Garmin autopilot shadow drive.

[BB marine]

I'm looking for some help in troubleshooting the Garmin Autopilot Shadow Drive installed on my 26 Cutwater. It has never worked since day one. I actually was told on delivery day you can't steer the boat with autopilot on. This was after I did try to steer the boat with auto pilot on and the pump started knocking and we lost steering . After a few minutes of turning the wheel back and forth with auto off steering worked fine and I never touched the wheel again with autopilot on. I have piloted other boats with Autopilot and adjusted coarse with the wheel while autopilot was engaged and it worked fine. I always questioned the dealers comment.

I have since learned many of the systems in the boat and in checking the hydraulic system for leaks, came across a shadow drive switch installed in the hydraulic system . I have read Garmin installation manuals on the installation of the auto pilot and installation of the shadow drive and checked the following.
Shadow drive enabled Yes

Shadow drive mounted horizontally , below helm, above pump, in between helm and pump Yes

All air bleed from the system . Helm has a solid stop on a lock to lock turn and has functioned ?

Shadow drive must be mounted at least 12 inches from magnetic sources . It is 12" from auto pilot pump , right next to hot water heater ( I moved the pump 24 " from shadow drive switch ) I talked to Garmin and they said this is a best practice it can interfere if it is that close, but usually doesn't.

What type of steering cylinder is installed on Cutwaters ? I removed the aft seat to inspect the rudder log and grease it and inspected the cylinder . My memory says it is unbalanced ( my memory is not good) Can anyone verify that ? If it is unbalance there is a block that is to be installed on the pump to help balance the hydraulic oil flow. My pump doesn't have it installed. I'm not sure if this is an issue with the Shadow drive but it is supposed to be installed.

Any information on trouble shooting the shadow drive , experience on working on it, or something I am over looking please send my way. Im sure it is something simple . I watched a Garmin YouTube video on the the Shadow Drive and the demonstration was on a 31 Ranger Tug .

Brian Brown
26 Cutwater
PORT-A-GEE


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[Red Raven]

Hi Brian,

I have been through a shadow drive failure and valve replacement so I have a bit of experience with it and maybe can help.

First. What you were told is incorrect. You can steer the boat when the autopilot is engaged if shadowdrive is enabled. That is the purpose of the shadow drive. The shadow drive feature disengages the autopilot automatically when you take over the helm and re-engages the autopilot when you release the wheel. If you turn the wheel slowly while autopilot is engaged the boat should respond momentarily but will try to return to the set course. If you turn the wheel more quickly and forcefully the shadowdrive engages, "shadowdrive" is displayed until you release the wheel. Then the autopilot should engage automatically to the new course.

My failure was a stuck shadowdrive valve that would not allow the autopilot to engage with shadowdrive enabled. Autopilot worked fine without shadow drive engaged and we used the boat that way until the valve was replaced. During this period I would turn off the autopilot whenever I wanted to take manual control. After the valve replacement I found the shadow drive did not engage when I manually turned the wheel. Ranger Tugs suggested adjusting the sensitivity in the settings and that did the trick. I think it is now set to 75% but I am not sure on that.

Now to your problem. What are the symptoms? Does your autopilot engage properly with shadowdrive enabled in the settings? When you take the helm and turn the wheel with autopilot on do you get the shadowdrive message? If so, when you release the helm does the message go away and the autopilot re-engage? There are also times when you may get a "pump stall" message if the auto drive has to turn the helm hard over to maintain course at low speed due to fighting the wind and current or fighting the captain at the wheel. Our shadow drive valve got stuck during a "pump stall" message. I would start by upping your shadowdrive sensitivity setting and see if that helps.

 

[BB marine]

Thanks for the response back. The initial time at delivery the Auto pilot stalled actually started knocking loud. We were cruising very slow on a straight run on a river just testing systems. I was told then never steer with the auto pilot on.
When I realized I did have Shadow drive ,I first made sure it was enabled (yes) Then tried it and nothing , I watched the YOUTUBE video and it showed a message at the top shadow drive is engaged. I have never seen that on the screen . My auto pilot works great with or without the shadow drive enabled .Enabled just doesn't disengage when I turn the wheel. We boat on Lake Michigan so it wasn't a big deal. When I needed to change coarse I just disengage the autopilot or use the coarse adjustment arrows on the monitor. I felt it was a problem and time to get it fixed last fall we took a trip on the Tennessee river, running a long straight run engaged auto pilot and cruising at a nice 8kts saw a log floating off the bow and first reaction grab the wheel and turn . Didn't turn next reaction grab throttle and neutral transmission. No harm but it is time to get it fixed. I have adjust sensitivity but not knowing enough about it I may have not adjusted as high as 75%. Did you get the message that it was activated on the screen when sensitivity was lower ?

 

[Red Raven]

No, I did not get the shadow drive message at 50% sensitivity after the new valve was installed. I got the message appropriately before the valve replacement but don't know what the sensitivity was then. I called Kenny at Ranger Tugs and he suggested setting it to 75%. That did the trick. You may have to go even higher. Take it all the way up to 100% and see what happens. The quicker and harder you turn the wheel the more likely for it to engage. Give it a yank and a full turn.

For some reason my brain associated "easier" engagement with a lower number. It's the other way around.

If that doesn't help it might be that the valve can get stuck in the other position causing the shadow drive to never engage at any sensitivity. If you can't get it to engage even at 100% try hitting the valve with a hammer while turning the wheel. :shock: Seriously, that's what Kenny suggested when my valve got stuck! Unfortunately it didn't work and we ended up replacing the valve.

Another thought is that there is an electrical wire running from the valve that I assume goes to the auto-pilot controller. I assume this is from a sensor or control function. It could be that it is broken or loose. Check that you have an intact wire from the valve to the controller with good contact.

Curt

 

[BB marine]

Thanks for the information. I have tracked all the Hydraulic lines down. Installed Tee's at pump , moved pump 24" from Shadow drive. My next is to check sensitivity setting, hopefully that fix's it. If not trace wire connections confirm connectivity. I also need to find out if Cutwater uses a balanced steering cylinder. I know it is a push-pull ram that attaches to the rudder arm. I saw this when greasing the rudder log .I didn't check to see if the cylinder shaft goes all the way though the ram ( seal on both sides and shaft visible on both sides of the cylinder housing) -Balanced cylinder . Unbalanced is a ram with a end cap on one side and shaft and seal on the other side. This ram requires a balancing block on the pump. ( balances hydraulic oil flow because one side of the cylinder has more oil then the other side because of the displacement of the shaft) It is an accessory Garmin sells for unbalanced cylinders to make them work better with autopilot pumps. I will reach out to Cutwater for this. Easier then removing the rear seat to gain access to see the ram.
Brian Brown
Cutwater26
PORT-A-GEE