Simrad AP20 Autopilot
102
20220505H
The two most important parameters that determine the
performance of the automatic steering are Rudder and Counter
Rudder.
Rudder
sets the rudder gain which is the ratio between the
commanded angle and the heading error ( P-factor).
•
Too little Rudder and the autopilot fails to keep a steady
course.
•
Too much Rudder gives unstable steering and reduces speed.
•
Low speed requires more rudder than high speed.
Counter Rudder
is the parameter that counteracts the effect of
the boats turn rate and inertia. For a short time period it is
superimposed on the normal rudder response as provided by the
Rudder parameter. It may sometimes appear as if it tends to
make the rudder move to the wrong side (counter rudder).
The best way of checking the value of the Counter Rudder
setting is when making turns. The figures illustrates the effects
off various Counter Rudder settings.
Too little rudder
New course
Too much rudder
Course to steer
Course to steer
Counter rudder setting too
low, overshoot response
New course
Counter rudder setting too high,
sluggish and creeping response