Is the Binnacle Compass Obsolete? - Page 3 - SailNet Community
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post #21 of 83 Old 04-01-2010
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Originally Posted by hellosailor View Post

All I'm hearing is that the compass is a really good thing. I KNOW that, the problem is that it is hogging valuable real estate.
Dude, how big is your friggin' compass? It sounds like the thing takes up half the cockpit, leaving no room for a navpod on the pedestal guard, or a RAM mount to the bimini bows overhead or...


I wish someone would develop a repeater interface to display radar/chartplotter display on a pair of lcd sunglasses. A head-up display with no daylight viewing issues, and no cockpit clutter.
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post #22 of 83 Old 04-01-2010
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Presbyopic you say? I'll tell you what's more challenging - a crew of two with a combined age of 150, only one good eye between them, and both half deaf with short term memory issues (CRS) to boot. Our territory is Virginia to Maine.
Thank God you're sailing, not driving!

Seriously, my hat's off to you for keeping on keeping on.
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post #23 of 83 Old 04-01-2010
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Would putting a compass in a Faraday cage protect it from lightning strikes?

s/v Laelia - 1978 Pearson 365 ketch
s/v Essorant - 1972 Catalina 27
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post #24 of 83 Old 04-01-2010
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Would putting a compass in a Faraday cage protect it from lightning strikes?
With a little luck it will.

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post #25 of 83 Old 04-01-2010
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I would think the the same Faraday cage would keep it from functioning as a compass. But it's a long time since I took Electromagnetic Wave Theory....
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post #26 of 83 Old 04-01-2010
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I would think the the same Faraday cage would keep it from functioning as a compass. But it's a long time since I took Electromagnetic Wave Theory....
But lightning would also keep it from functioning as a compass, so there.
Okay, okay, okay, QUESTION: Stephen Hawking or Chuck Liddell: Who would win in a Faraday Cage Match?
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post #27 of 83 Old 04-01-2010 Thread Starter
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bl-
Maybe you missed the part where I said any kind of arm or pod is one more thing to foul a line on and get destroyed? Size is not the issue, you go hang a chartplotter someplace where a line can foul on it, and tell me that's a good idea. I've always figured the hallmark of good design, is that you can't really see how good it is because it just makes problems impossible.


Adam-
Consider the classic Faraday cage, which is made of copper screening or copper sheeting. Does copper stop magnetism? No, not at all. A compass in a Faraday cage will work perfectly well, unless the cage is made of iron sheet or mu metal, or something else that can block magnetism.
The Faraday cage blocks EMI (electromagnetic interference) and RFI (radio frequency interference) but not magnetism itself.
So if a lightning strike goes over the skin of the Faraday cage, or through a conductor next to it, there can still be a magnetic pulse that will reach right through the cage and grab your compass by the short hairs. The cage *may* help, but a small tinned iron box, or a mu metal box (the stuff is used in sheet form to keep speaker magnets from affecting computer monitors, etc.) would be better "compass insurance". Or even a couple of "iron" soup cans, clamped head to tail nice and tight with the compass inside them.

Time to drop the compass and get a good reliable sunstone as a backup! Oh you kids with your newfangled and unreliable compass technology!
:-)
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post #28 of 83 Old 04-01-2010
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Originally Posted by hellosailor View Post
bl-
Maybe you missed the part where I said any kind of arm or pod is one more thing to foul a line on and get destroyed?
:-)
Maybe YOU missed the part where I mentioned a RAM mount from a bimini bow overhead? If you're snagging sheets on your bimini, the problem ain't your compass.

If you plan to remove your pedestal compass and replace it with a Display, the display is going to be larger than your compass, and will not have roundy smoothy edges like a compass, instead it will be all sharpy squarey, so it will foul a line much more easily than a compass will in the same place. If your problem is failing eyesight, then bolt your plotter to the cabin with a magnifying sheet over the screen. now the display is nice and big and it is out of the way and you still have a compass.

Checkmate.
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post #29 of 83 Old 04-01-2010
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I was wrong...

From Wikipedia "Faraday cages cannot block static and slowly varying magnetic fields, such as Earth's magnetic field (a compass will still work inside)."
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post #30 of 83 Old 04-01-2010
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You would think that a steel boat is a pretty good faraday cage. When the lightning struck the top of the mast it blew everything off the top but I was inside at the time and not touching anything metallic [ I think ]

The air went fuzzy blue and the noise meant I was deaf for about two days but other than that I was fine.

Some electrics which were unplugged including the tv which was sitting on a wooden table with no leads attached were fried.

The hull was magnetised though.
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