I am going to update my old hummingbird fish finder, which is an old black and white model. I am looking at the Helix 7 series, not sure witch is the best for me. I fish mostly for crappie, brim, and catfish, I try to make several trips to fish the ICW every year. After that I am getting a trolling motor that has a spot lock and other features that I can put to good use. I need to be able to use in saltwater, and hopefully compatible with each other. Any and all information will be appreciated.