B&G Autopilot installed correctly?

[Gilligan8]

So I bought this vessel a few months back (43' Moorings 432) and the autopilot was kind of funky when you say "Go north" and give it a bearing to go. It will kind of go WAY out of the way and MAYBE get back that direction.

It does "better" when you give it a waypoint to get to, but it's still a bit quirky.

Is this just normal or is it because the compass is mounted in the rear berth right under the cockpit floor?

Should I try to relocate it closer to midship and the waterline?

[smac999]

I would redo all the setup and calibration.

Swing compass. Auto learn pilot etc.

[cr180]

I have the 2015 vintage with the RC42 rate compass and the zues2 MFD as controller. I can set an offset due to rate compass being off the center line. Go to Settings, Network, Calibration, Heading. Then click offset. Units are degrees of heading. Suggest adjusting either plus or minus while under way until your heading (the value the rate compass is seeing) either matches your course over ground or magnetic ship’s compass. Having said that, if you select “Heading Hold” mode on the autopilot, it should match the direction the boat is headed even if the rate compass is reading a different value. Agree with rerunning commissioning set up. You may also have a rudder position indicator out of adjustment. Be sure to observe your quadrant position as you run the set up. Hope this helps, Jeff.

[Gilligan8]

Thanks guys.

Yeah, it will go at LEAST 10 degrees off course for a good while and maybe it will come back but usually just keeps veering. We eventually turn it off.

I'll shoot some video of it on my next outing.

[cr180]

10 degrees. That’s actually the offset adjustment for my off center condition. So if you are entering a course to steer, what you are describing makes sense. Try selecting heading hold mode and see what happens. I manually steer the boat on the course I want, and then engage autopilot on heading hold mode. If heading hold works, then an offset adjustment should be the fix

[smac999]

Originally Posted by cr180

I have the 2015 vintage with the RC42 rate compass and the zues2 MFD as controller. I can set an offset due to rate compass being off the center line. Go to Settings, Network, Calibration, Heading. .

the heading offset is to correct a compass not mounted straight in the boat. and has nothing to do with where the compass is mounted.

a mounting offset would be in feet not degrees... like setting up GPS antenna on AIS.

even if the heading is wrong the pilot should still hold a straight line when activated. it will just hold the incorrect heading.

[cr180]

SMAC999: You’re logic is reasonable and what I initially believed. However, owning this same B&G autopilot, have learned that the rate compass offset is real. Think about it as a point in the distance and the angle in degrees between the center line and a point offset such as the rate compass not on centerline. Took me a while to understand. My rate compass is probably 6’ off center resulting in a 10 degrees offset adjustment. I know, agree with you doesn’t make sense, but in the B&G world real.

[Gilligan8]

No, if I do heading hold it bobs all around and rarely actually holds the proper heading.

[BillKny]

Just answer your original question, an autopilot that is 10 degrees off course is WORTHLESS. That is entirely NOT normal, and totally unacceptable.

As has already been suggested, dig up the manual, and start the entire install process including dockside commissioning, underway calibration, and compass calibration. If you still have problems after that, then start looking into hardware.

Your system is hardly "vintage." even if the components are no longer in the current catalogs. It should perform as well as any out there.

[pjShap]

I don't know that particular autopilot, but both an older RayMarine a current Garmin model start out by holding an electronic compass bearing. Over the next 10-30 seconds they switch to using GPS course over ground. Once it stabilizes using the GPS COG everything is great. If the compass is not sufficiently accurate, it goes off the desired course in the beginning, while it's using the magnetic bearing. Calibrating the compass and going through the full autopilot setup/tuning made big improvements, and is well worth doing.

[mglonnro]

Originally Posted by smac999

I would redo all the setup and calibration.

Swing compass. Auto learn pilot etc.

^ This.

Our B&G autopilot did wild things when the compass wasn't properly calibrated. So make sure everything (compass + auto pilot) is calibrated!

[Gilligan8]

So does everyone think it's fine installed where it's at and I probably just need to recommission it?

[cr180]

1. Suggest you confirm that in heading hold mode boat holds course but bobs back and forth. If so rate compass off centerline is your 10 degree error and either can be adjusted as described above or you can just add or subtract 10 degrees when you enter your selected course.
2. The bobbing back and forth is a separate issue that definitely can be helped by rerunnning the commissioning set up. In particular make sure your set as a sailboat (large rudder vs small rudder power boat).
3. Will likely draw some comments from others with this statement but there is some bobbing back and forth even in the best case. It is called dead band. Intentionally designed into the set points to keep the autopilot from continuously trying to correct the smallest error. We find this bobbing is not detectable in open water but is noticeable in narrow channels.

[cr180]

The B&G (actually is the Robertson system) does not switch to Course Over Ground. And in cases where you can be set by current, would not want it to. The B&G system does have a No Drift mode which compensates for current set.

[Rucksta]

Originally Posted by Gilligan8

So does everyone think it's fine installed where it's at and I probably just need to recommission it?

Yes. If there was a position at the waterline close to the roll centre free from ferrous metal and electrical interference it would be better.

Should be OK where is.

If your MFD is a Zuess 2 check software version is at least 18.3. look for a later WiFi patch if you run the external GoFree unit.

The version previous v18.3 was glitchy and lost calibration if you hit the rudder stops 3 times.

Are you running a discrete AP computer e.g. NAC* with a rudder position sensor or is it a integrated wheel or tiller system ?

Recalibrate.

P.S. the recalibration swings the RC42.
If it doesn't match the steering compass then have the steering compass swung.