Sperry Marine 4914-CA, Operation, Installation And Service Manual

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Correlation of heading error and latitude (0.4° x sec. lat.)
As shown in figure 1-11, the heading error is increasing with higher lati-
tude (correlation of dynamic heading error 0,4° x secans of latitude).
Due to physical principles, this correlation is a general system imma-
nent attribute of any spinning mass gyrocompass as a north seeking
system.
As a result, the heading information of the gyrocompass may become
unstable/unreliable resulting in possible deviation, when navigating in
polar waters. For safe steering of the vessel in polar waters, the heading
information of the gyrocompass may therefore not be used and heading
information of a GNSS compass be preferred instead.
`^rqflk Risk of damage to the gyrosphere through shut-down
A shut down of the NAVIGAT X MK 1 system, while the vessel is navigat-
ing, will damage the gyrosphere, as the gyrosphere is only self protected
against physical damage, as long as the system is running.
NEVER shut down the NAVIGAT X MK 1, while the vessel is navigating.
A shut down of the NAVIGAT X MK 1 system for good reason is only pos-
sible when the ship is NOT navigating.
2,5
2
1,5
E
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o
r
(d
e
gr
e
e
s)
Error
1
0,5
0
0 10 20 30 40 50 60 70 80 90
La!tude (degress)
kçíÉ Sperry Marine requires to NOT shut down the NAVIGAT X MK 1 system
as long as the vessel is navigating, even when operating in polar waters
with possible unstable/unreliable heading.