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Old 03-03-2011, 08:47   #31
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Re: Struck by Lightning

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one of the winches started operating of its own accord, pulling the carbon fibre boom down onto the fibreglass cockpit roof causing lots of damage. The relay on the winch clearly malfunctioned. The winch carried on running for about 10 minutes!!!
Yep, I think everyone on the board kinda predicted this. Imagine how exciting it's going to be when the windlass does that!
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Old 03-03-2011, 09:38   #32
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Re: Struck by Lightning

[QUOTE=GordMay;633337]Charge equalization, static dissipation, corona discharge, Voodoo, or whatever discredited term they are using this week, does NOT work.
There is no way to 'discharge' or 'drain' the charge from a storm .. . . /QUOTE]

I am glad you are the only definitive authority here on CFand major universities and aviation experts are all wrong. Especially when you are talking about something totally different from what I was addressing.
- - The only valid part, I have highlighted - agreed you cannot drain the electrical charge from a storm. But I was in no way talking about that. I was talking about lowering the odds - not preventing - a lightning event involving your boat. Using similar techniques and principles we have used on large aircraft for the last 50 years.
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Old 03-03-2011, 11:02   #33
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Re: Struck by Lightning

I'll have to side with Gordmay on this one. From what I have read the broomhead lightening arrestors have an equal chance as the typical straight wire lightening rod. Induced charges from a strike can cause significant damage. I.E. the burnt relay on the above winch example. Most likely the relay, (which has a mechanical linkage had burns on the pivots, or springs causing it to stick once activated). Every year a new super lightening system is promoted, but the statistics don't prove they are any better than the one invented by Benjamin Franklin.

There are ABYC standards for lightening protection, which basically boils down to have a heavy guage conductor from the highest point on the boat to ground, and ground all exposed conductors away from people and electronics. Anything else falls into the catagory of snake oil.
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Old 03-03-2011, 11:24   #34
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Re: Struck by Lightning

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The engine can be run successfully while on the hard.
Another easy way (no special hardware required)

1) Close the thru hull
2) Take the cap off the raw water strainer
3) Modulate your garden hose nozzle to keep the strainer full
4) Run the engine
5) To winterize, finish with anti-freeze instead of water, and open the thru-hull so it back drains.
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Old 03-03-2011, 11:43   #35
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Re: Struck by Lightning

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Originally Posted by osirissail View Post
Quote:
Originally Posted by GordMay View Post
Charge equalization, static dissipation, corona discharge, Voodoo, or whatever discredited term they are using this week, does NOT work.
There is no way to 'discharge' or 'drain' the charge from a storm .. . .
I am glad you are the only definitive authority here on CFand major universities and aviation experts are all wrong ...
While I donít claim to be the Forumís resident expert on lightning, nor have I personally conducted any independent research, I will lay claim to having read as much of the readily available science as anyone here.
Iíve published my informed opinions about lightning mitigation several times on CF, beginning as early as 2003. Iím worn out on the subject.
Notwithstanding, here are some other informed opinions (to which Iíve previously linked) on the subject:

Some contrary opinions, representing the informed view:
From Post #9 ➥ Sparks, Wicks, Sticks and Stuff

A CRITICAL REVIEW OF NONCONVENTIONAL APPROACHES TO LIGHTNING
PROTECTION ~ BY M. A. UMAN AND V. A. RAKOV
MARTIN A. UMAN, Distinguished Professor: ECE-UF Dr. Martin Uman
http://www.lightningsafety.com/nlsi_lhm/Uman_Rakov.pdf

WAR OF THE LIGHTNING RODS ~ By Abdul M. Mousa, (Ph.D., P.Eng., Fellow IEEE)
http://www.lightningsafetyalliance.c...htning_war.pdf

There Is No Magic To Lightning Protection:
Charge Transfer Systems Do Not Prevent Lightning Strikes ~ William Rison
(Professor of Electrical Engineering, New Mexico Institute of Mining and Technology)
Ē... The principles of traditional lightning protection are basic ó 1) provide preferential strikes point for lightning (an array of conductors higher than the objects being protected), a good grounding system, and conductors between the two to conduct the damaging current from a lightning discharge away from the structure to be protected; and 2) provide appropriate transient protection on power and signal wires entering the structure to protect equipment and personnel from the effects of induced lightning currents ..."
http://www.lightningsafety.com/nlsi_lhm/magic.pdf

Charge Transfer System is Wishful Thinking, Not Science ~ Charles B. Moore*
(Professor Emeritus, Atmospheric Physics, New Mexico Institute of Mining and Technology)
Charge Transfer System is Wishful Thinking, Not Science - National Lightning Safety Institute

*Charles B. Moore is internationally known for his research on the electrical aspects of thunderstorms and volcanoes. He is an expert in many different areas of atmospheric research, including the scientific and political aspects of weather modification, the scientific and practical issues of lightning protection, and the efficacy of different kinds of lightning rods:
Lightning and Thunderstorm Research - Langmuir Laboratory
http://infohost.nmt.edu/mainpage/news/2005/7feb02.html


Fundamentals of Lightning Protection ~ By Richard Kithil, President & CEO, NLSI*
*National Lightning Institute
Fundamentals of Lightning Protection - National Lightning Safety Institute

Evaluation of Early Streamer Emission Air Terminals ~ By Scott D. McIvor, Roy B. Carpenter, Jr., Mark M. Drabkin, Ph.D.
...ĒCONCLUSIONS: There is limited test data on ESE performance, and no available data substantiates the suppliersí claims; conversely, the data collected by independent researchers prove otherwise. That is, the ESE performs no better than the conventional Franklin rod.
2. The physics related to the situation, as provided by the atmospherics physics community, demonstrate that the claims made for all of these ESE are wildly exaggerated ...Ē
http://www.ees-group.co.uk/downloads/ESE%20paper.PDF

See also ➥ Lightning Protection

And ➥ Aluminium Mast - Lightning Rod, Benefits?
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