Re: Salties, how do you protect against lightening?
Some golfers have been struck 2 X and are still playing golf. Lightning dangerous ? Maybe. A sailboat with loads of SS wires running up to the top of the mast is a prime target. Carbon fiber mast just made it more attractive in a storm.
There is a simple Copper conductor spike mounted above the mast top. It has a heavy Copper wire running straight down thru the hull to a LARGE THICK Copper plate on the outside of the hull. Right next to the keel.
The plate in theory will provide a large area for the current to find a way thru the water to the bottom of the lake or ocean, under the boat.
Sometimes the lightning electrons get crowded on that wire & start jumping off of it anywhere they want to. If they do jump around, a carbon hole can result in plastic boats.
With lightning they are NO positive protections.
Realize this. By putting a Copper spike & wire you are... ATTRACTING....more lightning from farther distances. All the other boaters around you are being more protected by you.
No, the theory is that you will disperse any positive charge on the boat, thus making the boat not a magnet for the negative charge in the clouds.
Same as a lightning rod on a barn or radio tower.
And if it should actually strike the mast, the charge will follow the mast, so it should be grounded straight thru the hull.
Otherwise, the bolt could jump from the mast, following a path of lesser resistance, which could be you, and it could actually try to reach ground by going through the hull, leaving a hole where the hull used to be.
Positive and negative will attract each other.
Anything that can hold a charge should be grounded.
There is no way the copper wire connected to that mast top spike could carry the power of a lightning bolt, but it can disperse the static charge so your boat is less likely to attract the negative bolt.
And, if it is actively dispersing a lot of positive ions, it actually provides a "desirable" point of contact for a strike. Desirable in that it is not you !!
Also, usually there is rain associated with lightning. The rain water has a way of dispersing the charge from your boat as well.
It is the pre rain lightning or the dry lightning which is more likely to strike you, as you will have more of a positive charge.
Best way to protect the electronic toys, is to use the smallest possible fuses, on both the positive and negative power leads, or so I have been told.
There is lots of info out there, google lightning, and google "protecting marine electronics from lightning"
http://edis.ifas.ufl.edu/sg071
Ground flashes can be expected to hit from 4-20% of moored sailboats per year in Florida.
http://www.sailnet.com/forums/cruising-articles/20355-path-lightning-protection.html
It is important to understand that adding a lightning-protection system to your vessel may actually increase the chances of being struck. You are inviting the lightning to come aboard and use your vessel as a path to ground. With this invitation comes the responsibility of installing the correct system?remember that the reason for installing the system in the first place is to minimize damage to the boat and injuries to the crew.
The basic lightning-protection system is based on a theory developed by Michael Faraday, called the "Faraday's Cage." The principle is to provide a grounded structure where all the parts are bonded together and have the same electrical potential.
http://www.sailnet.com/forums/gear-maintenance-articles/20102-lightning-precautions.html
