🔍 Key Concepts

• Propeller interaction with the seabed in shallow water and its effect on vibration • Typical causes of hull and shaft vibration in marine propulsion systems • Differences between engine-related issues and shafting/propeller/flow-related issues

💭 Think About

• Which option directly changes the flow of water around the propeller and hull in a way that could cause uneven forces and vibration? • Which options describe conditions that would more likely show up first as temperature, pressure, or engagement problems rather than physical vibration of the hull? • Think about when ships notice increased noise and vibration underway: is it usually tied to depth of water, clutch clearance, bearing temperature, or just any high engine speed?

✅ Before You Answer

• Identify which choices involve shallow vs. deep water and consider how proximity to the bottom affects propeller wash and hull vibration • Ask yourself whether slight overheating of bearings would be a symptom or a cause of vibration in this context • Distinguish between a transient mechanical fault in the clutch and a continuous operating condition that would consistently create hull/shaft vibration