Prop wear?

Ran over a mostly submerged branch/log of some sort. Heard it and felt it go under the boat. Immediately put in neutral. After it passed started to throttle up, once hitting about 10mph started to vibrate pretty good so thought for sure prop was damaged. Putted back to pull boat out of water to inspect. Under 10mph no vibration and made it in. Upon putting boat on trailer so could visually inspect, no nicks, bends etc to prop or shaft. Thinking maybe some weeds or something maybe got wrapped around shaft and came off while putting through no wake zone and loading on trailer. It was end of day and last night so never put boat back in to go test to see if vibration was gone now that I knew I had no obvious damage to prop or shaft. When getting home spent more time inspecting again and noticed back side of prop appears to have wear spots on 3 of the 4 blades. Curious if this is normal from use? Prop is about 3 years old or so. Is this wear enough to cause very noticeable vibration? Tried to get pictures, bottom blade has no wear but left and right do in the picture. Top blade also has wear, just didn’t capture in picture. Planning on taking it back out this upcoming weekend to test. Probably more detail than need for my question but wanted to give the whole story of what led me to my question.

My sister in law hit something with our boat. There was no apparent damage but it vibrated at 8 mph. Changed the prop and the vibration went away. Took it to the prop repair shop and there was a slight bend on one of the blades, causing the prop to be out of balance. You have three blades different from the fourth. That could be enough.

If the log hit hard enough it could have tweaked the brackets holding the prop shaft (going to get roasted for not knowing the term).

Zog is also right. It doesn't take much for vibration. Could also explain the wear. Depending on how long to putt back it could have caused the polishing effect from the fiction of the water over the 3 blades.

Thanks to the both of you. Will swap prop out with my spare and see if issues solved. Great way to describe the wear “polishing effect”. See if the prop change solves (hopefully that all it is), if not may have to to move onto the strut (bracket) ;) as well. When turning prop by hand, all seems to be smooth turning so we shall see. Will follow up after I get chance to drop it back into the water.

How fast were you moving when you hit the log? Even going really slow, if the log was big enough in mass, it could have slightly knocked the pitch out of one of the blades. That would be hard to see by just rotating it on the shaft. If you take it off, you might be able to tell measuring it on a flat surface.

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Was probably moving about 20 or so, storm was rolling in so was heading in to get off lake. Waves were pretty good as well so think that contributed to not seeing the floating debris. Daughter was sitting up front, when running it over she said cant believe you didn't see it, it was HUGE! Changing prop out this evening and will head to lake in the morning to give it a run.

It really is about the balance of the prop overall. Like I said, our damage was almost imperceptible. My brother-in-law hit an underwater shoal at Lake Powell last weekend and trashed his prop, with all 4 blades getting trashed. He was able to drive his boat at 15 mph before vibrating since the damage was more balanced than ours.

Prop change took care of the vibration. Looks like will be sending out the old to get checked/balanced so I still have a backup. Thanks all.

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Originally Posted by Seahawk

Prop change took care of the vibration. Looks like will be sending out the old to get checked/balanced so I still have a backup. Thanks all.

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It is amazing how the slightest imperfection you can't see with the naked eye can throw a prop outta balance. Could be a warped ear or bent at the hub. Put it on a flat surface, if it wobbles, it is the hub and most likely shot. Hopefully not though and just needs repitched.

I think what you see on the back of your blades is not wear. I am pretty sure its just where material was removed as part of the balancing when the prop was made.

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Originally Posted by rdlangston13

I think what you see on the back of your blades is not wear. I am pretty sure it’s just where material was removed as part of the balancing when the prop was made.

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I would take it out again. Weeds on the prop,prop shaft will definitely cause issues.