Compass dip - questions for the southern Hemisphere people.
 

Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

I believe that the better compasses (all real compasses?) are built for either
the Northern or Southern Hemisphere, or have an adjustment.

http://www.ritchienavigation.com/ser...albalance.html


"Simple Simon" wrote in message
...
Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

So, when I decide to circumnavigate I'll need several compasses?

I have to wonder at the fact of all the circumnavigation stories
I've read that not a single, solitary author even made mention
of compass dip?

S.Simon


"Jeff Morris" wrote in message ...
I believe that the better compasses (all real compasses?) are built for either
the Northern or Southern Hemisphere, or have an adjustment.

http://www.ritchienavigation.com/ser...albalance.html


"Simple Simon" wrote in message
...
Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

Donals Dilemma wrote in message ...
Jesus Christ Cappy!?



Why clutter up the newsgroup with stupid expletives
if you don't know the answer?

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

More inane obfuscation from the wizard of obiter dictum.

Other than oblique obsequiousness oz oinks only obstreperousness.

S.Simon




Donals Dilemma wrote in message
I know the answer, I'm stunned that a licenced captain like yourself
with thousands of ocean miles has absolutely no clue!

Compass dip - questions for the southern Hemisphere people.
 

And either a boat or a plane.

"Simple Simon" wrote in message
...
So, when I decide to circumnavigate I'll need several compasses?

I have to wonder at the fact of all the circumnavigation stories
I've read that not a single, solitary author even made mention
of compass dip?

S.Simon


"Jeff Morris" wrote in message
...
I believe that the better compasses (all real compasses?) are built for
either
the Northern or Southern Hemisphere, or have an adjustment.

http://www.ritchienavigation.com/ser...albalance.html


"Simple Simon" wrote in message
...
Since the north magnetic pole is not resting upon the surface of the
Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north
side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or
something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC

Simple Simon wrote:

Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

But the greater question is this. A northern hemisphere compass card
has a magnet with the south pole facing the North cardinal point on
the card. This magnet also has a north pole that aligns itself opposite
of the Earth's poles.

Does a southern hemisphere compass, in order to minimize card dip,
have the magnet placed the opposite direction on the south side of
the card?

S.Simon


"The_navigator©" wrote in message ...
You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC

Simple Simon wrote:

Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

Sorry Oz. I was just trying to respond to what I thought was a genuine
request for information. I just can't stop myself trying to help those
seeking information...

Cheers MC

Donals Dilemma wrote:

On Thu, 27 Nov 2003 12:15:30 +1300, The_navigator©
wrote:


You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC


Aaaaargh!
Ya always gotta show how smart you are!
I was hoping that Cappy might bail out of the internet porn for a few
minutes and actually learn something about his "trade".


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you.

Compass dip - questions for the southern Hemisphere people.
 

I'm sorry I don't really understand the question. Dip is generally
corrected by weights. So take a northern compass south and card tilts
and develops a dip error. The dip in the south is gernerally in the
opposite direction to that in the north if you like to think about it
that way.

Cheers MC

Simple Simon wrote:

This magnet also has a north pole that aligns itself opposite
of the Earth's poles.

Does a southern hemisphere compass, in order to minimize card dip,
have the magnet placed the opposite direction on the south side of
the card?

S.Simon


"The_navigator©" wrote in message ...

You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC

Simple Simon wrote:


Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

But, as you well know, the magnet(s) cannot be place at the center
of the card because that is where the bearing resides. Therefore,
it follows that the magnet is off center favoring whatever side
of the card minimizes the weights placed opposite of it to compensate
for dip.

Are your southern hemisphere compasses built the opposite of northern
hemisphere compasses with respect to magnet and weight placement?

S.Simon


"The_navigator©" wrote in message ...
I'm sorry I don't really understand the question. Dip is generally
corrected by weights. So take a northern compass south and card tilts
and develops a dip error. The dip in the south is gernerally in the
opposite direction to that in the north if you like to think about it
that way.

Cheers MC

Simple Simon wrote:

This magnet also has a north pole that aligns itself opposite
of the Earth's poles.

Does a southern hemisphere compass, in order to minimize card dip,
have the magnet placed the opposite direction on the south side of
the card?

S.Simon


"The_navigator©" wrote in message ...

You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC

Simple Simon wrote:


Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

The magnets can be placed either side of the bearing so the sapphire
bearing is free of mechanical obstrction. The weight is placed on the
other (N on card) side in the southern hemisphere

Cheers MC

Simple Simon wrote:

But, as you well know, the magnet(s) cannot be place at the center
of the card because that is where the bearing resides. Therefore,
it follows that the magnet is off center favoring whatever side
of the card minimizes the weights placed opposite of it to compensate
for dip.

Are your southern hemisphere compasses built the opposite of northern
hemisphere compasses with respect to magnet and weight placement?

S.Simon


"The_navigator©" wrote in message ...

I'm sorry I don't really understand the question. Dip is generally
corrected by weights. So take a northern compass south and card tilts
and develops a dip error. The dip in the south is gernerally in the
opposite direction to that in the north if you like to think about it
that way.

Cheers MC

Simple Simon wrote:


This magnet also has a north pole that aligns itself opposite
of the Earth's poles.

Does a southern hemisphere compass, in order to minimize card dip,
have the magnet placed the opposite direction on the south side of
the card?

S.Simon


"The_navigator©" wrote in message ...


You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC

Simple Simon wrote:



Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

Thanks.

It sounds like you know of which you speak.
It sounds like a northern hemisphere compass would
not work too well in the southern hemisphere just
as I thought and for the reasons I suspected.

Poor Oz was clueless as are the greater percentage
of subscribers here.

S.Simon


"The_navigator©" wrote in message ...
The magnets can be placed either side of the bearing so the sapphire
bearing is free of mechanical obstrction. The weight is placed on the
other (N on card) side in the southern hemisphere

Cheers MC

Simple Simon wrote:

But, as you well know, the magnet(s) cannot be place at the center
of the card because that is where the bearing resides. Therefore,
it follows that the magnet is off center favoring whatever side
of the card minimizes the weights placed opposite of it to compensate
for dip.

Are your southern hemisphere compasses built the opposite of northern
hemisphere compasses with respect to magnet and weight placement?

S.Simon


"The_navigator©" wrote in message ...

I'm sorry I don't really understand the question. Dip is generally
corrected by weights. So take a northern compass south and card tilts
and develops a dip error. The dip in the south is gernerally in the
opposite direction to that in the north if you like to think about it
that way.

Cheers MC

Simple Simon wrote:


This magnet also has a north pole that aligns itself opposite
of the Earth's poles.

Does a southern hemisphere compass, in order to minimize card dip,
have the magnet placed the opposite direction on the south side of
the card?

S.Simon


"The_navigator©" wrote in message ...


You are correct. The dip would throw the card off and might be a
problem. In fact some tasco binocs with built in compass sold here did
not work for the reason! No compass seeks the pole(s). They just align
themselves with local field. If you look at a large scale chart with
variation the lines can often wander a great deal (let alone the local
anomalies).

Cheers MC

Simple Simon wrote:



Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.

Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.

Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

The first answer was the closest. Yes there is a difference and yes in most
compasses including the one's we find on our sailboats and powerboats are,
in fact, different. Some compasses, such as the one on USNS Bob Hope, are
built to be self adjusting when crossing the line. On a previous ship one
of our main bridge compasses (magnetic not gyro) showed a marked tilt some
degrees south of the equator. It was recalibrated in Darwin, Australia.
Great seafood buffet place down there by the way. Smaller less expensive
compasses do not have this ability for self adjustment and this includes
those in the many hundreds of dollars category. No need since most boats
don't make it across the equator one way or another. The easiest way to
solve the issue is order up a compass from some company in Australia, NZ
etc. and have it airmailed. Get the exact same compass you already have.
When crossing the equatorial region at some point you will observe the tilt
or dip. Switch compasses and re-swing. Not hard to do even way out there.
In fact I think it was Ole Thom who first gave me an explanation on how to
determine exact bearings out of sight of land. This phenomenae does not
happen exactly at the equator. The reason it happens is the distance from
the mass of iron in N. Canada that is the Magnetic Northern Pole increases
while the mass of earth's iron making up the Magnetic Southern Pole
decreases in distance. At some point one becomes the major attraction to ye
olde compass instead of the other and it becomes off-balance. Here's the
humorous part. When the compass on our ship acted up none of the highly
trained and experienced deck officers realized what had happened. One of
the other AB's remarked to me, "Southern Dip?" "For sure", sez I. Finally
we were asked what we meant by that phrase. They didn't believe us and had
to look it up in Bowditch. Score one for the home team!

Three more days and we're outta here. OT is running 4 plus hours a day and
tomorrow for T-Day we will work about 12. You all enjoy the turkey . .. I'm
loving the paycheck!

Here's one for you. The new Chief Mate on board has the unlikely name of
Despot.She just finished being Captain of a smaller vessel and is now
qualifying in the big ones. Yes, I did say 'she'. Imagine "Captain Despot"
being your boss. Haggie, Katy, LP don't worry about ole Neale . . . .Your
gender is more than holding it's own in the commercial mariner's world. The
best part is it's no longer necessary out here for someone to say, "How do
you find working for a woman?" The question never comes up. But it's kinda
fun knowing I work for a 'Despot'.

Few more days and I'll talk to you all in two months or so . . . .

MST

Compass dip - questions for the southern Hemisphere people.
 

Great and informative post. Thanks. It's nice to see some
people around here are more interested in providing in-
formation instead of only trying to belittle and build up
their own sagging egos (Oz).

Your observations pretty much confirm my suspicions
about compasses and nobody's mentioning dip in their
world cruises. It also confirms what I know about deck
officers like those who frequent this group - they know
little about what we sailors know instinctively because
we are so close to the water and the real world in
comparison.

Fair winds to ya. Enjoy your mission.

S.Simon


"Schoonertrash" wrote in message ...
The first answer was the closest. Yes there is a difference and yes in most
compasses including the one's we find on our sailboats and powerboats are,
in fact, different. Some compasses, such as the one on USNS Bob Hope, are
built to be self adjusting when crossing the line. On a previous ship one
of our main bridge compasses (magnetic not gyro) showed a marked tilt some
degrees south of the equator. It was recalibrated in Darwin, Australia.
Great seafood buffet place down there by the way. Smaller less expensive
compasses do not have this ability for self adjustment and this includes
those in the many hundreds of dollars category. No need since most boats
don't make it across the equator one way or another. The easiest way to
solve the issue is order up a compass from some company in Australia, NZ
etc. and have it airmailed. Get the exact same compass you already have.
When crossing the equatorial region at some point you will observe the tilt
or dip. Switch compasses and re-swing. Not hard to do even way out there.
In fact I think it was Ole Thom who first gave me an explanation on how to
determine exact bearings out of sight of land. This phenomenae does not
happen exactly at the equator. The reason it happens is the distance from
the mass of iron in N. Canada that is the Magnetic Northern Pole increases
while the mass of earth's iron making up the Magnetic Southern Pole
decreases in distance. At some point one becomes the major attraction to ye
olde compass instead of the other and it becomes off-balance. Here's the
humorous part. When the compass on our ship acted up none of the highly
trained and experienced deck officers realized what had happened. One of
the other AB's remarked to me, "Southern Dip?" "For sure", sez I. Finally
we were asked what we meant by that phrase. They didn't believe us and had
to look it up in Bowditch. Score one for the home team!

Three more days and we're outta here. OT is running 4 plus hours a day and
tomorrow for T-Day we will work about 12. You all enjoy the turkey . .. I'm
loving the paycheck!

Here's one for you. The new Chief Mate on board has the unlikely name of
Despot.She just finished being Captain of a smaller vessel and is now
qualifying in the big ones. Yes, I did say 'she'. Imagine "Captain Despot"
being your boss. Haggie, Katy, LP don't worry about ole Neale . . . .Your
gender is more than holding it's own in the commercial mariner's world. The
best part is it's no longer necessary out here for someone to say, "How do
you find working for a woman?" The question never comes up. But it's kinda
fun knowing I work for a 'Despot'.

Few more days and I'll talk to you all in two months or so . . . .

MST

Compass dip - questions for the southern Hemisphere people.
 

"Simple Simon" wrote in message ...
Since the north magnetic pole is not resting upon the surface of the Earth
compasses made for Northern Hemisphere use are usually weighted on the
card on the southern side to keep the card more level as the north side of
the card seeks out the north pole buried well inside the Earth.



Ever see a chart of the magnatic field of the earth?

Seems to me the weight used to hold the card level-upright is effected
by gravity not magnetics.




Are the compasses you Australian and New Zealand ******s use weighted
any differently? What if you were going to sail to Canada or something.
Would your southern compass work in the Northern hemisphere? Also
does you compass really seek the North magnetic pole or is it made
backwards to seek the south magnetic pole.


What I want to know is: Do seashells grow clockwise in the s.
hemisphere?
How about barley twist canes? And in the S. Hemisphere will you Neil
swirl your ceder bucket the other way?.


Joe
MSV RedCloud .......With a Counter Clock wise flushing head.





Enquiring minds want to know . . .

S.Simon

Compass dip - questions for the southern Hemisphere people.
 

Why clutter up the newsgroup with stupid expletives
if you don't know the answer? BRBR

Got that right, bro. There is something about this Newsgroup that seems to
evoke the worst in people.... Pity.

Compass dip - questions for the southern Hemisphere people.
 

I was just trying to respond to what I thought was a genuine
request for information. I just can't stop myself trying to help those
seeking information... BRBR


Please keep it up, it's refreshing and appreciated.

Compass dip - questions for the southern Hemisphere people.
 

Actually, he's the one who started it. Before you make
judgements, do some research.

"Hmseconomy" wrote in message
...
Why clutter up the newsgroup with stupid expletives
if you don't know the answer? BRBR

Got that right, bro. There is something about this Newsgroup that seems
to
evoke the worst in people.... Pity.

Compass dip - questions for the southern Hemisphere people.
 

Not likely from him....

"Hmseconomy" wrote in message
...
I was just trying to respond to what I thought was a genuine
request for information. I just can't stop myself trying to help those
seeking information... BRBR


Please keep it up, it's refreshing and appreciated.

Compass dip - questions for the southern Hemisphere people.
 

Haven't seen a post from you in a coon's age.
Where have you been? Off cruising?

S.Simon


"Hmseconomy" wrote in message ...
Why clutter up the newsgroup with stupid expletives
if you don't know the answer? BRBR

Got that right, bro. There is something about this Newsgroup that seems to
evoke the worst in people.... Pity.

Compass dip - questions for the southern Hemisphere people.
 

It's more than just the compasses. I often wondered how the folks down
under managed to keep their feet planted firmly on the ground. Having had
the chance to visit Oz I found out it has nothing to do with gravity and no
.. . .it isn't velcro. The magic trick that keeps them from plunging off
headfirst is (fanfare, drum roll, . . . .. . . . . that's enough and fire
the drummer) The substance is . . . . .Vegemite!!!!!!!!!

Still have half a very large jar left.

MST

Compass dip - questions for the southern Hemisphere people.
 

Simple,

If you ever sail around the world, I'm sure you won't need a compass as
much as a "Dinner Jacket" The trip will be on a cruise Ship and you'll
be a passenger.

Hope you had a wonderful day of Fasting & exercise. I had a wonderful
Turkey Dinner with stuffing (Oyster) gravy, Mashed potatoes, Sweet
potatoes with marshmallows, asparagus; Pumpkin and Raisin pie. Two
Manhattans GREAT DAY

I'm one of your FAT American. Obese to my eyeballs. Called Morbid
Obesity.

Wish you lived closer so I could name you to carry Ole (Fat) Thom the
last mile

Ole Thom

Compass dip - questions for the southern Hemisphere people.
 

Wish you lived closer so I could name you to carry Ole (Fat) Thom the
last mile

Don't talk thay way, Thom. Time is an invention and a shakey one at that.
Stick around, the world needs you.

RB

Compass dip - questions for the southern Hemisphere people.
 

Schoonertrash wrote:

The first answer was the closest. Yes there is a difference and yes in most
compasses including the one's we find on our sailboats and powerboats are,
in fact, different. Some compasses, such as the one on USNS Bob Hope, are
built to be self adjusting when crossing the line.

Sounds like a good but probably expensive feature to have.

.... The easiest way to
solve the issue is order up a compass from some company in Australia, NZ
etc. and have it airmailed. Get the exact same compass you already have.

Actually, you don't need to order from Australia (not intending to hurt the
Aussie economy, sorry). All good compass makers will have the same model compass
made in several dip ranges. The dip angle changes by latitude, not just when you
cross the equator.


When crossing the equatorial region at some point you will observe the tilt
or dip. Switch compasses and re-swing. ..... The reason it happens is the
distance from
the mass of iron in N. Canada that is the Magnetic Northern Pole increases
while the mass of earth's iron making up the Magnetic Southern Pole
decreases in distance. At some point one becomes the major attraction to ye
olde compass instead of the other and it becomes off-balance.

Total malarkey. Compasses are polar, north poles & south poles of magnets both
attract metal but only opposite poles of other magnets. Try it yourself with a
kids toy bar magnet.

The reason for the dip angle is that the Earth is round (well, it's an oblate
sphere) and the lines of magentic force between the North and South Poles are
more apple-shaped. So, the Earth's magnetic field pulls either the north or
south pole of the compass card down more as it approaches the poles.

Here's the
humorous part. When the compass on our ship acted up none of the highly
trained and experienced deck officers realized what had happened. One of
the other AB's remarked to me, "Southern Dip?" "For sure", sez I. Finally
we were asked what we meant by that phrase. They didn't believe us and had
to look it up in Bowditch. Score one for the home team!

I guess if you don't think about a compass very often, you forget stuff like
that. I can't believe a qualified sea officer would have never learned about
compass dip. For that matter I am surprised you can't explain it more clearly &
accurately yourself, ST!

Fresh Breezes- Doug King

Compass dip - questions for the southern Hemisphere people.
 

Well . . it was clear to me?????

Compass dip - questions for the southern Hemisphere people.
 

Subject: Compass dip - questions for the southern Hemisphere people.
From: "Schoonertrash"
Date: 11/28/2003 18:52 Pacific Standard Time
Message-id:

Well . . it was clear to me?????




I'd be curious as to what they had to do in Australia to fix the "dip" problem,
plus, curious how they "balance" small yacht compasses to make them good, world
wide.

Compass dip - questions for the southern Hemisphere people.
 

As Doug mentioned the cost of doing that is prohibitive. Much easier to get
two compasses. When you see the need, and it will be very apparent. Switch
to the other one. Then you only have to swing the compass for correction
which is not all that difficult. Remember you now have things like GPS to
help you out. Or use a star sight for N. and S. Figure amplitude on the
sun's rising and setting to find E. and W. Sounds much more intimidating
that it really is.

MST

One day left.

Compass dip - questions for the southern Hemisphere people.
 

Subject: Compass dip - questions for the southern Hemisphere people.
From: "Schoonertrash"
Date: 11/29/2003 10:31 Pacific Standard Time
Message-id:

As Doug mentioned the cost of doing that is prohibitive. Much easier to get
two compasses. When you see the need, and it will be very apparent. Switch
to the other one. Then you only have to swing the compass for correction
which is not all that difficult. Remember you now have things like GPS to
help you out. Or use a star sight for N. and S. Figure amplitude on the
sun's rising and setting to find E. and W. Sounds much more intimidating
that it really is.

MST

One day left.


If that's directed at my response, I'd have to disagree.
Since balanced compasses are available, I'd consider it a better investment to
go for the single, potentially better compass, rather than two cheaper models
(which may end up costing about the same).
Naturally, there are always advantages to having two.....and even though it may
be unbalanced, doesn't mean it won't work.
I'd still be curious as to what they had to do to that ship compass to correct
it, as I've never heard of any problems with dip on one of these (might have
something to do with hanging the magnets well below the compass card and pivot)
Taking azimuths/amplitudes/polaris, should be a normal occurence for anyone
doing serious offshore work..... BG devising methods to get accurate ones on
many small boats, is another story

Compass dip - questions for the southern Hemisphere people.
 

We're moving soon and will be within cell phone range one more time before
heading 'way' out. I'll make a point of asking some tech questions and
report back.

MST

Compass dip - questions for the southern Hemisphere people.
 

Schoonertrash wrote:

Well . . it was clear to me?????

Massive iron deposis in Canada have nothing at all
to do with compass dip. It's only that the earths
surface is not parallel to the lines of the Earths
magnetic force. Closer to the poles, the magnetism
of the Earth pulls either the north or south pole
of the compass down more. Close to the equator,
the force is almost parallel.

You may be thinking about variation, which is
definitely affected by local magnetic anomalies
like massive iron deposits.

BTW in a couple of "around the world" sailing
books, the skipper/author talks about either
correcting for compass dip or switching compasses.
One of them is 'My Old Man & The Sea' which is a
good read all in itself; but they planned to take
three compasses with them (on a 25' boat no less)
and in the last minute rush, forgot. So they
disassembled their compass and remounted the
magnets to correct for dip. Interesting book, I
gave my father a copy.....

Fresh Breezes- Doug King

Compass dip - questions for the southern Hemisphere people.
 

DSK wrote:

Massive iron deposis in Canada have nothing at all
to do with compass dip. It's only that the earths
surface is not parallel to the lines of the Earths
magnetic force.

100% correct.

Closer to the poles, the magnetism
of the Earth pulls either the north or south pole
of the compass down more. Close to the equator,
the force is almost parallel.

Not really, the region of zero dip wanders about 12 degrees north and
south of the equator. Check out Chart 30 for this info?


You may be thinking about variation, which is
definitely affected by local magnetic anomalies
like massive iron deposits.

Dip is also affect by anolmalies.


Cheers MC

Compass dip - questions for the southern Hemisphere people.
 

The_navigator© wrote:



DSK wrote:

Massive iron deposis in Canada have nothing at all
to do with compass dip. It's only that the earths
surface is not parallel to the lines of the Earths
magnetic force.


100% correct.

I exaggerated. It's about 50%

Cheers MC

Closer to the poles, the magnetism
of the Earth pulls either the north or south pole
of the compass down more. Close to the equator,
the force is almost parallel.


Not really, the region of zero dip wanders about 12 degrees north and
south of the equator. Check out Chart 30 for this info?


You may be thinking about variation, which is
definitely affected by local magnetic anomalies
like massive iron deposits.


Dip is also affect by anolmalies.


Cheers MC

Compass dip - questions for the southern Hemisphere people.
 

"The_navigator©" wrote in message
...
....

Closer to the poles, the magnetism
of the Earth pulls either the north or south pole
of the compass down more. Close to the equator,
the force is almost parallel.

Not really, the region of zero dip wanders about 12 degrees north and
south of the equator. Check out Chart 30 for this info?

He was refering to the Magnetic Equator.



You may be thinking about variation, which is
definitely affected by local magnetic anomalies
like massive iron deposits.

Dip is also affect by anolmalies.


Dip and variation are the same phenomenon, measured on different axis.

Compass dip - questions for the southern Hemisphere people.
 

Jeff Morris wrote:

"The_navigator©" wrote in message
...
...

Closer to the poles, the magnetism
of the Earth pulls either the north or south pole
of the compass down more. Close to the equator,
the force is almost parallel.

Not really, the region of zero dip wanders about 12 degrees north and
south of the equator. Check out Chart 30 for this info?


He was refering to the Magnetic Equator.


Not as I read it he wasn't.


You may be thinking about variation, which is
definitely affected by local magnetic anomalies
like massive iron deposits.

Dip is also affect by anolmalies.


Dip and variation are the same phenomenon, measured on different axis.

What is the phenomenon you have in mind?

Cheers MC

Compass dip - questions for the southern Hemisphere people.
 

"The_navigator©" wrote in message
...


Jeff Morris wrote:

"The_navigator©" wrote in message
...
...

Closer to the poles, the magnetism
of the Earth pulls either the north or south pole
of the compass down more. Close to the equator,
the force is almost parallel.

Not really, the region of zero dip wanders about 12 degrees north and
south of the equator. Check out Chart 30 for this info?


He was refering to the Magnetic Equator.


Not as I read it he wasn't.


It was a joke, Swifty. And besides, it all depends on how you interpret "close
to the equator." From where I am, 12 degrees N or S is pretty close.



You may be thinking about variation, which is
definitely affected by local magnetic anomalies
like massive iron deposits.

Dip is also affect by anolmalies.


Dip and variation are the same phenomenon, measured on different axis.

What is the phenomenon you have in mind?


Ah, how about The Earth's Magnetic Field? Or is there something else?

Compass dip - questions for the southern Hemisphere people.
 

What is the phenomenon you have in mind?

Jeff Morris wrote:
Ah, how about The Earth's Magnetic Field? Or is there something else?

Hey Jeff! Quit poaching my bait!

Actually, I don't particularly want to reel in the Navvie©-fish this time. Too hard
to clean and they look unsavory in the pan.

DSK

Compass dip - questions for the southern Hemisphere people.
 

I was wondering 'cos most scientist wouldn't call a magentic field a
'phenomenon' that's all. I was wondering if you were maybe thinking
about solar pressure effects on the field or something like that.

Cheers Swifty.

Jeff Morris wrote:


What is the phenomenon you have in mind?



Ah, how about The Earth's Magnetic Field? Or is there something else?

Compass dip - questions for the southern Hemisphere people.
 

Tut tut. Now I'll only give you 25% correct for your statement

"Massive iron deposis in Canada have nothing at all
to do with compass dip. It's only that the earths
surface is not parallel to the lines of the Earths
magnetic force."

Cheers MC

DSK wrote:

What is the phenomenon you have in mind?


Jeff Morris wrote:
Ah, how about The Earth's Magnetic Field? Or is there something else?


Hey Jeff! Quit poaching my bait!

Actually, I don't particularly want to reel in the Navvie©-fish this time. Too hard
to clean and they look unsavory in the pan.

DSK