Johnny whalechaser there has been a time or two when i knew it was over when it started...nothing like heading to your local dive for some " comfort food" aint it getting close to another showdown with cabelas.... ???

Yes sir ! its sneaking up on us quickly , you guys coming ?

Me and Sam are hitting Kerr lake tomorrow, we will try to decide tomorrow if we are coming down this year. I had to put a lot of money in the truck the last 6 months but I think I can swing it. Looking forward to coming down and watch the wind blow 90 mph when we get there .

I like johnny's positive attitude Or is it experience talking??? Drawout it is on our list to arrive with cerimonial grade skip-jacks and 50lbs of gizzard shad & watch the wind blow 30mph & drive around visiting all our Texas friends we made over the years!! but if the lake lets us fish......(knock on wood) lookout

Screenshots from the last few weeks at Lewisville. First screenshot I caught about 10 blues from 4-18lbs. Second screenshot just a couple little ones about 3-4lbs AND one giant that beat my butt for a good 10 minutes before wrapping around my motor and breaking off. I only saw its tail end when it was thrashing around in my bow anchor rope. Considering the epic battle and only seeing part of him/her, my guess was 50-60lbs. When I saw the big mark on the screen I honestly thought it was a log. Now I'm wondering if it was the big one that got away???

that long mark you got there is a big fish but not because it's long .. the reason it's long is because the fish is moving the same direction as your boat ... you go by width to judge how big a fish is or that's the most accurate way I"ve found to judge how big fish are ... not by length because if they're moving the opposite direction it'll be just a really short blip on the screen ... same direction it'll be a long mark because they're staying in the path of the transducer for a longer period of time. some can take up three or four times that length because if they stay in the path of the transducer for 5 seconds then that fish will look like he's 20 or 30 ft long. I hope I"m explaining this properly

Thanks tiny, I think I'm with you on this and I really appreciate your feedback! I need to look at the width of the mark, not necessarily just the length. So if a fish is moving with me will it affect the shadow it's casting too? And in the first screenshot, upper right corner, there is a double mark with no shadow, I see this a lot, can you explain?

you mean the upper left? that is just the fish you're seeing are suspended off bottom and the shadow doesn't have enough room to show up because the shadow is out of range because the fish you;re seeing there is probably near the surface and you're in shallow water so at that angle the shadow would be well off the screen ... maybe out to as far as 70 ft when you've got your fish finder set on 65. The shadows only show up when the fish's shadow is at an angle or close to bottom at that angle in shallow water... it's just like your transducer is a flashlight and if the shadow doesn't hit the ground then you won't see it on the HB screen as the suspended fish way out there near the end of the 65 ft will actually be sideways from the fish compared to the fish that are right on bottom ... now if that was in 20 ft deep water and it was suspended to 10 ft from the surface the shadow would be about 10 ft away from the fish but since you're in 5.4 ft and the fish is just a foot under the surface the shadow would be hitting the bottom about 12 to 15 ft past where the fish is which is well out of range... the way you'd figure that is divide the distance the fish is from the boat with the depth which is about 60 ft so the equation would be 60 divided by 5.4 and if you could actually see the shadow at that distance on the other side of the fish and guess as to how far away the shadow is from the fish... like if the shadow was 40 ft on the other side of the fish then the fish would be about 1.5 ft from the surface... now I'm not actually figuring that up exactly but that's how you tell how deep the fish are from the surface with side imaging is by how far the shadow is from the fish and the total depth. Like if you had your unit set to 50 ft out and you're in 20 ft of water and the shadow of the fish is 10 ft from the fish and the fish is 25 ft from the boat then the fish is suspended at 10 ft deep. I know... it's confusing but the most simple explanation is the fish is suspended some and the shadow is out of range. Also fish on or near the surface won't cast a shadow because you're in shallow water and the fish is almost parallel with the transducer so the shadow won't be able to be seen unless the fish is between the angle of the distance you've got your unit set out to or the fish has to be between your transducer and the bottom of the lake at some point out to the max distance you've got your unit set to ... just like if your transducer is a flashlight and you're shining it on a fish close to bottom out to 20 ft then the shadow is going to be close to the fish ... the further off bottom the fish is the further away from the fish the shadow will be and if the shadow of the fish would hit the bottom at 68 ft then you won't see the shadow.

went ahead and drew up a diagram to show you what I mean. The blue circles represent catfish at various depths and distances from the boat... marked fish A. B. C. and D .... Fishes C and D will cast a shadow but A and B won't because the path of the transducer hitting the fish will cast the shadow beyond the 65 ft distance your transducer is set at. Pretend the depth on this photo is 5.4 ft also ... I didn't draw it accurately but you can see what I mean. The direct beam pointing towards all the fish predict where the shadow will hit the bottom and in order for the shadow to be seen on your fish finder the shadow has to hit bottom. Like in this diagram/drawing. I've shown where the shadow will hit on C and D but since your fish finder is set to 65 ft and the direct line of sight between the fish you were talking about will make the shadow not appear because it can't as the fish would have to be on absolute bottom in order for it to show a shadow on the screen since the fish is very close to the outside range you've got it set on ... now if you had your range set at 80 ft or so then you'd see the shadow of the fish you're talking about most likely unless the fish were on or near the surface. All the fish on your screenshot is right on bottom except for the ones all the way out to the edge. Here's the diagram ... hope this helps ya understand what I'm talking about.

[img]http://www.catfishing.tv/cattalk/viewtopic.php?mode=attach&id=172[/img]

Great drawing. Makes sense to me now.
Thanks again Tiny

Thanks for the diagram, it certainly helped!

Great thread-
Thanks To all who added to this-

I would appreciate some help; I am a total novice on these sonar units. I would like to get a good one and assume side scanning is the way to go, but that's the limit of my knowledge. I also know Humminbird and Lowrance are two of the best brands. What do you all suggest with a budget in the $500.00 to $1,000.00 category? Not that I've got the loot, but when I buy, it is probably for life, and I hope not to make a mistake. I would also like to be able to use the one unit on both a boat, 18 foot SeaArk, and a 15 foot sonar equipped kayak. I have friends who have some pretty impressive set-ups on their kayaks. I haven't made it that far yet, obviously.

And when it comes to the images, I can figure a little out, but not much. After reading 14 pages of this thread I figure I'm the least knowledgeable person here on sonars, but I would like to learn.

In the image below, what do the various color lines indicate, the clear/white with small blue specks? Are those fish? The larger blue curves above the red, the red, and then the yellow fading into blues and greens? Are the red dots in those areas more fish?





I appreciated the lesson on what was in this image and had recognized a little. There are a couple of larger masses on the lower part of the LEFT side image, right next to the ridge line or underwater drop off; are those logs or downed trees, or what?





In this image where you identified the mass school of catfish 100 yards long, 100 feet wide, and 10 or 20 feet deep (can't remember the dimensions but BIG), there is a mass of something on both sides of the image it appears to me. I see all of that, but is that a lot of fish on both sides, the same school, or what. This is what I mentioned earlier; I don't know how to interpret that image and am trying to learn.

Or, are you sitting right on top of the school and what you are seeing with a side scanning sonar is the massive school sitting right under you? Bet that is correct but don't know until you tell me.







In this image, the BIG catfish is the large shadow in the outlined section, correct? What are all of the other smaller contacts that are spread across the screen; are those fish, or are those downed trees and debris with some fish mixed in, and how do you tell the difference?



I apologize for asking so many questions, but this is the only way I've got to learn. I greatly appreciate any help you can give me. This thread, which I just found, is exactly what I had hoped for but had never seen before. I realize this is "old hat" to many, but to a sonar novice, this is pretty confusing stuff!!

Thanks, guys!!!!!!

Ray