[PUP] Being prepared (for everything ?)

[bob england]

I wonder just what the statistics are on being struck by lightning at sea. I
would guess the chances are small, sure everyone "knows" a person/boat/story,
but what is the milage per strike ratio for cruising powerboats. I respect
lightning, and nature in general, but it seems like we sometimes look for any
reason to stay home, safe. In 25 years messin around on the water I have had
one vhf radio ruined by lightning (I liked that radio to) that's it, I guess
I've just been lucky. As a Journeyman lineman working maintenace in rural
areas in the tornado alley, I've seen some lightning, up close and personal.
Our mantra was "if you're not a path you don't have a problem". I've watched a
direct strike two poles away from the powerline pole I was changing an
insulator on, using a belt and hooks, I had the 2f copper line in my lap with
a gut (insulator) on it and a ground jumper to the neutral on both sides of
me. I never event felt a buzz, because I was not a path. Your electronics on a
boat are the same way, if you put them in the path they will get zapped, but
they don't need to be in the path at all to work, except maybe sonars with
bronze transducers.> From: rcrogers6@kennett.net> To:
scottebulger@comcast.net; passagemaking-under-power@lists.samurai.com> Date:
Thu, 22 Mar 2007 18:57:44 -0400> Subject: Re: [PUP] Lightning preparedness> >
Well, I thought that's what I said. Protect the crew - that's feasible by >
creating a cone of safety using the mast. There is general agreement that >
this has a high probability of success.> > Equipment protect for gear that is
connect to any electrical or bonding > system is futile. Depending upon the
nature of the strike and the consequent > EMP, it is unlikey anything will
survive. Rewiring the boat is a little > unusual, but depends upon doing a
real analysis. Example: My RG8U VHF cable > looked perfect and passed a
continuity test. However, a buddy at EG&G wanted > to take sections of the
cable and place them under an electron microscope. > The cable was in fact
damaged by heat.> > Therefore, Scott, your idea of having disconnected spares
is the best > civilians can do. Spare batteries, a GPS, and VHF any other
spares you need > for survival and that you can afford, should be stored
aboard. I think I saw > a Faraday cage instrument panel built by Palmer
Johnson for a Mason (PAE) > sailboat. It was a complex, screened, metal framed
structure and I can only > wonder if it worked. On another list, it was
pointed out that most > electronic engine have a "limp home" mode. Whether
that mode is available > after a lightning strike was not mentioned.> > One
point not previously mentioned is the physical damage that can occur. > For
example, I know several sailboat owner whose thru-hull depth transducers >
blew out of the boat. Two boats were manned and survived while the third was >
unattended in its slip and sank. It is likely that these were direct >
strikes.> > When Navy CICs were run by DG mini computers, every component
(that I could > see) was wrapped in tantalum foil. The mini itself was
residing in a > thick-walled metal safe that formed its outer casing. There
was a lifting > ring built into the top of the box. I don't know if the Navy
uses that > technique anymore and several novels have suggested that a
battlegroup could > go blind from nuclear EMP. I'd like to think that they can
survive lightning > strikes without damage.> > My personal experience was that
electronics not connected survived a near > strike while everything connected
was damaged. One thing I learned was not > to allow anything to be repaired
because there are incipient failures that > will emerge long after the initial
repair - I know this! Datamarine, for > one, would not do repairs on lightning
damage - they were right.> > Ron Rogers >
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