Given the definition of pitch, you might wonder why you wouldn't choose a propeller with higher pitch in order to gain additional power. But propellers must be sized in relation to the rest of the propulsion system, and must match the power curve of the engine, as well as the rpm range afforded by the reduction gear. As such, a propeller with excessive pitch may not actually generate additional thrust, since it would overload the engine and prevent it from reaching the designed rpm, which can reduce fuel efficiency and increase wear to critical engine components. Additionally, an overloaded propeller is susceptible to cavitation, which happens when a prop rotates and creates a partial vacuum. Water rushes in to fill that vacuum, creating tiny bubbles; when they collapse, they basically pound the prop. While cavitation will occur in small amounts in very localized areas on almost every propeller, excessive cavitation will result in a loss of thrust, excessive noise, and vibration, and can be violent enough to actually pit or erode the propeller.