Compass Dip and being down under

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jeffsterinsf

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I'm well aware that card-style compasses have significant problems if used well outside of the part of the world that the card is balanced.

The Suunto SK-7 has a bit more horizontal freedom than a card-style compass. Does anyone have experience using a "Zone 1" (upper northern latitudes) compass in Australia, or vice versa?
 
Are you talking declination?

If so...just peruse a topo map for your aread that you will be diving in, and look at the notes on the top of the map to learn what the declination is for your area...then adjust accordingly. You can also look around on the net, and find a declination "map" for the entire world giving you degrees east/west of declination you must use.
 
No, not declination, but dip. Because the magnetic field lines do not run parallel to the earth's surface, compasses have a little bit of weight on one side or another of the card so that it remains horizontal. Otherwise the north or south side of the card would be "pulled down" the magnetic forces.
 
I don't believe that this is an issue for most scuba compasses because they are generally designed to be useable in a variety of orientations. I believe that Rodales tests this feature and found that some compasses will function when up to 30º off of level. Most scuba compasses will function at least to 10º off level.

This is not always true of terrestrial compasses. As you mention many of the better compasses are balanced for the northern or southern hemisphere but Brunton makes one balanced for both. I don't know how they do it. No magnetic compass will work well if you are near (with 100's of miles) of one of the magnetic poles.
 
https://www.shearwater.com/products/perdix-ai/

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