Compasses and Geographical Zones

[VFV]

I was interested in purchasing a suunto sk 7 compass as I used one recently and I liked it. I find, however, they are calibrated to one of five geographical zones. I live in zone 1. I dive here. I also dive in zone 2 (southern Carribean), though, just as often. I really only want to buy one compass. Can a suunto zone 1 compass be used in zone 2, realistically? My next dive trip is in zone 2.... I'm doing recreational diving and so maybe I have enough margin for error that zone difference doesn't matter... Or maybe there's a better compass manufacturer recommendation that isn't limited by geo zones... Thanks!

 

[altaskier]

Huh? There are magnetic declinations... Magnetic declination - Wikipedia, the free encyclopedia

 

[bleeb]

Found one reseller's opinions on the Interweb:
Compass / Clinometer FAQs

The comments under section 3 are particularly interesting:
World Magnetic Zones
Given the relatively low accuracy that can achieve under water, and divers already have to level the needle, I'm wondering if it might be even less of an issue for a dive compass. Haven't checked it myself. You might still run into problems changing hemispheres though.

 

[Hatul]

My SK7 is a zone 1 compass and it worked fine in Cozumel which is zone 2. I don't think it's a question of accuracy but the tilt of the compass face, and as bleeb pointed out you already have to level the compass to some extent when diving. Also the SK7 is quite forgiving with respect to tilt.

Adam

 

[VFV]

Thanks much for replies!

 

[lonebrave]

If there is enough inaccuracy between locations to make a difference, I could see there being issues with following directions while navigating. If the compass is being used for relative navigation (e.g. for navigating my way back to a given point...say the exit), it doesn't matter if it's off or not as long as it's consistent throughout the dive.

I'm a newbie, and I dive in warm water with 60+ ft vis almost all the time, so my experiences and expectations are likely different from others who are more experienced and/or diving in more challenging conditions.

 

[Samppa]

I have also that SK7 zone 1 compass and used it without problems even in zone 3.
When looking closely I could see the needle being slightly tilted but no issues underwater, at least with basic navigation...expanding square etc.

 

[memorex77]

In the last 2-3 months I've used my only Oceanic compass in the Philippines, Germany, Florida and California and always found the boat or exit again. Good enough for me..