Hi Dean, if you look at the Oceanic compass listed below, it saw southern hemisphere. So i am asuming there is a difference. Th Oceanic compass is also on Leisure Pro web page under Oceanic, can someone say what the differnce between northern and Southern hemisphere compass?
Oceanic SWIV Compass Module, Southern Hemisphere
RICHARD M When using a S Hem. compass in the N. Hem., there may be a slight dip in the needle. Therefore, you may have a slightly different heading as a compass designated for N. Hem. This would not pose a problem because you are still following the same line. If you are taking a Navigation Specialty course with other students and alternating students using a fixed compass point, the end result of returning to your starting point will be thrown off slightly . The compass module works well and I use it with students on every open water dive. Buy from Leisure Pro.
Monica s For a compass to work properly, the compass needle must be free to rotate and align with the magnetic field. The difference between compasses designed to work in the northern and southern hemispheres is simply the location of the "balance", a weight placed on the needle to ensure it remains in a horizontal plane and hence free to rotate. In the northern hemisphere, the magnetic field dips down into the Earth so the compass needle has a weight on the south end of the needle to keep the needle in the horizontal plane. In the southern hemisphere, the weight needs to be on the north end of the needle. If you did not change the weight, the needle would not rotate freely, and hence would not work properly.