Gori 3 blade folding prop vibration

[Strikhedonia]

I have a catamaran with Yanmar 3YM30 (SD20 sail drives) with Gori 3 blade folding props. If I haven't recently cleared my starboard prop there will be a vibration with any RPMs above 2000. Even after cleaning there is a slight vibration. On my port engine I don't have any vibration regardless of growth on the prop. Is there a process to balance a propeller? Any other ideas of how to eliminate the vibration?

[senormechanico]

Probably not practical, but I can't help wonder if you swapped prop locations.
Would the vibration go to the other drive?
If not, the sail drive shaft could be slightly bent. Just a thought.

[Strikhedonia]

Originally Posted by senormechanico

Probably not practical, but I can't help wonder if you swapped prop locations.
Would the vibration go to the other drive?
If not, the sail drive shaft could be slightly bent. Just a thought.

Thanks, I had considered this and the next time out of the water I plan to try the swap. Just wasn't sure if there was a procedure to balance the props (both look perfect with no visible damage)...

[Don C L]

Not sure if this applies, but I have heard some folding props will vibrate or cavitate if they are too close to a surface (hull or rudder) above or below. Are both props exactly the same distance from the hull?

[Strikhedonia]

Originally Posted by Don C L

Not sure if this applies, but I have heard some folding props will vibrate or cavitate if they are too close to a surface (hull or rudder) above or below. Are both props exactly the same distance from the hull?

They are both the same distance. I have looked underwater while under way and there doesn't appear any cavitation.

[Orion Jim]

Have you contacted the manufacturer? I'll bet an email would get a definitive answer. All propellers require balancing as part of the manufacturing process. Any subsequent balancing would be per the manufacturers specifications whether it was done back at the manufacturers or by an authorized professional. These are very pricey props and I'm sure they hold very tight manufacturing tolerances. Good luck.

[EWOL Props]

I suppose the props are not new ?
If the case please check the plastic inserts, on that brand you have to replace them after some time to avoid vibrations

[Strikhedonia]

Originally Posted by EWOL Props

I suppose the props are not new ?
If the case please check the plastic inserts, on that brand you have to replace them after some time to avoid vibrations

They are seven years old. I had no idea there was a plastic insert, thank you very much I will look into replacing them.

[sailon46]

I have a Gori 3 blade 20' on my beneteau 51.4 Cyclades. I have noticed occasionally some vibration as you are indicating. It has always gone away with cleaning growth or if it occurs while underway and motoring by gently applying reverse to clear the sargassum weed caught in it.

[CarlF]

On a previous boat, I had a Gori prop come off (fortunately it occurred in a harbor but a diver was unable to find it). The prop was about five years old and had lots of use.

The "expert" consensus was that the shaft key had not been exactly the right size and it eventually allowed the prop to wiggle a bit on the shaft. Of course the key was lost too so this is conjecture. I was told there should have been some tell-tale vibration before the prop fell off but I never felt any.

You might want to pull the prop and check the key's fit.

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