Crappie Fishing deep lake with no structure

I have a 56 acre 42 ft. deep lake with no structure that I fish regularly. The lake has good crappie population, but I often have a difficult time finding them. Will these fish be suspended in the deepest part of the lake? will they be up shallow? There ares some weeds that grow out to 15 feet around the entire lake, but it slopes off quickly into deep water. Any help would be appreciated