Cavitation vs. Ventilation
Is your prop losing grip? Learn the difference between "boiling water" (Cavitation) and "sucking air" (Ventilation) and how to fix both.
It's Not Just "Slipping"
Both phenomena feel like the engine is revving but the boat isn't moving. But the causes are opposite.
Cavitation: The Boiler
Cause: Low pressure. When water moves too fast over a blade, pressure drops, making the water "boil" cold. These steam bubbles implode against the metal.
Symptoms: "Orange peel" burns on the blade surface. Noise like gravel in the drive.
Fix: Fix cup damage, check for hull obstructions, or clean the bottom.
Ventilation: The Air Sucker
Cause: Surface air being sucked into the prop blades.
Symptoms: RPM spikes in turns or when trimming up. No physical damage to prop.
Fix: Lower the engine, check the anti-ventilation plate height, or add a cupped prop to hold water better.