White chalky film on prop

[bj2455]

I've got a '89 SeaRay 230CC with the 5.7L engine and Alpha One outdrive. The wife and I spend 3 days on the water in Lake Michigan this past weekend and when we pulled the boat out on Monday, I noticed the prop had a white chalky film on it and the trailing edges (cupped area) seemed to be much rougher than the rest of the prop.
I'm wondering if I'm getting cavitation that is causing the issue or if there is something else going on. Trimmed out properly, we get about 48 mph (GPS) at top end which seems pretty good for a boat this heavy. We did run it hard on Monday for the return trip from Grand Haven to South Haven (about 60 miles).
Anybody have suggestions what I might look for to eliminate the build up?
Thanks in advance for any suggestions!

Bill

 

[QC]

Re: White chalky film on prop

Stainless Steel?

LimeAway will melt the build up off. May have to scrub a little but you can even get them off with your fingernail without a cleaner. Probably just hard water deposits. If you are seeing any pitting as opposed to build up, that would indicate cavitation which is much more rare than the use of the word . . .
I get the build up on the Lakes, but not on the river (Colorado) . . .

 

[bj2455]

Re: White chalky film on prop

Yes...Its a stainless steel prop. Is that typical of stainless? Thanks for the info!

Bill

 

[QC]

Re: White chalky film on prop

Yes, typical. Pitting of stainless is not . . . LimeAway will take care of the chalk.