I commercial fish in shallow water (surf to 15') for red salmon, a lot of times we are throwing our bouy right on the beach, so I think that downward imaging sonar is not useful under these conditions. I need a fish finder that with practice would allow me to differentiate between flounder and salmon (there is no market for flounder here, our flounder tend to be half the length of salmon). Throw into the mix the fact that on windy days there can be a fair amount of particulate drifiting in the water. Have any of you forum members used Humminbird SI under similar conditions? And if so, what is your experience?