True or False

[steve28]

i have had a friend that emailed me this :"Almost in the water, just stepped the mast and sorting out the rigging. A chap at Mailspeed Marine supplies was saying that I would need to make a break in the guard rail wire so as to avoid creating a 'Faraday circuit' which could affect the compass etc, have you come across this?"

Im at a loss as to why this would be the case, i know that a lashing/binding at the end of the guard wire is a good idea to aid cutting in an emergency but have been unable to find any info on the faraday theory



steve

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[StugeronSteve]

Heard this one before, I think the consensus was that it is b****x.

<hr width=100% size=1>Semper Bufo

 

[Vara]

It used to be the case that a complete circuit (according to my Lokata manual) could cause problems with RDF(you wont remember that children./forums/images/icons/smile.gif).
But I think that affecting the compass or anything else nowadays is indeed b*******s

<hr width=100% size=1>If it can't be fixed with a lump hammer dont fit it!

 

[bruce]

thought that faraday had to do with lightening strikes and 'cone of protection' formed with the tip if the mast forming an area 'safe' but you could not touch any of the metal aboard. if in a car and hit by lightning, you are safe as long as you don't grab the door handle or metal on steering wheel. refered to as 'faraday cage' therefore your answer is prob false...

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[mickp]

Cant see how two lines of guardwire would form a Faraday cage ? Yet alone affect Compass ? Surround yacht in mesh yes. All yachts i have ever seen / been aboard / sailed have a break in guardwire anyway where lashings are used. These are cut with knife to assist Man overboard recovery.

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[Dave99]

All I know is that Faraday was a famous physicist and had something to do with electric current

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[john_morris_uk]

In the days of RDF it used to be argued that the complete loops round the boat of guard rails and pushpit and pulpit could cause "quadrilateral errors" in taking bearing with an RDF inside the loop.

If you want the details of why this might be - ask, otherwise I will not bore you with what was probably a fairly facile argument in the first place. (If you have ever used RDF for real you will understand what I mean (The point being that even when RDF worked really well it sometimes could tell you which side of the channel you were on ... alright - maybe a bit better than that, but you get the idea)

In the modern context, I cannot see it affecting anything.

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[Alex_Blackwood]

Don't confuse this with Faradays cage.
Faraday found that an EMF could be generated in a coil, or, loop. Basic stuff so won't go into all the detail. However he also found that if the loop or, coil was closed a current would flow. If it was open no current would flow but an EMF would still be present.
The EMF or magnetic field is what would effect the compass. So assuming you have a situation where all the bits come together and there exists the means of generating an EMF in the guardrails it seems to me that open or closed doesn't matter. If you do generate an EMF then you stand the chance of anyone in contact with "Earth" discharging it with a short sharp shock.

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[Bergman]

Re Er

EMF is Electro motive force

Think the principle is that if a closed loop of wire like a guard rail when moved through a magnetic field ie the earths magnetic field, a current will flow around the conductor forming the loop. This current flowing in a 1 turn coil will itself form a magnetic field which will affect the compass.

Personally I wouldn't worry about it, effect will be negligible.

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