Garmin GHC20 Autopilot won't go to standby!

[CGW]

Hello all,

I have a problem with the Garmin GHC20 Autopilot on my 2018 RT31CB. If I come to a stop without disengaging the autopilot (heading hold), when I go to resume movement I can not disengage the autopilot into standby. This has usually happened coming into a marina or leaving a pump-out station. I do realize the initial problem is user error and I should turn the auto pilot to standby before stopping. However, the result is pretty terrifying when I can't get manual use of the steering system. Today, we moved out of the way of a barge heading up the Columbia River and paused a moment to let the barge pass. The autopilot would not disengage and put us into "crazy ivan" circle turns (Hunt For Red October reference) until my very frustrated wife pushed the standby button for more than 5 seconds.
I called Garmin support today and they had never heard of the issue before and suggested that I purge the hydraulic lines. However, we spoke to a person last night on the river in Arlington that used to have the exact same issue on hs RT29. The autopilot has worked perfectly EXCEPT for these times where I come to a stop. Is this just me or a problem that others are having? Any good solutions? We haven't had a chance to re-try the 5-second standby button rule. Let me know your thoughts and suggestions.

 

[watson1987]

Is the button on the autopilot screen half-broken? That fact that it eventually responds makes me wonder if the contact is dirty or failing.

Have you tried to press the Standby button on the main MFD? Does that respond?

 

[scross]

Yes heading hold will go nuts at slow speed. I’ve learned to always go to STANDBY when under 4 kts. The worst is accidently tapping ENGAGE on the MFD before leaving the dock and finding your helm wheel completely frozen! It’s now on my departure checklist to make sure the heading hold is on STANDBY before leaving the dock!

 

[CGW]

Is the button on the autopilot screen half-broken? That fact that it eventually responds makes me wonder if the contact is dirty or failing.

Have you tried to press the Standby button on the main MFD? Does that respond?

Once the system is confused by slow speed and probably rotation, it is not easily returned to standby. My wife kept pushing the standby button (more than 5 seconds) and that seemed to work but I need to test this again to confirm. The system is working normally in all other conditions.

 

[CGW]

Yes heading hold will go nuts at slow speed. I’ve learned to always go to STANDBY when under 4 kts. The worst is accidently tapping ENGAGE on the MFD before leaving the dock and finding your helm wheel completely frozen! It’s now on my departure checklist to make sure the heading hold is on STANDBY before leaving the dock!

I have only owned this boat for about 2 months. I have created this situation at least 5 times by stopping while in heading hold setting. You would think I'd learn already because it is pretty terrifying when it happens trying to get off the pump out dock at Roche Harbor or when a tug boat is approaching. My wife is saying she won't go back on the boat until I have mastered the situation. If someone knows for sure that a 5 second hold on the standby button resolves the issue it would be great to know.

 

[AGLyme]

Have you engaged the “shadow drive” option ? Which allows for manual steering of the wheel steering whilst engaged.

 

[CGW]

Have you engaged the “shadow drive” option ? Which allows for manual steering of the wheel steering whilst engaged.

Great question. The shadow drive was enabled which probably allowed me to get to the pump out dock and could be the cause of my issue. I have recently turned it off in an attempt to simplify things.

 

[Full_O_Fish]

I would recommend checking to see what steering mode you have the pilot set to. Garmin offers a "Rudder" mode and a "step" mode. When in heading hold with the rudder setting, pushing and holding the direction buttons results the the system applying full rudder till the hard lock in that direction. Sometimes if the rudder limits haven't been set properly this results in the pump driving the ram all the way till the pressure is so high that the helm/wheel can't break it free to go back, especially if there's a small amount of air in the system.

Same can happen if you stop with the pilot still active, it can keep running till it reaches that hard lock state and makes it difficult to release. If that happens it's best/easiest to use the autopilot to release itself and the ram by placing a "go to cursor" on your MFD in the opposite direction of the lockup then setting the autopilot to "follow route" which will make it start trying to steer in that direction. After a second or two the steering should be free and you can put the pilot into standby and stop navigating on the MFD.

 

[CGW]

I would recommend checking to see what steering mode you have the pilot set to. Garmin offers a "Rudder" mode and a "step" mode. When in heading hold with the rudder setting, pushing and holding the direction buttons results the the system applying full rudder till the hard lock in that direction. Sometimes if the rudder limits haven't been set properly this results in the pump driving the ram all the way till the pressure is so high that the helm/wheel can't break it free to go back, especially if there's a small amount of air in the system.

Same can happen if you stop with the pilot still active, it can keep running till it reaches that hard lock state and makes it difficult to release. If that happens it's best/easiest to use the autopilot to release itself and the ram by placing a "go to cursor" on your MFD in the opposite direction of the lockup then setting the autopilot to "follow route" which will make it start trying to steer in that direction. After a second or two the steering should be free and you can put the pilot into standby and stop navigating on the MFD.

Thanks for this recomendation. I will investigate in this direction when I'm at the boat on Friday.

 

[Durbi 69]

Hi, I am having a similar issue. The Engage / Standby tab on the touch screen doesn't seem to work. This is the only tab that doesn't work on the screen.
I have a 7408 XSV and an older 1020 XS which i use to engage the auto pilot. I have the 7408 as the sounder which has the standby tab. There is no standby function on the 1020. Any idea how to get the tab working again....maybe a reset or can you reprogram the tabs to locate the standby to another area on the screen?