When steam power became practical in the early 1800s, shipbuilders turned to three methods in an attempt to harness this improved power source: paddle wheel s, jet propulsion, and the screw propeller. Jet propulsion was attempted but with little practical success. Paddles were often used at the sides or backs of ships navigating on western rivers because they could take a great deal of punishment and could be easily repaired since half of the paddle wheel sticks out above the waterline. But early steam-powered, oceangoing ships equipped with paddle wheels experienced difficulties in rough seas. The ships would roll, and the wheel would often come completely out of the water, wasting power and making the vessel difficult to handle.

There was a third alternative for transforming power into thrust: the screw. As early as 1785 the Englishman Joseph Bramah patented a sixteen-blade propeller to drive boats. But...