Occassional Odd Behavior with 711c

[cp10415]

I have my 711c hooks up to a couple of TZT2. I have been using these for a year and a half now. These have worked fine most of the time.

However, there were occasional random issues with the autopilot. The autopilot was set to go to a waypoint. While it's going along, the autopilot would sometime try to make some kind of course corrections and sway on its own and seemed to totally lost its sense of direction of where it wanted to go. It would run the boat in a big arc and I had to put it in standby and take control of the boat or it's going to set the boat to run in a big round about.

This had happened more time than I liked. Sea conditions were mostly 1-2' swell. Nothing out of the ordinary when these happened.

Any idea what could have caused this behavior? Anything I can try to address this?

Thanks.

 

[Johnny Electron]

It sounds like your heading is being pulled by something. It can be a motorized fishing reel, toilet up flush pump motor or just about anything. When you start experiencing problems, check what the heading of the pilot is in comparison to the steering compass and the GPS course over ground. I expect you will find that the heading is off.

 

[Taniwani]

I had my boat go in a circle over a high voltage power cable some 200 meters deep.

 

[cp10415]

Thanks. But how do I check the heading??

Also, how could something like motorized reel or flush pump affect the heading?

 

[Johnny Electron]

Pumps have magnets, as do electrical motors/reels. The basis of magnetic north is based on magnetism. To keep it simple there are items that can interfere with your compass. If you have trouble locating your heading information on screen, I recommend contacting technical support while you are on the boat. They can talk you through showing the information and how to compare it to your COG and Steering Compass.