🔍 Key Concepts

• Controllable pitch propeller (CPP): How thrust is changed (blade angle) versus how speed is changed (shaft RPM) • Rudder effectiveness: What actually creates flow over the rudder and when you have good steering control • Neutral pitch position: How precise the control has to be to create zero thrust with a CPP

💭 Think About

• Think about how a CPP lets you go from ahead to astern thrust: do you have to change shaft RPM, or just change the blade angle? • If you suddenly go from full ahead pitch to full astern pitch while still making way, what happens to water flow over the rudder and your ability to steer? • When the control is set to "neutral" on a CPP, is it always perfectly zero thrust, or can a very small pitch error still create some headway or sternway?

✅ Before You Answer

• For each choice, ask: Is this describing pitch control (blade angle) or RPM control (shaft speed), and is that correct for CPP? • Check whether rudder control depends on flow over the rudder, and whether that flow is coming from ship’s speed through the water, propeller wash, or both. • Consider whether finding a truly zero-thrust pitch setting is easy or sometimes tricky in real-world CPP operation.