Prop Cavitation

[fishhuntwork]

I installed a new 4 blade alum prop in the beginning of the summer and now I noticed there are burn marks on each of the blades. The performance of the boat is awesome and it has improved everything that I wanted it to. What can cause this and is there anything I can do besides replace the prop?

[CAMAN]

Turn your afterburners down slightly

[marine_man]

I presume you didn't notice any cavitation problems while running?

marine_man

[shamrock7]

The erosion is caused by the water boiling as it goes over the blade. Yes, boiling. The increase in pressure allows the water to boil as it passes over the blade. The anti-ventilation ring on most props slows the flow of water enough to reduce or eliminate this problem. Is your ring in place? If not, get it replaced. If not.....not sure what you can do, maybe try changing your trim angle a little. But a new prop will not likely fix the issue.

[boatfixer]

Its actually a decrease in pressure allowing it to boil.

[delcecchi]

And it isn't actually boiling, more like the water is ripped apart.

[kfk]

Actually, yeah it may be boiling. As the atmospheric pressure drops as it would around a prop while water goes by it (look up Bernoulli's principle), it may get low enough to decrease the boiling point so that it will boil at normal open water temperatures. The decrease in pressure is the reason why a prop moves a boat and the same reason why a wing will lift a plane.

[Whoaru99]

Cavitation is caused by decreased pressure that allows cavities/voids to form, when the pressure goes back up the cavities/voids implode which causes a shock wave that can/will damage the surface if strong/frequent enough.