What determines the surface area of a propeller?

The surface area of a propeller is determined primarily by the number of blades. Each blade contributes to the overall surface area that interacts with the water, generating the thrust needed for propulsion. More blades generally lead to an increased total surface area, allowing for greater efficiency and improved handling characteristics, particularly in specific operating conditions such as low-speed maneuverability.

While other factors, such as the diameter of each blade and the shape of the blades, also play a role in the overall hydrodynamic performance of the propeller, the influence of the number of blades directly correlates to the propeller's ability to create thrust through increased contact surface with the water. The type of material used can affect performance characteristics like strength and weight but does not change the calculation of surface area itself. Similarly, the length of the shaft, although important for the overall function of the propulsion system, does not impact the surface area of the propeller blades.