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Simrad NAC 2 Evo 3 Autopilot issues

Old 06-19-2018, 01:35 PM
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Default Simrad NAC 2 Evo 3 Autopilot issues

Hi,

I've got a Pursuit 3070 Offshore. I have Simrad Evo3, the NAC2 computer, Precision 9 Compass, and the Rup80 motor. I recently installed the NAC2 and have passed the dockside and seatrial commissioning. I followed the onscreen directions for the seatrial and the machine executed a number of S turns at low speed.

I've only begun trying to use it, but I am noticing that it does not hold course and I'm wondering if there are any suggestions. So far I've tried to navigate to a waypoint with it and it drifts off course and does not correct. I've also tried to maintain a heading in auto and it also drifts off course.

Any advice on things to check or tweak is appreciated.
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Old 06-19-2018, 01:51 PM
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Same here....
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Old 06-19-2018, 07:26 PM
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Try the auto-tune at faster speed than recommended and report back.
I usually get barely on plane... 15mph or so.
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Old 06-20-2018, 06:00 AM
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MikeBador,

Do you mean repeat the seatrial tune at a higher speed? Or is there another auto tune feature?
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Old 06-20-2018, 06:06 AM
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I've just upgraded from AP24 to AP44 (complete pilot) on one of my boats and have done the dockside. I will do the seatrial in near future, I will report back how it goes.
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Old 06-25-2018, 12:56 PM
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I haven't had a chance to sea trial tune at a higher speed yet, but I'll report when I do. CME, the heading sensor is accurate to my course as well as overlay. The Navigation feature on autopilot is supposed to use the GPS and that's not working correctly either.
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Old 07-17-2018, 07:28 AM
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Sorry to take so long to get back. I tried auto tuning at planning speed around 18mph and I reset the 0 rudder setting. I'm still having issues holding course.
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Old 07-17-2018, 09:27 AM
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CME
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All AP's essentially work on two modes.....

heading hold (pressing Auto)
"goto" navigation (using a chart plotter for the waypoint goto data)

The best way is to trouble shoot is as a heading hold FIRST. If it don't work for squat, then your issue is AP centric. All things being equal, thats assuming the gps, heading sensor, not having air in the lines, and software is up to date---and are all installed correctly. After that, then you should be fine with all the brands. So, make damn sure the heading is accurate (installed in the right spot with little to NO deviation), there is NO AIR in the lines....and that will solve 98% of AP issues. DO NOT MOVE ONTO AP FEATURES WITH PLOTTER UNTIL THE HEADING HOLD SCENARIO IS PERFECT.
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Old 08-27-2018, 09:20 AM
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It took awhile, but I've got the heading hold fixed. I ended up having to do everything at once, but it is finally working at 50%. I re-calibrated the precision 9 compass. I reset the zero rudder setting. I redid the dockside commissioning. This time the big difference is that when asked if I saw the motors turn to starboard I said yes when I saw the slightest movement. Before I had waited to see a decent movement. I then performed the sea commissioning at just under planning speed. At the end of all this the system works well on an auto heading hold. I have one final issue that I can't figure out. My heading shown in my data field and on the autopilot screen is dead nuts on with my gps course over ground, which is great. However, on my navigation screen, the wheel compass is 20 deg off. So is the heading data sent to my VHF. So it seems there are two different heading data items in the system. And now, when I try to navigate to a waypoint with autopilot, it uses the wrong heading and wants to take me 20deg off. No bueno. So I have half a working autopilot that I can't use to navigate to waypoints and follow routes etc...

Any advice on how to get these two headings to align?

Thanks!
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Old 08-27-2018, 01:28 PM
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Do you have anything metallic near the autopilot heading sensor. Mine operates well on local trips but on Bahamas trips when I have the console loaded with stuff I have noticed it gets off so I assume its pretty sensitive to interference.
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