On Wed, 20 Aug 2008 16:21:10 -0400, "Eisboch"
wrote:


"Wayne.B" wrote in message
.. .
On Wed, 20 Aug 2008 15:28:55 -0400, "Eisboch"
wrote:

Makes sense to me and since it is a totally passive device (not powered
....
just grounded to the arch) I left it on.

If you go to a harbor like Newport, RI that has a lot of really large
sailboats at the dock, you will frequently see wires clipped to the
rigging and hanging in the water. Typically these will be something
like the zinc "fish" that West Marine sells. They come with an
attached wire and large alligator clip. The theory is that if you
keep the rigging well grounded that charge will bleed off the mast
before it gets to dangerous levels. I have no idea whether or not it
works, but my theory is that it can't hurt, and a lot of people who
manage large expensive boats seem to believe in it. We do it on the
GB when it is docked in the summer, one on each side. I usually end
up drilling and tapping the fish after a year so I can attach a fresh
wire and clip.


That makes sense.

I think that often too much effort is made to "attract" the strike, thinking
it's potential can be managed through grounding schemes. I think it's
better to devise systems that minimize the chances of a strike.

They wire lightning rods with 000 wire. I am surprised they can handle
20 000 amps. My previous address, farm buildings on a hill, had them
and were struck repeatedly with no damage. A mast will attract
lightning. It should be grounded with a 000 wire, unless you want to
see exploding fiberglass. Score one for a metal boat. The connection
from that 000 wire to the sea doesn't really need to be enormous, but
I don't know how they figure it. You can expect a steam explosion no
matter what you do. Trees sometimes explode. So do wood, or glass
boats, on occasion. You need a lightning rods to protect the radios,
if not the hull, especially on powerboats where those ten foot whips
are the highest thing around. If you don't get a rod and a strike
fries your radios, console yourself that had the juice gone through a
glass hull there might have been sinkage type damage. Lightning
strikes on aluminum planes make a one to two inch hole. But they are
of course, ungrounded. A metal boat is pretty safe, although the
radios are not. Lightning bolts average 20 000 Amps at 20 000 000
Volts. I think you should be able to run a 000 wire from the mast to
ground. Did I mention that is is scary to be within four feet of a
strike? There people that don't learn and who are relatively lucky who
have been struck at least three times. One pro golfer said that if you
were caught out on the course, hold up a one iron because even god
couldn't hit one of those. I have a one iron, and I can't although one
guy, only, Ben Hogan, one of the best ever, a legend, one of those
guys they name lines of golf clubs after, could hit one. Nobody
carries one. Not worth the weight. I digress, but 80% of the posts at
this NG are off topic. So what I say. Gives something to do after you
finish the five minutes of boating stuff.

Casady