Should be self-explanatory:
http://www.straightdope.com/columns/070112.html

Apologies for the near-sailing related content.

-signed- Injun Ear (formerly known as Eagle Eye)

wrote:
Should be self-explanatory:
http://www.straightdope.com/columns/070112.html

Apologies for the near-sailing related content.

-signed- Injun Ear (formerly known as Eagle Eye)


Deviation is the difference from magnetic north and north shown on a
boats compass due to magnetic influences induced by the boat, not the
shifting of the magnetic poles injun ear.

Shifting of the magnetic field is known as Variation.

You would be better of getting the latest local variation and updating
the local variation listed on the compass rose on your charts.

Joe

Should be self-explanatory:
http://www.straightdope.com/columns/070112.html



Joe wrote:
Deviation is the difference from magnetic north and north shown on a
boats compass due to magnetic influences induced by the boat, not the
shifting of the magnetic poles injun ear.

Shifting of the magnetic field is known as Variation.


Very good Joe.

Did you read the whole article? Or just the easy words?

Dip angle is changing too, which is why I said a new dev card would be
a good idea. When was the last time you did this, Joe? Steel boats have
big problems with magnetic compasses.


You would be better of getting the latest local variation and updating
the local variation listed on the compass rose on your charts.


What do you do when variation reaches 180 degrees?

-signed- Injun Ear (formerly known as Eagle Eye)

wrote:
Should be self-explanatory:
http://www.straightdope.com/columns/070112.html



Joe wrote:
Deviation is the difference from magnetic north and north shown on a
boats compass due to magnetic influences induced by the boat, not the
shifting of the magnetic poles injun ear.

Shifting of the magnetic field is known as Variation.


Very good Joe.

Did you read the whole article? Or just the easy words?

I learned TVMDC when you were still putting baby ruths in your diaper

Dip angle is changing too, which is why I said a new dev card would be
a good idea. When was the last time you did this, Joe? Steel boats have
big problems with magnetic compasses.


Sure they do Injun.. You're an expert right?


You would be better of getting the latest local variation and updating
the local variation listed on the compass rose on your charts.


What do you do when variation reaches 180 degrees?

Work backwards.

Joe

-signed- Injun Ear (formerly known as Eagle Eye)