I've sunk cover in Norrell before I moved up here. The crappie I did catch were very large black crappie. Same for bluegill. They are some of the thickest bg's I've ever caught. Try a drop shot with two #6 wire hooks at 1.5 and 3' above the weight, about 1-2" piece of nightcrawler, pitch it out in 12-30' of water and slowly drag it across the bottom. Dragging this next to some of the docks will get you bit too.

If you leave the ramp and go to the right, there is a large cedar sunk out in that cove. We dumped some crappie and bluegill remains on it one evening and went bass fishing a while. Came back and hauled dozens of large channel cat off that tree.