Furuno NAVpilot 711C, Operator'S Manual

Page: 150 / 176

7. INITIAL SETTINGS
7-38
[ Counter Rud. ]: 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 the 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
before settling in the new course, increase the counter rudder setting.
7.11.2 Trim gain
The NAVpilot continually monitors the boat's trim in order to keep the trim sensitivity
optimum. A lower setting is common because boat's trim usually does not change
quickly. A large number changes the trim compensation value more frequently. Too
high of a setting may result in the following problems.
• Trim sensitivity is over-affected, resulting that a trim appears in both port and star-
board directions alternately.
• Trim compensation mechanism responds to the yawing, resulting in more serious
oscillation of ship's heading.
Note: Trim gain is not available with Fantum Feedback
™
.
To automatically set the trim, do as follows:
1. Rotate the Course control knob to select the current setting for [Trim Gain] from
the [Parameter Setup] menu then push the knob.
2. Rotate the Course control knob to select [Auto] or [Manual] then push the knob.
3. For [Manual], do as follows:
1) Rotate the Course control knob to select the current setting value and push
the knob.
2) Rotate the Course control knob to set a value then push the knob (setting
range: 1 to 20).
The default value is automatically calculated according to length of your boat,
entered on the [Ship’s Characteristics] menu.
Counter rudder:
small setting
Counter rudder:
proper setting
Large course error
Intended
course
The counter rudder feature functions to smoothly
return ship's heading toward intended course.
Fast
Heavy
High
Slow
Light
Low
Speed
Load Condition
[Counter Rud.]