Not a crank but something along the same line are the propeller shaft in navy ships. Some are 200 feet long or more and 36-48 inches in diameter. When docked they turn them very slowly to keep from bending. If they have to work on any part of the shaft they put blocks every so many feet for support, they will bend if not done.If it bends it's remachined where it rides, quite a process since it can't be removed from ship