What does a propeller do on a boat?

A propeller is a critical component of a boat's propulsion system. Its primary function is to rotate, creating thrust that propels the boat forward or backward through the water. As the blades of the propeller spin, they push against the water, generating the movement necessary for the vessel to travel in the desired direction. The design and size of the propeller can greatly influence the efficiency and speed of the boat.

Understanding the propeller's role helps boaters better appreciate how their vessels operate and the importance of proper maintenance for optimal performance. Other options do not accurately describe the function of a propeller; they relate to measurements and navigation control, which are separate aspects of boating.