🔍 Key Concepts

• Shaft-driven generators must turn at or near a constant speed to produce proper electrical frequency • How fixed-pitch vs controllable-pitch propellers adjust thrust and speed • Why some propeller types are chosen to keep the engine/shaft RPM nearly constant while still varying ship speed

💭 Think About

• If the shaft that turns the propeller is also turning the generator, what does that imply about how much you can change shaft RPM? • Which propeller type lets you change ship speed and thrust without needing large changes in shaft RPM? • Which of the listed propeller types is mainly a construction feature (how the blades are attached) rather than a way to control thrust at constant RPM?

✅ Before You Answer

• Identify which choice allows variable thrust at nearly constant RPM • Eliminate any option that mainly describes blade construction rather than control of pitch or speed • Ask: for a shaft-driven generator, is it more important to change RPM a lot or to keep RPM steady while still controlling ship speed?