Prop sing

[Conall63]

One of the bugs on my new built boat last season was my prop singing at certain rpm. The 30 x 18 four blade would make a loud, running ones finger around a wine glass sound , between 1200 and 1600 rpm. It was loud and big time annoying. So annoying that I ran her mostly @ 1700..

While on the hard this winter, I had the prop shop check the wheel and grind the leading edge to try to stop the singing . We launched today, and I'm big time happy to rport the anti sing edge worked ,and she's running quiet.

The prop is a Chinese unit and was about 800 less expensive than one from Michigan wheel.

Anyway, I'm happy we're back in the water, and that a low cost remedy fixed a gremlin.

Conall

 

[markpierce]

Had the same issue and remedy (after two attempts).

 

[twistedtree]

Wow, this is really interesting to hear you guys had this problem. A friend of mine with a new Nordhavn has the same problem. I had never heard of such a thing. Fortunately mine is quiet.

 

[BlueYonder]

Same problem and same fix on a previous boat

 

[Ski in NC]

Once you get some barnacles or mineral coating on the wheel, it will stop singing. That's how I know it's time to clean.

Mine only does it when at non-cruising rpm. I kinda like it. But it is not loud.

 

[Gulf Comanche]

Mine sings at low rpm, around 1100. At 1600 no sing, then back down low and sings till boat slows way down.

 

[Nomad Willy]

I had that problem on my Albin .... 12 years ago.

 

[FlyWright]

I believe that 'singing' is telling you that the prop speed is causing a resonant frequency to set up which sends vibrations through the prop. I remember some airplanes which had this problem and the remedy was to avoid continuous operation at that RPM range causing the resonance. Failure to avoid these speeds could cause fatigue damage to the propeller.

Not sure if it's the same with boats, but I'd be cautious to avoid continuous operation at that engine speed range.

 

[Brooksie]

I had a singer too and it was a new Michigan... a soprano I think. It also had 3 craters in it which had been welded up with incompatable brazing rod at the factory. They had their local distributor fix it but nothing for hauling, removing or shipping. They tried to make me think they were doing me a big favor at that. Needless to say my last Michigan wheel.

 

[Capt.Bill11]

http://hydrocompinc.com/wp-content/uploads/documents/HC138-SingingPropellers.pdf