Noisy prop/cutlass bearing/ or what?

[PetiteFleur]

On a friends boat this afternoon and there was a terrible noise coming from the prop/cutlass bearing or what?? It occurred soon after engine is put in gear, also when the engine is off and the prop is rotating when sailing. It is really loud. With the engine switched off and prop rotating you can hear the noise but no obvious vibration from the shaft or g/box, even when one holds or touches the shaft or gearbox. We've come to the conclusion it's the cutlass bearing but I've never heard this noise before. Anyone have any ideas?
The boatyard are going to have a look at it tomorrow.

 

[lpdsn]

Something around the prop? Getting some speed up then going astern might help dislodge it.

Was there no vibration at all when motoring? If the cutlass bearing is worn the play is more often than not in a vertical direction. Anything wrong with the prop itself is likely to result in vibration.

Maybe also worth thinking about whether it is the gearbox.

 

[miyagimoon]

Propeller cavitation noise. https://www.google.co.th/search?q=p...9i60.1503j0j8&sourceid=chrome-mobile&ie=UTF-8

 

[vyv_cox]

Rope cutter? Shaft anode? Either of these coming loose make a lot of noise.

 

[fisherman]

get a broomstick/long screwdriver, one end on gearbox other end in ear, then try sterntube, should isolate the source.

 

[Don107]

As Vyv said i would check the shaft anode (if it has one)

A mate of mine removed his gearbox and put a set of bearings through it chasing a noise that ended up being a loose shaft anode when the boat was eventually slipped

Regards Don

 

[[70521]]

What does the "terrible noise" sound like?

My prop makes a noise at low revs under engine, then again when we reach 4.8 knots when sailing. I am sure it is just cavitation through the water, but will be doing something about it as I'll go mad if I hear it for weeks on end.