Discussion: Compass for Brazil

We will be at the WMOC2014 event in Brazil in November, and were planning to use the Silva Jet thumb compasses that we used previously in Australia. I remember seeing somewhere that Silva actually makes five different compasses intended for five latitudinal regions (although we have used our 'standard' Jet without problem from Morocco to the Arctic Circle, so I don't know what the supposed need for more specificity might entail). Nevertheless, I have heard other rumbles about one needing a specific type of compass for O in Brazil, which I don't really understand. Has anyone had experience with using orienteering compasses in Brazil?

According to this map I found, a zone 5 compass only works in Aus and NZ. Brazil is supposedly zone 3. We are just too exclusive down here.

From what I've heard (and it matches my experience in as much as it exists), you can get reasonable results with a compass up to two zones outside its nominal zone.

My experience is that the same compass that works in Australia will work fine in Brazil.

There is a previous AP discussion thread on this topic; lots of good information there.

One of my Bay Area OC clubmates orienteered in Brazil a few years ago, and yesterday I asked him what he did about the compass situation. He told me he bought one there, and then very kindly insisted that I borrow his since he has no present need for it. In line with some of the comments in the thread referred to above, the bottom of the needle of the this compass has "BR" hand-written on it, presumably for "Brazil".

Finally, another of my clubmates,, who is also headed for Brazil, just ordered a "Southern Hemisphere ME - Brazil" compass here.

All good information - many thanks to everyone for your insights.
I think that my current bias is to go to Brazil with my Oz compass; if nothing else, it will give me another good explanation for any less-than-stellar race results ;-)

So glad I was able to buy a Brazil compass from the Moscow Compass man at his table booth a couple of months ago in Switzerland.

Here is what he taught me about how to tell if the compass you currently have is balanced for the location where you are:

Hold the compass in your hand facing either east or west. (You can move the housing so the red arrow is under the needle if you like.) Now tilt the compass in front of you vertically, rotating it vertically along the needle/red arrow, so now it is on its side. You are still facing east or west, so it should remain aligned north and south, though now tilted 90 degrees. If the needle stays fairly horizontal, it is balanced OK for where you are.

I just stepped outside and tested my new Brazil compass. The red north end of the needle does a big swooning nose dive to nearly vertical!

Just a follow-up for completeness. We are now in central Peru, which is substantially further north than the WMOC event in southern Brazil. Had a chance to run in a casual sprint O event in Cusco this morning, using my Jet thumb compass that I had acquired in Oz over a decade ago. The needle had a pronounced dip, but did not drag on the capsule housing, and seemed to hold to north without any problem. I think it is therefore fair to say that the dear old thing will be even happier in southern Brazil, and that an Oz compas should be quite adequate for competing in WMOC2014.

Cusco is special place. I hope you have a few days to enjoy it. And yes, your compass will be fine. Enjoy the races in Brazil.