🔍 Key Concepts

• Compare the underwater shape in figure B to how a z-drive (Schottel-azimuthing) unit normally looks (a pod that can rotate 360°) versus a conventional shaft with rudder. • Recall that a Voith-Schneider drive has vertical blades rotating under a flat plate, very different from a normal propeller and rudder arrangement. • Think about what visual clues (rudder, shaft line, pod shape, vertical blades) can or cannot distinguish between a fixed pitch and a controllable pitch propeller just from an external profile view.

💭 Think About

• Look closely at the aft end in figure B: do you see a steerable pod hanging below the hull, or do you see a shaft leading to a propeller with a rudder behind it? • Ask yourself whether the drawing shows any sign of the distinctive vertical-blade Voith-Schneider unit, or if it looks more like a standard screw in a nozzle with a rudder. • Between fixed pitch and controllable pitch, which one would have an obvious external difference in a side profile drawing, and which would look essentially the same as a normal propeller and shaft?

✅ Before You Answer

• Identify whether there is a rudder drawn behind the propeller or a pod that turns instead of a rudder. • Confirm that you do NOT see a circular plate with multiple vertical blades (which would indicate a Voith-Schneider drive). • Decide if the illustration realistically can show the blade-pitch control mechanism, or if from the outside a controllable-pitch propeller would look just like a standard propeller.