Big Indiana Bass

In response to the question of signal strength relative to depth from the previous post, the answer is depth accounts for a little extra strength in the return, but not as much as you might think. Soft bottoms return soft echos, and just moving them closer to the transucer won't turn them into hard bottoms (relative to the sonars way of thinking). Hopefully the picture above will help explain this. Keeping in mind that I never make adjustments (outside of depth) to my sonar settings once I'm dialed in for the day, this somewhat blander hump actually tops out 2 foot shallower than the hump in the previous post. However, you can clearly see the transition to a much harder bottom that occurs right at the back edge of the hump as I start to crest it and proceed down the back side drop. Everything up to that point, including the rise and part of the top left of the hump is just typical return strength for this lake. Not necessarily silty or soft, but certainly not anything overly solid and firm.

A large part of this is simply controlled by the content material of the bottom. Hard bottoms are hard bottoms and they will reflect as such regardless of most settings. I also believe a small part is the nature of humps, that being rises in the bottom that tend to A.) be shallower and potentially subject to more 'washing' either by natural or man made currents, hence silt not being as likely to get settled, and B.) being more vertical objects (esp. the 'sides') , much like dust doesn't settle nearly as bad on the sides of your furniture, neither does silt settle comfortably (angle of repose?). Last, most of these type structures in our lakes tend to be found on the lower end of the lakes where the majority of silt is least likely to settle. Most material falls out in the first available location with minimal transport power, i.e. really calm water. Areas like the back of creeks and the headwaters of impoundments. The material that clouds water way down on the lower end of the lake is usually the lightest material suspended and subsequently the least likely to fall out in the first place.   

Here is another screen capture from last weekend. This one is a great example of settings for distinction of hard bottom areas. Notice the bright, wide yellow band under the hump, all the extra orange in the return as well as the 'arching' red and magenta well underneath the hump. There is also an easily discernable double echo in the shot. This whole thing being in stark contrast to the relatively benign flat bottom leading up to and following after the hump.

We can see a lot of small scattered fish that are represented by the small blue arches more or less suspended through the wid water column. And that clump on the left before reaching the hump would most likely be some type of sunk wood such as a small stump with fish hanging around it. If I had to guess what type fish, my first thought would be crappie due to the pyramidal (Christmas Tree) shape to the school, a very common crappie return signal.

I've got a series of shots I captured off my Lowrance graph this past weekend I wanted to share. They are all good examples of settings or readings that should be helpful for those still trying to dial-in or read their units. You'll be able to click on any of these pics to get a larger view.

This first one is a good example of several different things. Notice the nice double echo readings indicative of hard bottoms under the "humps". At their peak there is actually a bit of a triple echo even. Also notice the object on the left side of the right hump. The fact that is is largely colored the same as the bottom (yellow/orange) suggests that this is a pretty solid object, most likely a stump or cut-off tree. Now contrast this with the fish and brush showing as the blue and magenta clusters down in the trough at the right side of the second hump. The color of return clearly suggests that these are less dense objects and they don't blend in with the bottom in any way like the stump did. This is how you can tell things apart based upon the color (strength) of the reading. On a black and white unit, you'd get really light colored banding of the stump making it look like the bottom, and a more darker and mottled gray for the fish and brush.