Most autopilots have NAV mode, which essentially asks the pilot to steer to a plotted route rather than just in a specific direction. It’s particularly useful in cross-currents and strong winds, or when travelling longer distances. NAV mode has not worked on our system since day one, and now that we’re doing longer trips it would be quite useful. We’ve been wrestling with this for about a month, where the pilot is getting all the data it needs to properly execute NAV mode (pictured above), but reports an error.
On advice from Furuno, we redundantly sent navigation data from the Furuno NavNet 3D Black Box to the autopilot. In the picture below, you can see the jumper cables while we were testing this temporarily. Presumably the pilot is looking for some proprietary Furuno data that wasn’t being sent through the normal path. It works great now, so we wired it in permanently. An added advantage of what we’ve done is the autopilot now gets all the rest of the navigation data redundantly, so a system fault is less likely to affect the autopilot.