Garmin GHC 10 Autopilot issue or malfunction

B

baz

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Jun 19, 2009
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C-24 C
We were out on Puget Sound this afternoon in calm seas and was motoring along in our R25 at around 3000 rpm. The Autopilot was engaged and steering the boat to a specified heading. My wife and I spotted another vessel with two very large white looking boats trailing behind it. They appeared to be moving slowly and were somewhat in our path. They were in fact a tug pulling two large Ferry boats one behind the other. We decided we would steer behind them and we wanted to change direction significantly to indicate to the tug operator that we would pass behind the stern of the 2nd Ferry boat being towed.

I took control of the helm as I would normally do to to have the Autopilot disengage ("You Have the Helm" flashes at the top of the screen in yellow) which is referred to as Shadow drive feature. However, the Autopilot for some weird reason did not give me control of the helm but rather went into a what I presumed was a "Pattern Steering" mode that turn out to be a 'Circle pattern' as the boat immediately turned quite sharply to Starboard and began a circular path.

I struggled with the helm but the wheel seemed to have a mind of it's own and there was considerable resistance to me rotating the wheel. Now what happened after this I'm unsure about as I acted somewhat in panic mode and things happened quickly.

Since the Autopilot seemed to have control, and the boat was not under my control, and was circling to Starboard with the engine at 3000 rpm, and I was struggling trying to regain control, I believe I pressed the STBY (standby) button on the GHC 10 or at some point the Autopilot decided to give me back control of the helm. After the boat had made almost a complete circle I regained control of the helm and reduced the engine rpm hurriedly. My wife who was the only other person onboard was wondering what I was doing. I explained the weird Autopilot issue and that I had not purposely turned the boat to Starboard so severely.

I kept control of the helm until we were well clear of the tug and its two Ferry boats.

I continued on and decided to engage the Autopilot again and placed it into heading mode and all was well. I tried several times taking control of the helm and each time the Autopilot relinquished control to me and after steering a constant direction for a few moment it would take control back again. This is called the Shadow Drive feature. The Autopilot was IMO operating correctly.

So what went wrong? Did the Autopilot suddenly misbehave or was it operator error ? No matter, I found it a bit unnerving that the Autopilot was so stubborn in giving me control back as it insisted on performing a starboard circle.

What would others have done in my place? Should I have reduce engine rpms immediately? Should I have done other things in addition to this?

I wonder if the Autopilot has a log of events that can be extracted, reviewed and analyzed ? Maybe Andrew can speak up on this for me.

Appreciate some feedback on this one.

All in all we had fun but we are wondering if something is amiss with the Autopilot or how come its possible for me to get into such a situation by operator error.
 
Sounds like a scary problem! :shock: I don't have a Garmin AP so I don't know what happened to yours but the Raymarine S-1000 has a red lockout button, that, if you push it, shuts the AP down completely. If for some reason it didn't, I'd go to idle and then neutral on the engine(s).

Since the Garmin appears to be standard (now) on the R-25, I'm sure the other folks with one will be glad to hear what you find out about yours. Glad you came out of it OK.
 
I don't have a lot of experience with the Garmin autopilot yet, and it will be difficult to tell you what happened without knowing a few more things. Were you just holding a heading, or were you following a route? The shadow drive lets you take control by grabbing the wheel and turning it (you know that I'm sure) - then leaves the steering to you until you straighten out the help again - and it will then hold that new (straight) course.

I could guess that when you took control, you did indeed turn the helm- the boat started in a circle. It would stay in that circle until you straightened out the rudder. I'd guess you "had the helm".

And yes, you should always be ready to disengage the autopilot - using the standby button - at all times (especially near other boats or obstructions). Reducing the rpm, in that situation would have reduced the stress as well.

Mac
 
Thanks Charlie & Mac for your responses. 🙂

In answer to Mac's enquiries...

1. I was just holding (AP engaged) a heading before grabbing the helm to make a course change.

2. Yes, I understand the Shadow Drive feature and it works well and have used it several times now, and I like it very much.

3. Yes, when I grabbed the helm I did change course to starboard somewhat severely and boat turned, but then that was when things went weird and I felt someone else was in charge of the helm as the starboard change of course continued beyond my control. The boat then performed a severe starboard circular turn. I say severe as the engine RPMs were at 3000. I struggled with the helm trying to correct the circular course but to no avail. It was only after the circle was almost complete did I regain helm control. As I said in my OP, I can't be sure of all the things I may have done to regain control. It may simply have been that the Autopilot mysteriously decided to let me have the helm. At least that was my sense.

If this ever happens to me again, I will do at least two things immediately

1. Reduce RPMs
2. Press the STBY button
3. Attempt to bring the boat to a stop (for obvious reasons)
 
I believe I've figured out what may have happened...

The GHP 10/GHC 10 Quick Start Manual states

"When you select Menu from the Heading screen, the first option listed depends on the current state of the autopilot:

- If you have the helm or if the autopilot is maintaining the heading. the first menu option becomes a shortcut to re-engage the most recently used pattern."

Given that I was initially using the autopilot to maintain a heading, I must have pressed the Menu soft key which then re-enaged the most recently used pattern which presumable was the "Circles" pattern. Maybe this pattern had been used to calibrate the autopilot by the Ranger people (who knows for sure).

No matter, if what I postulate is correct then when the "Circles" pattern was re-engaged the autopilot should have given me control as soon as I struggled to physically steer the boat with the helm to take control. This action should have cancelled the "Circles" pattern.

To test this I will try this sequence out when next on the boat and have clearance in all directions.

I'll post back what I find out.
 
I had a chat with Andrew today about this issue.

Andrew's advice was that if a course correction/change is required use one of the two methods

1. Use the port and starboard heading change soft arrow keys
2. Press STBY and make course correction

Andrew did indicate that by simply taking control of the Autopilot when it's 'maintaining a heading' and steering abruptly (as I did in my case) can cause the Autopilot to get a real twist in its knickers and make desperate attempts to get back on course. As I had taken control of the Autopilot by steering abruptly to starboard and then letting go of the helm, the Autopilot's shadow drive feature presumable was attempting to get the boat back on course -- and did this by circling the boat.

No matter, I still claim the Autopilot should have given me control back without such a struggle on the helm. 🙂
 
baz":2t04udtc said:
What would others have done in my place? Should I have reduce engine rpms immediately? Should I have done other things in addition to this?
...
Appreciate some feedback on this one.

All in all we had fun but we are wondering if something is amiss with the Autopilot or how come its possible for me to get into such a situation by operator error.
Click to expand...

I am reminded of some advice I was given by a Commanding Officer while I was learning the fine art of submarine driving, "There is almost no surfaced transit situation that will not improve by slowing down and figuring out what is going on". That said, and you did not indicate exactly how close you were, I would slow down and disengage the auto pilot.

I have since figured out several situations that increased speed is helpful for, but only by thinking them through ahead of time, so that they were recognizable when they occurred.

Joe
 
Joe:

I was fortunate as there was no other boat in my immediate area and the tug + ferries was over 1/2 mile away.

Slowing down is kinda like applying car brakes if danger/collision appears imminent. 😉

I agree with you about slowing down.
 
Glad all worked out well,

Bet the Tug Capt had a good laugh :lol:
 
This has now happened a 2nd time. This last occurrence was on my return to Edmonds from the Bremerton GTG this past weekend.

I contacted Andrew about this and he advised I contact Garmin at 800-800-1020 and select the Marine Autopilot menu number. I did so and talked and explained things the the technician at length. The technician was dumfounded and collected all of my detailed info on the matter and will forward it to Garmin engineers who will be getting back to me to followup.

My actions with this last occurrence are very clear in my mind so I was able to accurately detail what happened to the Garmin person.

My hypothesis is that the Autopilot Control panel's starboard soft arrow button when pressed is being confused with the center Menu being pressed. That is, the control panel thinks the center Menu button has been pressed when in fact it was the starboard soft arrow button being pressed. This action (i.e., Menu button being pressed) will cause the Autopilot to auto engage the last steering pattern configuration which in my system it's the 'circle pattern' presumably.

When a get a few spare hours I'm going to find some clear water to experiment to see if I can duplicate the Autopilot anomaly on demand.

Will post back my findings, as well as whatever the Garmin engineers come up with as an explanation.
 
OK -- Today the west coast Garmin Autopilot specialist/trouble-shooter called me and we had a good and very long discussion about this Autopilot anomaly I've been experiencing.

His name is Robert Archer and his direct Cell number is 541-207-6233.

Robert has agreed (and he insisted) to visit with me at my boat in Edmonds to check the Autopilot installation and to also go out on the boat if necessary to try and duplicate the problem. He is very intrigued with the anomaly and agrees with me that it seems the Autopilot control head (the display box with the soft key buttons) is misinterpreting the input commands. However, that is to be determined. Robert did say that if he found no issues with the Ranger's installation of the Autopilot and we cannot duplicate the problem on demand he will simply start replacing the Autopilot components, one by one -- starting with the control panel.

Robert says he always travels with a complete working set of Autopilot components.

Robert also wanted to know who to talk with at the Ranger Tug factory to see if he can be of any help with Autopilot installation questions etc that they may have. I gave him Andrew's phone numbers as well as the Ranger Tug factory contact info.

At this time Robert has agreed to come to Seattle/Kent/Edmonds next Monday and stay in the area until Friday. Our tentative schedule is for Robert to visit my boat in Edmonds on Wed morning for a full shake down of the Autopilot.

All I can say at this time is that I'm pleased I've got Garmin's attention on this one. Garmin is certainly taking this issue of mine seriously and acting responsibly as the issue of the Autopilot not disengaging via the Shadow Drive feature and turning the boat severely to starboard in a circular pattern has serious consequences.

In our conversation, Robert gave me advice of disengaging the Autopilot when approaching and passing under large metal bridges. The large chunk of 'iron' can affect Autopilot's sense of where North is and will struggle and do weird things. He also mentioned under water power cables can have similar affects. Not very comforting information to receive but nonetheless, good advice. Maybe others here can take note of this also. 🙂

I'll certainly post back what Robert discovers as being the issue with our Autopilot.
 
Update...
Robert called me today and we've arrange to meet up and be on our boat 9am Wednesday at our Edmonds Marina. Robert will also be visiting with Andrew at the Kent Ranger factory on Tuesday to discuss the Garmin Autopilot installation process/techniques done on the Ranger Tugs. Thus Robert will be familiar with how Ranger installs the Autopilot prior to looking at things on our boat Wed. 🙂

It will be of interest if we can duplicate the Autopilot problem that gave rise to Robert visiting with me in the first place.

I believe on Thursday Robert will then go to Bellingham to be with another Ranger owner to review Autopilot issues etc.

So far, all I can say is that Garmin is providing excellent support service and I sure hope Robert can find the root cause on/in our Autopilot.
 
Robert spent 4 hours with me on my boat today. The bottom line is that my Autopilot issue has now been resolved -- but not without some very interesting findings especially from Robert's standpoint and Garmin's Autopilot architect/designer. Robert had never seen the Autopilot perform the way it did on my boat and the designer who Robert was talking to on the phone was also dumbstruck. However, there's a little more to this problem that I'll reveal later on below.

So, the first thing Robert discovered at his visit to the Ranger factory yesterday (Andrew Custis and crew) was that they were installing the Autopilot's shadow drive valve too high. By too high I mean it was being located higher than the position of the capstan tank (the large black circular tank that the steering wheel is attached to). As air can be in the hydraulic lines there's always a tendency for the air to gravitate to the highest point in the system. This meant the air would be settling into the shadow drives valve. Air in the shadow drive valve will cause the shadow drive feature to misbehave badly. Air can be compressed but hydraulic fluid for the most part is nigh incompressible. The shadow drive valve should not have air in it for it to operate correctly.

I suspect and hope Ranger will from now on locate the shadow drive valve lower down and below the capstan tank.

Robert indicated that the Garmin person who trained the Ranger Tug Autopilot installers originally gave them very bad install advice.

So -- Robert's first task was to relocate my Autopilot's shadow drive valve. That was easy as he simply moved it from above the hatch opening to backside of the helm dash to the lower surface and about 2" lower than the capstan tank.

Robert's second task was to bleed any air from the system. This he did and I show some photo's of the setup here http://gallery.me.com/barrysharp#100374

There was significant air in the system! One could see the air bubbles flowing along the plastic lines that were attached to Robert's air bleeding toolkit (see photos).

Robert then spent the next 30 mins checking out the Autopilot's setup and configuration while at the slip.

Next we went out on the water to make sure the Autopilot was functioning correctly. Robert did all of this and calibrated various things.

Now he asked me to take control and to try and duplicate the problem I had called him in to fix (see my OP). I took the helm and within a few minutes was able to duplicate the issue where the Autopilot was set in Heading Mode and I changed the heading a degree at a time in sequence. First I pressed the right pointing arrow to change 1 deg to starboard, then, again, then again and then the Autopilot suddenly put the boat hard over with full rudder. Robert was absolutely taken aback as he had never seen the Autopilot perform such a maneuver. He then tried to duplicate the problem and could not. I then took over and was easily able to duplicate it again. This time Robert observed closely what I did and how I was pressing the buttons. He noticed after awhile that I sometimes would hold the button in for maybe a second or two before releasing. He conveyed this to the Garmin's Autopilot's designer who was flabbergasted. Robert and designer were chatting away over the Cell phone when, as I learned later, a software engineer had overheard Robert talking with the designer and chipped in with "that's how it's supposed to work. It's a feature!". Both Robert and designer were dumbstruck that such a feature existed in the software.

So there you have it -- If Autopilot configured for "Rudder" mode when Heading soft button are pressed for 2 or more seconds the Autopilot treats this command as an instruction to turn the boat hard over. We all agreed this was a very dangerous feature and the Garmin technicians are going to research to find out what this feature is REALLY designed for. For a beginner like me this feature is plain out dangerous and I'm lucky to have not damaged the boat so far.

The good news is that the "Rudder" mode can be changed to "Step" mode which allows the same kind of heading changes by pressing the buttons except that holding the button down for 2 or more seconds will increment the heading change by 5 degs rather than 1 deg for a quick button press/release. The 5 degs can be configured to be, 5 deg, 10 degs, etfc all the way up to 90 degs. Robert set it to step 5 degs.

With this change to the Autopilot's config I was now unable to cause the Autopilot to engage the hard over feature. 😀

BTW - the air that was in my Autopilot's hydraulic system was the root cause of me not being able to regain control of the steering wheel when the Autopilot turn the boat hard over as the air was inside the shadow drives valve and the shadow drive was unable to correctly react to me taking control to stop the boat from turning.

I learned a great deal about the Autopilot from Robert during these 4 hours and feel a great deal more comfortable with using it.

Robert said that when they've resolved the "Rudder" mode 'hard over' feature they would contact me and let me know the real intent of that feature. They may even have it removed from the software as it's obviously very dangerous if inadvertently activated -- as was my case.

Robert also learned a few things during the 4 hours and was appreciative of my patience with him and with Garmin.

Robert also said that the Ranger Tug crew were excellent and did excellent Autopilot installations bar the shadow drive valve location which of course was not covered correctly by the original Garmin person advising the Ranger Tug's crew.

Ranger Tug also has the same air bleeding toolkit that Robert had. This is good and Robert said he was surprised as he knows that only 1 in 100 boat builders goes to the expense of having one.

If air is in the hydraulic system the symptom is that the steering wheel will not turn smoothly and it will feel a little wobbly as you turn it. The wheel will turn smoothly is there's no air in the system.

I was able to observe the actual rudder movement when the Autopilot was engaged. It was amazing how little the rudder moved while holding a heading.

As I watched Robert tuning the Autopilot I was truly amazed at all the features this Garmin Autopilot has. It's very smart -- but as we now know, it can also be fickle. Ain't technology great. 😉

Well -- hopefully my problem has been resolved and I hope others have found this informative.
 
Barry, thanks for all the documentation as this saga unfolded. Looks like you have winner with Ranger Tug and Garmin customer service.
 
One of the interesting thing I learned during Robert's visit was watching him layout out a course for the Autopilot to traverse. If during the Autopilot's activity following the configured GPS course one manually takes the boat off course and then re-engages the Autopilot's GPS configured course the boat will not be steered directly back to the course line. Rather it computes a rhumb line (or loxodrome) and navigates this line to get back on course. This rhumb line is shown on the Autopilot's display panel as a wide brown line with an arrow showing the boat's direction.

Another really interesting Autopilot action is to see it perform a very acute turn at a way point. It's very precise if the Autopilot is operating correctly.

Robert made it seem so easy to setup courses for the Autopilot to follow. One of these days I hope to be as expert as Robert is.

I tried to setup a "safe course" from my current location just outside the Port of Edmonds to the La Conner Marina. The 5212 found La Conner Marina without any issue but when I instructed it to plot a safe course to the La Conner Marina it refused to do so. With Robert's help we determined the cause for this was that the chart plotter did not have any depth information in and around the La Conner Marina and it therefore COULD NOT compute a safe course. The trick was to find a spot as near to La Conner Marina on the chart that did have depth info and use that location instead. Then the 5212 computed the safe course and the Autopilot had what it needed to engage and navigate the safe course. Nifty -- but again one has to work around the technologies at hand, right ? 🙂
 
Thanks for the info. I've always believed an undocumented feature IS a bug. Fix the bug or fix the manual!

I've had similar routing problems with the "Guide To" feature, also caused by lack of depth information. But in my case, the depth info was lacking in my home port marina (Elliott Bay). The solution is fairly simple. Given I don't need the chart plotter to exit the marina, I can select my destination prior to getting underway and wait to hit the "Guide To" button when I get outside the breakwater.

Two things worth noting. This feature is only available if you have the BlueChart g2 Vision card installed. And, the suggested course is based almost entirely on depth information. It does not take into consideration, for instance, vessel traffic lanes which should be crossed as directly as possible. So, even if auto-pilot is engaged, you still have the helm.

Cheers
 
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