Final answer:
In the early 19th century, improvements to ship propulsion were largely due to the development of the steam engine, specifically with advancements made by Robert Fulton.
Step-by-step explanation:
In the early 19th century, ship propulsion was transformed by the advent of the steam engine. Robert Fulton, who is notably credited for envisioning a practical use of steam power for watercraft, developed the first successful steamship in the United States, named the Clermont.
In 1807, powered by a Boulton and Watt engine, this steamship significantly reduced travel time between New York City and Albany, demonstrating both speed and reliability over sail-powered boats, which were dependent on wind.
As steamboats proliferated on American rivers, the steam engine allowed ships to travel both downstream and upstream with ease, not constrained by river currents or prevailing winds. This was a massive step forward in transportation, enabling an explosion of travel and shipping that transformed life on the frontier.
Ocean-going steamships also benefited from steam power, enabling safer and quicker voyages, and facilitating travelers and merchants to maintain regular schedules.
By the end of the 19th century, electricity and internal combustion engines began to play a more dominant role, gradually supplanting steam power in transportation. These developments led to improvements in efficiency and the spread of the Industrial Revolution, further revolutionizing how people and goods moved across distances.