Mounting a fluxgate compass, ST4000

[landonshaw]

Purchased a used ST4000 and mounted it on the boat. Then I decided to print an instruction manual and read. Situation that I am questioning is:
I mounted the fluxgate compass at a 90 degree angle to the direction of the bow, but on a vertical surface. It fit very nicely in my cockpit at this location out of the way. Since the autopilot uses direction of travel, I believe it should not matter at what angel to the boat I mount the compass. The instruction manual details where to mount the compass but never mentions this deviation.
So will there be a problem with this? I have not taken the boat off the mooring to see how the instrument reacts, will do this on Saturday.
Thanks, Aloisius

[Pblais]

So will there be a problem with this? I have not taken the boat off the mooring to see how the instrument reacts, will do this on Saturday.

The compass will point north - always

Ideally you want it in a place not subject to magnetic interference. Inboard vs outboard and forward vs aft is better but not totally required. You'll do the calibration procedures noted in the documentation (Or go to the RayMarine web site and get the manuals in PDF format). If you have problems doing the motoring in circles part of the calibration it means the location for the compass was probably the problem. A temporary mounting in that case allows you to try other locations and see which one works better.

You need to do all the calibrations in order to get decent results. It really makes a difference. It may seem OK out of the box without any but don't stop there. It also helps to check the heading against a GPS and your own ships compass once calibrated to feel confident. The calibration will find the deviation errors on the boat and store corrections in the memory.

[delmarrey]

Mounting it as low as possible helps too. You want to try and get it on the pivot point of the vessel rather then having it swing back and forth in a seaway. It helps to keep it pointed in the right direction.

I mounted mine at the waterline on the front of the rudder bearing/casing. Seems to do well there.

[noelex 77]

It will be fine 90 degrees off. The electronics will allow the compass heading to be adjusted back to normal.
As well as the other advice, make sure there are no big electrical cables near. These fool people because the calibration will report everything is ok if it's done with out the cables carring current.
It's alo worth checking the location with a hand bearing compass.

[landonshaw]

I might remount after this info. I could possible run the line below deck and mount in the center and at waterline. It currently is at center, although above waterline by 4 feet.. I was wondering why there was so much electric wire supplied, now I see why. Thanks. Aloisius

[Jbaffoh]

My instructions said to mount it facing forward, on the centerline, at the fore/aft pivot point, and near the waterline. That's what I did, and it works great.

[roverhi]

I couldn't find a place to mount mine that I was sure would be free of electrical interference except near the mast. Mounted it low on the bulkhead at the forward end of the main cabin. Works fine there and completely out of the way after some boat yoga to tuck it up under the settee. Don't know what the effect would be of not facing it at right angle to fore and aft.

[xeon_tsd]

Now jsut to get the boat up to 88 knots!!


When i read the title this was the first thing I saw...

[Pblais]

It's also worth checking the location with a hand bearing compass.

Another way is to unmount the compass at the dock and slowly rotate it clockwise then counter clockwise having someone read the heading values. It's easier than spinning the boat.The compass only works in 90 degree sections so the transitions between the 4 quadrants is something to test going in either direction. You can usually find out if a spot has a problem or not. Little bumps along the way could just be correctable deviations but I fixed an autopilot where the original install was not in a good location even though we found nothing physical at all that should have made it less than a perfect location. Looking like a good place is all fine but the compass will know if it is a happy spot.

[Kita]

I bought a boat that has a problem with the compass & have a replacement in hand but before I put it in I want to make sure that first it was mounted correctly in the first place..when I handle the replacement just out of the box I realized yeah its a compass & suddenly I thought the mounting of the original unit might be the problem altogether. It is mounted on a vertical wall not on a floor and I'm wondering if that is a problem? Should the unit be mounted just like it's sitting on a table or can you mount it to the wall on a vertical surface? I understand how a magnetic field can affect it but I'm wondering if horizontal and vertical has an effect as well. It would make sense to me that it needs to be mounted horizontally but I don't know

[Jbaffoh]

Originally Posted by Kita

I bought a boat that has a problem with the compass & have a replacement in hand but before I put it in I want to make sure that first it was mounted correctly in the first place..when I handle the replacement just out of the box I realized yeah its a compass & suddenly I thought the mounting of the original unit might be the problem altogether. It is mounted on a vertical wall not on a floor and I'm wondering if that is a problem? Should the unit be mounted just like it's sitting on a table or can you mount it to the wall on a vertical surface? I understand how a magnetic field can affect it but I'm wondering if horizontal and vertical has an effect as well. It would make sense to me that it needs to be mounted horizontally but I don't know

I have only seen them mounted on vertical bulkheads. They work great in both of my boats. Try to put it near the centerline, at the pivot point where the boat pitches, and near the waterline. In other words, where it will move the least in the rough stuff. Also, keep away from metal and magnets. Not easy, but do the best you can.

[GordMay]

➥ https://www.sv-zanshin.com/r/manuals...ationguide.pdf

➥ https://www.simrad-yachting.com/Root...222543_B_w.pdf