An Archimedean screw is a machine used for raising water, usually for irrigation purposes, thought to have been invented by Archimedes in the third century BC with the purpose of assisting irrigation in Egypt. The most common form of the machine is a cylindrical pipe enclosing a helix, inclined at a 45° angle to the horizontal with its lower end in the water. When the machine rotates, water moves up through the pipe.

In the nineteenth century, the same principle was applied to propelling ships. During trials, however, this particular design of screw broke in half, and the result was an immediate increase in the speed of the vessel. In this way, by happy accident, the science of machine propulsion advanced about 50 years.