Hunter 41DS with original Raymarine C120 chart plotter and electric compass issues

[MFD]

Hey All,
So I have been working around this since (second owner) got the boat about 5 years ago.
Bottom line is that the digital compass tied into the C120 chart plotter typically trends off so that the boat is looking like it is heading about 15 degrees to starboard after things are running for a while.

The compass/gyro (or whatever it is) is located relatively well forward on the starboard side bulkhead that separates the forward cabin from the main salon. There is also other 'electrics' in there from the 'mariner package' which appears to have been commissioned by the dealer and not hunter themselves given the quality of work (run a 110-vac line with NO external/abrasion coverage from the port side?).\

edit: Also, when I test, do figure-8-resets, and rely on it, the 'after market electrics/inverter' are shutdown.

I have worked with this quite a few times doing the 'figure eights' and all that to reset the compass yet it still consistently goes off track.
Had some fog today so it reminded me of it since I had to manually re-align the radar with coastal profiles as normal procedure to see what was where.

My understanding is that with older C120 Raymarine there is a resistor or something that wears out and is the root cause of the problem. For better or worse, I am not in a position to upgrade all the electronics right now

Just curious if anybody has come across this, perhaps replaced (or moved) the digital compass, etc.

Thanks in advance!

 

[sailtheworld79]

I had this happen to me on my Catalina 34 with an ST70 AP. It really annoyed me. I finally gave up and replaced the fly gate compass and course computer and it worked flawlessly after that. Cost me less than a thousand bucks. I just bought a 41 DS with an E80 MFD and ST6001 AP and I pray I don’t have the problem again. Everything checked out in the sea trial and I need to get at least a year out of these before I go drop 10k to upgrade everything. Good luck!! BTW, I HATE Raymarine electronics!! Switching to all B&G when the time comes.

 

[RoyS]

Not sure if I understand your issue. If you mean the vessel image on the chartplotter screen is pointing 15 degrees off then I had a similar issue with my C120 once. My compass is under the galley sink inside the cabinet there. We keep a small trash can under there right next to the compass. One time my boat appeared sideways on the chart. This turned out to be caused by an empty Pringles container with a metal bottom leaning against the compass. Once discovered and removed, boat appearance on the plotter was normal. Possibly you have an iron object too close to your compass device. BTW my 14 year old Raymarine C120 chart plotter, radome, and array of ST60 instruments continue to serve me well.