Counter Rudder; Checking; Adjusting; Autotrim - Raymarine SPX-5 Installation & Setup Manual

Chapter 3: Commissioning & setup

Counter rudder

Counter rudder is the amount of rudder the SPX-5 Wheel system applies to try to
prevent the boat from yawing off course. Higher counter rudder settings result in more
rudder being applied.

Checking

To check the counter rudder setting:
1. Set RESPONSE to level 5 (see page 41 ).
2. Motor your boat at cruising speed in clear water.
3. Press auto to switch the SPX-5 Wheel system to Auto mode, then make a 90°
course change:
• When gain and counter rudder are both set correctly, the boat performs a
smooth continuous turn with minimal overshoot.
• If the counter rudder is too low, the boat will still overshoot.
• If counter rudder is too high, the boat will 'fight the turn' and make a series of
short, sharp turns: this results in a very 'mechanical' feel as the boat changes
course.

Adjusting

To adjust the counter rudder:
1. Access the COUNT RUD screen in Dealer calibration. (see page 53 )
2. Use -1 or +1 to adjust the counter rudder.
3. Press and hold standby for 2 seconds to save the changes.
4. Press auto to check the SPX-5 Wheel system performance in Auto mode.

AutoTrim

You may also wish to adjust the AutoTrim setting. AutoTrim determines how quickly
the SPX-5 Wheel system applies 'standing helm' to correct for trim changes, caused,
for example, by changes in the wind load on the superstructure, or an imbalance of
engines.
Increasing the AutoTrim level reduces the time the SPX-5 Wheel system takes to get
back onto the correct course, but makes the boat less stable. If the SPX-5 Wheel
system:
• Gives unstable course keeping and the boat 'snakes' around the desired course,
decrease the AutoTrim level.
• Hangs off course for excessive periods of time, increase the AutoTrim level.
Adjusting
Before attempting to adjust the AutoTrim setting, ensure you have sufficient
experience using your SPX-5 Wheel system.
If you need to adjust AutoTrim, go up one level at a time and use the lowest acceptable
value. The range of settings is from OFF (no trim correction) to 4 (fastest trim
correction).
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