Garmin autopilot- shadow drive?

ixlr8

Well-known member
Joined
May 2, 2017
Messages
756
Fluid Motion Model
R-27 (Outboard)
Hull Identification Number
FLMT2762C818
Non-Fluid Motion Model
2018 R-27OB w/Yam 300
Vessel Name
Maggie
I have a few questions on the Shadow Drive for the Garmin autopilot. I was on a boat today that had a Garmin autopilot with a shadow drive. With the autopilot engaged, I turned the wheel and I expected to see something on the auto pilot indicate that the auto pilot was no longer engaged. But there was no change. I turned the wheel 3 revolutions and no sign that the autopilot had disengaged.
How much wheel movement should it take to disengage the autopilot?
What, if any, indication should there be on the autopilot controller that the autopilot had disengaged?
Thank you
 
On our Ranger with the Garmin 5215 the autopilot doesn't disengage when you turn the wheel. You have to disengage on the autopilot controller. My first time out using the autopilot and forgetting it was engaged it was a bit unsettling frantically turning the wheel with no results!
 
There is a Garmin setting to increase the sensitivity. Give that a try.
 
It will say “Shadow Drive” on the top of the display. If it does not then you need to increase the sensitivity in the settings as Connerkip says. It depends on the rate of change so you may have to turn abruptly. If you hold the wheel on a new heading long enough it should re-engage at the new heading. Otherwise it will return to the old heading when the wheel is released.

If it does not do this even when adjusting the sensitivity to maximum there may be air in the lines or the shadow drive valve could be stuck.
 
my experience is.
Heading hold - autoplot engaged. a log appears ahead, I turn the wheel and the boat responds to the directional input giving me control temporarily. After I have made a turn the autopilot slowly brings the boat back onto the original heading.
 
The autopilot should show "Shadow drive"on the top of the screen when activated. It takes more then a smooth turn movement to activate it. The sensitivity needs to be set very high for it to activate. The Shadow drive needs to be installed horizontal and 12" from any type of magnetism. It also needs to be mounted as close to the helm as possible to work properly. Find the shadow drive and make sure it is mounted level, away from the auto pilot pump,Shadow drive location in the boat you can't do much about unless you want to replace hydraulic lines. C26 shadow drive is mounted in the aft starboard compartment, originally right above the pump motor. Ours didn't work at all. Garmin told me to move the pump motor and set the sensitivity to 90% it should work. If I want it to work as designed the shadow drive solenoid needs to be mounted as close to the helm as possible. It is best if it is mounted port to starboard not fore and aft because of the attitude of the boat running bow up when under way.
 
Before we jump off the deep end here, make sure the shadow drive is enabled. Go to menu, setup and user autopilot. Then make sure it’s enabled and just engage at the dock. See if it disengages. If it doesn’t, turn the sensitivity up and repeat. If you go too high, it may cause it to disengage permanently.
 
On mine, the "Shadow Drive" only comes on the display if I the AP is in a heading hold mode. If I am following a route, the wheel still moves the rudder....but "Shadow Drive" doesn't display.
I learned that this weekend.
 
I was back on the boat today. The Shadow Drive was enabled and the sensitivity was set to 54%. I increased the sensitivity to 70% and tried it again, it then seemed to be working properly. When I turned the wheel, maybe 1/2 a turn, the autopilot seemed to disengage and the message "Shadow Drive" came up on the screen. After a short period, 15-20 seconds, the message said "Heading Hold", the autopilot seemed to be engaged and I had the option to resume navigation. I selected the resume option and the autopilot steered us towards the programmed waypoint. Looks like it was just a matter of increasing the sensitivity a bit.
Thanks for all the feedback.
 
After the auto pilot returns control to you after having employed the shadow drive for manual override, and you then select to resume the computed navigation route be ready for a severe change in the boat's direction, especially if you've deviated a fair distance away from the original course line.

I'm guessing that for the outboard engine RT models more sensitivity is required compared to the inboard engine RT models.
 
Sorry for jumping off the deep end. The fact that your sensitivity setting of 70%( and working) is a good indication that the installation is expectable. My deep end explanation was based on all the checks that Garmin had me do to troubleshoot our issue. I was just passing this on to you. I was very surprised at the high sensitivity level(90%) that we are set at to get the Shadow drive to respond. I asked Garmin if this is an issue ? They responded back saying if it works at 90% its ok. It is a marginal install. It is good that you had success at troubleshooting the shadow drive and and it is functioning properly. Shadow drive is a important safety feature when using AutoPilot.
 
BB marine":3v1e7o1t said:
Sorry for jumping off the deep end.
No need to be sorry about "jumping off the deep end". Your comments helped me understand the system better and saved me some time.
 
We leave the shadow drive off. We navigate on the Columbia River and "Heading Hold" works very well. There is a lot of debris in the river, so frequent jogs are necessary. It is very convenient to let "Rochester" go back to the original course. When changing course a little bit, we push the buttons on the autopilot (or the remote). For larger changes, or larger debris fields, we disengage the autopilot until we get on the course we want.
 
Lenny and Louise":1lr6sfzf said:
We leave the shadow drive off. We navigate on the Columbia River and "Heading Hold" works very well. There is a lot of debris in the river, so frequent jogs are necessary. It is very convenient to let "Rochester" go back to the original course. When changing course a little bit, we push the buttons on the autopilot (or the remote). For larger changes, or larger debris fields, we disengage the autopilot until we get on the course we want.
When we took delivery of our boat the dealer told me we did not have shadow drive installed. I learned to operate the boat as you do. When there are open clear runs autopilot is on when I need to make a adjustment or change course, push arrow buttons or Stand by make adjustment and back to heading hold. When I realized that I did have Shadow drive it just didn't work. I spent time troubleshooting and waited for off season to make repairs and adjustments. I am slowly getting use to relying on the Shadow drive more for quick adjustments, If I am planning a course adjustment I still push arrow or Stand by adjust course and go back to heading hold.
 
Same here. I view shadow drive as a safety feature only, allowing quick return manual control in an urgent situation. Under normal circumstances I always use the adjustment buttons or go to standby to make corrections.
 
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