Lightning

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C

Clay

Anyone care to share your lightning experience, I would be very interested. I heard once a blue arck appeard while draining the rain water from a bimini into a pan. I have spent a many a nights under the mast on the hook during heavy cloud ground lightning. My question is about jacobs cage if anyones heard of it ? I also carry 30ft of 5/8" chain just to make sure.
 

higgs

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Aug 24, 2005
3,736
Nassau 34 Olcott, NY
Cross your fingers

Lightning, cloud to ground in particular, is indeed a concern and frightening. Boats being struck are rare occurances and injuries or death is extremely rare. I look at it in the same vein as an automobile accident - the potential is there everytime you go somplace. You pays your money and takes your chances - Se la vie.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
Clay you can generate a very large static charge

when pouring liquid from one insulated container to another insulated container. When the potential is great enough there will be an equalizing discharge that may be visible as a spark or an arc. If the liquid being poured is flamable this can result in a fire and/or an explosion. If it is water then it is an oooh! that was cool! let's try it again.
 
Aug 3, 2005
181
Morgan 33 O/I Green Cove Springs FL
There is a Faraday Cage

and a Jacobs ladder, I have never heard of a Jacobs cage. Is it an oopsie by you or a new type of goverment secret weapon. Fair Winds Cap'n Dave I suffer from CRS
 

Alan

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Jun 2, 2004
4,174
Hunter 35.5 LI, NY
Clay

Capn Dave is right, there is a Faraday Cage that is formed with the mast and rigging of your boat if the mast base is properly grounded. A heavy-duty Faraday cage can protect against direct lightning strikes. When properly connected to an earth ground, the cage conducts the high current harmlessly to ground, and keeps the EM pulse from affecting personnel or hardware inside. What this means is that anyone inside this cone of protection has little fear from a lightning strike.
 

Ross

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Jun 15, 2004
14,693
Islander/Wayfairer 30 sail number 25 Perryville,Md.
The faraday cage will leak if

you can stand inside and use a portable radio to call outside. To be effective the shield must be continous and grounded.
 
C

Clay

Jacobs cage

I know about Micheal Faradays experiment, but didn't think they were the same. This had to do with reference to mast hight, only effective if the mast is under 50ft. As for boats not getting struck ?? I have witnessed a strick on a boat anchored next to me, mast was higher then mine (I like to do that, anchor next to a higher mast) Next morning he told me the stick fried all of his electronics. My other question is how do you tell if your mast is grounded correctly without having full access for inspection. I wonder how to electronically test with a meter... But where under the boat to I connect that has continuity to the mast The other part of the question is, since we are all fiberglass, what is the acutal ground without throwing a square plate in the water. Faradays principles, from my understanding, has to do more with continuity then the cone created under 50ft.
 
Jul 20, 2005
2,422
Whitby 55 Kemah, Tx
grounding of mast

If your mast is grounded, you will see a large wire running from your keel bolt on up to either the mast or something connected to the mast. In my case, its a stainless steel compression post.
 
C

Clay

Txs Franklin

But I was hoping that I have already demonstrated through my previous postings that I knew at least that much. Having said that, I also said I didn't have full access to make a visual inspection and didn't want to rely totally on the manufacturer that this was properly taken into consideration. I can only assume there is a negative cable connected to the through-bolt of the keel. I guess a test light when the boat is out of the water. The 30ft. chain connected to my chainplate(stantion) gives me that extra security. I have heard of sailors using car-booster jump cables to accomplish the same security only to find out that the cables could not withstand the volts and left burn marks near the chainplate stantions. What I am trying to conclude is how not to invite a strick as well as protected.
 
Dec 12, 2005
128
Hunter 34 Lowestoft
Your neibour

was very unlucky to have all his electronics damaged by lightening. It seems that the electrical charge in the air is conducted away due to the rain that is normally associated with lightening. The problem comes when things are kept dry like under biminis (or umbrellas). So either get out there in the rain or keep inside the cabin, turn the radar on and watch the storm move away. I've always kept all the electronics on and not had anything damaged so far and my mast is not grounded. I've heard of people saying that they have heard of other people suffering damage but never to anybody who has had damage to their own boat but perhaps we can hear from forumites who have?
 
Jul 12, 2006
85
- - nc
we were aboard and were struck May 14 2006

search the archives, I wrote a play by play of what it was like to be struck and be aboard- and live. Mike
 
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