Raymarine ST4000+ GPS Receiver User Manual


 
Chapter 6: Setting-up the ST4000+ 99
6 Setting-up the ST4000+
Step 3 - Adjust the rudder damping
If you have connected a rudder position sensor to a wheel drive
autopilot system, adjust the rudder damping. Check the rudder
damping when your boat is moored dockside:
press
auto and then +10
if the helm overshoots and has to drive back, or starts to hunt back
and forth, you need to increase the damping level
adjust the damping one level at a time, and always use the lowest
acceptable value.
Step 4 - Adjust the rudder gain
The next step is to adjust the rudder gain, as described on page 96.
Step 5 - Adjust the AutoTrim setting
When there is a change in boat trim and/or sea conditions the boat will
change course. The autopilot will immediately apply rudder to
correct for this. However, it may not apply sufficient rudder to
overcome standing helm and bring the boat fully onto course. Over a
period of minutes the AutoTrim function will apply more rudder until
it achieves the desired course.
Increasing the AutoTrim level reduces the time the autopilot takes to
get back to the correct course. But if the AutoTrim level is too high,
the boat will snake around the desired course.
You should gain experience with your autopilot before attempting to
adjust the AutoTrim setting. On sail boats, you can only evaluate the
effect of AutoTrim while under sail.
If you need to change the setting, increase the AutoTrim one level at a
time and use the lowest acceptable value:
decrease the AutoTrim level if the autopilot gives unstable course
keeping and the boat snakes around the desired course
increase the AutoTrim level if the autopilot hangs off course for
excessive periods of time
Step 6 - Further adjustments
You may need to repeat these steps over a range of sea conditions and
different headings to achieve a good overall performance.