You've heard of a s**t disturber? That is what it is!
Used to stir lagoons of the stuff (also called a pond stirrer as bcp posted)
I did walk out on the pier one time. It held my 6'5" 250lbs, but I don't plan to chance it very much...lol The end of the pier is actually held up by and old stump! I would like to build something floating down the road, but I have a lot to keep me busy before I will have a chance to work on it.