Simrad AP25, Manual, Page: 120 / 172

Simrad AP25 Autopilot
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20221495F
compass to a different location. The local field angle will aid you
to the local interfering magnetic object. See drawing.
Lubber line Lubber line
Magnitude of local
field in % of
earth’s magnetic
field.
Direction of local
field with respect
to lubber line. It
can also be on the
reciprocal.
Note !
In certain areas and at high latitudes the local magnetic
interference becomes more significant and heading errors
exceeding ±3° may have to be accepted.
Compass Offset
After calibration, also check the compass readout against a
known reference, a compensated compass or a bearing. If the
reading has a fixed offset, proceed to next menu item by pressing
STBD button or return to STANDBY mode by pressing the
STBY button.
Note !
Offset correction is always performed after the calibration. If
you use COG as a reference for the offset remember it has to be
a magnetic reading.
The compass OFFSET feature allows you to correct for a fixed
heading offset. This offset may be present as a result of the
compass being installed with a lubber line offset or if a fixed
offset remains after the calibration procedure has been
completed. The value of compass offset is specific to the heading
sensor that is selected at the time the offset is entered. This
means that you can have individual offsets for each compass
installed.