Black Warrior/Tenn Tom River System

Here I come with my questions again.
Talked with a man this week who goes fishing twice a week for crappie most weeks this time of year. He lives on the Black Warrior River. He said he hired a guide on Weiss Lake a few years ago to show him how to troll for crappie. He said they did very good on Weiss but he could not make trolling work for him on the river here where we live. I know this guy is a very good single pole fisherman. He has fished this same area all his life.
What do you guys think? Is there a difference in the river systems or maybe he's not good with fish finders like locating the bait fish?

Without knowing the conditions - mainly current - it's hard to say. Crappie don't like strong current and will hide in wait in eddies. Lakes will have good structure in deeper water without a current providing a good spot to troll. It's harder to troll on a river - one needs to find ideal conditions for the crappie.