Propeller Cavitation
Formation and collapse of vapour bubbles on propeller blades due to local pressure dropping below water vapour pressure.
In practice
Audible from the engine room as a 'rattling' or 'singing' propeller. Vibration sensors on the shaft pickup the resonance; chief engineer alerts the bridge to reduce shaft RPM. Persistent cavitation erodes blade tips, costing tens of thousands per drydock visit.
Regulatory detail & full definition
Causes vibration, noise, blade erosion, and reduced thrust. Classical signs: sudden drop in propulsion efficiency, high vibration in aft accommodation, characteristic 'singing' propeller sound. Prevented by appropriate blade design (tip clearance, Cp), avoiding excessive shaft RPM at low draft. Modern wake-improving devices (Mewis ducts, pre-swirl stators) reduce cavitation.
Related
Source: Industry usage; ITTC propeller cavitation procedure
High confidence
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