Navpilot drifting and no nav data


Furuno Super Fan
I am doing extensive sea trials on my Furuno network of instruments... and 2 issues that i don't understand. The Navpilot is defined as a "sailboat". Today it was 30 knots on the water and some rough sailing so a lot of work for an autopilot.

Wind mode; works perfectly. Very capable on all wind (rear wind is a little bit difficult because of the precision asked) and globally this function works very well.

Auto mode; (both advanced and normal). I love the feature but after a few minutes, it start to drift. Suppose i ask 300 degrees. For the few seconds it works to it, but after a few minutes i look back and the Navpilot can be as far as 250 or 350 degrees. Even if i wait 30 minutes it only get worse. But as soon as i turn the know asking for 1 degree more to starboard or to port, it seems to "awaken" the Navilot which then try to recover all the accumulated error.

Nav mode; yesterday i was on a route generated on the NN3D, works well. Today i draw a route on a PC connected to the Navnet network through Maxsea and when that route showed up on the Navnet i wanted to do a "Nav" to it... whatever i did i alway got a No Nav Data. Altough i have all the required PGNs ... all day it refused to take the route.

So from this first trial, i definitely have some work to do but i have revisited the installation procedure and can't find someting that i havent done. Where should i look for a clue to these problems ?

An update on my trial. Today on calm water the AUTO mode worked perfectly. After reviewing the documentation i think i should have put the Navpilot into "precision" setting and ajusted the "response" feature.

But the issue with the "no data" is puzzling me. I have redone the factory installation procedure, checked all PGNs, all the Navnet sensors are correctly seen by the Navpilot. Why does it refuse to get a route from the Navnet3 i definitely need help in getting deeper into the diagnosis of this issue.

Thanks for any clue provided
Thanks for the update/sharing. I have heard great things about the new NavPilot 700 series with sailboats.

I would recommend that you check your NMEA 2000 configuration in your NN3D and verify that it has XTE (Cross Track error) info turned on to the autopilot. If it doesn't work; can you tell me what NMEA 2000 items you do have "On"?
Hello Johnny,

Yes i do have the XTE since the previous post on my first installation. I think i have found the problem which lies just a few inches in front of the Navpilot; me. Most often i drove the boat out of the marina and the first thing that i do is to put the Navpilot on "auto" mode while we prepare the boat for sailing. It is said in the documentation that there is an interval of 15 seconds between the moment a "route" is defined and the moment the Napilot can use it. It seems the 15 seconds delay should be spent while the autopilot is on "Standby" only and not while it is on "auto" mode.

Is this the possible cause of my perception of a problem, because now that i wait the 15 seconds in the "standy" mode it seems to work every time i need it.

Here is the list of PGN received by the Navpilot:
127250, 127258,129025,129026,129029,129033,129283,129284,129285,130306,130311


I agree. I think you found your problem. You should command the unit to NAV after the unit is on STBY. When you have the unit in AUTO it is already following your instructions and if you wish to change modes, it should be taken to STBY first.
Hi Johnny

Today i had a lot of problems on the water with the MFD12..related to the Navpilot. I had 3 occurences of "Furuno.Blackbox.MFD.exe - native exception" while the Navpilot was navigating to a route from the MFD12. I have the MFD12 since a year and i never experienced this. Is is a coincidence...

I also had 2 occurences of the MFD12 hanging and the Furuno blue page appearing and the MFD12 was stuck in the reboot loop.

This is very serious issue, should i call Furuno support or is the Furuno.Blackbox.MFD exception is a known issue ?


The error(s) and problem(s) you are seeing concerning the "Blackbox.exe" has to do with the TIDES & CURRENTS overlay. Please do NOT leave the Tides or Currents Overlay turned “On” in your system. (Check each MFD, and each section of your screen if running split screen) It is okay to use your tides and currents when needed, but turn them OFF when you are finished with your planning. Each tide and current icon is calculated. There are thousands of them and it takes a lot of CPU power to keep them all constantly updated, in real time. Leaving them “On” puts a great burden on the CPU, along with everything else the MFD is doing. If you leave tides and currents turned "On", you WILL crash your MFD. If you do this enough times, you might have to reload your unit software due to software corruption caused by crashing the system over and over. This is the only issue known to crash the MFD8 or MFD 12 and only happens when these items are left “On” for extensive amounts of time.
This is almost a good news :) Indeed my tide overlay was on. I'm glad you are explaining this i will put to remember forever. So that may explain why the Navnet was not capable of sending navigation information to the Navpilot. The RD33 saved my day :)

thanks for explaining the situation,

Good afternoon Andre,

I believe I can help you to get nav data from your NN3D to the NavPilot 700. It sounds like you have all the wires terminated properly and all the PGN's going from the NN3D to the pilot. You probably have all your sensors in use correctly set up for the pilot as well. Could you please verify whether you selected the Nav Option source. To get to the Nav Option source menu for the NavPilot 711 please put the pilot in standby. Next hold down the [menu] button until the menu appears. Next scroll down to choose [other menu], continue to scroll down until you find Nav Options and select it. Once in the [Nav Options] menu choose [Data Source]. In the [Nav Options, Data Source] menu you have to choose how many sources you want the ability to navigate from (source 1, source 2, or both). If you have two sources please choose both, if only one choose source 1. Once you choose how many sources, you still have to tell the pilot what those sources are, so scroll down to source 1 and choose the NN3D option, if you have 2 sources you can choose the second source device as well. Once those are made please hit the menu button a couple times to get back to the standby screen. After that choose a point or a route to navigate to either using the NN3D or the MaxSea. After that wait a little bit then hit the Nav button on the pilot, and confirm the source that is sending the data IE: NN3d. After that it should work fine. Best of luck

Hello C-Bass,

Thanks for the explanation, indeed i had defined two sources originally in my Navpilot installation. The GP-33 and the Navnet. My first problem of not having navigation data was because as soon as i went out of port, i used to put the Navpilot into Auto mode (i'm lazy). While in Auto mode the Navpilot is probably busy. Now that i wait the 15 or so seconds, it is functionnal. The other issue i had was because i left the overlay with the tide, and Johnny explained that this consumes a lot of ressources and it may explain why the Navpilot was not gettting valid information.

I plan in the future to define my MaxSea as a backup source through the serial port as a backup.

thanks very much !