How High Off The Bottom Does Side Imaging Show?

[TMF89]

I'm wondering how far off the bottom the SI on depth finders will show. I realize this has to do with the cone angle, but I'm not familiar with that on the SI transducers, so I'm hoping someone will chime in. Does it get lower as you go out further, because of the cone? I'm sitting here with cabin fever thinking about trying my hand at some Lake Superior trout/salmon this year, and I'm wondering how helpful SI would be with locating suspended fish. Not much I'm guessing, but I'll wait and see what you guys say. Thanks!

[JohnMickish]

Side imaging goes straight to the bottom under the boat and stays on the bottom all the way out to the distance you have set. it will show you everything in the water column out to your distance the bottom.

[reddog]

It will/ should show any suspended fish in the water column off to the side. BUT the higher the fish is in the water column, the better you are going to need to be to interpret what they are. That is because when fish are closer to the bottom, their shadow is more pronounced than the actual fish itself, which looks like a small white cigar shaped image,in the case of a walleye. A suspended fish will still look like a white streak, but the shadow may be less pronounced because of the projected distance to the bottom... It's all going to depend on the settings used and your ability to interpret what the unit is telling you.

[TruthWalleyes]

Google images, side imaging cone

[TruthWalleyes]

Also, check out the quadra beam

[Kyhl]

I think what you are looking for is what angle out does the SI cone run to be able to see suspended fish 60 feet off starboard that are only 20 feet down instead of seeing the bottom 60 feet off the starboard and 60 feet down.

Not sure about the validity of the chart I saw via a goodle search but if you search for Structure_Scan/Structure_Scan_Cone_Angle_Chart.pdf you should find a chart showing cone measurements for an HDS presumably.

For example, at a 60 foot depth you would be able to see 113 feet to the side. Based on that chart, you could see a fish suspended at 20 feet, independant of the actual lake depth, if it is within 38 feet of the transducer.

Suspended at 40 feet could be out as far as 75 feet from the transducer.

edit that is based on the 800khz transducer. It looks like the 455khz has a wider angle.

I printed the graph to put in my tacle box.

[reddog]

Since walleyes are my targeted species, I dont have may screencaptures of suspended fish..

Heres a couple..

Like I said, depending on how high they are in the water column, their shadow may or may not get projected onto the screen, If the fish are high, and your range is narrower than their projected shadow, it wont print the shadow, like in this picture, but, the fish itself is pretty pronounced even outside of the printed water column

Here, you can see how much more the shadow is than the actual fish. Suspended fish that are in the water column on the SI screen will readily show up, because of the darker background..

Changing color pallettes may help:

With this color pallete, the actual fish is black, and the shadow is lighter. You can hardly see the actual fish, bbut the shadow is quite pronounced..

I dont need a "perfect" image in order to know what my unit is telling me. I just need to be able to interpret what is on the screen. These units are very, very settings specific. In a fishing application, its not conducive to sit around punching buttons on the screen to get the "optimum" image, or youll never get any fishing in..

[reddog]

As far as how high up the water column they see, SI sees from the bottom to the top (455) .

Here is what SI sees :

Here is what is actually being printed:

[reddog]

Here is a picture of a boat going by on the right. This image does not belong to me, it belongs to TNPerry, but does show that SI goes from the surface down..

[TruthWalleyes]

That's awesome red... Can even see the ribs on the hull

[reddog]

That's awesome red... Can even see the ribs on the hull

I thought it was a incredible shot also. Hope he doesnt mind that I borrowed it..

EDIT: Got permission from TN to use it, and a little background. It was a no wake lake, He was going 3.5 mph as shown in the capture, and the other boat was going approximately the same, about 35 feet away from him.

You learn something new every day you use SI. Thats what I love best about SI, whether fishing, or just cruising with the wif, SI is on and being watched and tinkered with. I truly dont think every aspect of this technology has been fully explored yet, particularly in regards to specific settings and applications. Ive had mine since 08, and am still learning new things it will do, and trying to make it do things better.

[TMF89]

Wow guys, thanks for the responses, especially the screenshots! So how accurately are you guys able to figure out the depth of suspended fish? I would imagine in deep water it can be pretty difficult?

[TruthWalleyes]

Wow guys, thanks for the responses, especially the screenshots! So how accurately are you guys able to figure out the depth of suspended fish? I would imagine in deep water it can be pretty difficult?

More time on the water the better you get at interpreting the image.

[reddog]

Wow guys, thanks for the responses, especially the screenshots! So how accurately are you guys able to figure out the depth of suspended fish? I would imagine in deep water it can be pretty difficult?

With a strictly SI screen, it can be somewhat of a guessing game, but throw in a small slice of 2D, like the first image, and it gets considerably easier to tell.

The deeper the water, the wider you have to stretch your SI range. The wider you stretch you range, the smaller (harder) the fish get to see.

How deep are you needing to be in Superior?

[TMF89]

Oh I've never fished it before lol, I was just doing some window shopping online and using a trip to Superior as an excuse, and that's how the question came about. I think the fish there are usually 20-80 feet suspended in depths of 100-150 feet, but that's totally guessing, lol.

What about sharp breaks/drop offs? Are those just steady gradients from light to dark? I've done some searching online but a lot of the stuff I found wasn't as clear or as well explained as I'd like, so I'm hoping you guys have some more information for me. lol

[TruthWalleyes]

Go to BBC Humminbird image interpretation. Great resource for you.

[TMF89]

Thanks for the link! I can't wait to start checking out some screenshots.

[hitthebricks]

I got the 997csi the second year after it came out. Every year their is a software up grade that both fixes minor glitches and adds new features that they added/developed, all available with a quick easy download to a SD card. I think almost all electronics show you the fish. It comes down to how you interpret the info and use it but it cant catch the fish for you.