Autohelm 4000 compass placement

[Rick White]

I've installed an Autohelm ST4000 on my 1986 34' and cannot maintain a straight course even while motoring in calm conditions. The autopilot varies by 10 degrees each side of the heading in a zig zag manner. I've reduced gain and response and this is the best it will do. Raytheon said to move the compass which I've mounted under the aft berth between the engine compartment and the rudder post. Can anyone suggest a better location where they have had success?

 

[Dick Carey]

Autohelm 4000 calibration

Rick,I can't offer a suggestion on a better location, but after I calibrated my 4000 (actually MIS-calibrated it), it also wandered back and forth in a zig-zag pattern as you described. I went thru the entire calibration menu again correcting my mis-inputs and it then worked fine. It's worth a try before trying to relocate the compass module.Regards,Dick CS/V Puffin ('90 H-33.5)

 

[Clyde Lichtenwalner]

Galley

Mine is mounted high on the aft bulkhead of the galley- above the dish stowage area. It has worked for the past seven years or so, but it likes to steer a perfect course ten degrees to the right of the set course. Autohelm says that my older unit should have a software upgrade, but I have not gotten around to removing the head unit to be sent back. I simply compensate by setting a course ten degrees left of where I want to go. You want to place the compass where it will see little or no influence from materials stowed near by. Could gear stowed in the starboard locker or aft birth be influencing the compass? Does this occur at all speeds? I take it the yaw never dampens even after ten or fifteen minutes of operation.My gut feeling is that this is a control problem, not a compass location problem.

 

[Steve Feinsilver]

autohelm gremlin

I had exactly the same problem with autohelm 4000 on my h33.5 a few years ago (I now have h410). After reinstalling the fluxgate compass a few places, including under cabin sole (on midline, aft of knot meter impeller), and in starboard lazarette, as per Autohelm's advice, it finally turned out to be a faulty control head (the brains of the unit). Autohelm replaced under warranty and it worked great ever since. (And my old boat is still out there somewhere with two fluxgates installed, because they sent me a second one and never asked for it back)

 

[Joe O]

Same thing too!

I had the same problem (zig zags). I then set the rudder gain to "2" and response to "2" and now it works fine. It still has problems holding a course during wind gusts. I'm thinking of installing the optional rudder transducer. My compass was replaced and had no affect on the problem. It is located under the galley sink just above the upper chart tube and on the centerline.Good Luck!JoeO