I don't pull cranks, but as you stated the ones you are catching are relating to brush. You need to experiment with where you put your brush. Looking at the pamphlet above, it clearly states that 51% of the black crappie are located on shallow flats so why put all your brush in 20 foot or deeper water where only 21% of the black crappie are located? If brush pile depths were more diversified, and plentiful. You would always have brush with active fish that could be caught using more conventional methods.