[C320-list] High pitch whining (singing) noise from shaft above 2800

[Irving Grunes]

Next time you are on the hard for a few weeks find a place to balance your
prop
Irv Grunes
Former 2001 #851

On Mon, Jun 19, 2017 at 6:09 PM, <jbrown5093 at yahoo.com> wrote:

> The singing is from harmonics off of the sharp prop edges.  Happens with
> both 2 blade and 3 bladed fixed props and is just at the rpm you mentioned
> and which I use a lot. Sounds bogus I know but my yard was well aware of
> the noise and cured it on the next haul out by slightly  rounding the prop
> leading edge with some sandpaper.  I would not worry about it until you are
> hauled.
>
> Jim Brown.   Desafinado 973
>
> Sent from my iPad
>
> > On Jun 19, 2017, at 4:51 PM, danny jensen <danny at jensenshouse.com>
> wrote:
> >
> > I have hull 972 with new shaft,strut  and stuffing box about 4 years ago.
> > Cutlass was replaced about 5 years ago.
> >
> > When I run above 2800 the singing starts.  Then at 3100 it stops.
> >
> > I've got GFO standard packing and the noise is not coming from stuffing
> > box. Only happens in gear. It Didin't sound like if was from
> transmission.
> >
> > If the prop hits a chunk of kelp, this fixes the problem for a while and
> I
> > don't hear any singing.
> >
> > Any clues?
> >
> > Danny
> > #972
>
>