interpreting the screen image



I have a NN3D with the digital fish finder and would like some help with interpreting the screen image. For example what do all the colors stand for on the bottom and the wavy blue line near to the top of the screen.
Thanks for posting your question on the Furuno Forum. The basic color spectrum on a 3D sounder runs from brown to blue, with brown being the hardest return and blue being the weakest. Can you post a screen shot on your sounder? That way we can better explain what you are looking at.

Dear Henry,

Color differences on the screen are used to indicate the amplitude of the target return. This color ranges from reddish-brown which indicates a strong return to a deep blue which indicates a weaker return. You use this color variance for a few reasons. One, you can get a quick visual indication of bottom hardness by judging how quickly the bottom return goes from reddish-brown to dark blue. Page 7-27 of the operators manual shows the spectrum of colors indicated from solid return all the way to weakest. This same color scheme is used for returns that you would use to indicate fish. If you see a strong return haystack with smaller returns around it, that's what you're looking for.

The wavy blue line is the surface. If it is not being displayed correctly, ensure that you have set your draft correctly in the machine in order to properly offset everything.

Section 7 of the users manual goes into the operation and customization of the sounder in great detail. Please review that section of the manual for good orders sake.

If you still have questions, perhaps posting a picture of your display would be helpful for other to weigh in.

Fair winds!
Thanks for your replies as I am not on back on board for a couple of months I can not send a screen shot until I return.

This forum seems a great idea.
Here's a pic drifting on 200khz with a 2 KW transducer with Blue eye travalla :furuno


  • Blue eye Trevalla.JPG
    Blue eye Trevalla.JPG
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  • Deep screen shot 2.JPG
    Deep screen shot 2.JPG
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Are you sure that you havent got your LF and HF freq wired backwards because i thought that a 2kw 200kh should not read that deep?. Snips is that reading possible??.
Nice fish. I agree, that's getting down there for 200Khz. I would be interested to see what the LF side looked like.


I definately have my wires connected correctly. I to was amazed at the pic. On this day there was no drift, no undercurrents, water was crystal clear.....everything was just perfect! When the water is sloppy I use my LF on about 5 gain to get the same pic.


I also peach at those depths but I understand.
I also see screens of this type, I wonder fish are definitely the ones you see in the zoom? screens so many times I am but hours without a railway
i have 295 whit 50-b9
I can see in the screen to echo what would be the fish? those that you see are all the fish in the screen on the left?
I have often a visual way, but I do not know if they are fish.