🔍 Key Concepts

• Examine how the propeller load curve shifts when hull or propeller resistance increases or decreases. • Understand that area B on the load diagram represents relatively high engine load at lower RPM compared to normal. • Relate each operating condition (wind/current, shallow water, fouled propeller, minimal drag/light draft) to whether it makes the propeller ‘heavier’ or ‘lighter’ to turn.

💭 Think About

• For each choice, ask yourself: does this condition make the engine work harder or easier at a given RPM? • Which conditions would push the operating point to the left into region B (more load at less speed), and which would tend to move it to the right toward region A (less load at more speed)? • Think about when a ship feels ‘draggy’ and slow for the same throttle setting versus when it feels ‘slippery’ and easily reaches higher RPM. Which of those belongs in region B?

✅ Before You Answer

• For each option, decide if it increases hull or propeller resistance (heavier load) or reduces resistance (lighter load). • Verify whether operation in region B corresponds to a heavier-than-normal propeller load at a given RPM. • Identify the one condition that would most likely move the engine operating point away from region B rather than into it.