I fished a power plant lake several times this winter and there were roaming schools of black crappie. These crappie would always show up in the water column when they swam by and it showed on the graph that they were 20' away or closer to the boat according to the graph's feet ranges. But it never failed that when a school came by that they were more like 50-60' by the fish we caught. On one of the hummingbird "how to" you tube video's they describe that the fish in the water column are as far as it says on the graph, but I'm not sure this is true. If the fish are in the water column on the unit is it not possible that they are much farther away and are only recorded in the water column because of the slant angle of the sidescan. Just speaking from what I experienced each weekend this winter and wondering if anybody else has noticed this.