The Ritchie compass in the Thoroughbred I just bought is off by almost 50 degrees. When I remove it, and move it around (away from it's mounting location) it's OK. I think it's the IMCO helm pump directly below it that's causing the error. I've tried to adjust it out, with no luck.

Will a Fluxgate type electronic compass work better? Are they adjustable for mag error?

Thanks!!!

I searching through the KVH Industries site and their Q&A section I'd say you'd have the same problem.
A fluxgate compass still works off the earths magnetic field. It may be able to compensate for the 50* deviation but I couldn't find a copy of their users manual.
KVH recommends mounting their compass no closer than 18" to a steel object.

Best thing to do is look for a fluxgate compass with a separate sensor that can be mounted as far away as possible from magnetic interference.