Author Topic: Flux gate compass wiring  (Read 2341 times)

filban

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Flux gate compass wiring
« on: July 29 2020, 18:23 »
I inherited this wiring and it’s been on my list of jobs to tidy up and try and hide

The autopilot works fine


What sort of connections should I use instead of the choc blocks or just get a longer length of cable

This is located under the chart table ; Bavaria 32 2002

Craig

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Re: Flux gate compass wiring
« Reply #1 on: July 30 2020, 04:50 »
I'd be very worried if my fluxgate was located under the chart table.

The Fluxgate needs to be well away from any metal or magnetic objects.

My wife almost crashed our boat by moving one of her Bras in the forward cabin locker where our Fluxgate was located in our Bav38 (2009). The wire in the Bra deflected the compass by 70 degrees, luckily away from a boat a few metres next to us. If it went 70 degrees in the other direction, the other boat would have T-Boned us.

 After talking to other sailors many had problems with the Fluxgate compass in the aft cabin or near the Galley. One owner was having problems when the metal plates stacked vertically in the Galley were flopping from side to side when taking or heavy seas.

It would be a great exercise to compare your fluxgate compass reading with your Binnacle compass and your GPS course when installed to see if you have any other issues.

Craig
"Shirley Valentine"
Gold Coast
Australia

Symphony

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Re: Flux gate compass wiring
« Reply #2 on: July 30 2020, 09:17 »
Under the chart table is a common location as it meets the conditions required by Raymarine. That is near the centre of the boat and away from large lumps of metal. Distance from the engine which is the largest lump, seems to be the most important issue as the other common locations of the aft cabin cupboard and on the bulkhead inside the lazarette seem to work just as well.

Rampage

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Re: Flux gate compass wiring
« Reply #3 on: July 30 2020, 10:04 »
OK, if the autopilot is working well with the compass where it is currently, then no need to move it.  As to how to connect it, I use small (2.8mm) crimped terminals to join the wires.  You need to take care to make a good connection and that the connection isn’t under tension but mines been fine for years since I replaced a broken compass.
You mention wanting to hide it away, if so then I’d be tempted to move it to the aft cabin locker, making sure that reinforced underwear and magnetic games aren’t stored near to it.....

Yngmar

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Re: Flux gate compass wiring
« Reply #4 on: July 30 2020, 11:44 »
Looks like it's just a short extension, not a means of disconnecting it. So I'd splice the wire, solder it, insulate and then make sure you have a continuous shield (all the ST60 cables are shielded) by wrapping it in some tin foil before applying heatshrink as the outermost layer. These splices are durable, restore the shielding and are barely thicker than the wire itself.

Just did the same for our new depth sounder :)
(formerly) Sailing Songbird  ⛵️ Bavaria 40 Ocean (2001)

Salty

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Re: Flux gate compass wiring
« Reply #5 on: July 30 2020, 19:12 »

What sort of connections should I use instead of the choc blocks or just get a longer length of cable


I used “wire gel crimp connectors” from ebay for connecting my flux gate compass, and while I had plenty of cabling supplied with the compass such that it was long enough to reach the course computer, if I had needed extra cable I would have been sure to use “tinned copper cabbling.”  Ordinary copper wire can be a problem because the copper corrodes quite quickly in a salt laden atmosphere, and that leads to communication errors.
The gel connectors have gel within them and when you squeeze the connector some of the gel gets forced out, but the rest remains in place and protects the ends if the cable and ensures a goid electrical connection. They are readily available through ebay.
As for location of the fluxgate compass, on my B36(2002), I placed it on the transverse half height bulkhead that separates the starboard saloon settee from the chart desk, and placed it behind the back of the settee. Sometime months later, absent mindedly I placed something metalic inside one of the plastic cupholders in the shelf above and then wondered why the autopilot would steer anywhere but where I wanted it. Not for long though as I soon realised what I’d done. The next problem for my wheelpilot was the day when I forgot to release the helm brake . . . . . . .(sigh !!).