Autopilot Issues AP44/NAC-3/Zues T8

[GLH71]

Hi All,

I'm new to the forum. I've recently had a new autopilot installed on my Tartan40. The new system consists of the NAC-3 Core pack from Simrad, AP44 controller, and B&G T1-12v ram. I already owned a Zeus T8 chart plotter.

I've gone through all the calibration steps and the autopilot works great in that it will correctly hold a heading or relative wind angle. The only challenge is that when the autopilot is on, I can only make course adjustments via the AP44 controller. The rotary knob or touch screen on the Zeus T8 chart plotter will allow me to adjust my heading to starboard, but if I adjust my heading further to port than the heading I'm currently sailing, the boat will turn hard to starboard in order to find the new heading. To clarify, if I'm sailing north and turn to a heading of 30 degrees, everything is fine. If I use the plotter to turn back from 30 degrees to 20 degrees before the boat has made it to 20 degrees, the wheel will turn back to port. But if I turn to port past my current heading, the wheel will turn hard to starboard to find the new heading. It will essentially turn 355 degrees to starboard in order to go 5 degrees to port.

I've just upgraded the software in the chart plotter and still have the same problem. I'm at a loss as to what is going on. It seems like it's something in the chart plotter software, as everything works great if I use the AP44 to make adjustments. Curious if anyone has encountered this issue or has any advice?

Thanks,
Garrett

[GLH71]

Hi All, I actually just found the answer deep in the recesses of the B&G website. The NAC-3 computer is not compatible with Zeus or Zeus Touch. You must have Zeus2, Zeus3, or Vulcan in order to get complete control of the autopilot via your MFD. So if you’re upgrading your autopilot to a NAC-3/NAC-2 computer and have an older plotter, you can install a dedicated control head as a work around. Guess I’ll be asking for a Zeus3 12 inch display for Christmas.

Also, attached is a picture of the grid I found on the B&G website that details the compatibility of various control and display units with the different computer units. Hope it helps someone out there waste less time than I did.