Raymarine autopilot control unit - Manual (Page 91)

74 ST7000 Plus Autopilot Control Unit Owner’s Handbook
Further Heading Alignment Adjustment
You should always check the compass alignment after swinging the
compass. However, once the initial deviation correction procedure has
been performed, you can make adjustments to the alignment as often
as you wish, without swinging the compass again.
Although the compass deviation correction procedure removes most
of the alignment error, you will probably be left with a small error (of
the order of a few degrees) that will vary depending on the heading.
Ideally, you should check the heading reading against a number of
known headings, plot a deviation curve, and determine the heading
alignment value that will give the lowest average alignment error.
This value can then be entered on the Heading Alignment screen, as
described above.
If the average heading error is more than 5°, you should perform the
compass deviation correction procedure again.
Checking Autopilot Operation
Having calibrated the compass the following procedure is
recommended to familiarise yourself with autopilot operation:
1. Steer onto a compass heading and hold the course steady.
2. Press auto to lock onto the current heading. A constant heading
should be achieved in calm sea conditions.
3. Use the -1, -10, +1 and +10 keys to alter course to port or
starboard in multiples of 1° and 10°.
4. Press standby and disengage the autopilot to return to hand
steering.
Checking the Rudder Gain
The factory set rudder gain level will provide stable control for initial
sea trials. However, vessels can vary widely in their response to the
helm, and further adjustment to the rudder gain may improve the
autopilot’s steering characteristics.
It is particularly important that the rudder gain is set correctly on high-
speed craft. Incorrect adjustment will lead to poor steering
performance and is a dangerous condition at high speed.
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