Installation Instructions

3. INITIAL SETTINGS
3-30
The following illustrations show how many degrees the NAVpilot steers the rudder in order
to nullify 4 degrees of course deviation with various settings of the rudder gain.
Set rudder gain so that the boat does not make frequent yaw. The figure shown below
provides general guidelines for setting rudder gain.
[COUNT RUDDER]: If the boat is heavily loaded, the heading could change excessively
because of inertia. This phenomenon causes the vessel to "overshoot" the intended
course. If this happens, the NAVpilot will steer the rudder to the opposite side and the
heading will turn in opposite direction excessively again. In an extreme case the heading
oscillates several times until it finally settles in the new course. An adjustment known as
"counter rudder" prevents this kind of oscillation.
Counter rudder is usually not required for small boats. When your boat zigzags a lot be-
fore settling in the new course, increase the counter rudder setting.
Rudder gain = 1° Rudder gain = 2° Rudder gain = 3°
Rudder an
g
le = 4° x 1=4° Rudder an
g
le = 4° x 2=8° Rudder an
g
le = 4° x 3=12°
4°
4°
4°
Speed
Sea State
Load Condition
RUDDER GAIN
Fast
Calm
Light
Low
Slow
Rough
Heavy
High
Intended
course
Large course error
The counter rudder feature functions to smoothly
return ship's heading toward intended course.
Counter rudder:
small setting
Counter rudder:
proper setting
Speed
Load Condition
COUNTER RUDDER
Slow
Light
Low
Fast
Heavy
High