Auto pilot

[Conall63]

Greetings all,

I was out in the boat today playing around with the Garmin auto pilot I recently installed. My steering system is totally hydraulic utilizing a hydraulic pump driven off the engine. The auto pilot interfaces with the steering system by a solenoid valve in the hydraulic lines.

The auto pilot is connected to my Garmin chart plotter, and all is working good. The AP follows routes , tracks, holds a heading and has three or four steering patterns it can follow, and all is working great, so I'm totally happy.

The question I have is how the boat fees with the AP engaged. With the AP engaged, the boat gets more of a roll. Once I place the AP in standby, and hand steer, the roll goes away. There's an adjustment screw on the solenoid valve to control how fast the rudder responds, so I'm wondering if the rudder is responding to quickly and causing a roll.

This is the first AP I've operated. Has anyone had this experience with how the boat behaves with the AP engaged vs not engaged?


Thanks,

Conall

 

[Ted]

Yes, slow the rudder action down and reduce the "throw" of the rudder.
you should have adjustment contols on the panel. If they are at the limits
then change settings to bring them into range.

Ted

 

[kartracer]

What Garmin system did you put in ???

 

[Conall63]

Garmin GHC 20

 

[sunchaser]

Several things could be at play.

First, how is your system configured? Things such as - does your install have a rudder position indicator tied into the control head? Is your course computer and heading sensor a matched unit to the control head?

Second, on an AP system the hydraulic pump has to be sized to the cylinder moving the rudder. Normally an electric driven separate properly sized pump is used for this. Optimum Cylinder size needs to be determined and then the pump speced to match.

Third, too little fluid flow (measured in CC/sec) means the rudder will not move fast to follow the commands of the AP system. Too much flow means the rudder will move too fast causing the rudder position sensor and heading sensor to over react with excess rudder movement/swings resulting.

Fourth, as mentioned tuning the rate and over compensation for rudder movements can be done through the control head.

Lastly, did you use a qualified instrument tech for equipment selections and install?

 

[BandB]

Everything sunchaser says plus read your manual sections pertaining to adjustments and sensitivity. You will want to adjust the sensitivity, even if everything is working perfectly, for different conditions.

 

[LarryM]

Everything sunchaser says plus read your manual sections pertaining to adjustments and sensitivity. You will want to adjust the sensitivity, even if everything is working perfectly, for different conditions.

Just a few notes from my recent conversations with Garmin support on my autopilot installation.

'Power Saving' is Garmin-speak for Rudder Sensitivity or Sea State.

Make sure to double check the Dockside Wizard, the Sea Trial Wizard, Autotune, Compass Calibration etc. If you are still having problems, the Advanced Configuration options can be accessed by Enabling Dealer Mode, where you can find the Acceleration Limiter Setting which you will increase if the autopilot turns too quickly, or decrease if it turns too slowly. As BandB suggested, "read your manual." These are all covered in the Garmin Installation Instructions.

If you are still having an issue with this, call Garmin directly. They are very helpful.

Good Luck

 

[DavidM]

On a related point I played with all of the settings to dampen out following sea S turns using my Raymarine 6000 autopilot and couldn't tame it. So I installed an add on module that provides gyro heading information to supplement the fluxgate compass information. The S turns dropped from 30 degrees to less than 10 during heavy following seas.

This was ten years ago and most new autopilots have the gyro feature built in. I don't think that the lack of it is your problem and tuning as described above will probably help.

David

 

[Conall63]

I have a rudder sensor. All the steering components came from one manufacturer, and Garmin told me what to buy based on my steering system.

We installed a solenoid valve supplied by my steering guy in the line that provides oil to the helm. Out of the valve, oil goes either port or starboard and along with being "T'd" into the port and starboard hydraulic lines. This all interfaces with the AP via the Garmin backbone I built with the chart plotter install.

The solenoid valve has a built in flow control valve. My steering guy recommends 11 seconds hard over to hard over on rudder speed. Tied to the dock today, I timed the rudder speed at a fuzz over 8 seconds, so the rudder appears to be moving to fast. I turned the screw in about 1/2 a turn, tightened it back down, and timed it again and got a fuzz over 11 seconds.

Doing another sea trial once the adjustment was completed had me happy that the roll has gone away. I'm pleased with how she turns when AP is engaged, so for right now all seems OK. Again, I'm a rookie with auto pilots, but for right now we're good.

I'm the tech on the job, so I guess the good thing is I know who to get mad at when things don't go as they're supposed to. Garmin has been very good to deal with, and I'm going to be calling them this week with some questions now that I know what to ask. Paying a local technician to do a once over on my install seems like money well spent, and I think I'm going to look into that. What others have said on this thread are the questions I'll be asking Garmin to see how this type of system gets tuned in.

An interesting item on my install was how to cool the hydraulic oil. Installing the solenoid valve with it's drastic restriction of oil flow caused the oil to heat up. The steering guy wants the oil under 140 degrees, and I was seeing temperatures of 160. My keel cooler for the main engine operates at 185... too hot for the steering oil. When I built the boat, I had welded another keel cooler into the hull for an air conditioner. That cooler was too small for my AC, so it sat vacant until I decided to run my steering oil through it. The steering oil passes through the keel cooler on the return circuit, then goes through a filter and back to the reservoir. During yesterdays sea trial, the oil temperature was 120... much better than the 160 I saw before putting the cooler in play.

Conall

 

[sunchaser]

Conall

What great progress with the AP. 11 seconds is about right for the AP system installs I've been involved with. A larger more responsive rudder can do OK with 15 to 18. And congratulations on the build. You are to be highly commended.

Might I suggest a spare modulating/solenoid valve for your AP?

 

[Ted]

I think you're doing well, that keel cooler is great.
Now adjust the yaw (amount of off course before correction applied)
and amount (angle) of rudder applied according to sea conditions as
they change, as you would manually if you were hand steering.

Ted

 

[Conall63]

Sunchaser...Our rudder is very large so I'm might play around with slowing it down more as you suggest. When hand steering, hard over to hard over is three turns of the wheel. With the large rudder and fast steering, that quick of a move will send stuff flying out of cabinets.

Ted... What you're describing is new to me. I guess I have to get on some long runs and learn how to deal with these adjustments. This type of tuning is done in the set up menu?

Larry... I saw "power saving" in the set up menu today....didn't know what it was until you clarified...thanks.

I'm taking my two college age kids and two of their friends to Key West next week, so I'll have an 18 hour passage to try to dial it in along with five or six days of down time at the harbor.

Conall

 

[C lectric]

Good that you figured it out. Left that way could have lead to damage.

My much older unit, not Garmin, was installed and not quite fully setup yet by the P.O. before we bought the boat as I learned the hard way after a couple years.

The rudder adjustment rate was way to high which I figured out after the overworked pump motor blew the power transistors. I did not have your signs to look at so missed it.

Once I repaired the motor control unit I started looking , read the destructions, and realized why. After slowing the oil delivery rate, a mechanical adj., the unit operated better.

So yes, continue to learn about the adjustments. Not only will the AP work better for you but those adjustments will protect your unit.

 

[LarryM]

Good that you figured it out. Left that way could have lead to damage.

My much older unit, not Garmin, was installed and not quite fully setup yet by the P.O. before we bought the boat as I learned the hard way after a couple years.

The rudder adjustment rate was way to high which I figured out after the overworked pump motor blew the power transistors. I did not have your signs to look at so missed it.

Once I repaired the motor control unit I started looking , read the destructions, and realized why. After slowing the oil delivery rate, a mechanical adj., the unit operated better.

So yes, continue to learn about the adjustments. Not only will the AP work better for you but those adjustments will protect your unit.

After reading your post, and others like it, I have come to the conclusion that when buying a used boat, as it relates to autopilots, a good best practice would be to record the present settings, reset the unit to its factory defaults, and perform the dockside and seatrial setup procedures again.

This can correct a multitude of sins like improper setup, compensating for changes in the vessel since the original setup, temporary settings left from the last use etc. Further, it is a good idea to become intimately familiar with the autopilot and its operation, and this is a good way to do it.

The setup instructions in the manuals can give the new owner a good overview of the kinds of features and behavior that are configurable so that when encountered underway, the new skipper might have a better idea of how the issue can be corrected. Just my $0.02

 

[Bigsfish]

Larry

Great advice. I hope I can remember it.

Thanks.

 

[BandB]

After reading your post, and others like it, I have come to the conclusion that when buying a used boat, as it relates to autopilots, a good best practice would be to record the present settings, reset the unit to its factory defaults, and perform the dockside and seatrial setup procedures again.

This can correct a multitude of sins like improper setup, compensating for changes in the vessel since the original setup, temporary settings left from the last use etc. Further, it is a good idea to become intimately familiar with the autopilot and its operation, and this is a good way to do it.

The setup instructions in the manuals can give the new owner a good overview of the kinds of features and behavior that are configurable so that when encountered underway, the new skipper might have a better idea of how the issue can be corrected. Just my $0.02

Read and study the manuals of all equipment on a boat you purchase. I ran across a captain who claimed to have 40+ years experience a year or two ago complaining about the sensitivity of his autopilot. He told us the model. We suggested pushing the button that said menu and to continue until he saw sensitivity (I think that's how it read on his unit but may have been something else). We were looking at the manual online. He said he never knew there was anything behind that button. Autopilots today have some amazing features. I've never had a real use for some of them, but still enjoyed playing with them, and I know they are there if needed.

 

[fishpcb]

Hello Conall63

Did you replace a older autopilot?
I'm looking to replace my old B&G with a new Garmin. Trying to find what works with my hydraulic pump and steering. Some dealers want to replace everything with new. I just want to do something like what have done.

 

[Conall63]

I wasn't replacing any equipment as my install was the first AP my boat has seen.

Conall

 

[Conall63]

I just got back from taking my two college aged kids and some of their friends to Key West ( the amount of partying they did can be subject to another post ), so I had some time to get to get introduced to my auto pilot. It was a 300 mile round that put about 50 hours on the engine.

I had some conversation with Garmin, and once I figured out how to access the dealer set up mode, it was a matter of adjusting things like rudder gain and a few other parameters to get the boat feeling good as the auto pilot does it's thing. It was a little sporty on the way down and back, with 3-5' on the beam ( wind's been blowing out of the east for a month down hear ), so I got to play with settings for those conditions, as well as some flatter seas (we hugged the coast on part of our trip home to get out of the beam seas).

I know I'm preaching to the choir, but I'm, going to say it anyway... I can't believe I've survived all these years without an AP. The AP is my new favorite thing in this world.

Thanks for all your input forum.

Conall

 

[Bigsfish]

Conall

The auto pilot can make a trip very pleasant and once you lose it you realize how much you really love it. Trying to steer a compass course in a sea for hours on end will really cramp up your neck and give you a big headache. My next boat will have two APs, one for a back up.

 

[BandB]

I just got back from taking my two college aged kids and some of their friends to Key West ( the amount of partying they did can be subject to another post ), so I had some time to get to get introduced to my auto pilot. It was a 300 mile round that put about 50 hours on the engine.

I had some conversation with Garmin, and once I figured out how to access the dealer set up mode, it was a matter of adjusting things like rudder gain and a few other parameters to get the boat feeling good as the auto pilot does it's thing. It was a little sporty on the way down and back, with 3-5' on the beam ( wind's been blowing out of the east for a month down hear ), so I got to play with settings for those conditions, as well as some flatter seas (we hugged the coast on part of our trip home to get out of the beam seas).

I know I'm preaching to the choir, but I'm, going to say it anyway... I can't believe I've survived all these years without an AP. The AP is my new favorite thing in this world.

Thanks for all your input forum.

Conall

Glad you took the steps to get maximum use out of yours too. That is learn all the adjustments and then practice and get familiar with how they can impact it. Today's AP's have amazing flexibility for various conditions but many owners just haven't learned all those capabilities.

 

[Bigsfish]

And then you have the Zeus AP system and you only have three button to push which don't do anything or change anything.