I've modified materials in making the fish attractor/spawn station (article in the archives) and have a photo and construction tip sheet to share if you are interested. Just pm me your email address if interested and I'll send the picture and page of comments. I don't know about crappie, but a fellow recently caught 4 bass near a cluster of 5 attractors.....the three went a little over 5 pounds each and the fourth went just a tad over 10. The clusters will be shock boat surveyed come September so I'll have a better idea about particular species later on.