[C320-list] Lightning

[Tom Grass]

David - we have a 2008 C320 MK II - # 1135.

Tom Grass

On Sun, Dec 13, 2020 at 10:57 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
>
>
>
>