I suspect because the VHF survived the lightning stike.

Terry K

"Terry K" wrote

The resistance profile may reveal that the shroud becomes the main
dissapative element in the discharge path. It may well vaporize, and
you at sea with sails in a squall?

My rig would stand without the forward lowers which I would use.

Ground the base of the mast as directly as possible to a bare keel or
clean plate, keeping in mind you must plan a fusible weak point
somewhere, but hopefully not where it will cause the mistress to burn
her bum.


I'm not talking about doing it right here or protecting the boat. The only
aim is to increase the chances of remaining alive on a possibly wrecked boat
to deal with the aftermath. I'm just looking for a quick stop gap to at
least do something until I can put in a proper system. It's tough on a boat
with ballast encapsulated inside a fiberglass keel.

I would not want to be making connections grounding equipment once the
storm gets close enough to make it seem an urgent neccessity

That's the reason for rapid deployment. BTW doppler radar available on your
cell phone from the Weather Channel is a great service where there is
coverage. I've used it both flying and boating to avoid and plan for
storms.

I'm glad I sail and plan to sail where there aren't a lot of thunderstorms.
Most of them lose a lot of steam when they get to the cold water in this
part of the world. They continue to rumble with cloud to cloud strikes but
not many of them are still putting out a lot of cloud to ground strikes. I
can't remember hearing of a vessel struck north of Cape Cod although I'm
sure it has happened.

--
Roger Long

Stephen Trapani inscribed in red ink for all to know:
Charlie Morgan wrote:

On Thu, 15 Mar 2007 15:34:33 -0400, "Roger Long"
wrote:


Like the vast majority of fiberglass boat owners, I'm sailing around
in a boat with next to no lightning protection. I have run a heavy
copper grounding wire from a chain plate to a couple of through hulls
directly below. That will help bleed off some charge and slightly
reduce the chance of being struck. If I am hit however, I imagine it
will make the results worse.

This is on my "someday" list and would be on the "already done" list
if I sailed more to the south. I nearly 40 years of sailing in this
part of the world, I've only once been in a situation that I was
huddled below trying to figure out the best place to be when the bolt
hit. That was long ago enough that I haven't gotten as worked up
about the issues as I should.

I don't know as much about the subject as I should since I've spent
my professional life working with boats that have metal masts welded
on top of metal superstructures welded to metal hulls. So, I throw
out this idea for comment as a suggestion for either an interim
solution or for cruising grounds where energetic storms are too
infrequent to justify a major retrofit.

How about a couple of plastic coated battery cables with a snap
shackle on one end and a length of chain on the other. If it looks
like you are going to get caught right in the path of an energetic
storm, the kind where you'll want to either anchor or drift while you
seek the safest place in the boat, just clip them to the shrouds and
drop over the side. Nearly straight run down from the stays (at least
if chain plates are not too far inboard), lots of surface area in the
chain, plastic coated wire to protect the topsides. You wouldn't want
to cruise around with this rig but it seems like it might at least
keep a strike from sinking the boat by blowing a hole in it.



Honestly? There is absolutely nothing you can do to a 30 or 40 foot
boat to
protect it in the slightest. It may make you feel better, but there's
truly no
way you are going to harness and direct a lightning strike that hits
your mast.
Lightning will vaporize (literally) your battery cables. POOF!
The only thing that MAY help you is to always anchor with boats that
have much
taller masts than yours.


How about a heavy wire connecting keel bolts to mast bolts, less than a
foot apart in my bilge?

Stephen


The problem is that a lightening strike is a pulse - it is not DC.
Corners in the wire path look like inductors at high frequencies, and
may force the lightening to leave the conductor and take a straighter
path (at least in its mind) to earth, avoiding the conductor altogether.
All wiring paths should be very heavy gauge, and as straight as
possible.

It might work.

It might not, but one always takes the precautions, right?

bob
s/v Eolian
Seattle, where a lightening bolt becomes the first item on the evening
news...