In my opinion, whether you use utility (telephone or power) poles or 4x6 treated posts depends on the height of the dock above the pond bottom. If it's less than 6 feet, I think the 4x6 would work fine. Any deeper, I would go for the bigger round poles. My little dock is only 12 feet long, 39 inches wide and is supported by 2-4x6 and 4-4x4 posts, otherwise all 2x6 lumber, and some smaller stuff for bracing. But, it's only about 34 inches deep at full pool at the far end. Really just a flat platform to feed from and stay out of the mud. This was taken Dec 27, at 13 inches below full pool.
