Page 117 - Electronic Navigation Cyber Book

the speed log as any error in the log speed will reflect in the auto-pilot
system.

The system also allows the users to manually input the speed, when
doing so it is important to set a value as close as possible to the actual
speed of the vessel.
7. Weather Conditions

Rough weather and hostile sea conditions have adverse effects on the
performance of the auto-pilot. Uncontrolled yawing of the ship can
result in excessive rudder movement. Modern auto-pilot system has
Weather control option in which the system automatically adjusts the
setting to adapt to the changing weather and sea conditions. It also
provides an option for the user to manual set a specific value.
8. Gyro Compass

The Auto-Pilot system is functionally dependant on the Gyro
Compass. If there is any error or fluctuation in the gyro heading, there
will be an equivalent change in the course steered. In worse cases,
when gyro fails, the system will lose track on its heading and will be
unable to steer the required course.

In any case of emergency, power blackout or gyro failure the system
should be immediately changed over to Manual mode and use the
helm to steer the course using Magnetic compass.

9. Important Alarms and signals
Apart from off course alarm, an auto pilot must be integrated with:

a. Failure or reduction in power alarm, which will sound in the event of
auto pilot failure or in case when there is reduction in the power supply
to heading control or monitoring system

b. Sensor status monitoring: If any of the sensors in the auto pilot
system fails to respond, it should be indicated by an audible alarm in
the monitoring system

c. Heading monitor: If the ship is required to carry two independent
compasses, a heading monitor to track the current heading
information by independent heading sources must be provided. An
audio-visual alarm both to be provided if the heading information in
use diverts from the second heading source beyond a set limit. It
should also be provided with clear indication of actual heading source.

© 2018 Digital Galaxy Index 117