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Old 17-09-2016, 06:26   #31
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Re: Does lightning strike cause delamination on fiberglass hulls?

"Attracting" is simply being the highest, sharpest object in the vicinity of the charge difference between cloud and earth. That's your mast and your antennas in the usual case, although it's a bit capricious given that the connection can be by multiple routes. It's a static charge, so being a conductor is irrelevant to the strike. Protection comes in two forms. First, supply a good conductor (now we're talking about flowing electricity) that the strike is more likely (it's a crap shoot) to follow to ground than other more damaging routes. Second, you electronics are particularly vulnerable because they have antennas and grounds, and they are delicate solid state stuff that can be destroyed simply by being in a strong electromagnetic field. Note that technicians wear anti-static grounded wrist bands when working on the stuff. Your only real defense would be to completely disconnect everything you can, and either take it home with you or store it in the oven (a Faraday box, offers some protection). Home is better. Your wiring, antennas, light bulbs, standing rigging, etc. are still at risk even if virtually all the current goes down your super-good mast ground.
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Old 17-09-2016, 07:11   #32
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Re: Does lightning strike cause delamination on fiberglass hulls?

You bring up a point.

First though, a faraday cage can work 100%, not just some. I watched an EMP experiment on youtube in which the fellow made a cage in the form of a trash can and loaded it with electronic devices. He closed it up and exposed the can to an EMP and everything inside fried. Then he did it again another way and got about 40% protection. Then he did it again and this time taped the seams of the lid/can and the EMP did not get through. And yes notice that the wrist straps have to be connected from you to the ground of your wall outlet so the charge can flow through you and terminate somewhere else.

So can any protect be afforded to a boat if you drape chicken wire over it? In the experiment there were no cables leading out of the can but had they been outside the can the charge would travel through the cables and then into the rest of the boat (?)

There must be a way either to shield the charge or dissipate it. Can a lightning rod terminate in sacrificial electronic device and end the charge there?
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Old 17-09-2016, 07:22   #33
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Re: Does lightning strike cause delamination on fiberglass hulls?

Quote:
Originally Posted by CharlesV View Post
You bring up a point.

First though, a faraday cage can work 100%, not just some. I watched an EMP experiment on youtube in which the fellow made a cage in the form of a trash can and loaded it with electronic devices. He closed it up and exposed the can to an EMP and everything inside fried. Then he did it again another way and got about 40% protection. Then he did it again and this time taped the seams of the lid/can and the EMP did not get through. And yes notice that the wrist straps have to be connected from you to the ground of your wall outlet so the charge can flow through you and terminate somewhere else.

So can any protect be afforded to a boat if you drape chicken wire over it? In the experiment there were no cables leading out of the can but had they been outside the can the charge would travel through the cables and then into the rest of the boat (?)

There must be a way either to shield the charge or dissipate it. Can a lightning rod terminate in sacrificial electronic device and end the charge there?
The faraday cage must be constructed to the current expected. Chicken wire would instantly melt if hit by a direct leader. The lightning still must return to earth(its a two way street after all). What is inside the cage is protected; what is outside, like the hull, is not.

Lightning rods conduct charge to ground(earth). Must have contact with ground. Mast is a lightning rod if there is a direct connection with the underlying water. If there is a gap, does not work so well. In any event, the enormous heat from the strike will do as much damage as the electrical current.
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Old 17-09-2016, 09:49   #34
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Re: Does lightning strike cause delamination on fiberglass hulls?

Good points well put. Cars and steel boats make adequate Faraday cages for the occupants, but if your car gets hit while you are in it you are going to need, aside from fresh underwear, new electronics. In my steel boat, I'll be OK, but all those antennas and exposed wiring leave the electronics vulnerable. NO. There is no way to totally protect a boat.
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