711C Turning Behavior When Switching WPTs Following a Route.

[or65041]

I would like to upgrade my GHC10 Autopilot to the 711C. The boat systems include TZT2BB (v7) and TZ Professional 4.1 connected with N2K and NavNet ethernet. My question concerns the behavior of the 711C in NAV Mode when following a route with the waypoint switching mode on both BB & TZ set to "Circle".

On reaching the arrival circle of WPT (marked X) and switching to WPT (#1) at 90 degrees from the current track, how will the 711C effectively execute the turn on receiving the new WPT Name, bearing and XTE from the route line ( #3)? This would be in contrast to the behavior one would expect if tracking toward WPT X and simply using the MFD to select GOTO WPT 1. In that case, I would anticipate the boat would follow line #4.



Unless the mix of arrival circle size is large and tolerance for XTE is generous (along with some configuration settings in the autopilot, i.e. hard over time, rudder travel), the GHC10 will aggressively turn the boat. Dumbing down the performance of the autopilot for tracking a course to avoid abrupt turns when following a route is not ideal.

On my prior boat, I had a Raymarine Evolution EV-400 system which appeared to differentiated between a new WPT being issued from the navigation system (like GOTO WPT 1 in the diagram) and a new WPT being issued as the next WPT in a route.

In reading the literature on the 711C, I am not confident of how the 711C manages these turns. Can you provide some further information on this?
Thank you for your help.

 

[Johnny Electron]

The plotter would be sending the command to follow the course and you can adjust the waypoint arrival (circle, line, or circle and line depending on the plotter settings) to trigger the switching to the next waypoint in the route. You can't spin a boat on a dime so the Navpilot will steer the boat gently in reference based on the turn and speed you are going. Speed is a big factor in what happens on turns. How sharp that turn is also part of the settings of the pilot called ECO (economy) or Precision. We normally recommend economy for less rudder changes and easier turns. With the Navpilot you can also control the max degrees of rudder movement to restrict how fast a boat is allowed to turn.