Simrad MFD - course and heading do not align.

[tiz]

I would be looking for some ferrous metal tools, food cans, parts, etc stored for the voyage after the initial setup, near the compass.

--kevin

 

[Jeff F]

Another contributor is that typical nav electronics now depend more on having an accurate heading reading, not just a consistent reading. Things like North up displays on chart plotters and radars require a good heading sensor, or even just a heading stabilized chart display vs COG. And (M)ARPA creates a whole new demand on heading sensors as well.

I think that's where the benefits lie, and for those using those capabilities it's very easy to see the value.

As far as improving AP performance, it seems like a solution looking for a problem in most cases.

 

[88FuHwa]

I had the same problem suddenly with my Simrad system. Then I realized that I had just placed my rechargable drill and impact driver next to the compass. Once removed, the system cleared up and we went on our way.

 

[rherten]

Fluxgate Compass?

I had a similar issue which I eventually traced to my fluxgate compass. My fluxgate compass is mounted inside a cabinet in the back of the cabin and provides autopilot/heading information to the chartplotter.

I inadvertently stored some metal deck chairs next to the fluxgate compass which threw the compass off and resulted in a skewed heading on my chartplotter just like yours. It took me forever to figure that out, but it was easily resolved after that.

 

[Csellars]

I would check the remote compass. Make sure someone didn't set a tool kit or flashlight with a magnet near the compass. That would be the most likely scenario. it looks way more than what current or calibration would cause. If there is no metal or magnetic interference, try manually adjusting the compass to align with the boats heading. they can sometimes vibrate off from the original alignment. Then check it on several headings to see if that fixes it.

 

[twistedtree]

I think that's where the benefits lie, and for those using those capabilities it's very easy to see the value.

As far as improving AP performance, it seems like a solution looking for a problem in most cases.

I'm not so sure. I know a number of people who have experienced significant improvements in AP performance when switching to a higher quality compass.

 

[Rico Adams]

Simrad

I have the same problem. I called Simrad tech support and they had me did deep into a menu on the unit. There was a number there that indicated interference with the compass. I relocated itge compass and the problem went away.

 

[LarryM]

I'm not so sure. I know a number of people who have experienced significant improvements in AP performance when switching to a higher quality compass.

Absolutely. Even upgrading from standard fluxgates to rate compasses on two previous Simrad systems made an enormous difference in accuracy, response and usability. Honestly, no comparison.

 

[Hippocampus]

Larry-what units did you use?

 

[psneeld]

I think the type of boat and use may have a lot to do with it.

For a simple 6-8 knot trawler and many other type boats run at those speeds in fair conditions.... I am not sure just how much (if noticeable) improvement over the simple fluxgate really is.

Buy what you want, buy what you need.... just realize that the minimum is sometimes "good enough". This is often a constant debate on TF.

Again is my stance is that many here with older TT's or equivalents with 20 year old APs with fluxgates are going to veer off course and wind up in Aisa or Africa because of the fluxgate. So don't panic and drop money on something that may add improvement but insignificantly measurable.

If you want to...upgrade to a more modern autopilot with the compass upgrade.

 

[oguidry]

Several posts about the obvious effects of magnetic fields on compasses.

Gemeco )a wholly owned subsidiary of Airmar) developed an iPhone app called iNstall. It had several features including a magnetometer specifically for the purpose of locating compasses. It may no longer be available.

There are several iPhone magnetometer apps available.

 

[LarryM]

Larry-what units did you use?

Both of the systems were installed in my former boat Boomarang, a Fales 30 Caribe (like a Willard 30) trawler, which is definitely a 6-7 knot boat.

Simrad AP21, AP22, JX300, FU50, RFC35, RF300, RPU080 - Robnet/NMEA0183-based Autopilot. The standard RFC35 Compass was upgraded to the optional RC25 Rate Compass.

This was then upgraded to:

Simrad AP26, AP27, AC20, FU50, RC36, RF300, RPU080 Simnet/NMEA 2000-based Autopilot. The RFC35 Fluxgate was installed as a backup compass.

In both systems, the performance on the rate compass was measurably superior to the performance on the fluxgate compass. It did take some fine tuning of the parameters to get either to perform optimally. Both systems steered the boat like it was on rails and were absolutely reliable.

My current sportfish is all Garmin. Works well, but no follow-up steering, which I do miss.

Larry