What type of propulsion uses external power to create thrust in a vessel?

The correct answer is related to the use of external power to generate thrust in a vessel. A propulsion system that utilizes external mechanisms to create movement operates differently from those relying solely on natural forces or human effort. The option that embodies this principle is the propeller, which typically operates using an engine or motor that generates the necessary power to turn the propeller blades. As these blades rotate through the water, they push against it, creating a thrust that moves the vessel forward.

In contrast, manual propulsion relies solely on human strength, such as paddling or rowing, and does not employ external mechanical power. Sailing involves harnessing wind energy through sails, which is also a natural force rather than a mechanically powered system. Water jets can represent a hybrid form of propulsion, often considered a type of engine-driven mechanism that forces water out to create thrust, but the fundamental process hinges on the propeller as a primary example of utilizing external power to achieve propulsion. Thus, propeller-based systems are clearly recognized for their dependence on engine-generated power, distinguishing them within the context of propulsion methods in marine vessels.