Kito,
I know I will take some hits for this, but I no longer use an integrated GPS, AWI, Knot meter, autopilot & depth gage on my boat (Seatalk System).
I did have this setup & then this integration of instrument failure happened to me at a critical moment 200 miles from land, at night, in a terrible gale. My GPS was off course, my AWI stopped working & my pretty lady onboard was white with fear. Well, we survived without any damage or injury, but it got me to thinking.
From what I have experienced on land of electronic failures from cable to wireless to cell etc., all of these fail all of the time. Sometimes for short periods, other times for longer periods. Experiencing this, I re-did my electronics thinking. I decided to disconnect my Seatalk system although, I have all the equipment but now, keep everything separate.
My GPS, autopilot, AWI & Depth Gage, are wired independently. I also rely on Charts, NOAA weather forecasts, alerts & my sextant to give me all the info I need. I always check the local conditions & I always end up dead-on to my destinations, no matter nite/day nor, the conditions. And, I only have a 30 footer.
I just felt that with an integrated system, if something went snap, I could not only lose my integration, but instruments that that were not shot dead first hand, With all integration, if the controller failed(as in my case), the other instruments may malfunction or fail also. This happened.
I have friends with this type combo package & some have had controllers fail. Sometimes this burned out their electronics in other units as well.
So staying on the side of caution, I NOW have a separate GPS, Depth, AWI & Autopilot instruments all isolated. If one goes out, I have the other instruments working. If these die, I have my backups, if these die, I have my sextant & if this dies, I have alot a sh**load of prayers as a backup.
Plus, the more one leans on integrated electronics, the more that can fail. I find that keeping it simple works best for me. Not to say that another sailor's preference is wrong, for me it's of a personal taste. Alot would depend on if you are a long-distance cruiser/racer, then the parameters surely change somewhat, but I'll bet your backup systems, are wired in also.
Remember the Prudent Navigator's motto:
"The Prudent Navigator never relies on only one form of navigation".
CR