Autohelm acting erratic

[WTunnessen]

The Raymarine ST 4000 autohelm on Gaulois began acting very erratic under our last sail.

Within about 30 seconds of being engaged and put into "auto" it began to first turn hard to starboard and then very hard to port - basically spinning the wheel - before I disengaged it.  This happened repeatably.   The clutch was engaged and does not seem to be stuck.

This occurred under power in claim conditions.  The compass reading on the autopilot matched the GPS  & +/- compass.

Turning the power on / off to the unit did not correct the problem.

Initially, it was working fine - under power and holding course while I raised the sails.  Also held the course under sail.   

The owner manual does not offer any suggestion on how trouble shoot this to this issue.  I wonder if I should try resetting the rudder gain.

Wondering if anyone has experienced this or it it is a symptom of something else.

I have not called Raymarine yet since I figured I would check here first.  Usually if find answers to my questions on the forum! 

[Stu Jackson]

The solution to this is to completely recalibrate the unit.

Start over.  Ya get to do the donut circles again.

[RV61]

I second Stu's solution.

[Ken Heyman]

By any chance did you have any electrical or magnetic interference near the unit. Years ago I had similar problems caused by a protable radio too close to the autohelm . I moved the radio and all was fine. Another sailor, because he had a gillion candlepower spotlight triggered the same anomaly. That aside recalibrate-- although I didn't think lack of calibration would cause or recalibration correct those kind of symptoms.

Ken

[Terry Forshier]

I had an autohelm 3000 that did the same thing. Back then you could call in and get advice because they were still making these. They told me the mother board was fried and to send it in and they would replace it. They did. Now that is not an option. You might find a replacement part on ebay for the control unit. ?? Terry

[sail4dale]

Yep, I had that problem for some time ... finally I moved my fluxgate compass and the problem went away.  It was in the wet locker near the floor and I moved it up to the top of the closet.  Presto .... all OK

[Peter Lewis]

It doesn't even take electrical interference to cause the problem-  the first time we took out our boat, the autohelm 4000 tried to send us all over the place.  Moving the canned goods to another storage area fixed the problem immediately.  Now using the storage area near the compass for wine.

[Roland Gendreau]

Our autohelm also started acting erratically during our shakedown cruise this weekend.

-It would engage in auto, control normally, then it would randomly turn 20-30 degrees to port or starboard, then slowly bring it back to course.

-When I hit the -1 key, the wheel would move a small amount to port, as usualy. When I hit the +1 key, the wheel would move about 10 degrees to starboard.

-When in auto, it would sometimes just stop controlling as if the plug to the actuator had become disconnected (which it had not).  I would put it in standby then auto and sometimes it would resume control, sometimes not.

I put the unit in Calibrate mode and verified that every setting was correct.

I'll call Raymarine, but I am afraid they no longer support repairs to the 4000.

Roland Gendreau
Gratitude#1183

[Ken Heyman]

Other than electrical interference, I had a problem once with low voltage causing a malfunction.  You may want to check this.

Ken