_____

From: owner-baba-l@ballreich.net [mailto:owner-baba-l@ballreich.net] On
Behalf Of dave@mybajaspot.com
Sent: Sunday, March 26, 2006 10:34 AM
To: baba-l@ballreich.net
Subject: RE: [Baba-L] Lightning Ground Project, Tashiba 40

 

If I am reading the information correctly on lightening, copper dissipation
plate, the lightening enters the water from the corners and sharp edges of
the plate. Just a thought, but would it be a further enhancement to give
this plate a rick-rack edge that could easily double its dissipation edge
surface to the water.

[Richard ] Well..Yes, this would enhance the disipatation of a strike into
the water; however, it will also introduce more turbulence as water passes
the plate. I don't think you can measure the difference in sailing speed
with a jagged edge compared with a clean edge. I'm going from no protection
to a massive ground plate so straight edges seemed ok to me.

 

The next task of course is to tie all metal surfaces that might also carry
part of the lightening strike current to this plate (with direct as
possible) wire runs.

[Richard ] Below the cabin sole is a bus bar where all the green bonding
wires forward of the engine terminate. I ran AWG #6 wire from the bus bar to
the copper grounding plate bolt. A #6 wire connects the forward bus bar with
a similar one located aft of the hot water tank, (behind the engine). One
important note on understanding bonding vs. ground: Bonding wire (system) is
never loaded carrying - there is never "supposed" to be electricity running
through it. On the other hand a "ground" wire is meant to complete a circuit
and carry electrical current. Nigel Calder does a great job of explaining
all this in his electrical and mechanical repair manual.

 

How did you get the internal wire down on the keel to connect to this plate?

[Richard ] the plate is directly below the mast step and bolts through the
hull into the side of a small bilge. It is assessable by lifting up the
floor board at the door to the head. The 1/0 wire I used to bolt to the
aluminum mast base and copper plate bolt is only about 18 inches long and a
direct run. In fact, I used two wires to attach the mast to both bolts
holding the plate. When I get to the boat again I will take a picture of
this and post to the folder on the ftp site.

 

My plan is to attach this plate higher on the hull in close proximity to the
mast. Then either connect a short run of copper pipe to the mast and bolt
the other end to the copper plate through the hull with a silicon bronze
bolt to complete the circuit. I would most prefer to use 4/0 copper wire
down the mat to this bolt to eliminate the mast as being the current
carrier, but not sure at this point which way I will install this
protection.

[Richard ] I located the plate as high as I could and not get into trouble
with the rounding of the keel up to the hull. Any further up and a flat
plate would not work. Again as I mentioned in a previous post I would stay
with the 3/16" thick plate if I had it to do over again. 3/16 will bend a
little when you tighten the bolts and this will allow it to conform to the
slight curves.

 

Rich Cassano

 

Dave

S/V Bella

Ensenada, BC, Mexico

 

  _____

From: Richard Cassano [mailto:rcassano@optonline.net]
Sent: Saturday, March 25, 2006 2:19 PM
To: baba-l@ballreich.net
Subject: RE: [Baba-L] Lightning Ground Project, Tashiba 40

 

Yes, I believe this is the reason for the thickness of the copper plate. I
ended up with a piece of copper a little thicker than required. 3/16 of an
inch is all that's called for in the specifications and may be better than
the heavier one as it will bend to conform to the hull curvature when the
bolts are torqued. At the location I bolted the plate it's relatively flat;
however as you can see in the picture there is a piece cut off at a 45
degree angle at the forward edge. I did this because the hull curve would
have left a deep space between the plate and hull.

 

A few years back I observed a boat hauled out after a lightning strike and
it had more than a dozen pin holes in the hull. I presume the lightning had
no where to go and so dispersed randomly through the fiberglass hull. By
installing this lightning system I hope the hull and metal through-hulls
will be spared and the electricity flows through the provided path.
Unfortunately, nothing is predictable or certain with lightning.

 

Rich Cassano

 

  _____

From: owner-baba-l@ballreich.net [mailto:owner-baba-l@ballreich.net] On
Behalf Of lists@collisters.com
Sent: Saturday, March 25, 2006 10:49 AM
To: baba-l@ballreich.net
Subject: RE: [Baba-L] Lightning Ground Project, Tashiba 40

 

Hi Richard,

 

Great article and very interesting as I plan to fix a large copper sheet
under the hull in 2 weeks time when I lift the boat out. This was intended
to be purely for the SSB earth but your text and pictures have me thinking
now.

I have purchased a copper sheet, but it quite thin compared with what you
used, I presume the thickness is needed to carry the huge currents
associated with the Lightning

 

 

Paul C
S/V Lady Stardust, Liverpool UK
www.lady-stardust.co.uk <http://www.lady-stardust.co.uk/>

 

RE:

I posted a description and pictures of a new lightning ground system to the
Baba ftp web site. This was supposed to be a four hour project that evolved
into a much longer more involved one.

 

 




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Received on Sun Mar 26 16:51:51 2006