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

[danny jensen]

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