"Evan Gatehouse" wrote in message ...
Anybody have any experience using a Northern Hemisphere compass as far south
as say New Zealand? I *know* you're supposed to have a s. hemisphere
compass in an ideal world, but I'm wondering how much the card deflects i.e.
is it still useable, even if tilted.

Yes as everybody knows southern hemisphere compasses point to the top
of the world (ie Antartica) and if you use a northern hemisphere
compass it will get confused and point halfway between north and south
and head east or west.
incidently thats why captain cook discovered Austrailia by accident
when he was looking for india.

[warning this email contains Sarcasm]

"Terry Spragg" wrote in message
....
It matters, but a southern hemisphere compass? Yuk, yuk, yuk!


Come on Terry, you're not supposed to make jaxie look smart.

Compasses do indeed need to be adjusted for the Southern Hemisphere. Here's the
Ritchie comment:
http://www.ritchienavigation.com/ser...albalance.html

here's the actual map of inclination (known to mariners as "dip")
http://www.ngdc.noaa.gov/seg/geomag/icons/wmm2000i.gif
As you can see, there's a serious difference between the USA and New Zealand - plenty
to make the card jam if not balance properly.

Everything you might want to know about the Earth's magnetism:
http://www.ngdc.noaa.gov/seg/geomag/geomag.shtml

On 23 Oct 2004 02:32:30 GMT, (JAXAshby) wrote:

a
magnetic card compass for the northern hemisphere is funcitionally different
from one for the southern hemisphere.

I knew I should have played the lottery the day JAX finally got
something right and explained it without sounding like Forrest Gump.

Point made, JAX, now stand down before you strain something.

R.

rhys wrote:


On 23 Oct 2004 02:32:30 GMT, (JAXAshby) wrote:


a
magnetic card compass for the northern hemisphere is funcitionally different

from one for the southern hemisphere.

I knew I should have played the lottery the day JAX finally got
something right and explained it without sounding like Forrest Gump.

Point made, JAX, now stand down before you strain something.

R.

ok, ok, ok.

So, it's been a long time since dippy compasses were discussed in my
presence. Please pardon my forgetting a subject so long disused.

So, if your 5Kbuck compass needs heart surgurey to keep it levelled
up with a north weight instead of a south weight, why not use your
pocket silva and give it enough tilt so it doesn't bind? I've
tried it now, and it seems to work just fine with a bit of a twist
on. Mind, I'm a dippy northerner, but we're not that far north, I
guess, nor that dippy, unlike some extant.

I don't usually bother with Jakz so I had to seek out the comment
regarding weighted compass cards.

It seems to me the amount of dip in the compass reading might be
some indication that you're way north, or you are passing over the
magnetic pole or something.

If I go all that far north or south, I will remember this gem: "A
cheap hand compass can be used where a millonaire's compass cannot."
Appropriate gear for the mission, eh?

I would also bring alernative nav devices, like homing pigeons,
odour samples, wave pattern transform almanacs, depth sounder, even
RDF, LORAN, pylorous, sextant, charts, or GPS, I guess.

Mind, dipping compasses would only be needed at extreme latitudes.

Who'da thunk? I guess crossing the equator means a major compass
replacement every time you cross the line, eh? Is that what the
shellbacks do while the nymphs are getting transsubstantiated?

Does this mean I can't trust my compass card inclinometer any more?

Vapour, right?

Terry K