SI interpretation...in 3d - (tutorial)

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Originally Posted by genec

Rickie, I don,t understand, I thought that anything that was less than bottom from transducer would have to show in water column even if it is to one side?

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I will work on some modifications to the depictions above to try and find a easier way to explain this ...

(if anyone else "---or Greg---" is following along that has a good explaination of the "dark water column", feel free to jump in here)

Rickie

Notice in the depiction that fish #5 is, in fact, in the dark water column of the Si image.... But that same fish (in the other view from behind) is very close to the SI centerline (boat's path)...

Notice fish #2 and fish #3 are not showing in the dark water column of the SI view..but both fish are still relatively close to the SI centerline (boat's path)...

This means that fish have to be very close to the boat's path to show in the dark water column...

http://i477.photobucket.com/albums/r...SIdistance.jpg

Rickie

Good Stuff on the video Rickie. That is the best way to explain it.

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Originally Posted by rnvinc

This means that fish have to be very close to the boat's path to show in the dark water column...

http://i477.photobucket.com/albums/r...SIdistance.jpg

Rickie

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This is what is confusing me. I've seen TONS of baitfish in the dark water column, but the info returned from the 2D sonar will give a different story. This tells me that there's no way that they would be under the boat...obvsiously outside of the 2D cone.

I'm not at all trying to prove you right or wrong, I'm just trying to figure out how to use the dang thing the way I think I should be able to. Generally when I go right over a ball of bait, it will show on my 2D and it will show on both sides of the dark water column.