Off the forum there has been a great deal of discussion in the past about trying to get the magnetic compass to actually work and a few have given up, saying it is a lost cause, even SHM....not good...every steel boat can fit a magnetic compass and get it to work and infact 60 percent of all the fishing boats in Hobart are steel and must have a working compass by law and do.
The best I have found for ICE is the Sunto D165 with Quadrantal spheres and a heel error corrector. It has a global card that is balanced for the entire world, not dipped for just the north or southern hemispheres and has a strong card magnet and excellent adjusting magnets in a frame under the compass, which are easy to use...the compensating balls are not just soft iron, they are special cancelling magnets in plastic balls which are supper effective...the heeling error will help me with the sailing rig.
I am using only marine compensated speakers for the stereo in the pilot house and they are both at the back and I am fitting the compass in the center of the pilot house so the card is above the window line with the steel below...all basic precautions to give the compass the best chance to work.
I still have the Comnav GPS compass...a must if you can afford it...and will use it to swing my magnetic compass and check it regularly on all headings...write up my deviation card...all very important for your insurance as if you ever had a claim and the question was asked about the accuracy of your Mag. compass if it was relivant...you may find yourself in deep water if you say it was not working...In Australia and virtually all international maritime juristrictions it is illegal to go to sea without an effective compass ....I would never go to sea with out a few things...one of the critical ones is a working Magnetic compass that you can rely on when the shit hits the fan.....a blind man can easily walk off a cliff if he cannot see and he has to walk beside it?
I hope to fit the compass in a couple of weeks and sail away with ICE, so will keep my fingers crossed that I actually can get it working...will let you know....but it is the best for the job....AUD$ 1850
Lifetime sailing including 1990 BOC Singlehanded Around World Race...many Antarctic sailing expeditions....lived together alone in a box in Antarctica for a year.