A welder making repairs in dry dock appears very small next to the massive ship's propeller located just behind him. The introduction of propellers and advances in engine technology during the late 19th century brought an end to the age of the ocean-going sailing ships.
A major development in ship propulsion was the screw propeller, fully submerged rotating blades that pushed the ship through the water. The screw propeller was first used in 1840 on the Archimedes, a river-going American steamer. British shipbuilder Brunel again pioneered ship design when he adopted the propulsion system of the Archimedes for his second ship, Great Britain, in 1853. At 98 m (322 ft), Great Britain was the largest steamship of its day, the first to be made of iron, and the first seagoing ship driven by a screw propeller. Great Britain's propeller measured nearly 5 m (16 ft) in diameter and weighed more than 3 tons.
The earliest screw propellers used on ships had two long, narrow blades, resembling the propellers of early aircraft. Soon propellers with three, four, and even more blades were in use, and ships carried two, three, or more propellers. Multiple propellers increased speed and provided alternatives in the event that one propeller malfunctioned or was lost.