I have an older ST 4000 on my C34. I understand there is was a change in the way it is calibrated, I think I have the correct button pushing sequence. My problem is that I can't get the ST 4000 compass to align with the ship's compass. I have tried a couple times, enter the cal mode, do circles until it the error is nulled. If I remember correctly it was about 8 degrees. Then align the compass and leave the cal mode. The compass appears to align correctly until I leave the cal mode then it resets itself 90-100 degrees off ships head. When in use the autopilot works normally, the compasses just don't align. Is this a case of operator error, not knowing all the tricks, or do I have a problem that hasn't fully manifested itself yet. This is driving me nuts. Any help very much appreciated.
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Michael
Calibrate ST 4000
Ken; I believe that the 2 circles just detects local deviation (metal objects on your boat), and adjusts the flux gate compass for that influence. The way I understand it the ships compass is a compass, and the AP's fluxgate is a compass, i.e. two separate compasses. They should be within a couple of degrees of each other. If they aren't then you probably need to have the ships compass swung to correct for the metal on the boat. You might also use a hand held bearing compass (away from the helm area) to determine which one is actually off. I hope this helps. Mike
Ken; I believe that the 2 circles just detects local deviation (metal objects on your boat), and adjusts the flux gate compass for that influence. The way I understand it the ships compass is a compass, and the AP's fluxgate is a compass, i.e. two separate compasses. They should be within a couple of degrees of each other. If they aren't then you probably need to have the ships compass swung to correct for the metal on the boat. You might also use a hand held bearing compass (away from the helm area) to determine which one is actually off. I hope this helps. Mike
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Ken Juul
More Info
I agree with your assessment. I feel that the ships compass is within a couple of degrees of being correct. I've compared the compass to gps courses and compared a couple of sightings against the charts. The flux gate appears to correct for the boat's inherent deviation, but then in step 2 the flux gate must be aligned with the ships compass. That is where the disconnect comes.
I agree with your assessment. I feel that the ships compass is within a couple of degrees of being correct. I've compared the compass to gps courses and compared a couple of sightings against the charts. The flux gate appears to correct for the boat's inherent deviation, but then in step 2 the flux gate must be aligned with the ships compass. That is where the disconnect comes.
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Michael
ST 4000 Calibration
Ken; I will read the manual on my ST4000 AP this evening, to see if I can understand what you are talking about. I do not remember any aligning procedure during calibration. I will respond later this evening (PDT), or in the A.M. Mike
Ken; I will read the manual on my ST4000 AP this evening, to see if I can understand what you are talking about. I do not remember any aligning procedure during calibration. I will respond later this evening (PDT), or in the A.M. Mike
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Bill Boudreau
Hold Down STANDBY
The autopilot does not know what orientation you have hung the compass or on which bulkhead. It could originally be up to 180 degrees off. After the Linearization and alignment you have described, you need to HOLD in the STANDBY key to exit calibration and save the changes to the setting you have just made. I hope this helps you out.
The autopilot does not know what orientation you have hung the compass or on which bulkhead. It could originally be up to 180 degrees off. After the Linearization and alignment you have described, you need to HOLD in the STANDBY key to exit calibration and save the changes to the setting you have just made. I hope this helps you out.
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Jim Hague
I have similar problem with ST4000
Mike, I have a similar problem with my non-plus ST4000. I swing, align and properly exit cal. Everything is ok for 1 to 45 minutes and then it jumps out of alignment by about 100 deg. If I leave it there and just set new desired heading all is well (except the ST4000 indicated heading is off by 100 deg). If I re-swing and re-align I get another 1 to 45 minutes before it again jumps out. Bill, the flux gate is mounted to an athwartship bulkhead with dome facing forward and mounting screws pointing aft. After swinging, but before alignment, it indicates about 100 deg error. I was expecting to see approximately 0 or 180 deg.
Mike, I have a similar problem with my non-plus ST4000. I swing, align and properly exit cal. Everything is ok for 1 to 45 minutes and then it jumps out of alignment by about 100 deg. If I leave it there and just set new desired heading all is well (except the ST4000 indicated heading is off by 100 deg). If I re-swing and re-align I get another 1 to 45 minutes before it again jumps out. Bill, the flux gate is mounted to an athwartship bulkhead with dome facing forward and mounting screws pointing aft. After swinging, but before alignment, it indicates about 100 deg error. I was expecting to see approximately 0 or 180 deg.
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Dakota Jim Russell
But the GPS
I had a similar problem and kept working on the 4000. Then one day I was playing around with my GPs and realized tht the 4000 was fine, it was the boat compass that needed major adjustment. What is the old saying . . . if you have one watch you know what time it is, if you have 2 watches, you never will know. . . . . Now if you have three compasses, take a large iron bar and place it in front of the compass, you can take the standard diviation between the three, take the square root of that and multiply it by the optimal boat speed, and after adjust the compasses to point toward the front of the boat . . . . if you think this paragraph is really serious, then I have one "I gatch ya" on you. <grin>
I had a similar problem and kept working on the 4000. Then one day I was playing around with my GPs and realized tht the 4000 was fine, it was the boat compass that needed major adjustment. What is the old saying . . . if you have one watch you know what time it is, if you have 2 watches, you never will know. . . . . Now if you have three compasses, take a large iron bar and place it in front of the compass, you can take the standard diviation between the three, take the square root of that and multiply it by the optimal boat speed, and after adjust the compasses to point toward the front of the boat . . . . if you think this paragraph is really serious, then I have one "I gatch ya" on you. <grin>
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Jim Hague
Reply to Dakota
Glad you found and fixed your problem but mine is not similar. We are talking about an unexplained 100 deg shift in indicated ST4000 heading. ,By the way if the ST4000 is engaged when it shifts it attempts to re-establish the heading by going helm hardover. Also, I previously swung my steering compass and confirmed its accuracy using a pelorus and solar azimuth calculations.
Glad you found and fixed your problem but mine is not similar. We are talking about an unexplained 100 deg shift in indicated ST4000 heading. ,By the way if the ST4000 is engaged when it shifts it attempts to re-establish the heading by going helm hardover. Also, I previously swung my steering compass and confirmed its accuracy using a pelorus and solar azimuth calculations.
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Ken Juul
Thanks
Unlike Jim's problem my ST4000 heading shifts immediately after leaving the Cal mode. I will try holding the button down longer the next time I try. Maybe that is what I'm doing wrong. Thanks for the help.
Unlike Jim's problem my ST4000 heading shifts immediately after leaving the Cal mode. I will try holding the button down longer the next time I try. Maybe that is what I'm doing wrong. Thanks for the help.
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Dakota Jim Russell
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