Simrad 000-15567-001, Instruction Manual

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Simrad GC80/GC85 Compact Gyro Compass
54
20221511 / D
5.8 Balancing the Horizontal ring
After the compass has been running continuously for at least 2
hours, the horizontal ring should be adjusted.
8
Locate the reference level tool on the horizontal ring, and
check that the level bubble is /-10 minutes from
the center. Each division equals 2 minutes.
9
If the level bubble not is within this limit, add or remove
weights from the horizontal ring until it is leveled.
Note!
It is important that the total number of weights on the horizontal
ring is as few as possible.
10
Let the compass run for at least 20 minutes before the
level is rechecked and eventually confirmed.
Caution
If the horizontal ring is tilted more than +/-10’, a bearing error
will be generated.
Adjusting True heading
After the GC80/85 is settled, the gyrocompass has to be
calibrated against an external reference, e.g.:
- a known target
- astronomical observation
- the heading of the pier or quay the vessel is moored to
- two fixed points on the chart that the vessel is sailing
between
The observation period for the heading difference should be as
long as possible.
If there is any difference between the gyro bearing and the
confirmed external reference that not can be corrected by
adjusting the mechanical location of the master compass, an
offset value may be inserted in the GC80. This value is entered
by using the Extension menu as follows:
1
Activate the Extension menu by pressing and holding the
SET
button and the
ACK/ENT
buttons simultaneously for
at least 3 seconds.
- Main category
A-1
will be displayed.
+/-10 minutes