Now to respond to your question about locating them. Try slowing trolling or as I like to call it, Crappie Creeping. Set out rods with baits at different depths and creep along near the banks at a very slow pace. If you get bit and catch a fish, toss a bouy out, set the rest of your rods about in the same depth range, then continue to Creep. This is a great method of locating fish that are out in the open. If they don't have to hide from other predators like big catfish, they can be anywhere. If there are big cats in the pit and no structure, there's a good chance they are going to hug the bottom, rock or ledge. When Creeping, try to keep at least one line within a foot of the bottom.