Turn of the century photographs of dirty, hot, cramped machine spaces filled with boilers, engines, gratings and bulkheads begin to tell the story of the state of steam power just after the birth of the propeller. Oil squirt cans, dancing connect- ing rods, and sweating coal passers and firemen characterized the engine rooms of the late 1800s when paddle wheels were gradually being replaced with the screw.
Pioneers of screw propulsion experimented with an assortment of propeller designs before commercial application of the concept began. The first screw-driven vessel in the U.S. Navy was the Princeton, built in 1843 by John Erickson. Even though the prop had many advantages over the paddle wheel, the fact that during the 1840s and 50s most ships were still made of wood posed significant challenges in terms of power, thrust, and managing the final drive to the propeller shaft.
In terms of engine design and construction, screw technology of the 1850s was much the same as paddle propulsion. Engineers tried a number of existing prime movers including beam, oscillating, and horizontal engines before finally deciding that the vertical direct-acting engine was the best solution. One of the first installations of a beam engine turned sideways was by shipbuilder Todd & MacGregor who laid down a 1,600-ton iron steamer in 1849. The ship’s overhead beam engine had two 66 in. bore by 5 ft. stroke cylinders, each connected to its own beam by means of a connecting rod.