Does anyone know why there is a magnet screw on the wall next to the upper helm compass? Do all these hatteras have them?
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Thread: Magnet screwed next to compass
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01-12-2020 06:36 PM #1Senior Member
- Join Date
- Dec 2014
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- 396
Magnet screwed next to compass
Pete. 1980 53 my. #575
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Re: Magnet screwed next to compass
It’s not on mine.
SEVEN
1979 53' MY Hull #563
Antioch, California
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Re: Magnet screwed next to compass
No magnet on mine
ENUFF. 1983 53MY.Hull #617 Barnegat Light Nj.
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01-12-2020 09:21 PM #4
Re: Magnet screwed next to compass
I suspect someone before you actually had the compass swung and the tech decided it needed that. You have a correction card anywhere? (List with cardinal headings and the correction to apply to the compass reading....) That would be evidence of the procedure having been done.
That's the obvious answer..... I'm probably wrong....Last edited by oscarvan; 01-12-2020 at 09:27 PM.
1978 53' Motor Yacht "LADY KAY V"
Hull number 524
Chesapeake Bay
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Re: Magnet screwed next to compass
Probably to compensate for compass error. Although depending on how long ago it was done, it might not need it. Good idea to have the compass swung and see if it's accurate.
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01-12-2020 11:43 PM #6
Re: Magnet screwed next to compass
Technically should do that when you buy the boat and every time you install/un-install electronics or metal fixtures near the compass, or LARGE metal fixtures anywhere on the boat. (Like a re-engine with different model engines)
I do think it's not as critical as it used to be when it was all you had for hours or days working a DR. That said, IF you're going to look at it and take the information into consideration it would behove you to know that it's at least close.
Paying attention first few trips when on a known heading based on GPS nav and checking what the compass says will get you pretty close. Do this at least for the cardinals and semi cardinals. If you notice any serious deviation you can do further digging.
Or you can do it the old style and find a known location where there's enough land based references to actually "swing" it either under its own power or at anchor with the dinghy pulling the stern around, a fun game to play..... I suspect "having" it done by one of the few remaining compass shops will be $$$.1978 53' Motor Yacht "LADY KAY V"
Hull number 524
Chesapeake Bay
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01-13-2020 09:00 AM #7
Re: Magnet screwed next to compass
Could it also be to compensate for the tilt experience by compasses when moving to different world zones? We sell compasses and north American made compasses are always special factory orders when operating in the Pacific.
The two big compasses on my own boat also have dial tilts now the boat is Downunder.+++
1984 61MY #353 with 9' cockpit extension.
Sydney, Australia.
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01-13-2020 06:27 PM #8Senior Member
- Join Date
- Feb 2016
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- 251
Re: Magnet screwed next to compass
You can use the compass app on an iphone as well. It is accurate enough to tell if you have a correction issue. I've used the iphone in my aircraft on the ground to validate the onboard compass correction card as our airport doesn't have a compass rose. The correction card was not correct, it was probably dated from the factory.
Matt
1976 58' YF, Hull #410
"Time Out West"
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01-14-2020 08:07 AM #9Senior Member
- Join Date
- Dec 2014
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- 396
Re: Magnet screwed next to compass
Thanks for the input. I’m in the process of prepping the helm for paint. I think I’ll fill in the holes and see if the compass needs correction when the boat goes back in the water
Pete. 1980 53 my. #575
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01-14-2020 08:16 AM #10Senior Member
- Join Date
- Apr 2008
- Posts
- 494
Re: Magnet screwed next to compass
It is a compensation magnet and most likely should not be removed without first verifying the compass course to a known heading. Using a iphone will get you pretty darn close. A recently calibrated heading sensor will suffice also.