The business end of a paddle-steamer, the Sydney Showboat II.
It was the elaborate (and bright red) web of ironwork that caught drew my attention to the Showboat II. I took the photo of the rear of the boat, knowing that the interest (challenge?) was how I cropped the final image.
Australia still boasts a dozen or so fully operational paddle steamers, with several operating on the Murray River. Included is the oldest wooden hulled paddle steamer in the world – the PS Adelaide, which was built in 1866.