[Rhodes22-list] Electrical grounding and bonding

[ronald]

This is a good reference:

http://www.thomson.ece.ufl.edu/lightning/

The bottom line is that there is no consensus on whether grounding the 
boat
increases the probability of a strike.  Lightning protection is intended 
to divert
the current of the strike through a good conductor rather than through 
the hull
of your boat (or through you) and not to lessen the probability of a 
strike.  Due
to the large currents involved it is difficult to do a proper job 
without substantial
conductors.

According to Thomson's study the probability of a strike can
be approximated by drawing an "attractive area" cone with an apex angle 
of
132 degrees at the top of the mast.  (This is an rough estimate based on 
lighting
strike data and not a calculated angle).  This gives the effective area 
of the
Rhodes 22 for lighting strike purposes as about 10,000 square feet.  So
it is roughly equal to the probability of lightning striking a house or 
yard.

Given the difficulty in protection and the low probability of a strike I 
would not
do anything unless I expect to be traveling in a stormy area.  I would 
stay away
from metal parts of the boat if caught in a sudden storm and take 
comfort in
the foam flotation in the Rhodes.

Ron Lipton

On Saturday, September 14, 2002, at 09:46 PM, Todd Tavares wrote:

> I was browsing through some books at the boat store (bought a book 
> about repairing fiberglass).
>   I was flipping through a book about the electrical systems.  This 
> book would give the "two schools of thought" but never saying which was 
> better.
>
>   I was reading about the grounding of the electrical system and 
> rigging for lightning strike/protection.  One argument was that 
> grounding the mast and rigging to ocean/earth potential would dissapate 
> building up ions and help prevent lightning strikes by lessening the 
> potential difference around the boat; and in the event of a strike, 
> give a more direct path to ground from the mast to ground.
>
>   The other argument was that grounding the mast and rigging was 
> creating a lightning rod and would attract a strike.
>
>
>   Has anyone researched this?  What do most of you owners here do?  If 
> you follow the first school of thought, how have you grounded your 
> rigging?  How (what path) and what size wire did you use?  How is it 
> routed to get below the water line??
>
> --
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