Lightning????

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fouz
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Re: Lightning????

Post by fouz » Wed Feb 29, 2012 4:48 pm

Thanks. I guess I'll move the connection from the chain plate to the battery so I don't have any corrosion on the post. since the cable is already hooked to it I may as well make use of it.


Catigale wrote:Fouz.....it sounds like a crude attempt at strike prevention to me.

The compression post on an :macx: isn't even in contact with water, so the grounding wire isn't doing too much IMHO.

Even battery cable is small gauge wire compared to the current carried in a lightening (for Kevin :wink: ) strike.



...and incidentally, one of the posters above professionally grounded antennae for a living in past occupation.

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Catigale
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Re: Lightning????

Post by Catigale » Sat Mar 03, 2012 6:27 am

I don't think grounding the post will have any affect on corrosion either. There isn't any electricity in the post after all.

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bjtaksa
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Re: Lightning????

Post by bjtaksa » Wed Apr 25, 2012 9:03 am

Ok... so I'm looking for some lightning advice: My boat was struck this past winter. :?

I keep it on a boat lift (mast up)... only the rudders and the boat lift itself are in the water. I didn't actually see it being struck, but have noticed the following (I haven't had a chance to investigate closely):
- The deck plug for the steaming light was blown out of its receptacle... the plug prongs were slightly melted.
- The VHF fiberglass antenna (attached to the mast crutch) shows signs of melting, as does the antenna wire leading to the radio. I can see bare wire in spots.
- The VHF radio is hotwired to the battery... the inline fuse assembly was blown apart.
- The electrical panel was blown to bits. Little pieces of plastic blown forward to the forward berth.
- I haven't been able to test the VHF radio yet, but know the battery still has juice.
- On brief inspection, no obvious hull damage.

My theory is this: lightning struck the mast, traveled down the mast to the hull with some electricity going through the steaming light to the electrical panel (and blowing it to kingdom come). It also either arced or traveled through the mast crutch to the VHF antenna and then to the radio, blowing the radio's inline fuse to pieces. It then exited through the rudders into the lake.

Not sure how to proceed from here. I plan on doing a closer inspection and, if OK, lowering it into the water to check for hull damage. I'm sure I will have to get USAA involved at some point. Advice on what to do next??? How in-depth does an inspection have to be? Is this something I can do myself, or are we talking structural integrity?

Brandon
Last edited by bjtaksa on Wed Apr 25, 2012 9:22 am, edited 2 times in total.

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Sumner
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Re: Lightning????

Post by Sumner » Wed Apr 25, 2012 9:15 am

bjtaksa wrote:Ok... so I'm looking for some lightning advice: My boat was struck this past winter. :? .......
Not sure how to proceed from here. I plan on doing a closer inspection and, if OK, lowering it into the water to check for hull damage. I'm sure I will have to get USAA involved at some point. Advice???
Not too sure if you are looking for advice on what to maybe do in the future or with the boat at the moment. I have added a page to our site with ....

Image

....what we are using and why. You can find that info here...

http://purplesagetradingpost.com/sumner ... de-43.html

It is a long read :wink: .

Good luck and glad you weren't on the boat and that the damage wasn't worst,

Sum

Our MacGregor 26-S

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links

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bjtaksa
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Re: Lightning????

Post by bjtaksa » Wed Apr 25, 2012 9:21 am

Thanks for the tip and link... looking more for advice on clean-up of the current situation and getting the boat sail-worthy. Edited my first post to clarify.

Brandon

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Divecoz
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Re: Lightning????

Post by Divecoz » Wed Apr 25, 2012 9:33 am

Don't bother buying any Loto tickets for awhile anyways .. cause your luck sucks.........Lightening Strikes are few and far between..
For every page and opinion about Lightening with Supporting Facts and Figures and Electrical Theory.. There is no less than another page showing Facts Figures and Theory.... saying NO.. Do Nothing or do this instead.. When your talking 100's of 1000's of volts? There seems to be little you can depend on concerning Electrical path to ground..
Case in point..Across the street from my brothers place, on a separate salt water canal , sits a 40+ ' Cat with a 50' mast and on a lift.. he's been hit 2 or 3 times .. He finally did as my brother told him to do ( we are both Licenced and Schooled Union Trained Electricians and Don taught our apprenticeship classes for 24 years and Taught Electronics and Radios in The USAF for 3) Did his solution work? OR ... was that Cat just never hit again??? We dont have any idea!
Right across from Don on the same canal, just 3 houses down , sits a bigger Sailboat with , A Taller Mast but he sits in the water.. he's Never been hit in twice as many years and he's less than a couple hundred yards from the Cat whose been hit as I said 2 and maybe 3 times.. Go Figure????

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Divecoz
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Re: Lightning????

Post by Divecoz » Wed Apr 25, 2012 9:45 am

IMHO and we all have one of those.. Take a subject you know really well something that maybe you get paid well to do professionally.. NOW ..go to the Internet and You Tube and spend an hour laughing at people misleading 100's maybe 1000's of others with bad solutions and improperly done projects.. SCAREY AINT IT! That Said....... Include my opinion ....with those whose opinions.... should be considered with a grain of salt..
Your Present Problem.. IMHO..
You have a huge mess to contend with.. NOW IMHO is the time to research everything you can find about electrics on this board and Completely Re wire your boat.. I wouldn't trust any of it to be worth saving and there is just not that much on the boat to rewire.. Nows The Time To Do It Right.. Do It To Personally Suit Your Needs.. Its ALL about YOU... No Doubt a few hundred dollars but then its done..You've been No Doubt...thinking about adding and changing stuff anyway.. Do It Now.. Get it over with..
PS.. Sorry to hear about this ....but its a LOT better than it might have been.. That Cat cost Thousandsssssssssssss repair and replace stuff , no less than 2 times .. I would HATE to be paying his insurance bill...

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Catigale
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Re: Lightning????

Post by Catigale » Wed Apr 25, 2012 11:35 am

Your strike was by no means limited to a single path..you probably had all kinds of current flows through your boat, metal, wiring, etc. fun to speculate but really pretty pointless

Protection schemes have been thrashed to death on this Board...but we do have someone who actually did lightning protection professionally here, so read and heed as you see fit...

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Re: Lightning????

Post by Captain Somebody » Thu May 17, 2012 11:01 am

What ever you do DO NOT connect a ground wire (battery cable etc.) to the mast or shrouds. A Macgregor's mast is stepped on the deck and the fiberglass hull isolates the mast from the water. If you ground the mast with a cable you are making your boat a better target for lightning because the mast is now at the same electrical potential as the water. A keel boat with the mast bonded to the keel or inboard motor is at risk of a lightning strike because the mast is in contact with the water through the ground wire to the keel, or the motor and prop shaft, or through a ground plate on the outside of the hull..

When the mast is isolated from the water there is no path to ground for the lightning, until you provide one with the cable clipped to the mast. I found a great article on line a few years ago that explained the best way to protect your boat from lightning. Get a length of #4 AWG welding cable long enough to drop in the water on one side of the boat, then around the base of the mast two or three wraps, and then across the deck and into the water on the other side of the boat. Remove the insulation on the two ends of the cable that land in the water only, DO NOT remove the insulation where the cable is wrapped around the mast. As long as the mast is insulated from the welding cable there will be not be a path to ground through the mast and cable. If there is a strike the lightnig will destroy the insulation on the welding cable where it is wrapped around the base of the mast and follow the cable to the water(ground).

The following link is not the same article I found years ago explaining the use of welding cable as a grounding system, but it does provide a lot of technical info for the geek in all of us. It also refers to a Macgregor in the article

http://pages.suddenlink.net/arlyn/saili ... ning2.html

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Mac26Mpaul
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Re: Lightning????

Post by Mac26Mpaul » Thu May 17, 2012 10:34 pm

Nothing to add other than, I remember reading an article a few years back that claimed nothing you can do will make any difference so dont waste your time.

Personally I believe that if the storm is real bad and you have the option, get off the boat, if this isn't possible, prey to whichever of the gods you like, or if you havn't got one, borrow a friends for the course of the storm. If these options dont cut it, take up a new hobby, probably not golf or pole vaulting though :wink:

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Ixneigh
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Re: Lightning????

Post by Ixneigh » Fri May 18, 2012 1:50 am

I did use that big engine to skitter away from a bad looking storm. I anchored in a group of other sailboats. Many with taller masts.

WidespreadSailing
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Re: Lightning????

Post by WidespreadSailing » Fri May 18, 2012 7:47 am

Ixneigh wrote:I did use that big engine to skitter away from a bad looking storm. I anchored in a group of other sailboats. Many with taller masts.
That was my technique as well down in the FL Keys. As Captain Ron says " Squalls - They come on you fast and they leave you fast". In CruZen's case - I pulled the anchor, started the 50HP motor and played dodge ball from 3 am till 6:30 am. (Not everyday is paradise.)

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Re: Lightning????

Post by Mac26Mpaul » Fri May 18, 2012 8:10 pm

Yeah I was running from a storm last October (actually, more like limping, because the swell picked up, and you can't run anywhere under motor or sail once that happens!). Could barely see it was so thick. The water must have got hit close by because I got a massive shock through the helm which was pretty exciting at the time :|

walt
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Re: Lightning????

Post by walt » Sun May 20, 2012 9:02 am

Hello Captain Somebody,

As far as I know, the Arlyn Stewart article is the only reference that attempts to convince that grounding a mast increases your chances of taking a lightning strike and it conflicts with pretty much all the real experts (Dr. Thomson, Don Casey, ABYC etc.)

What this article ignores (Mr. Stewart is no doubt a bright guy but keep in mind he is a carpenter by trade) is how easily an ionized path in air is formed between the bottom of an insulated mast and the water surface. The same electric fields that are able to create an ionized streamer up from the top of the mast also very easily create an ionized streamer from the bottom of the mast to the water surface. The basic argument in that paper is that there isn’t a source of current flow at the bottom of the mast if it’s insulated and it’s very incorrect.

As an illustration, this is an actual video of a discharge from a negative point source to a positive ground plane. http://www.youtube.com/watch?v=X-siV6L5 ... e=youtu.be – same polarity as you would experience in a lightning storm.

There is a “mast” and in one case, the mast is metal to metal grounded to the ground plane and in the second case, the “mast” is completely electrically isolated from the ground plane. The discharge path for both cases is pretty much identical and it’s simply that when the insulator is under the mast, the charge simply ionizes air and jumps through the insulator.

There are many other points in that article that I think are also misleading if you want to discuss.

I also want to point out the only clear statistic I know of regarding grounding a mast.. This is that Catamarans are something like twice as likely to get struck by lightning that monohulls. Catamarans pretty much never have grounded masts – yet they take strikes more often. http://www.marinelightning.com/catamara ... oatUSStats If we were drawing wild conclusions, it would be that not grounding increases your chances of taking a strike. A grounded mast will have higher positive ion emissions off the top of the mast.

I hope can give more references to back things up. To divulge my own interest here, I am an EE and the partial inventor behind this http://zenpole.com

jschrade
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Re: Lightning????

Post by jschrade » Sun May 20, 2012 11:17 am

walt wrote:Hello Captain Somebody,

What this article ignores (Mr. Stewart is no doubt a bright guy but keep in mind he is a carpenter by trade)
I hope can give more references to back things up. To divulge my own interest here, I am an EE and the partial inventor behind this http://zenpole.com
So that's better than a carpenter? :)

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