On one of my favorite lakes the crappie spawn on rip rap. The funny thing is sometimes those fish are 2ft from the bank. The best way to catch them is to use a small floating Rapala minnow bait and work it parallel to the bank. I can't use a slip cork but most of those fish are in 18 inches of water. When fishing deeper rip rap I use a slip cork and a tiny zoom fluke. I think any bait will work but you have to keep moving.