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System con guration | AP70/AP80 Operator Manual
Manual tuning
1. Stabilize the vessel on a heading, and then select AUTO mode
2. Set the speed as close to cruising speed as possible
3. Activate the Quick menu by pressing the MENU key
4. Se
le
ct Rudder and adjust according to the description below
5. If required, adjust slightly Counter rudder
Rudder
This parameter determines the ratio between commanded rudder and the heading error. The
higher rudder value the more rudder is applied.
A. The the value is set too high. Steering becomes unstable and often the overshoot will
increase
B. Rudder is too small. It will take a long time to compensate for a heading error, and the
autopilot will fail to keep a steady course
AB
• Range: 0.05 - 4.00
• Default: Defi ned by system based on boat type and length
Counter rudder
Counter rudder is the amount of counteracting (opposite) rudder applied to stop the turn at
the end of a major course change.
The settings depends on vessel’s characteristics, loaded/ballast conditions and rate of turn.
• If the vessel has good dynamic stability, relatively small settings will be suffi cient
• An unstable vessel will require high settings
• The greater the vessel’s inertia, the greater value will be required
Increasing counter rudder settings may result in some higher rudder activity also when
steering a straight course.
The best way of checking the value of the Counter rudder setting is when making turns.
The fi gures illustrate the eff ects of various Counter Rudder settings;
A. Counter rudder too low; overshoot response
B. Counter rudder too high; sluggish and creeping response
C. Correct setting or counter rudder; ideal response
A
C
B
Perform various course changes and observe how the boat settles on the new heading.
Start with small changes, 10-20 degrees and proceed with bigger changes, 60-90 degrees.
Adjust Counter rudder value to obtain best possible response as illustration C below.
Note: As many boats turns diff erently to port versus starboard (due to propeller rotation
direction), do the course changes in both directions. You may end up with a compromise
setting of Counter rudder that gives a little overshoot to one side and a bit sluggish response
to the other.
• Range: 0.05 - 32.00
• Default: Defi ned by system based on boat type and length
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