Too close?

[oscarvan]

Somewhere buried in another thread Mr Clarkson mentioned a magnet/whacky compass situation which was an "aha" moment for me.... The PO's choice for compass sensor and Algae-X

So is this too close?

[SKYCHENEY]

Try a hand held compass and move it around the area and see if/how much it's affected.

[oscarvan]

Try a hand held compass and move it around the area and see if/how much it's affected.

Simple yet elegant and scientifically sound..... why couldn't I think oft that.

And the answer is...... Nope. The magnet has a serious effect on the handheld compass up to about a foot away. Down by the hull it's nothing.

[racclarkson@gmail.com]

Simple yet elegant and scientifically sound..... why couldn't I think oft that.And the answer is...... Nope. The magnet has a serious effect on the handheld compass up to about a foot away. Down by the hull it's nothing.

You might have to de-power the boat other than AP and plotter. Then you can energize circuits and look for a swing. Or maybe the compass is just too close to the iron. In that case, detaching it and moving it even a few inches will produce change.

[Captain Ralph]

The later flux-gate compasses can be calibrated. A special program helps them make a real 360 degree swing. Check your owners manual.
I remember working on older APs like Benmar, a real compass with spokes in the card that an optical eye would read. No calibration on these beast.
Other mfg's used this style and some are still in service.

I have also chased later compass issues when mounted close to bilge, sump and black water pumps.
I remember an engine alternator driving one compass crazy at different speeds.

The best horror story; compass installed in the bottom of a state room closet. All was good till suddenly one weekend the AP went crazy; Found steel toed shoes in there also.

What model AP do you have?
Find the compass and survey the area well. Could be a tool box close by.

[SeaEric]

Did I miss the comment that says what brand the A/P is? If it's a Garmin, I own one and have some related experience.

[oscarvan]

Yep, late model Garmin.

[bigbill]

is the garmin networked with other stuff through a nmea 2000 backbone? mine had similar problems until i put a terminator plug on the backbone. check to see if you have a terminator

[Captain Ralph]

Is that the AP compass in the bottom of the pic?

[rsmith]

Is that the AP compass in the bottom of the pic?

Looks like the depth transducer to me.