[Public-List] lightning protection & grounding plates

[John Birch]

My thoughts exactly Gord, probably the best way to avoid lightening is a 
very thick King James version of the Good Book. Live an honest life, after 
reading the book, sit on it and pray. I love a good electrical storm when 
I'm on land (like that marvellous scene in the Bard's Julius Caesar) and 
fear it on the water.

We watched a well grounded IOR 50'er with massive keel bolts, all well 
grounded, take a massive strike and it did huge damage to the boat 
structurally.

Mercifully the crew was not aboard at the time and she did not sink - but it 
blewout big chunks of glass in the Rudder,  hull near the chainplates, 
stem - so go figure

ATB

John


----- Original Message ----- 
From: "Gordon Laco" <mainstay at csolve.net>
To: "dlandrigan at landrigan.net, Alberg 30 Public List -- open to all" 
<public-list at lists.alberg30.org>
Sent: Thursday, March 06, 2008 1:45 PM
Subject: Re: [Public-List] lightning protection & grounding plates


> Hi Dan -
>
> This comes up regularly... The simple answer is there is no simple answer.
>
> Common engineering wisdom goes like this:
>
> If your rig is thoroughly grounded, you are more likely to get hit but 
> less
> likely to be damaged seriously.  If your rig is poorly grounded, you are
> less likely to be hit but if you are hit, it may be worse.
>
> I have looked, and can report that you can find 'scientific' evidence to
> support both grounding and not grounding.
>
> What do we do?  Well first I'll say that I am never comfortable when in a
> thunderstorm because of the risk of a lightening strike.  I rationalize my
> concern (fear?) like this:
>
> The energy of a strike will tend to seek the most direct route to the 
> water.
> I hope that would be down the forestay to the bowplate then down the keel
> band to the water.  We also snap a 6' length of 1/4" chain onto the 
> backstay
> and toss the end overboard.
>
> I know of two stories first hand were people were killed by strikes on
> yachts; one poor fellow was standing in his cockpit with the mast down and
> was hit directly (the charge went through him to the engine and blew out 
> the
> through hulls.  The rest of the people had a bad time trying to revive 
> him,
> put the fire out and stop the leaks...)
>
> The second fatality story involved a yacht being struck, and the poor guy 
> in
> the cockpit had his leg muscles make an involuntary jump - he went 
> overboard
> and drowned.
>
> I hate those stories.
>
> To balance them, I know of two other boats both of which were struck; in
> both case there was no damage other than the electronics being blown out.
> One was obsessively grounded and the other was not grounded at all.
>
> So, who knows what is best to do?
>
>
>
>
>
>>
>>  Quick question for you more experienced sailors. What protection do
>>  you take against lighting strikes?
>>
>>
>>  We had a rigging inspection done in preparation for spring, and the
>>  inspector noted that we had no ground to the mast. But he said there
>>  was no simple way to add a ground. He mentioned a grounding plate as a
>>  solution, but he doesn?t particularly recommend it.
>>
>>
>>  How have other people addressed this?
>>
>>
>>  Thanks.
>>
>>  Dan Landrigan
>>
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