I just got a 12 ft jon boat last month with a 7,5 gamefisher engine(86 model) . It came with an Garmin echo 100 . I finally got an atv battery last week just to run it. I have a pull start motor and no trolling motor..yet! Some of what is on it is obvious. I can tell what the depth is . Ican see dips on the bottom or what looks like grass. The brush is kind of hinted at ..haven't seen any big piles yet or maybe they just don't seem obvious on this model. It's the fish images I'm not sure about. what I wonder about is...are the images on that screen representing one fish or schools(the big fish)??..Really small ones I'd guess are bait fish. But are the images accurate as to numbers of fish in the area? This doesn't have arcs and no color. I also wonder how far around the boat it scans? It's mounted on the left side of the boat so if I see a possible brush pile.. How far out from the boat would it be? Thanks for any help given! This is my first time using a fishfinder and it may be some time before I can get something that's more advanced.