Simrad AP70 Installation Manual download pdf (Page 63)

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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

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

• 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

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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Simrad AP70 Installation Manual Page 63