Last christmas I got into droppng structure. My father has a dock on a 300acre lake and its in a cove that is 4-8 feet deep. 4 foot off his dock. He has lived there for 10 yrs now and we NEVER caught crappie at this location except for spawners. WEll I put in one tree and two PVC structures and caught fish from last febuary to November almost every time we went. I will say that the tree was closer to the dock and held less fish but bigger fish. Also when the bit was tough/slow the trees would always produce some slabs. also caught the biggest bass of the year off the tree. It only took two days from sinking to catching. well worth the work.