Saildrive SD130 noise

[Hotzenplotz]

Hello all,

I have (do I ?) an issue with my saildrive but I'm not really sure. There is a noise coming from the saildrive which I can't locate.
I made a video where the sound can be heard.

https://youtu.be/KPPlwRaF9q0

"test"conditions:
6,5 kn / 2200 rpm
freqency of the noise: 190/min.
I declutched and let the engine run at same rpm and the sound was gone. So the engine seems fine.
I checked gear oil, clear and good level.

Boat:
B36 Cruiser 2011
Volvo Penta D1-30 / SD130
low engine hours (300)
flexofold 2 blade folding prop.

It's from day one this season, so I am sure that the prop has been clean and without damage. Last year was our first season with her and I can't remember if we had this sound - but there were so many new things last year that I may not have noticed.
In winter we changed the gearoil from atf to engine oil as recommended.

Any idea of what could be the reason ? I read about cavitation and singing props but as far as I understood these issues have a higher frequency.

btw. others can hear it, too 

Thanks a lot

Jens

[lawrence_craig]

Hi there.

Have you checked for play in the prop? Or in the folding blades?

Its so high pitched it sounds like resonance caused by cavitation. Therefore I would possibly rule out anything mechanical in the saildrive. If it was mechanical, it wouldn’t sound as good I believe. Although bear in mind it’s hard to say without hearing it in person.

[Hotzenplotz]

I checked the prop in April, it has no play at all and is as new. Since then I made 50 hours. It's clean.

I know that it's hard to hear via a video. But to be sure, what I mean is the roaring sound in the background. You can hear the high engine sound and in the background a deeper roaring.

/Jens

[tckearney]

Hi I Have a 2000 B42 and I have three props one in use two as spares that I refurbish in the winter. .  Everytime I lift out I change the prop for one of the refurbished ones.  During one of the changes I had a definite high pitch wine between 1500RPM and 2000 RPM before 1500 nothing and after 2000 nothing.  Is yours permanent?  After much adivice It was decided that some props "sing" while others do not.  It could be that the cleaning you carried out during layup has caused this and if so I dont think you need worry.   There was a good article in this forum a few years ago about singing props .  Its also mentioned on youtube

[Salty]

.
.
I made a video where the sound can be heard.

https://youtu.be/KPPlwRaF9q0

.
.

Unless I am mistaken, your video made a single sound from start to finish such that I couldn’t determine what was normal and what was not. It would help if your video included the normal sound with the prop out of gear and at a point where you announced that you were about to put the prop in gear where we could then hear the difference.
With both sounds clearly defined we might have a better chance to help diagnose the problem.