Easiest is a set of battery jumper cables cliipped tothe shrouds with a
round turn andthen drag them in the water. One for each side. I don't
remember the exact physics but it creates a cone of safety effect and
wonder if anyone else remembers and can address that particular point.

"Larry Demers" wrote in message
...
Jim,

I can get a #1 cable from the mast receptacle on the deck (deck
stepped), down
to the encapsulated keel with a couple small gentle curves. Tapping into
the
keel with a fair sized threaded rod will be interesting I suppose. Any
hints?
I have a Cape Dory 30.

Any consideration to the idea that the conductor that the lightning
streamer
takes upwards at the start of the stroke, will be vaporized by the
streamer,
forming a very low resistance plasma pathway for the main downward stroke
to
follow. This would seem to throw away the inductive effects of the
conductor
for the main charge. The leader though, would feel that inductance I
suppose,
which would effect how high the stepped leader goes and how far downward
the
main charge has to reach for a completed path.

Inductance in the boats ground path (too small a conductor) would seem
to
cause side flashes to surrounding metallic objects on the boat that have a
lower
resistance (impedance really?), and then to a local ground. It can get
into the
laminate and do real damage that way.

Cheers,

Larry DeMers

Jim Donohue wrote:

Lightning does what it wants..not what you want. The mast is a much
larger
and somewhat shorter conductor than anything you could run along the
shrouds. So the stroke will divide and almost all of it will stick with
the
mast. When the stroke reaches the bottom of the mast some of the energy
will return to the shroud ground via whatever path...destroying anything
in
the way.

Straight to the water is best. If not then very gentle and heavy curve
to
water. Shortest is best...if not shortest than as close as practical.
All
deviations from straight and shortest increase the probability of
damage.

Jim Donohue

"Courtney Thomas" wrote in message
...
What would be wrong with a long, ....straight.... piece of aluminum
rod
in contact with a location as desired/convenient near the mast top,
(running alongside a shroud) into the water ?

Courtney




Parallax wrote:

Thunderstorms every day and my fear of lightning (totally justified)
have caused me to once again scheme up a way to protect my sailboat.
For protection while anchored, I have a 2'X2' copper sheet with very
thick stranded tinned cable with a clamp for attachment to the mast.
I have considered using this while underway but it would cause too
much drag and would probably foul the prop.

So........another useless idea. How could you tow a lightning
ground?
Such a ground doesnt have to be a sheet. it just has to have large
surface area. Could attach it to the bottom of the dinghy and tow
it
with proper cable going to the mast but I try not to tow my dinghy.
OK, why not something like a boogie board (foam) covered with Cu
foil.
No matter which side it had in the water, it would have lots of
area
submerged. It would produce minimal drag. Any thoughts?



--
s/v Mutiny
Rhodes Bounty II
lying Oriental, NC
WDB5619