B&G Precision 9 rate compass

[Fearnow]

I had a RC 42 rate compass that died. My autopilot and CP seem to work fine, but thought I would contact Navico before purchasing a Precision 9. The RC 42 is no longer made. I didn't have any luck understanding Navicos' explanation on what, exactly the Precision 9 does and how is my AP following routes with out either. I have checked utube and other sites, but still looking for answers.

[skipmac]

Have used the Precision 9 compass on my mixed B&G/Simrad system for a couple of years now and am really happy with how the AP works.


Since it's been a couple of years since I installed it I remember enough detail to give a good breakdown of how it works other than mutiple axis, rate of turn and heave data (which was not implemented in the original units but supposedly will be added in future software update). Bottom line, it holds a good course with minimal correction compared to my previous APs.


Regarding how your AP is following routes, I'm guessing it is getting heading information from GPS data on your network. Do you have radar and some other possible source of heading information? That is another possibility.

[Fearnow]

Skipmac: I think you have the answers!

The AP is getting position from CP GPS or the other GPS under the deck. The AP is following courses, but only after some erratic behavior. Sometimes going a full 360 degrees before figuring out where it should be going. And forget about rate of turn and heave data. Also, must be why my electronic heading on the cp doesn't match my fixed compass? I guess not having the P9 is making my ETA info way off?

[Bill O]

A 9 axis IMU is a relatively inexpensive item ($10-15) and is approx. the size of a quarter. It always amazes me when they put a plastic housing on it then charge a ridiculous amount of them (B&G ~$645).

We have an IMU in our pypilot AP and it works well. Haven't looked for a DIY IMU interface for your B&G AP, but maybe its out there.


Bill O.