Here we use air hammers even smaller electric hilti hammers to drive 6 inch steep pipe possts in for floaters. My friend William even made one that has spud poles the walkway pivots hold it inplace against the current. William had a work barge with a tower on it, the tower had a sliding 500pound weight attached to a car axle type drop hammer winch. then later and old dozer winch. the poles were plubmed them hammered in. If its a TVA site you may want to check with the authorities to see what the deck square footage is there . Here I think you can have 3 decks that have 400 sf each.