Prop noise

[dcollinge]

Last year I replaced the standard 2-blade prop on my Hunter 33 with a 3-blade prop (purchased through my Hunter dealer). There is a whirring noise from the new prop that is almost unbearable when I'm under sail with the transmission in neutral. I can make the sound (and the prop) stop by putting the transmission in gear, but Yanmar states that this is not a good idea, and will void the warranty on the engine. Any ideas to lessen the noise would be appreciated.

 

[Alex Dare]

Without putting the boat in gear, about the only thing you can do is install a prop shaft lock.

http://www.shaftlok.com/cover_photo.htm

 

[Rick D]

Either a shaft lock or feathering or folding prop are about your only options. http://www.shaftlok.com/

 

[Don12364]

Singing Prop??

You may have a "singing prop". The water flow causes the blades to oscillate which generates a high pitched whining sound.
If this is the cause some prop shops can machine it a little to stop this nuisance.
Ask around among your locals to verify if this is your problem.

 

[Ken Palmer]

Have your first mate at the helm and go below to see if the prop shaft is rotating as you are sailing in neutral. My H33.5 2-blade prop will cause the shaft to turn under sail. I place the transmission in reverse which I have read over the past years to be the acceptable method. Only problem is shifting back to neutral while under sail. One way to ease the pain is to start the engine in reverse, then shift it to forward.