Sometimes one gets so focused one one thing, one forgets what every 10 year old knows ... keep magnets away from the compass
For the sandpiper 565 I made two really nice hinged panels
with a battery
switch, 6 switches and fuse holders each side, a volt meter, and a 1 mA meter installed for future usage as a battery current
meter when I made or otherwise sourced a suitable shunt. I had all the nice parts
in stock because I was buying
for the Ontario
32, so proper marine
wire, heat shrink ring terminals, the whole nine yards. It was beautiful.
Then one day in the driveway with the boat pointing pretty much north, I noticed the compass
said east! It dawned on me what was likely the problem. I did some quick research
and realized that much error wasn't going to be compensated away.
I now have two large holes, and a few smaller holes that are now assigned to be a very custom grandson photograph mounting system.
I'd still like a voltmeter some day, but I'll have to mount it elsewhere, and I am not sure where the elsewhere will be on an 18 foot boat.
After I dug the meters out, I performed some tests. The meter began swinging the compass at about 18 inches of separation. I originally had the two meters mounted at about 10 inches of separation.
I now quote Mr. Simpson: "D'oh"