Propeller cavitation?

[pjllewh]

I have a new Gori 16.5X13 2 blade folding prop on Sigma 362. From 1700/2600rpm I get a loud drumming noise. Any one else have 362 with this size?

 

[catmandoo]

sounds like low frequency and resonating at natural frequency of system. Have you checked your cutless bearing . Cavitation is more like a crackling noise ie like gravel running down a pipe

 

[ex-Gladys]

The other poss is prop "knock" as a result of the prop/hull clearance not being large enough. Not that the prop hits the hull, but the pressure wave does.

 

[pjllewh]

Thanks for your reply. The noise now has a better description, a throbbing noise. Maybe caused by too long a length unsupported shaft. Although the same as before but propeller has greater pitch.