[C320-list] Lightning

[Irving Grunes]

  The damage from a lightening stoke comes from the electromagnetic field
that is generated from the high currents of the strike.
That is what fries all of the electronics.
The oven will protect portables and should be used.
Everything else will be destroyed.
Irv Grunes
Formerly 851

On Sun, Dec 13, 2020 at 11:57 AM David Nolte <dcnolte at mac.com> wrote:

> Hi Allan!
>
> Thanks for your continuing contributions to the list!
>
> Tom - what is your Hull#?
>
> David Nolte
> Beach House
> #0004
>
> > On Dec 13, 2020, at 11:39 AM, Allan Field <allanfield47 at gmail.com>
> wrote:
> >
> > Tom - Practical Sailor has several articles on their website that speak
> to
> > lightning protection. You would need a login and password to access. But
> > following is just one article with a recommendation at the end that might
> > help.
> >
> > Allan S. Field
> > Sea Shadow - C387, #103 (formerly C320, #808)
> > Columbia, MD
> >
> > Most boat owners have only the vaguest idea of what is involved in
> > protecting their boats from lightning damage. Many believe that their
> boats
> > are already protected by the boats grounding system. Most are wrong.
> >
> > Just because your boat may be bonded with heavy copper conductors
> > connecting the masses of metal in the boat doesnt mean that it is
> protected
> > against lightning. A bonding system may be a part of a lightning
> protection
> > system, but bonding itself offers no protection to the boat unless a
> good,
> > direct path to ground is part of the system.
> >
> > While neither aluminum nor stainless steel is an outstanding electrical
> > conductor, the large cross-sectional area of both the mast and the
> rigging
> > provide adequate conductivity for lightning protection. The trick,
> however,
> > is getting the electricity from the mast and rigging to the water.
> >
> > The straighter the path is from conductor (mast and rigging) to ground,
> the
> > less likely are potentially dangerous side flashes. Put simply, side
> > flashes are miniature lightning bolts which leap from the surface of the
> > conductor to adjacent metal masses due to the difference in electrical
> > potential between the charged conductor and the near by mass of metal.
> > Ideally, therefore, the path from the bottom of the mast and rigging to
> > ground would be absolutely vertical. In practice, this is rarely
> achieved.
> >
> > If the boat has an external metal keel, the mast and standing rigging is
> > frequently grounded to a keelbolt. There are pitfalls to this method.
> > First, the connection between the bottom of the mast and rigging to the
> > keelbolt must be highly conductive. ABYC (American Boat and Yacht
> Council)
> > standard TE-4 for lightning protection systems require that these
> secondary
> > conductors have a conductivity at least equal to that of AWG #6
> > copper-strand cable. There is no drawback to using an even larger
> conductor.
> >
> > Connecting the short conductor to the mast and keelbolt presents some
> > problems. A crimp eye can be used on the end that is to be attached to
> the
> > mast, but you may have to fabricate a larger eye for attachment to the
> > keelbolt. This can be made from sheet copper. Soldering the connections
> is
> > not recommended, since the heat generated in a lightning strike could
> melt
> > the solder.
> >
> > Then you have to face up to a basic problem. Your mast is aluminum, yet
> > youre connecting it to ground with a copper cable. Everyone knows that
> > aluminum and copper are not galvanically compatible, so whats the
> solution?
> > While it will not eliminate corrosion, a stainless steel washer placed
> > between the copper cables end fitting and the aluminum mast will at least
> > retard it. But this connection is going to require yearly examination to
> > make sure that a hole isn’t being eaten through the mast. In addition, of
> > course, the process of corrosion creates wonderful aluminum oxide
> > byproducts, which have very low conductivity. The aluminum oxide may
> reduce
> > conductivity to the point where your theoretical attachment to ground is
> in
> > fact non-existent. Once again, disassembling the connection and cleaning
> it
> > yearly are essential to maintain conductivity. Constant attention to all
> > the conductor connections is essential in any grounding system, whether
> its
> > for lightning protection or grounding of the electrical system.
> >
> > For more information on how to best protect your boat from lightning
> > strikes, purchase Nigel Calder’s “Boatowner’s Mechanical & Electrical
> Manual
> > <
> https://www.practical-sailor.com/subscribe/main.html?t=Ad1&s=P_Waypoints050813F#books
> >”
> > from *Practical Sailor*.
> >
> > On Sun, Dec 13, 2020 at 10:51 AM Tom Grass <tgrass462 at gmail.com> wrote:
> >
> >> Wondering about lightning protection on Catalina 320 boats?  I don't
> >> believe they come grounded (mast to keel) from the factory - wondering
> what
> >> the members of this forum have done in an attempt to minimize the
> impact of
> >> a possible lightning strike?
> >>
> >> Also what is the collective opinion of installing a Forespar Performance
> >> Products Forespar Lightning Master™ - Static Dissipater
> >> on your mast?  We're planning on sailing down to the Chesapeake Bay and
> >> perhaps to the Bahamas in 2021 - just preparing in advance.
> >>
> >> Thanks,
> >>
> >> Tom and Tracy Grass
> >> Bucket List
> >> 2008 Catalina 320 MK II
> >>
>
> David Nolte
> SuspenderStore
> 800-393-4508
>
>
>
>