William_H
Well-Known Member
Faraday Cage........ The concept is to provide a low resistance wire cage around a person or device which will act as an aerial to elctromagnetic radiation or a low resistance path for lightning or high voltage such that anything inside will be protected by the bypassing effect.
Now as stated a mast and rigging will provide quite a large usefull cone of protection from lightning if it is earthed. It usually is via damp hull or deck even if not deliberately earthed. This will protect people on board from lighning electrocution.
However the disadvantage is that the mast will to a degree attract lightning. You can't avoid that. The huge current that can flow in the mast and rigging can easily damage by overheating the rigging wire and less so the mast. If the current has to find its way via wet hull then it will overheat and burn that area. This is why trees are a bad risk. They have enough conductivity to atract lightning but when the current flows through the sap it vaporises the moisture exploding the tree.
The huge current can also induce large magnetic fields which can in turn induce current and voltage into sesitive electronic gear. (Especially via long connecting cables). Hence the idea of putting GPS in the oven. This is another farady cage protecting gear from the magnetically induced current from the current in the rigging. The first fadaday cage.
So I don't think there is any case for electrically insulating the guard wires. Except perhaps that they may be a problem when you are touching them if connected to the rigging in a strike so reaching a high voltage if the rigging is not well earthed.
So if you are concerned about lightning I suggest the good earth wire mast to saltwater.( as heavy as your starter cable) Preferably the steel keel or an earth plate at least 2 square ft. Hopefully this will avert current from the drive shaft where it can damagee bearings etc. olewill
Now as stated a mast and rigging will provide quite a large usefull cone of protection from lightning if it is earthed. It usually is via damp hull or deck even if not deliberately earthed. This will protect people on board from lighning electrocution.
However the disadvantage is that the mast will to a degree attract lightning. You can't avoid that. The huge current that can flow in the mast and rigging can easily damage by overheating the rigging wire and less so the mast. If the current has to find its way via wet hull then it will overheat and burn that area. This is why trees are a bad risk. They have enough conductivity to atract lightning but when the current flows through the sap it vaporises the moisture exploding the tree.
The huge current can also induce large magnetic fields which can in turn induce current and voltage into sesitive electronic gear. (Especially via long connecting cables). Hence the idea of putting GPS in the oven. This is another farady cage protecting gear from the magnetically induced current from the current in the rigging. The first fadaday cage.
So I don't think there is any case for electrically insulating the guard wires. Except perhaps that they may be a problem when you are touching them if connected to the rigging in a strike so reaching a high voltage if the rigging is not well earthed.
So if you are concerned about lightning I suggest the good earth wire mast to saltwater.( as heavy as your starter cable) Preferably the steel keel or an earth plate at least 2 square ft. Hopefully this will avert current from the drive shaft where it can damagee bearings etc. olewill
