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Old 20-03-2015, 15:54   #1
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Dynaplate as a Lightning ground; Yea nor Nay?

Howdy Cruisers,

I hope this thread finds you all doing well...


I read this article today:

Lighting Protection

It claims that a Dynaplate can explode during a lightning strike...
(2/3 down in blue text, "What Should I Not Use?")

I was planning on using the smallest size Dynaplate as an AC ground for my electrical only, (no radios) and as a lightning ground from the mast. I figured I'd run some jacketed copper cable up the inside of the aluminum mast, possibly even put a copper rod outside at the masthead. Also I would tie in the Galvanic isolator ground for AC to it as well to eliminate any floating current.

QUESTION:

Can a Dynaplate explode during a lightning strike when loaded up with current due to the water absorption that takes place with these plates??

Because, WOW!! That wouldn't help the situation. Have you heard of this?


And as a post script, for you radio guys, If I decide to use the Dynaplate for a radio ground, and decide that I must use another type of High Voltage ground for lightning and AC, is the smallest Dynaplate any good as a SSB ground on all the different meter wavelengths/antenna tunings? Or, should I buy the middle of the road (Loran C), or the Caddy (SSB big boy?)
The last one is like $350 = cost prohibitive for the amount of time I care to spend making contacts...

Loran? Is anyone seriously still using Loran??

(Certainly that last question deserves its own thread!)

Thanks and Happy Sails!
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Old 20-03-2015, 21:05   #2
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

A "Dynaplate" is a Sinter plate used to. Dissapate current to the water as a more direct pathway, as not to affect the metals and electronics aboard.
However it is not the only protection available.
Mast head dissipaters are as well added protection.
Both are a good idea.


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Old 20-03-2015, 21:47   #3
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

I haven't done any scientific analysis of lightning protection but I have read a fair amount on the subject. Based on what I have read, Dynaplates are not a good choice for lightning dissipation for the exact reason you mention. Also, masthead disappaters have not proven to be very effective.

I think the conventional wisdom amongst lightning protection experts is now to install a long, narrow copper bar on the outside of the hull that it connected via a heavy cable to a pointed lightning rod at the top of the mast. There is also a lot of talk about installing discharge anodes just above the waterline, connected to a common buss.

These ideas all look great on paper but even the experts will agree that regardless of what you do, there is no guarantee. Lightning is just too powerful and unpredictable. If there was any form of lightning protection that offered even a modicum of protection, insurance companies would demand it.

Fair winds and calm seas.
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Old 20-03-2015, 21:54   #4
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

It is doubtful a dynaplate will explode. They make good grounds for radio too.

The galvanic isolator doesn't connect to any ground on the boat as far as I know. It does connect to shore power ground.

Nothing will guarantee protection from a direct lightning strike. But they are rare.
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Old 20-03-2015, 21:59   #5
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

As for Loran , it's been discontinued in the PNW region, not really sure about other areas.
I believe it was Federally run by he CG?
So it's probably not active anywhere now.


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Old 21-03-2015, 09:22   #6
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

All LORAN in US is off air indefinitely. New LORAN systems are going up in UK and S. Korea. US is thinking about it. For now there is no point in having a LORAN receiver in most of the world.
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Old 21-03-2015, 10:06   #7
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

I have heard of Dynaplates exploding due to the instantaneous conversion of water into steam, within the porous plate.
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Old 21-03-2015, 10:14   #8
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

Quote:
Originally Posted by Terra Nova View Post
I have heard of Dynaplates exploding due to the instantaneous conversion of water into steam, within the porous plate.
I have not seen any statistics or even specific instances of dynaplates exploding. Can you provide any?
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Old 21-03-2015, 10:18   #9
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

Google.
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Old 21-03-2015, 11:22   #10
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

Quote:
Originally Posted by Terra Nova View Post
Google.

That proves it? I believe the dynaplate rumors are not founded in any science. I did a Google and found this.

http://www.practical-sailor.com/issu...ry/4162-1.html

If someone documented such and event I could not find it.
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Old 21-03-2015, 11:35   #11
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

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Originally Posted by transmitterdan View Post
That proves it? I believe the dynaplate rumors are not founded in any science. I did a Google and found this.

PS Advisor 07/01/99 - Practical Sailor Print Edition Article

If someone documented such and event I could not find it.
I also suspect that the "additional surface" created by the pores in the Dynaplate is useless for SSB purposes. I taught enough Physics in my younger years to be skeptical of unfounded claims of that type.
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Old 21-03-2015, 12:58   #12
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

Yes, the "surface area" myth is a hard one to kill. In college we had a standing punch line, "it's all about the surface area". Amazing how many topics that phrase covers.
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Old 21-03-2015, 14:13   #13
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

MaineSail, a frequent and reliable contributor here (at least I think so) says he has seen a Dynaplate explode and do damage. See here.
So that is at least one instance of an exploding Dynaplate. I have no idea what would have happened if the plate had been solid. Maybe the damage would have been worse, but I doubt it. The question that begs asking is, if the sintered plate really offers no benefit over a solid plate as an SSB ground, and there is some question as to it's suitability as a lightning plate, why use it at all? Why not just use a 1/4" flat copper or bronze plate. It would have less drag and be cheaper. There must be *some* benefit to a sintered bronze plate, as they've been made for a long time and seem fairly popular.
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Old 21-03-2015, 16:56   #14
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

I can think of no radio benefit to sintered bronze. I am sure lightning can damage the plate. I doubt the boiling water explanation.
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Old 21-03-2015, 19:31   #15
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Re: Dynaplate as a Lightning ground; Yea nor Nay?

Quote:
Originally Posted by Saltyhog View Post
...if the sintered plate really offers no benefit over a solid plate as an SSB ground, and there is some question as to it's suitability as a lightning plate, why use it at all?...
I don't believe that. Far as I know, the sintered plate benefits SSB function. It is its use as a lightning ground that is in question, due to reports of "explosions".
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