In the early 19th century, what development greatly improved ship propulsion?

The development that greatly improved ship propulsion in the early 19th century was steam power. This technological advancement allowed ships to move more efficiently and reliably compared to traditional sail-powered vessels. Steam engines converted thermal energy from burning fuel into mechanical energy that could drive paddle wheels or screw propellers, enabling ships to maintain speed and direction regardless of wind conditions. This marked a significant shift in naval engineering, leading to the rise of steamships, which would, over time, dominate maritime transportation and warfare.

In contrast, while sail technology was essential before the advent of steam power, it was limited by wind availability and variable weather conditions. Gas engines and electric motors, on the other hand, were not developed and deployed for marine propulsion until later periods, making steam power the transformative innovation of the early 19th century.