NAV Menu Options 711C

[Quitsa]

I installed a new 711C system on my boat recently. One of the menu options when using NAV mode is whether to use "Course" "XTE Precision" or "XTE Economy."

In the manual, it says that when set to course, the autopilot will calculate a new course straight to the designated waypoint after dodging. I notice that when set to "Course", the autopilot consistently shows a very small cross track error of less than 4-5 yards and often only 1 or 2. When set to "XTE Precision" it will wander up to 10-15 yards off the track and with "economy" even more.

I am a bit puzzled by what is happening when set to "Course" and why it appears that the autopilot is steering much more precisely and thus running a straighter line.

 

[Johnny Electron]

What is the hard over time for your pilot? Does your pilot have a RRU or are you running virtual feedback? How fast are you going when testing? How long have you had this problem?

 

[Quitsa]

I have a RRU installed. This is operating at 28-30 kts cruise. It’s not a problem per se, I am just trying to understand what the mode settings are changing. I never measured the hard over time but it is pretty fast as I recall from the dockside setup. The heading and GPS data are from an SCX-20. Thanks

 

[Johnny Electron]

Your rudder speed might be too high. I recommend measuring the time from hard over to hard over and see what you get.

 

[Quitsa]

Your rudder speed might be too high. I recommend measuring the time from hard over to hard over and see what you get.

Using the arrow button on the 711C it takes 11 seconds to go from hard lock port to hard lock starboard. The rudder test in setup says “Rudder speed OK”. The turn rate in ship parameters is 5 degrees/second.

Hope that tells you something. Thanks

 

[Johnny Electron]

The hard over times are good. The rate of turn should be based on what the rudder test has provided and the size of the boat. The larger the boat, the lower that rate of turn should be.