Water type can't be changed


Furuno Fan
I have never been able to change the water type from salt water to fresh. I always get an error that it is unable to change. Any ideas as to why, and what the solution might be?

I am using the Airmar P79S. It is also sold with a Furuno part number.

Please don't tell me that Furuno won't recognize it unless it has a Furuno label on it...

The setting you are talking about is for NETWORK sounders like the BBFF1, BBFF3, DFF1 or DFF3. This is because these units are being controlled by the NN3D.

The Airmar smart transducers have their own computer and calculate depth independently. They only feed NMEA information (Digital depth) to the NN3D which can be displayed. It offers no visual bottom like a sounder does. We have nothing to do with the Airmar internal calculations. If you have a problem with your depth being off, you should adjust your depth offset.
Thanks for the explanation. Helpful as always.

I was misled by a thread on Cruisers Forum that MFDs set the calibration in the sensors, rather than applying the correction in the MFD to the data received from the sensors. Clearly it is better to have the sensors transmitting corrected data, assuring that all displays on N2K show the same numbers, but I am only aware of one display (RM ST70+) that supports programming sensors. I hope this feature will be included in future Furuno software.

I have learned that Airmar's Weathercaster software, through an Actisense USB-N2K adapter, is able to program the calibration in the Airmar sensors. Since I already have the Actisense bridge I will go that way.

Thanks again,

Maretron adjusts a Salt water / Fresh water depth calculation of the Airmar? I think you might be confusing a depth offset setting. That has already been discussed in another thread and is different than the speed of sound through water calculation.
-- On the subject of depth offset adjustments to the sensor itself.

I hope this feature will be included in future Furuno software.

The TZT has this feature. I do not know if we will see it added to the NN3D or not. I am not in the product development loop, but I will pass the suggestion.
You're right - I had generalized the discussion at that point to all calibration (in the case of depth, both offset and water density). Clearly the keel offset is more important for most folks, and I am glad to see that the TZTouch is making the adjustment in the sensors. Let's hope that code gets moved to the NN3D products.

Thanks again for you efforts.