Cavitation Burns

[LarsonSenz]

Morning All,
Pulled the prop for winterization and see what looks to be cavitation burns on the leading side of the prop? Can't say I've ever seen them on this side, always see them trailing side (side that faces outward) and not this close to the hub
I've checked the drive, I don't see anything that looks to cause water disturbance, I have no in water transom or hull mounted sounders or sensors that would cause disturbance.
Aluminum prop was due to low water levels, didn't want to find anything with a stainless

Thoughts? Ideas?

4 Blade Turning Point Hustler 14.5x17P
2010 Larson Senza 206
5.7gi- 300 VP
4900-5050 WOT

 

[Scott Danforth]

Thoughts? Ideas?

spray paint and go boating

cavitation burns are common, more common on DP drives

 

[QBhoy]

Likely just from the vents on the prop there. Paint is easily removed from a prop like this. But if a coincidence that’s it’s in line with the vents there.

 

[Chris1956]

I had the same thing on the TP prop on my speedboat. The metal was actually pitted. Fill the pits with marine putty and prime and paint.

Not sure if it is cavitation or ventilation burns.

 

[Texasmark]

Only time I had it was back in 1971 with a Chrysler 85 hp. The OEM Aluminum prop had a funny shaped leading edge. When emanating from the root/hub interface, rather than the blade sloping back in normal fashion, it had a reverse "S" whereby the metal went forward and then assumed the normal reverse slope. Right at the vortex of this reverse curve, on the blades. the aluminum was being burned away...pitted and all.

 

[jimmbo]

I first saw Cavitation Burn back in 1975, on our 1965 90hp's small hub props, on the same side of the Blade, just closer to the Gearcase. Likely caused by the Vacuum Bubbles formed as water went past the End of the Gearcase, and when it contacted the prop blade, collapsed, hammering little pits in the Metal

 

[harringtondav]

Aluminum prop was due to low water levels, didn't want to find anything with a stainless.

Good move. I do the same. Aluminum props act as a fuse in an impact and likely avoids a bent propshaft....better than a SS prop. My best performing prop is SS, but I save it for higher water once the spring flood trash clears.

 

[jimmbo]

In 2002, I found a submerged Rock Ridge, with my Stainless. Neat thing about Stainless, the blades will tear, bend, but not break off, eventually you end up with a bent propshaft, and a sculpture


Aluminium is more forgiving