S1 Fluxgate Compass mounting orientation

I'm on my boat now getting ready to move the fluxgate compass to hopefully a better location. On the compass there is a flat mounting surface and a rounded housing. All the illustrations in the install manual show the housing part facing forward. My ideal location would require the housing part to face aft; is this not good? Will it affect the operation of the compass? There is no specific mention of compass orientation in the install guide other than to mount it vertically.

Mark, you can face it aft and it will work fine. You have to remember to reverse the wires when connecting to the computer though.

There are five color coded wires. The manual does not indicate which are power, data or ground. Are you saying that it should be wired completely backwards if it is mounted facing aft?

I guess I could call Raymarine but I'm sure there will be no one there until Monday.

Sorry Mark I should have been more clear. You only need to reverse the red and green wires.

Excellent! I'll give it a try.

The story so far...

Mounted fluxgate compass facing aft, dead center athwartships and slightly aft of center fore/aft and about an inch above sole - as low as I could get it. Wired with red and green reversed and grounded SmartPilot computer (it hadn't been before.)

With steering compass reading 248, autopilot was reading 64 - almost exactly 180 degrees out. Ah ha, I thought, if I just reverse green and red again it will read 248! No luck. Didn't change at all.

Mounted fluxgate facing forward, red and green wired normal; autopilot reads 300. Hmmm. Reversed red and green again; autopilot reads 137.

I'm going to leave the fluxgate facing forward and try to swing the compass tomorrow and see what happens. Then I guess I'll be calling Raymarine on Monday...

Success...finally...

Turned the Autopilot on Sunday morning and now it matches the steering compass. Go figure.

Went out to do the Seatrial Calibration and swing the compass. Started doing slow, wide circles; as big as I could do in Channel Islands Harbor. Two complete circles: nothing. But I didn't get the "Too Fast" error that I had gotten before. Three complete circles: nothing. Decided to tighten the circle a little. Two tighter circles: nothing. But still no "Too Fast" error. Tighten the circle even more. Now I'm turning in about a 20 yard circle. Two more complete circles and finally the Autopilot calibrates: 4 degree deviation. (Apparently you don't need a really large circle.)

Corrected the heading alignment along several headings and now the Autopilot is within 2 to 4 degrees of the steering compass depending on the heading.

Finally, success. After one year and two hours or driving around in circles...

Tried to call Raymarine to find out if I can mount the Fluxgate compass backwards but haven't been able to get through yet...

Response from Raymarine

I received a response from Raymarine regarding how the Fluxgate compass can be oriented.

It is OK to orient the compass housing facing aft and doing so does not require changing any of the normal wiring connections.

The only thing that needs to be done is to go through the SeaTrial Calibration procedure again to recalibrate the compass.

Latest update...

I re-oriented the fluxgate compass to face aft and recalibrated the autopilot. Everything works fine.

I finally realized that the fluxgate compass doesn't really know where north is; you have to tell it by adjusting its reading to the steering compass reading after it has been calibrated by the swinging procedure.

The instructions just say, "Do this" and "Now do this." They don't explain why. It makes a little more sense when you know why. And that would have made it obvious that it wouldn't matter whether it was facing forward or aft...