I have never seen a pier net in use but decided making one would be a good project to keep me out of the house a few hours. It is not perfectly round but shaped in an octagon, like a stop sign. A bit of research turned up the fact that you can make any diameter octagon you want by making each side's length (diameter * .4142). I wanted a diameter close to 30 inches so each side of my hoop is about 12.5 inches. It's not perfect but good enough for who its for.
The hoop is made of 1/2 inch rebar that was left over from a previous project. After bending it, I put several coats of trap dip on it for a bit of a seal. If it still rusts after a rinse, WD40 does wonders. The net is a big heavy replacement net made for salmon fishing. The two ends of the rebar overlap a few inches. After threading on the net, the overlap is held together with two stainless radiator hose clamps. I tied parachute cord to 3 points around the hoop to hold it level then put a swivel between those three cords and the rope that I hope gets to lower it to the water.
Next project will be a cart!