Need Help With ST4000+ Settings on 37C or .....

[Bob Miller]

I'm having trouble setting up my new ST4000+ wheel A/P. I would like to hear what settings anybody else is using who have a ST4000+ wheelpilot on a 37C or similar sized boat. (I do not have a rudder position sensor. I have zero rudder backlash.)First: What kind of performance did you have with the default settings?If you changed any of the default settings, what settings did you use:1. Rudder Gain2. Response3. Turn Limit4. Auto Trim5. AutoAdapt6. Any other changes?With the best combination of settings, 7. How big and how many overshoots with a 20 degree heading change in calm, no wind conditions?8. How much heading swing when locked on to a heading in calm, no wind conditions?Thanks for your help.

 

[Frank Walker]

Infinite Combinations

Bob, try a rudder gain of about 2 or 3, auto trim off, the rest factory defaults. Keep in mind that the ruder gain will have to be adjusted slightly depending on speed and sailing conditions. In calm water at cruising speed put in a 90 degree change (1 and 10) together. If the gain is correct then the boat should overshoot about 15 or 20 degrees and settle out on the new heading smoothly. If you are still having problems you might look at the fluxgate location. Ideally it should be in the roll and pitch center and free from magnetic distortions. Sometimes hard to come by, but a cood calibration swing should yield a value of 5 or less.

 

[Bob Miller]

Frank,

I've done all that. At Rudder gains of 1 thru 3 and 6 thru 9, control goes unstable, i.e. increasing overshoots until boat just jurns in a constant circle. What are your answers to my questions 7 & 8? Where did you mount the fluxgate? Did you install a rudder sensor? My autopilot goes out of control at anything larger than a 20 degree turn. My compass swing was a "3".

 

[Frank Walker]

Handlebars on backwards.

Bob, first I have a Hunter 30 so the dynamics might be slightly different. For small heading changes of 20 degrees the overshoot is probably on the order of a few degrees. Calm water, straight and level the heading swing is say +- 1 degree with response set on 2 and +- 2 degrees with response set on 1. Autohelm response is essentially dead band. Are you sure that your control directions are set correctly. ie when the bow swings to stbd does the AP try to move the rudder for a turn back to port. Make sure that autotrim is set to off or zero, I do not remember any autoadapt settings. I do not have a rudder feedback sensor in my system, with tight steering you should not need one. The turning sense is one of the parameters that you set up in the initial dockside testing.

 

[Sanders LaMont]

fluxgate location

I inherited mine installed and working, but did read up on the fluxgate location. If I recall the termonology right, it is to be as near the centerline as possible, away from metal/electrical sources.The previous owner set it up underneath the nav station, attached to the bulkhead, which seems to be an acceptable compromise. When it breaks, I am in trouble...Sanders

 

[Bob Miller]

Sanders,

Can you give me some of the settings that your autopilot is set to and a measure of the quality of control you get? i.e, can you answer my questions? I need data to pass on to Raymarine to show them the unit I have is bad. Thanks.