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Old 11-04-2007, 11:54   #16
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One item I noticed that wasn't mentioned is the transmission bearings. Anytime an electrical charge is put through ball/roller bearings there is a chance that they have been pitted.

It may not show up right away but after several hours of stress the pitting could enlarge causing noise and/or failure. Also true when doing any welding on equipment. The ground should always be placed close to the welding area with the path of least resistance not going through any bearings or electronics.

Even welding on new equipment theses days we use anti-zap connectors to avoid frying the computers.

http://www.matson.com.au/product_frameset.html

That could go for the alternator, water pumps or anything else that has ball/roller bearings. Bushing bearings will usually survive a current providing they were not the direct paths to ground.............................._/)
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Old 11-04-2007, 12:22   #17
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"is it worth it to get lightning 'protection?' "
What do you call protection? And what is what you are protecting worth?
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Old 11-04-2007, 13:06   #18
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lightning

In other words....in your opinion and experience, is there such a thing as 'minimising lightning strike damage' by installing aftermarket products that claim to do that. Or is there no real ability for a sailboat, regardless of what extra grounding product one purchaes and installs, to minimise the damage from a lightning strike. The reason I ask is because here in South Florida, lightning, especially from August to November, is a daily occurrence.
Thanks for your reply.
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Old 11-04-2007, 13:23   #19
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"is there such a thing as 'minimising lightning strike damage' "
Minimise, yes. Protect from, no.

"by installing aftermarket products that claim to do that."
That's more debateable. There are recommended procedures and the main products you need are conductors not patented gizmos. AFAIK the one "bottle brush" that promised a warranty payout, refused to pay out folks who put in a claim.

All you can do is encourage lightning to take a path that does less damage. To you, or your electronics, or your hull...
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Old 11-04-2007, 13:26   #20
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so, for a new sailor in a Potter 19, is it worth it to get lightning 'protection?' Especially since I sail in S. Florida...lightning capitol
The others have bet me to it. But my comment is, mate, if you can find protection from lightening, you'll be a wealthy man and the next Noble prize winner.

The main problem with protection, is that there are many "side" issues with a strike. It's not just the initial bolt of electrical discharge. That electrical discharge is followed along side by huge static energy, enormouse magnetic energy, humungouse RF spikes and the main fact that the electrical discharge has just traveled 10's of thousands of meters through poorly conductive air, a few mm and metres across conductive materials is totaly meaningless to it.
The only one true way of protecting, is to be able to sink absolutely every last bit of energy into the sea instantly. That would take a conductor the size of the mast made from pure Gold to do. It might be cheaper to take a strike.
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Old 11-04-2007, 15:38   #21
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I have heard that, aluminium or steel boats, Never get struck by lightning.

Is this true, do any of you have FIRST HAND accounts.
I am not interested in comments that are based on hearsay, because they( the comments) are usually wrong.
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Old 11-04-2007, 22:28   #22
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Not sure who would tell you that, but any conductive material can get struck by lightening. Steel and Alloy has an even higher chance because it is well bonded to the sea. The only safe part about it is, the good bonding will be better at sinking the current discharge to earth. Possible damage to hull may be no more than just paint blown off underwater. The only time you would possibly be safe or at least slightly safer than steel/alloy is in a plastic boat with a plastic mast. Compleatly rule out Carbon fibre, it conducts. You would also need synthetic rigging and no SST rails.
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Old 11-04-2007, 23:02   #23
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As for a steel or aluminum boat being struck by lightning, the answer is yes they can be. More than one tin can on Canada's west coast have been struck by lightning. The tin cans( commercial Seine boats ) were lower on the horizon than many moored sailboats nearby, on several occasions. Not only were the electronics and the entire electrical systems destroyed but the hydraulic system in one boat was totally destroyed. Hydraulic lines are all metal or wire braided hoses, all connected to a common ground which is the hull. With that much available current any fluid quickly turns to a gas or steam under extreme pressure. Something has to give.
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Old 11-04-2007, 23:30   #24
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what i have heard is that the metal boats don't build up the negative or positive ions because they are well bonded to the sea. whereas as fiberglass with an Aluminium mast can't get rid of the ions that attract the lightning.
I spoke with a cruiser who has done three circumnavigations over 25 years in a steel boat and he told me he has seen plenty of glass boats get struck but never metal boats.
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Old 11-04-2007, 23:38   #25
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No, the "leader", comes from the Ground up. Lightning is only interested in the ground. The huge energy potential is created between ground and cloud. It's like one Ginormus capacitor. The air is the insulator. Eventually the charge becomes so large the energy jumps the insulative air gap and discharges to ground. The "leader" just shortens that gap. But for a "leader" to be created, ti must be able to flow fromt he ground up into the air. So something that is well bonded to the earth has a greater potential of generating that leader.
Please not that this is a general rule of thumb that follows normal electricle principles. However, there have been circumstances that have also defied those principles, so you can not say that this is the only way lightening works.
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Old 12-04-2007, 00:36   #26
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Originally Posted by Alan Wheeler
No, the "leader", comes from the Ground up. Lightning is only interested in the ground. The huge energy potential is created between ground and cloud. It's like one Ginormus capacitor. The air is the insulator. Eventually the charge becomes so large the energy jumps the insulative air gap and discharges to ground. The "leader" just shortens that gap.
So, I would get the impression that if one has a lighting rod and ground to the water, the chances are higher of getting hit.
I would think, under these circumstances that a plastic boat without any lighting gear, and the mast insulated from the keel, would be better off. No leader! It would be a poor conductor!
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Old 12-04-2007, 01:07   #27
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In theory yes, but in reality, well....it's easier to say lightening doesn't like to always follow theory written by mare mortals :-)
A leader can reach up many hundreds of metres into the air. So a few metres from the water to the shrouds are nothing in comparison. So no, even a plastic boat is suseptible. It has been seen many times and has even been captured on video, that in a marina, a strike does not always go for the highest mast nor does it prefer any material over another. Although a lot more is now understood about lightening, there are still many occurances that continue to baffle the scientists.
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