What additional effect does propeller rotation have besides thrust along the shaft axis?

The effect of propeller rotation generates torque, which is the rotational force created around the propeller shaft. As the propeller blades spin in the water, they not only create thrust that propels the boat forward but also generate an opposite reaction that results in torque. This torque affects the vessel's steering and alignment in the water, typically causing the boat to turn in the opposite direction of the propeller's rotation due to the principle of action and reaction.

For example, if a right-handed propeller is used, the torque will cause the stern of the boat to move to the left. Understanding this principle is crucial for boat handling, as the effect of torque can influence the maneuverability and control of the vessel. Thus, recognizing the role of torque in conjunction with thrust is key for effective operation of a boat and is a vital aspect of being a proficient boat crew member.