We have a 1999 Hunter 340 and have a problem with the Ritchie compass having magnetic interference. Our compass repair tech says something in the pedestal ( radio, Thrittle lever etc ) is causing the interference. Howeverer nothing has changed since the boat was new. Any insight is appreciated.
Hunter 340 compass interference.
- Thread starter MARK340
- Start date
It’s hard to imagine a 25 year old boat on which “nothing has changed”. What is the specific problem you notice and with what other compass have you compared it?
Depending on what kind of interference you are seeing, as Don says, it may be that someone may have twiddled with the compass adjusting screws leaving it a bit confused.
This is a good one to watch:
DIY Compass swinging
This is a good one to watch:
DIY Compass swinging
Thanks. I just got back from the boat and found that the throttle cables and shifter had been replaced with OEM parts from Hunter.
Here's what i observed today:
* auto pilot heading and i phone compass heading 120 degrees
* boat compass heading 190 degrees
* if i remove the compass from the pedestal to the side 3 feet , the heading changes to 120 degrees
* if I put the compass back in the pedestal and move the shifter to reverse the compass reads 200 degrees.
I don't know if this issue existed utilizing the old shifter which I still have. The old shifter and new shifter are made from ferrious metals. Both magnetic.
Here's what i observed today:
* auto pilot heading and i phone compass heading 120 degrees
* boat compass heading 190 degrees
* if i remove the compass from the pedestal to the side 3 feet , the heading changes to 120 degrees
* if I put the compass back in the pedestal and move the shifter to reverse the compass reads 200 degrees.
I don't know if this issue existed utilizing the old shifter which I still have. The old shifter and new shifter are made from ferrious metals. Both magnetic.
The radio would be my first guess, as anything with a speaker has a magnet. Since you say the shifter is magnetic that could be a possibility too.
It is possible that this wasn’t from a change at all - the original design may not have considered compass accuracy. It’s pretty common for builders to put chartplotters with magnetic SD card doors in pedestals, Lots closer to the compass than the 36” most plotter manufacturers recommend. For your compass to be off by 70 degrees does seem extreme, but it may have never been spot on.
It is possible that this wasn’t from a change at all - the original design may not have considered compass accuracy. It’s pretty common for builders to put chartplotters with magnetic SD card doors in pedestals, Lots closer to the compass than the 36” most plotter manufacturers recommend. For your compass to be off by 70 degrees does seem extreme, but it may have never been spot on.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,520
I liked the compass swing video attached by @kloudie1
It provided an easy-to-understand method of magnetic compass use. You identify the variation of the compass and then apply that variation while in use. If you have not sailed in fog or had your electrical system fail, this may not seem relevant. When your sensors are reduced to twenty feet beyond the edge of your boat, the tools you have on board become critical to your survival. A proper compass and its use can get you home when everything else fails.
It provided an easy-to-understand method of magnetic compass use. You identify the variation of the compass and then apply that variation while in use. If you have not sailed in fog or had your electrical system fail, this may not seem relevant. When your sensors are reduced to twenty feet beyond the edge of your boat, the tools you have on board become critical to your survival. A proper compass and its use can get you home when everything else fails.