Mounting a fluxgate compass.

[Slade]

I've got a Raymarine ST40 fluxgate compass. No problem with mounting the display away from interference but the tag on the actual compass shows to not mount near a motor, transmitter, metal bulkhead, etc. It does not say on the tag or in the instructions about distance from say..a deep cell battery. I have a perfect place to mount it on the centerline and near the center of pitch but it's only 18" from the battery.

This is on a Starwind 223 so there's not a ton of places that fit the pitch/roll criteria to choose from....this is my first new fangled, high faluting, electronic compass so I'll take all the wisdom you can throw at me.

Thanks in advance for your time and wisdom.

Jim

 

[Maine Sail]

I've got a Raymarine ST40 fluxgate compass. No problem with mounting the display away from interference but the tag on the actual compass shows to not mount near a motor, transmitter, metal bulkhead, etc. It does not say on the tag or in the instructions about distance from say..a deep cell battery. I have a perfect place to mount it on the centerline and near the center of pitch but it's only 18" from the battery.

This is on a Starwind 223 so there's not a ton of places that fit the pitch/roll criteria to choose from....this is my first new fangled, high faluting, electronic compass so I'll take all the wisdom you can throw at me.

Thanks in advance for your time and wisdom.

Jim

Use a boy scout hand held compass. It the compass moves as you get close to the batteries it's not a good location.

 

[bria46]

Mount it Under the "V" berth as far forward as possible

 

[Bill Roosa]

Avoid locations that pitch wildly. If you can't stand in that part of the boat in rough weather then the pitching will cause the fluxgate to have issues with staying on bearing. It has something to do with the magnetic field not being parallel to the earths surface and the vertical component (dip) interfering with the compass trying to sense the horizontal component. You would not want to mount it "up high" either for the same reason. I believe the manual recommends locations closer to the center of buoyancy are preferred.
As for the batteries, MS compass idea has merit. Get a helper to switch electrical items on and off to make sure the testing compass does not have a large change when an item is on. course if the item is an anchor windlass you might be able to ignore it as you will not be using the fluxgate while weighing anchor much.

 

[Slade]

Thanks folks for the quick responses. The bulkhead I was thinking of using is just a bit aft of the pitch access but dead on the centerline. Handheld compass exploration it is.

Thanks again.

Jim