Engineers always ask for 4-1 on cantilevers but 3-1 is usually the most economical when calculating out structural sizes. Less than 3-1 just increased the footings, anchors and beam sizes which increase cost. I would not go less than 3-1 without an engineer doing calcs. and detailing the connections. The dock at Jim’s place uses 80’ beams for a 20’ cantilever.
I would also suggest using square tubes and not pipes, lot more strength for the cost. I also think they look nicer than I-Beams.
Jim do you have any photos of the finished dock?
