From: "Richard C. Harrington" <rmharrington2@juno.com>

To: w1348@online.no

Date: Tue, 17 Jul 2001 21:33:43 -0400

Subject: Re: Lightning Strikes !!??

 

Dear Ken,

 

A most interesting and superbly written reply.  You are far more informed

on this subject than myself.  Thank you for your effort.

 

For those of you who may have lost the trail, the original question

regarding lightning protection was posed by Olaf Bertram-Nothnagel of New

York State, who sails the lower Hudson River.  This is an area that can

experience violent thunderstorms.

 

My stance will probably remain the same as before, which is to be

proactive and go with as good a grounding system as I can manage on the

dinghy.  But as Ken says, I may be inviting disaster rather than avoiding

it.  The system that I employ consists of a automobile jumper cable

bolted to the sail track of the mast half way down from the gooseneck.

The free end of the cable has a aluminum bar (1/8" x 1") by 18" long

(these dimensions are corrected from my original e-mail) connected to it

which I insert as far down as possible the front end of the centerboard

trunk.  The cable should be short enough to allow a straight path.  This

idea is patterned along some diagrams that I once saw in a Wooden Boat

Magazine (I believe!) for grounding in bigger boats.  As I mentioned

before I believe that the cables recommended were much larger than what

I'm using, which could be my downfall.  I have weathered at least 4 or 5

strong electrical storms while in my boat, but this proves nothing.  In

all cases I've been within a few hundred meters of shore where there have

been higher trees or structures.  Again, stay as far as possible from the

mast and shrouds.

 

In consideration that we may wish to put some of this information on the

USWA web page I would like to solicit additional comment from those of

you on the "cc".

 

Thanks again Ken.

 

Regards---DICK H. - W887, Blue Mist

******************************************* 

 

On Tue, 17 Jul 2001 23:30:58 +0200 "KEN/K.H.Jensen" <w1348@online.no>

writes:

>     

> Subject: Lightning Strikes !!??

>    

>         Dear Ralph,

>

>                     Hopefully you are well back home as I am - upon

> your command, Sir - to write about+look back at lightning strikes.

> Frank Dye wrote(W.News No 67, P. 34) and scared me as I had

> `converted“ away from lightning-conductor-use, which polarizes yr.

> W. and thus invites the "path-finder-lightning" to select yr. W. as

> target for the main charge(W.News No 68, P. 32).

>

>                     Then Charlie Taylor writes(W.News No 70, P. 64)

> and I contacted the highest authority(with connection to NASA) here

> in Norway on this topic, and was given a throughout verbal briefing

> and some very interesting study-results amounting to really not

> being able to conclude WHETHER   1)  the classical grounding

> method/lightning conductor   OR   2) the newer philosophy to avoid

> polarization  should be the chosen one.  There are apparently a few

> more followers in group 1) than 2).

>

>                     Quite interesting the professor told me he had

> just received information of a rather bad and damaging lightning

> conductor accident at the Kennedy Space Center, where they take

> these matters seriously.

>

>                     Now this is a couple of years back, and I wrote

> about it to our Scandinavian W-magazine, but it was“nt printed so it

> seems.  I flew the DC-3(much too many years ago !) and remember the

> wicks fitted to the trailing edges. They were there to get rid of

> the induced static electricity, and lessen the chance for the plane

> to become a jumping board(reducing distance) between two nasty +

> probably unfriendly charged thunderclouds and/or ground-A/C-cloud.

> It surprised me the huge 70x1000footer thunderstorms over Vietnam

> along the China Sea(1950ties - no radar then) being less dangerous

> than the 33x1000footers of our northern latitude.

>

>                     When the Corona starts to play like a flashing

> light-sword from the nose of the A/C the pilots immediately switch

> on full blast white cockpit-lights and put on their sun-glasses to

> avoid being blinded in case of a discharge, being a tremendous flash

> and bang !  Quite a number of people turn religious during lightning

> and thunder.

>            

>                      A W-couple here, father and son, capsized when

> the roll-cloud of the storm hit, and they stayed sheltered under the

> mainsail from the big icy hail, then rightened their W. and sailed

> home.  May well be the very proper method!  Once my late wife, two

> youngest boys and I ran from our W., bringing along the

> cockpit-cover for a roof, and finding shelter by a 25 foot rock-wall

> through the storm, and not until the next day did we know of a man

> being killed by lightning on the next, close by, skerry isle. He had

> exposed himself on top of the rocks watching the mighty scenery!

>                                                                      

>                                         Best W-regards Ken, W 1348

> "Maitken"      

>

>

>

>

>

>

 

----__JNP_000_52ee.46da.722e--