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4317Re: Lightning Protection

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  • Graham Horne
    Jul 2, 2008
    • 0 Attachment
      There is a very good section in Nigel Calders book "Boatowner's
      Mechanical & Electrical Manual" ISBN 007009618X. I find the book very
      practical with lots of detail on understanding why a solution works
      with experiences of what others have tried as well. Perhaps this will
      help you.

      Regards
      Graham
      --- In campernicholson@yahoogroups.com, "Colin Campbell-Dunlop"
      <colinj@...> wrote:
      >
      > Dear Albert,
      >
      >
      >
      > My boat, Trutz #225 has lightning protection. It was originally
      built for a
      > German owner who had plans (and all the charts) for a trip down the West
      > coast of Africa. He was clearly expecting to encounter some
      thunderstorms.
      >
      >
      >
      > It sounds like a similar installation to your own. The mast is
      grounded via
      > a cable attached to the port side of the mast just above the mast heel.
      > This wire goes to a sintered metal grounding plate which is bolted
      through
      > the hull. This sits on the port side of the hull about a foot below the
      > waterline. We also have another pair of these plates stbd aft but I
      think
      > that they are to do with the disused SSB installation.
      >
      >
      >
      > I have done a bit of research on this subject and all I can say is
      that the
      > arrangement that we have on board is probably not really up to the job.
      > This isn't a problem in the UK where thunderstorms are not quite so
      regular.
      > However, for use in sub tropical or tropical areas you might want to
      talk to
      > a specialist. The problem seems to be that a really big strike
      might not be
      > properly dissipated in time leaving you with a lot of high voltage
      flying
      > around in the rigging and bouncing off of important things like
      instruments
      > and crew. Not a nice prospect. Those sintered metal plates are
      very good
      > at spreading the load though so maybe adding another one or two of
      those and
      > upgrading the cable might give some peace of mind.
      >
      >
      >
      > There are some very specialized companies out there who will no
      doubt charge
      > you a lot of money to upgrade your protection but, at the end of the
      day, it
      > seems that keeping your fingers crossed is the best policy. You
      probably
      > already know this but apparently if you can disconnect all your valuable
      > electronics and put them in the oven during a storm they will be
      protected
      > from the strike.
      >
      >
      >
      > Hope this helps in some way.
      >
      >
      >
      > All the best
      >
      >
      >
      > Colin & Jo
      >
      >
      >
      > _____
      >
      > From: campernicholson@yahoogroups.com
      > [mailto:campernicholson@yahoogroups.com] On Behalf Of Albert G. Boyce
      > Sent: 02 July 2008 03:06
      > To: campernicholson@yahoogroups.com
      > Subject: [campernicholson] Lightning Protection
      >
      >
      >
      > I am wondering what other Nicholson 35 owners have done for lightning
      > protection. I have developed a keen interest in lighting protection
      > after getting caught out on the Chesapeake in a thunderstorm last week
      > and getting a mild electric shock at the helm while steering the boat.
      > Quite a wake up call. I have hull number 132 and there is a small
      > sintered bronze plate on the outside of the hull that is connected
      by #8
      > wire to the mast.
      >
      > None of the shrouds, stays, lifelines, stanchions, or any other metal
      > objects are grounded or otherwise connected to this plate
      >
      > I look forward to hearing what lightnting protection arrangements
      others
      > have in place on their boats.
      >
      > Al Boyce
      > Discovery CN35 #132
      >
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