Dramatic AP failure

Capt. Wanabe

Well-known member
Joined
Oct 9, 2009
Messages
64
Fluid Motion Model
C-28
Hull Identification Number
FMLT2721H010
Non-Fluid Motion Model
River King
Vessel Name
My Precious
At the end of last season I experienced an unfortunate and dramatic failure of the autopilot (AP). This occurred when I was moving at about 5 knts (2011 R27 & Garmin GHC 10 AP) straight down the middle of a narrow fairway with the AP on. Without warning the helm went hard over to port and was not recoverable by manual force on the wheel. At the same time there was a loud screeching sound (plus panic on my part as the boat was headed into a mooring field). The only way to stop the sound and recover the steering was to shut down the AP. When I engaged the AP again the exact same thing happened. Needless to say we stopped using the AP and only steered manually for the rest of the trip. After getting back I tried the same maneuver to see if I could figure out what happened but only got a display dialogue on the Garmin GHC 10 screen that said, “searching for autopilot.” That condition has persisted until today. Some life issues prevented adequate address of the problem until this spring. What I found then was that the single screw which secures the CCU to the bracket in the cave had broken (it was made of plastic) and allowed the CCU to spin in the mounting bracket. That could have explained the sudden course change and possibly precipitated a current overload in the AP system. I looked for fuses or wires connecting the GHC 10 display, CCU, ECU and power but found tracing wires to be very difficult as everything seemed to route behind an immovable object. I did find a single 20A fuse behind the helm that was blown and replaced it. I was hopeful that would be the culprit but, unfortunately, the display dialogue remained unchanged still indicating “searching for autopilot controller.” The status lights on both the CCU and ECU fail to light.

I went online to troubleshoot and found Garmin’s recommendation to be to check the yellow power wire from the CCU/ECU interconnect cable and the yellow power wires from the ECU and GHC 10 display and make sure they were still connected. The only place there seems to be a ghost of a chance at checking connections is behind the helm. Nothing obvious there. I have spoken to Kevin at RT a couple of times and he says he thinks the yellow power wires may be connected behind the frig. I am very reluctant to remove the frig just to check the wiring as all threads I have reviewed on that topic describe the task as very not easy. That, coupled with the likelihood that the yellow wires did not fall apart at the same time the CCU came loose, lead me to conclude that loose yellow wires is probably not the issue. I also called Garmin support. They could not give any definitive suggestions as to why the GHC 10 can’t find the AP but did offer to ship a new bracket and screw for $15. They also stated that the ECU for the GHP 10 AP is “no longer supported” so that if ECU failure is the cause of the AP failure it cannot be replaced. The upgraded Reactor 40 AP core package is about $2000 if I use the existing pump. $3000 if I buy the SmartPump package! As I was not unhappy with the original AP I am not enthusiastic about paying $2000 to recover from the failure of one plastic screw.

So—, does anyone know where the AP yellow wires (and black ground wires) from the display, ECU, and CCU are connected? Are there any fuses that I am overlooking? Is it worth tearing the frig out to see what wiring is behind it? Has anyone upgraded from the GHC series to the current “Reactor” AP from Garmin? Garmin did suggest some procedures to check and see if my current ECU was busted but they were not straight forward either.

Any suggestions appreciated,
Frank
 
I just had something similar happen. When I engaged “route to” the AP would veer off to port 70-90’ then slowly work its way back to the course line and hold the correct course. The boat would travel about 1/2 nm for the correction to take place. When I looked at the AP CCU I also found the thumb screw loose and the plastic bracket cracked where the screw hole is. I did find that by aligning the AP heading with the GPS heading the AP operated normally. I am awaiting the new mounting bracket. I called Garmin support yesterday, the person I spoke with wasn’t aware of the mounting bracket with a thumb screw. He also wasn’t sure that I would have to go through a new setup procedure on the system.
Have you installed the new mounting bracket?
If you have slowly turn the CCU to align the AP heading to what the GPS shows.
I found that when the two are way out of alignment I would get an alarm and warning message.
 
West Marine claims they have replacement brackets in stock:

https://www.westmarine.com/buy/garmin-- ... gIX3_D_BwE

Replacement CCU Mounting Bracket for GHP 10
GARMIN Replacement CCU Mounting Bracket for GHP 10

$9.99 In stock online.
Model # 12030425 | Mfg # 010-11173-00 | UPC # 753759082048
 
When I first took ownership of my R27, I found the GCU to be misaligned and the bracket loose (fortunately not broken). I aligned the GCU so the AP display heading matched the wet compass. It seems to be working fine to date (2 years). That's after 2 trips from San Diego to Catalina and back.
I removed my fridge to replace the controller module about 8 months ago. It was not to difficult a job, 4 screws and a gentle lifting/pulling action to get it out of the space. I was even able to put a support (2x4) with some supporting foam in the bottom of the space for additional support of the fridge. With a pending replacement of the VHF antenna it'll probably have to come out again soon.
 
When we had a bad fuse holder in our Garmin AP system and got the dreaded "Searching for Autopilot Controller" message, the Garmin folks had me look at the CCU connections. Well I broke a clip on the fragile CCU bracket checking it. New one was about $10 from West Marine. The bracket is not hard to reinstall.
Then you need to carefully calibrate the CCU again - first at the dock while stationary then on sea while cruising in different directions. Ours in off by 0 to 5 degrees (depending on course) now and I'm satisfied with that.
 
If you are going the "rip everything apart route", what not buy new cables and run them to the connection points without routing them behind everything and then see if your system works. If it works you found your problem, if it does not work you saved a hell of amount of time and grief and then it is time to look for another possible culprit. Sounds like the culprit is the CCU. It may not be getting power or it has burned out.
 
Honest Question, not an attack on OP...

Is it good practice to use AP in close quarters operations like in a Marina Fairway??? The only autopilot I have ever used was a cog type heading lock coupled to Gyro Compass on a large heavy Vessel...Modern AP's might be different...

Thanks,

Tex
 
"Recent accident investigations indicate that there have been incidents in which the fluxgate compass that directs the autopilot to follow a prescribed course can be suddenly influenced by the massive amount of steel in bridge support members and ships, leading to disaster." https://www.boatingmag.com/perils-autopilots/
 
Thank you to everyone for the prompt responses.
Knotflying--Good idea on the cabling. It looks like eBay/Amazon prices for the ECU/CCU interconnect cables and the power/data cables for the ECU and display will run about $150 - $180 for all. Not cheap but I am seriously thinking about it as I am not in the mood to upgrade to the Reactor.
Trisailor--I appreciate the encouragement on the fridge move as I am guessing that is where most of the connections are. I would have to do that to run new cables anyway. I haven't found the ECU power cable fuse yet so it may be hiding back there.
TexasEye--I have used this AP for the past 8 years and it has performed very well. It has excelled in areas such as a straight fairway as it seems to do a better job of keeping the boat straight instead of my constant corrections manually. While using the AP, I have never left the helm, even in open water, as unexpected things can happen fast. Two points for posting this is that 1) this event was NOT recoverable with manual steering even though ShadowDrive is included in the system. The only thing that worked was throttling back to neutral and disengaging the AP. If things are so tight that you don't have time to do that then you are absolutely correct. 2) If anyone upgrades their AP system you can sell the used, working components on eBay for a good price!
It will take me a while to sort this out but when I get some answers I will post the f/u.

Frank
 
Hey, I totally understand and honestly appreciate your post, we learn by hearing war stories...I'm a novice at AP use on small boats. My questions and post were an opportunity to get folks talking. I enjoy the helm too much to share it with electrons...
 
Aye Captain, I too had a similar experience. I was traveling on a course, went to make a course correction, reengaged the AP and it went hard to starboard. I could not correct nor counter the AP. The pump made a lot of noise like grinding. Shut the AP off and took manual control. Several attempts to reuse the AP all ended up with the AP turning hard to starboard. Ended up replacing the AP pump. Everything now works. Big issue in replacing the pump is bleeding the steering system to get all the air out of the system. Took me about 5 hours, using the kit they sell for that purpose. Some yards may have a power pump for bleeding the system, but with patience, it can be done manually.
 
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