Cruiser 32 Saildrive making high pitch sound

[keremerdem]

Hi,

I own a Bavaria 32 2010 with D1-30 Volvo Penta and sail drive. I just recently had an oil change when on land, now it is making a high pitch sound when in gear and between 1800-2300 rpm.

I checked the oil, it is at the upper line and clear. The problem had appeared after my first taking to land as well. In the next servicing on land, I had to replace the propeller, since the anode did not do its duty. After this, I did not have a noise. Now with my last servicing on land, doing antifouling paint, I have the same problem.

My question is, is it really the propeller doing the noise (wrong painting??), or some problem in the gearbox?

If it is the propeller, is it something bad and can cause damage on the gearbox? Since I have a sail drive replacement history (because upper seal broke and all oil spilled into the engine compartment, killing gearbox, noticed before engine went on fire!) I am very cautious.

Appreciate your comments

Kerem

[JEN-et-ROSS]

A worn, damaged or dry gearbox would most likely make a whining or regular clunking noise. This sounds more like the propeller fouling against something, e.g. the anode.
Depending on the type of propeller you have there is likely to be a spacer that slides onto the propeller shaft before the propeller is fitted, could it be missing or fitted 'back to front'?.
I think if it was me I'd like solve this before this before using the engine again.

[landes_h]

Hi Kerem.
You may not need to worry to much. What you experience is a so called singing propeller (google it..).
I had the same phenomenum. If you only have the sound at a certain rpm-range and before and after it's gone I would say your prop is singing.
May old Elan-33 had the same problem and only after replacing the prop it was gone. However there is no need to replace the prop unless the sound is getting on your nerves.
As you wrote, it happened after you had the boat on land and new antifouling done. Asuming you also did the prop. This is exactly the problem. A very clean propeller tends to sing easier then a dirty one.  Once the boat is in the water for a while and a few mussels have settled on your propeller, the singing gets less.

[keremerdem]

Thank you both.

It looks like there are two different views, depending on personal experiences. With my limited knowledge, I can say that there is no clunking noise coming from the gearbox, rather like the screaming old-belt noise that comes from some old cars (it is not the belt by the way, since it only does when in forward).

I guess that the best way to solve is that I make a video with the engine sound and rev meter. In this way, you may help identify if it is the singing propeller or something worse.

If I had not lost a sail drive before, I would be more relaxed.

[landes_h]

If the sound only appears at a certain range of rpm, like you said between 1800 ans 2300 rpm this is very much a resonance tone created by the prop. I had little improvement after filing an angle to the rear edge of the propeller blades which helps the water flow to cut off differently. A rather scientific essay is here: 
http://hydrocompinc.com/wp-content/uploads/documents/HC138-SingingPropellers.pdf
another version:
https://www.youtube.com/watch?v=tdsfQbvZWyo
As you can see, the internet is loaded with helpful information (as always  ).

Seriously the sound is more embarrassing then worrying. As you also mentioned the noise of a slipping belt in a car, that is exactly the noise, a pretty clean sine wave tone. I also had the sound when I was sailing, because I had the prop free turning (shaft drive). It was a very reliable speed meter.

[dawntreader]

......the sound is more embarrassing then worrying. As you also mentioned the noise of a slipping belt in a car, that is exactly the noise, a pretty clean sine wave tone. I also had the sound when I was sailing, because I had the prop free turning (shaft drive). It was a very reliable speed meter.

Just to confirm the above information, I also experience this noise on my B37. However, the information provided now tells me what it is - although I was  not concerned that it was from any 'mechanical failing' - so thanks for the post 

[tckearney]

Hi just read the very interesting articles about the "singing Propeller"  I had never heard of this.  I have just had to change my propeller on B42 volvo sail drive.  Since then I have high pitch noise between 1200 and 1700 rpm.  I don't think it was there before the propeller change, although can't be sure. If it was there it wasn't as bad.  It is only in ahead.  Is there any chance this could be the trust bearing ??  I assume there is a thrust bearing in the sail drive leg.  I must admit, I feel a lot better and more confident after reading these comments on the subject.

[dawntreader]

I have just re-launched with a sparkly clean, anti-fouled propeller. It has been singing it's heart out - all night