Raymarine ACU400 autopilot tracks parallel to track

[AllenRbrts]

Looking to see if somebody has had a similar issue or thoughts.

I have a Raymarine system with ACU400 autopilot, P70 head and two Axiom MFDs. System has been installed for many years and has worked well. A month or so ago I noticed the XTE was consistently 100' to the starboard instead of less than 10' off of the track it would normally be. If the XTE is cleared, system turns to starboard until it gets 100' starboard of the new track and then parallels from there. It will do a great job of following a track with wind and current, just 100ft to starboard. I have repeated this with both MFDs with the other turned off, so pretty sure they aren't the cause. I have done a factory reset on the ACU400 and then a new commissioning. That seemed to move the distance out to 120', but didn't fix the problem. All Raymarine components running current version of the software.

Thoughts?

[AllenRbrts]

Here is a follow up. I chatted with Raymarine a couple of times and it had them scratching their heads. They did make a suggestion which lead to the cause. They suggested turning off all third party equipment which in my case was a Vesper Cortex AIS. That turned out to be a good suggestion because the problem then went away. I next tried to change the source for GPS and heading information from Auto to the gps instrument. That did not seem to solve the problem. Next I turned off all output from the AIS except AIS targets. That seemed to fix the problem. It must be some weirdness of GPS data from the Cortex messing with the autopilot and/or chartplotter

[shimari]

This is a bit concerning. I'm about to install a Cortex and have an ACU200.

What exactly did you turn off, and what can't you do now as a result? My guess is this diminishes the value of the Cortex greatly.

Have you reached out to Vesper/Garmin?

[AllenRbrts]

Originally Posted by shimari

This is a bit concerning. I'm about to install a Cortex and have an ACU200.

What exactly did you turn off, and what can't you do now as a result? My guess is this diminishes the value of the Cortex greatly.

Have you reached out to Vesper/Garmin?

I have sent a note to vesper but haven’t heard back yet.

I don’t think this changes the value of the product. Best I can tell no feature is impacted. In the network setup under NMEA 0183, I deselected GPS out, NMEA out and System out.

Under sensor setup, I disabled Heading to NMEA.

[shimari]

thanks!