Replacing our Fluxgate Compass

The Bloke has being driven crazy by our Raymarine C80 Chartplotter display. Quite randomly the boat icon that displays on the electronic chart has begun to be unreliable. The display for vectors is fine; things like the heading and wind speed, but the boat icon occasionally reverses or goes sideways! Mr Murphy who is constantly lurking and enjoying such opportunities, more often than not reverses the icon at the worst possible moment, for instance, whilst traversing a tight channel. This is as much an annoying distraction as unsafe. Hours of research on the Raymarine knowledge base has pointed to a likely culprit - the Fluxgate Compass.

Our Chartplotter and ST6002 Autopilot are by now old and superseded. If we are lucky it will only be a Fluxgate Compass issue. If not, we could be up for a new computer/chartplotter - think big buck$$. Oh, and should it be a Fluxgate Compass issue, Raymarine no longer manufacture them anyway. The newer E Series Autopilot/Chartplotter systems don’t use them. A replacement might be difficult to obtain and in any instance, more likely to be 2nd hand than new. The Bloke is not giving up without a fight.

Baby steps and a process of elimination would be required to resolve this and fingers crossed that it's not a fist-full of dollars to remedy.

Here is the Fluxgate Compass.

Note the weight at the base that assists with the gimbal effect.

Step 1 Upgrade the Raymarine firmware. 

The final firmware upgrade for our by now, legacy Raymarine C80 Chartplotter, was released in 2012. Until now we'd never thought nor needed to install it. This should have been a fairly straightforward matter but wasn't. We located a pair of brand new blank 2GB SDK cards we’d bought (with difficulty) the previous year when wanting to download extra charts for the Pacific. The Chartplotter couldn’t read the cards. It was manufactured before cards of this capacity were produced. We wondered if our efforts would end right here and The Bloke was pretty annoyed with this prospect. I then suggested checking our original SDK card, the one that held only the charts for Western Australia. We at least knew that it did once work. Would it have enough space to also accommodate the freshly downloaded firmware upgrade and data back-up?  Fortunately it did and so did the back-up that was necessary of stored Way Points: hundreds of Way Points and chart embellishments such as where we’d previously anchored. It was now possible to run the upgrade. Phew.

During the installation The Bloke needed to confirm deletion of data. He hesitated, his finger hovering nervously over the button for some time. Delete? What if this all went to custard? Happily the firmware upgrade was completed without incident. As a bonus it also meant that our new brand new 2GB STK cards could be read by the system for future backups and file transfers. The firmware upgrade did not however, fix our spinning boat icon. Move on to Option 2.

 

The Fluxgate Compass conveniently located behind the holding tank.

Who'd have thought! 

Step 2 Recalibrate the Fluxgate Compass.

The Raymarine knowledge base didn’t actually explain how the compass could become uncalibrated but recalibrating was the next thing to do. We needed calm water and then to motor the boat through a series of 2 minute circles while clicking the key sequence to initiate a factory re-set and to then adjust the off-set between the Autohelm and the boat compass. Sadly, still no joy. Move to Option 3.

  

 The Bloke checking the replacement with his multi-meter. 

Resistances were in the correct range, unlike our existing one.

Step 3 Install a replacement Fluxgate Compass. 

The Bloke’s internet search lead to eBay, which indicated a $250-300 AU outlay plus a wait for delivery. This had the potential to delay our trip south. The cost? Well, we'd just have to wear it. We did strike a little luck here though. A post on the Sailing Australia Exchange - Buy, Sell Swap Services Facebook site came up with a a reply within 20 minutes for a Still-New-in-Box replacement for only $180 AU from people we knew. AND they were only a day away from us. They were waiting for the very same weather window to travel south from Southport and would be delayed long enough for us to rendezvous with them. Golden!

The said device has now been installed. We’ve traveled 320nm since, in which time there has been an improvement but an incomplete fix. We’ve had a 2nd go at recalibrating the new fluxgate compass but no real opportunity to test it for a prolonged period. Our previous recalibration efforts were for the old one. We'll get to try things out on our next leg from Port Stephens to Pittwater on Sunday. Wish us well. If this replacement is unsuccessful we'll be parting with a lot of boat dollar$ sometime soon!!

 

Connecting the device to the Autohelm computer.

As usual, locker contents have to be removed to access anything.