[Rhodes22-list] Roger, I need your input...

[Grayson/Ena Lynn]

The ticking/snapping sound is a sure give-away that a static charge is
building up in the rigging and periodically discharging across a dielectric
(insulating) gap to "ground", i.e. the water or something electrically
connected to it.  The sound you hear is made by a miniature lightning bolt
from the rigging to the water (some say it jumps from the water to the
rigging, but who cares?).  Which, by the way, you don't want happening
anywhere around any concentration of LP gas or gasoline fumes; you have
enough problems without explosion and fire.

As I recall, there is nothing really grounded on the stock R22;  the mast,
stays, shrouds and rails all terminate in chainplates or brackets embedded
in fiberglass, which is a pretty good insulator.  The motor may or may not
be grounded, depending on whether the motor mount is lowered or raised.
Otherwise there are no conducting (metallic) thru-hull fittings or any other
conducting path to ground from inside the boat.

A proper job of static control would involve bolting an expendable copper or
monel plate below the waterline (about 1 square foot for Rhodie-sized boats)
and electrically "bonding" everything to it with copper wire or tinned and
braided strapping,  A pretty good job could be as simple as snapping a short
length of chain to a backstay, leaving a foot or so hanging in the water...
anything to bleed off the static charge directly, before it builds up enough
voltage (in thousands) to arc over.

For static purposes, the aluminum spars and standing rigging are already
connected by metal-to-metal contact.  The pulpit is not connected thus, and
the boom  is insulated by its plastic mounting to the mast, so these would
require their own wiring.  Of course, the better the bonding job the more
your boat looks like a purpose-built lightning rod (from a cloud's-eye
view), but if the big bolt has your name on it, grounding probably won't
make all that much difference anyway.

The boat's electrical system is a whole 'nother subject; having nothing to
do with static.  It is virtually impossible for the engine and service
wiring to foster high static charges except at the magneto and spark plugs
where they belong when the engine is running.  However, volumes have been
written on the pros and cons of interconnecting and grounding your 12-volt
and shore-power systems, and there are countless horror stories of boats
sinking at their moorings when stray currents corrode and dissolve fittings
and clamps, of skippers getting electrocuted when stepping ashore, and of
electronics fried by nearby lightning strikes.  Let's not go there today.
Read the books first.

As for where the static comes from, you are pretty well limited to
atmospheric conditions and, to a lesser extent, nearby high-tension electric
wires.  I might be persuaded to add luffing sails to the list.  St Elmo's
fire comes to mind.  Static can be spooky stuff; I've been loafing below, at
anchor in a thunderstorm, and felt my (thinning) hair standing on end, while
clear-air lightning (a "bolt out of the blue") is not uncommon.  Some may
remember the post-war days of low-carbon synthtic rubber tires and AM-only
radio in automobiles, when there was a serious problem with static buildup
and radio interference, and every car sported bronze grounding springs in
the bearing hubs and one or more static drops hung from the chassis to the
road; now you see them only on gasoline tankers and other haz-mat vehicles.

<G>


----- Original Message ----- 
From: "Roger Pihlaja" <cen09402 at centurytel.net>
To: "The Rhodes 22 mail list" <rhodes22-list at rhodes22.org>
Sent: Saturday, August 07, 2004 9:37 AM
Subject: Re: [Rhodes22-list] Roger, I need your input...


> Carol,
>
> The aspect of all of this that I'm having the most difficult time
> understanding is; why would ions from the air tend to accumulate on your
> body when, only a few feet away, are literally acres of water in which
these
> same ions could flow to ground potential?  Ions, either + or -, mutually
> repel one another & they seek the lowest energy state.  If there were so
> many ions present in the air that your body could build up a static charge
> just by sitting there; then, why didn't the ions just flow into the water?
>
> The earth has a natural electric field.  During fair weather, the field
> gradient is about 100 volts/foot of elevation.  During a thunderstorm, the
> local field gradient can be somewhat greater.  In fact, lightening is the
> local field gradient trying to even itself back to the global average
value.
> I have two reasons why I think a shorted electrical connection inside your
> mast is the root cause here:
>
> The 1st reason is the field gradient.  The tip of your mast is something
> like 28 feet above the water.  At 100 volts/foot or more, that means
there's
> at least 2800 volts of potential across the mast.  An internal short in
the
> mast would directly introduce that voltage into the boat's electrical
> system, potentially causing all of the symptoms you've noted.  Contrast
that
> with the much lower potential generated across the length of your, much
> shorter, body.
>
> The 2nd reason has to do cause & effect plus frequency of occurence.  The
> boat has been located at the same marina since 1999 with no electrical
> shocks until this year after the mishap with the mast.  Now, these
> electrical shocks seem to occur fairly regularly.  What has changed?
Again,
> a short inside the mast caused by the mast lowering accident potentially
> explains all the data.
>
> Here in Michigan, we have what I like to call the "Standard Summer
Forecast"
> (SSF).  The SSF goes something like this: Mostly fair skies, 5 - 10 knot
> breeze, waves 1 - 3 feet, scattered afternoon thunderstorms, wind & waves
> briefly higher during thunderstorms.  If that forecast kept you off the
> water because of the thunderstorm potential; then, you would miss over 50%
> of the sailing days in the summer!
>
> I don't claim to completely understand what happened to you.  But, I'm not
> prepared to attribute it all to the common lightening "urban myths" yet
> either.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
> ----- Original Message -----
> From: <CarolN8 at aol.com>
> To: <rhodes22-list at rhodes22.org>
> Sent: Friday, August 06, 2004 5:01 PM
> Subject: Re: [Rhodes22-list] Roger, I need your input...
>
>
> > Roger,
> >
> > Thanks for explaining the static theory everyone else is mentioning...I
> was
> > getting confused (which is easy to do for me). I find it interesting
that
> Alex
> >  had this problem in CO. Thanks for letting me know that Rummy (and
> welcome
> > back!) I've had this Rhodes out here since 1999 (when I bought it), and
> this
> > is  the first season I've ever had the shocking problem. That is why I'm
> also
> > somewhat suspicious of something in the mast. It was last fall that I
> broke
> > the  connections.
> >
> > When the outboard shocked me, it was in the water. If static had built
up
> in
> > me, once I the shock happened, it would be over, right? I don't think I
> would
> >  continually build up a charge again. It would shock me every time I
> touched
> > the  stern rail with my hand, and I wasn't moving around. It felt like a
> live
> > shock  (like touching an electric fence). I had no other symptoms like
> > tingling or hair  standing up.
> >
> > The second time, there were five of us on the boat, and there was some
> > static in the air and some hair was standing up which was why I was
trying
> to  get
> > to shore as quickly as possible. That's when the stays started clicking,
> and
> > that's the most nervous I've felt being exposed on the water.
> >
> > I think a storm in the nearby area is feeding the problem but I'd be
> awfully
> > surprised to think it was causing it because this is the only season
it's
> > happened. We have storms here all the time in the summer afternoons.
> >
> > For those who suggest I avoid these storms, that is a great idea in
> theory,
> > but in CO, there is almost always a storm in the area in the afternoons
> and
> > you  just have to keep an eye on how close they are to you, and what
> direction
> > they  are going. You can be in a downpour and lightning storm one
minute,
> and
> > drive  ten minutes north and be in sunny blue skies.
> >
> > I'm hoping to go out tomorrow but may not be able to sail again until
> Sunday.
> >
> > Carol
> > __________________________________________________
> > Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >
> >
>
>
> __________________________________________________
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