We are adding a compass to the wheel area and already have a Raymarine C70 built in. On another forum I read that some units require a good amount of separation. I checked the Raymarine instructions and they say 3 feet. I tested the compass with the C70 on and off and the compass was steady at 3 inches from the display. Does this experiment settle the interference question?
Compass and multifunction display
- Thread starter Quoddy
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No, because the interference may only show up in certain directions. It may have no effect when the boat is headed north or south but effect it considerably when headed east/west. You'd really have to swing the compass before declaring it fine.
Magnetic north
The boat isn’t in the water and the compass enclosure will be difficult to construct on the mooring. I was thinking, I might be able to get similar results by testing the compass on all sides of the C70. This would change the relationship between magnetic north, the compass and the C70 .Might this yield similar, but not exact, results to moving the boat through 360 degrees?
The boat isn’t in the water and the compass enclosure will be difficult to construct on the mooring. I was thinking, I might be able to get similar results by testing the compass on all sides of the C70. This would change the relationship between magnetic north, the compass and the C70 .Might this yield similar, but not exact, results to moving the boat through 360 degrees?
I was on board when a professional swung the compass on our 40' ketch in the early '70s. We ended up with several small magnets fixed around the compass to correct for deviation on very specific headings. You can't predict the outcome without going through the process.
Quoddy,
You can install whatever you want but you should then have the compass professionally swung. There is Charlie Cook out of Yarmouth and Bob Witherill in Belfast. This needs to be done in the water with the instruments running how they normally would. They will usually first adjust the cardinal positions then check the inter-cardinal. When done they will leave you with a deviation card. Best money you can spend in Maine...
You can install whatever you want but you should then have the compass professionally swung. There is Charlie Cook out of Yarmouth and Bob Witherill in Belfast. This needs to be done in the water with the instruments running how they normally would. They will usually first adjust the cardinal positions then check the inter-cardinal. When done they will leave you with a deviation card. Best money you can spend in Maine...
No, this generally won't work, as the physical relationship of the display needs to remain the same relative to the rest of the boat as well as the compass, so doing it with the boat on the water or using a travelift is the only way. 
Thanks
Thanks for the help on this one. I tried the compass on all sides of the display while turning it on and off and running various features. The compass was rock steady, so I will build it in as planned and then move to the on the water adjustment.
Thanks for the help on this one. I tried the compass on all sides of the display while turning it on and off and running various features. The compass was rock steady
, so I will build it in as planned and then move to the on the water adjustment.
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