On Sat, 08 Nov 2008 16:33:21 -0500, Marty wrote:

Roger Long wrote:
This winter's major project is to add some serious lightning protection
to "Strider". What I have now is probably sufficient to increase the
odds of being alive to climb into the dinghy and watch the boat sink but
I'd prefer to sail home. It's not a subject that comes up often for a
designer of metal vessels so I've been look around the web and learned:

Do it like is done for tall buildings, strap a copper ribbon, 8" x 1/4"
up the length of your mast, one on each side. bond these at the base of
the mast to copper bus, 8" x 1/2", this bus is then bonded to a braided
copper cable approximately 6" in diameter and led to copper grid.
The grid should consist of an array of 1/2" diameter rod laid out to
form a square of no less 100' on each side, or any configuration giving
you an area of 10,000 sq. ft. The rods should be configured to form
squares of about one foot on each side, each junction should be bonded.
The main cable should be laid across at least 3/4 of the grid, or the
braid unraveled and broken into many smaller strands, each strand to be
bonded to the grid at intervals of two to five feet.

This will probably, but is not guaranteed to, protect your boat,
remember a lighting strike may exceed a million amperes, for a brief
time, but it does have a tendency of vaporizing anything smaller than I
have described.

Sounds like BS. My house barn and corn crib all had half inch or so
braided copper cable connecting 1/2 inch pointed rods. The ground rods
are presumed to be the standard ones the electrical places all sell.
They were struck hundreds of times, they were on top of a hill.

I heard it was 20 000 amps, at a million volts.

Casady