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Old 07-11-2013, 06:45   #1
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S hemisphere compass to N hemisphere compass

Hi,

I have a southern hemisphere compass. Can it be converted to a northern hemisphere compass? If yes, is it worth the effort/cost?
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Old 07-11-2013, 06:51   #2
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Re: S hemisphere compass to N hemisphere compass

Interesting question. Don't know whether the error from magnetic dip is worth correcting nowadays as reliance on magnetic compasses is getting less and less.
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Old 07-11-2013, 07:01   #3
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Re: S hemisphere compass to N hemisphere compass

i have had both n+s aligned,in opposite hemispheres,apart from at anchor or on the dock you will hardly notice the dip once the boat starts moving.
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Old 07-11-2013, 07:14   #4
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Re: S hemisphere compass to N hemisphere compass

Atoll,

I'm not sure what you are saying, is your compass both N & S, or is it one hemisphere but you don't notice when in the other hemisphere? I was told the compass card would stick.

Thanks,
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Old 07-11-2013, 07:26   #5
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Re: S hemisphere compass to N hemisphere compass

my first boat had a southern hemisphere silva compass,that we circumnavigated with and eventually sold in the med,never had any problems.

our current boat has a northen hemisphere gemini compass that we have circumnavigated with and spent a lot of time in the southern hemisphere,never had a problem with the card sticking.

all you will notice is a slight dip that underway is hardly noticeable
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Old 07-11-2013, 07:27   #6
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Re: S hemisphere compass to N hemisphere compass

We've sailed as far north at 60N and south as 45S, all with the same compass and never had any issues. I suppose if you were moving the boat permanently from one hemisphere to the other you might want to bother. Or get a new compass, probably cheaper if you are going to pay someone to make the adjustments. Of course getting and installing a new one that fits like your old one could be a pain.
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Old 07-11-2013, 07:33   #7
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We did a circum with a S compass. Now we are at 28S on another boat with a N compass. No problems ever.
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Old 07-11-2013, 07:49   #8
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Re: S hemisphere compass to N hemisphere compass

Well, despite the above posts, it can be a problem. We had a Danforth binnacle compass on our previous boat, purchased in SF and nominally being compensated for that latitude.

As we approached New Zealand in 1990, we noticed the card tilting more and more. By the time we reached about 32 south it began to hang up, and by the time we were in Auckland it had ceased working due to excessive dip. Interestingly, a fellow SFbay sailor who we had been in company with and who had a Ritchie compass had no problems. We were able to have the compass re-balanced in Auckland, and chose what they called an "equatorial" balance, and it seemed to suffice for the rest of our voyaging in that boat, but we never got very far north!

So, it seems to depend on the specific model that you have on your boat because they vary in their susceptibility to dip angle changes.

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