Also, I believe your boat is not moving in a straight line. Try to idle at 3-5mph with chart speed at the same number or maybe +1. Depend on what you try to find. In very low speeds, wind can move the boat sideways, and it adds blur and distortion to the image. I usually set sensitivity to get some part of the picture to full saturation (as light as it could be), then I go back a step or two. However, if you are interested in fish primary, I suggest reduce the range to around 60ft and add contrast and reduce sensitivity. That will make the bottom less bright and fish will pop out better.
