Sonar Quiz #24

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Originally Posted by genec

THE OBJECT IS ONLY ABOUT 4 FEET AND IS LET DOWN TO ABOUT 8 FEET OR STILL 4 FEET AND HE TURN BOAT TO LOOK LIKE 8 FEET DEEP, AND IF DOWM RIGGER HE WAS NOT FISHING THEN, TOO SHALLOW AND TOO NEAR BOAT,SO HE MUST HAVE SET IT JUST TO WHAT IT ON SI?

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I don't think the boat is turning any, the image is to clear, not skewed at all. Whatever it is could be moving horizontally (closer then farther from the boat) instead of vertically in the water column. It would show as being deeper on the screen, distance not depth.

Quote:

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Originally Posted by larryb227

I don't think the shadow has anything to do with it. That looks like traveling up a feeder which is showing up on each side as the boat is in the middle.

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You'd have to be traveling perfectly up the middle of a feeder for the shadow to show like that.....Kosmo's shot has a little bit if that effect also....I think we have a double quiz.

Ok guys ... Some great discussion ...

Many different ideas being offered ... And additional "mini discussions" of each of those ideas being analyzed ...

These "mini discussions" (within the main topic) is how we learn tidbits of info that we didn't even know we were learning ...

Here is the quote from Spearfish III ...:

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Originally Posted by spearfish III

I was slow rolling for trout with a drift sock tied to the starboard cleat to slow me down and the side scan kept picking it up.

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Attachment 274210
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Now someone explain why the echo return from this drift sock is "undulating"...(you guys have already touched on the answer in the "mini discussions"...

UN•DU•LATE (verb) ... move with a smooth wavelike motion

Rickie

And the dark lines are not shadows ...

We will discuss this next ...

Rickie

Dang.....drift sock was my first thought......:biggrin

Are the dark lines the "tunnel" effect caused by the all in 1 transducers? I have never seen a shot where it was that pronounced, if that is it.
I have never seen that effect on my SI units, but there is some of it on Kosmo's shot also.

Because the sock is moving left to right? Ie steering corrections?

Ok, I didn't expect it to be a drift sock.but the two pictures are still similar. The object is just under the surface in both pictures, leaving no shadow to reference but they are different in that one picture the object is moving with the boat , while in the other that's not the case.

Kosmo, is that a floating swim line rope?

I think that as Spearfish III is trolling, he is making course corrections, which causes the wind sock to drift in and out

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Originally Posted by justinp61

Kosmo, is that a floating swim line rope?

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It's an empty river barge.its down in the water about 1 ft.thats why there's no shadow in the shot.my transducer is mounted on my trolling motor and I'm moving it slightly as I'm going by the barge and that's why it's not showing a straight line.