cavitation burn

[MBAKER]

I have 2 props, different makes but both 14.5x18 4 blade. Performance is very similar but one has paint coming off through the middle of the blade on the pressure side. The othe looks like new.

Is this an indication one prop is working better than the other or just a fluke?

Was told the paint coming off is cavitation, is this true?

 

[Maclin]

May just be a not-as-good paint prep. Were either one of those refurbished in the past?

I had a Merc aluminum prop refurbished, and the paint came off after a run or two. At the same time I had a new Michigan Wheel aluminum prop for the same boat, it was powder coated and looked brand new after 8 hours or so.

 

[Chris1956]

Is the metal pitted? If not, I would expect a bad paint job is to blame. What sort of boat/motor combo do you have?

Also, normally cavitation burn would be on lee side of blade.

 

[MBAKER]

It is 20' runabout, Alpha 1 with 5.7.

neither was refurb, both were new when I got them.

Going from memory here....I don't know if it necessarily pitted or just natural porosity in the aluminum. It does not look aggressively eroded though, and seems like once the paint comes off it doesn't really change texture any.

We do a lot of skiing tubeing etc, and I have wondered if the prop slips on launch and that creates a high pressure area on the blade at that area and that then scuffs paint off. Maybe one of the props is just better at distributing that pressure across the blade instead of being concentrated.