Here is the best lightning expose I have ever read:
http://www.thomson.ece.ufl.edu/lightning/

-----Original Message-----
From: owner-baba-l@ballreich.net [mailto:owner-baba-l@ballreich.net] On
Behalf Of dave@mybajaspot.com
Sent: Tuesday, November 29, 2005 2:13 PM
To: baba-l@ballreich.net
Subject: RE: [Baba-L] Lightning... more input

Rick,

Very interesting... you're input on lightening arrestor. I have the same
concerns as I intend to sail in waters where lightening is prevalent. My
plans pretty much parallel yours as stated and I intend to run as large a
copper conductor from mast head to keel and thru hull to copper plate as I
can fit to the application. I am assuming and will check, but think 4/0 is a
reasonable thickness, now stranded or solid? If one want to avoid corrosion
in areas that we have little control I guess we would insist on marine grade
copper conductor properly tinned. Lightening arresting seems to be a black
science with most novice sailors still thinking lightening strikes down, but
sure will be surprised to find that it strikes up earth (-) to positive to
cloud (+) ions. Apparently this is why that little lightening dissipater
fuzz ball on the end of a one foot conductor makes sense. There is a
condition that we have not talked about with high static charged electrical
storms and that is corona discharge. This is when all metal surfaces on a
fiberglass (insulator) boat act as a big capacitor and it is possible to
have static discharge onboard between these surfaces... thus we have a
bonding system that a lot of boater fail to understand and simply disconnect
these green wires as they add new metal appliances onboard. I recommend
keeping the bonding system in tact and inspect clean contacts and properly
tightened to provide good contact.

Have a great day. Please accept the fact that I am a student of lightening
safety and do not know it all, but sure wish I did.

Dave Lewis
S/V Bella
Ensenada, BC, Mexico

-----Original Message-----
From: owner-baba-l@ballreich.net [mailto:owner-baba-l@ballreich.net] On
Behalf Of Richard Cassano
Sent: Tuesday, November 29, 2005 7:44 AM
To: baba-l@ballreich.net
Subject: Re: [Baba-L] Lightning story from Harris Gabel

Interesting you should bring up the subject. A few years ago a boat just a
few mooring away took a direct hit. No one was aboard but all the
electronics were fried and the mast head blackened from the hit. Other boats

took the strike as well with one leaking badly from two dozen pin holes in
the hull. I guess this is where the lightening bolt dispersed and exited the

vessel. At the time, I checked all electronics aboard Gray Eagle and all
powered up as they usually did. Off I went for a sail down Long Island
Sound. As night closed in I turned on the GPS, laptop, Sailing Instruments
and nothing was making any sense. Quickly the laptop shut down and would not

restart. The GPS display was intermittent and the sailing instruments the
same. To make a long story short the above listed items all had to be
repaired or replaced. The laptop was fried on the motherboard where the
serial port connected from the GPS. The motherboard looked like a satellite
photo of a urban community with a major fire in one of the buildings
(chips).

During this winters haulout I would like to re-wire the lightening ground
system to bring it up to what the latest ABYC or NFPA standards are. My goal

is to give the crew a greater level of protection. I do not believe any
prevention, circuitry or standard will protect electronics. If you take a
hit, kiss the high tech stuff good bye and pull out the sextant and paper
charts. Hopefully the crew will be ok. The dilemma one faces when providing
lightening protection is what size and shape of copper or stainless plate
will be bolted to the outside of the hull with interior wiring connection.
The new specifications call for a strip of copper, copper alloys, or
stainless steel installed under the water craft running fore and aft with
minimal thickness of 3/16" ,width 3/4" wide and not less than 4' long. This
strip must start below the termination point. In our case below the mast
step. The ground plate should have an area that covers one square foot. the
more edge it has the more effective the disipitation of the lightening
charge to the water. A strip with jagged edges would be more effective than
a rectangular clean edge strip. The installation problem on a Tashiba 40 is
where to bolt on a 4' long copper strip with as few holes in the hull as
possible and start the installation under the mast step area. If you want to

read the details check out, "NFPA 780 Standards for the Installation of
Lightening Protection Systems 1997 Edition" there may be a newer version of
this publication but this is the one I have.

Rich Cassano

----- Original Message -----
From: "Cindy Ballreich" <cindy@ballreich.net>
To: "Baba Mailing List" <baba-l@ballreich.net>
Sent: Monday, November 28, 2005 7:53 PM
Subject: [Baba-L] Lightning story from Harris Gabel


> Harris Gabel has written a letter which appeared in the November issue of
> Latitude 38. (Latitude 38 is a free sailing magazine with a San Francisco
> bay area focus, but which covers all of California and the Pacific coast
> of Mexico. It's a very cool magazine with excellent content.) Harris wrote

> about being at Catalina the night of September 19-20. The letter can be
> found at http://www.latitude38.com/letters/200511.htm about 25% of the way

> down the page entitled "ELECTRICAL STORM AT CATALINA".
>
> We (Rick and I) experienced the same thunder storm and also worried about
> our boat. However, we did it from the safety of our home. Harris and Linda

> did it from a mooring ball in Emerald Bay!!! I've experienced thunder
> storms in Florida and Nevada and this was as wild as any of them. (BTW: We

> just got back from Thanksgiving at Catalina and everything is green and
> beautiful because of the rain from that storm.)
>
> Anyone else have any lighting stories? Do others worry about lightning
> strikes?
>
> Cindy
> --
> Cindy Ballreich
> S/V Mandisa
> Baba 30 #218
>
>
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Received on Tue Nov 29 20:43:59 2005