Tom, I might add that floating cover/structure is also good for bunching up bait and predator fish.

For these Oaks, you could take a long chain (maybe 15-20') and fasten one end to the Oak and loop the other end around 3-5 cinder blocks.

That way, the Oak would generally stay in one area, and if it never sank, no big deal.

An important note is to give as much slack in the chain to compensate for high water levels. For instance, if you put the Oak in 10' of water, and the water can fluctuate by +/- 3', then you want to have a minimum of 13' of chain between the log and the cinder blocks.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."