Cutless Bearing, Advise Please

[Juan]

When I bought my boat two years ago I noticed -while on the hard- that the cutless bearing was slightly loose. However, once in the water I could not sense any vibration or any sound from the cockpit. Two seasons went completely fine. A month ago we decided to take the boat out of the water to paint the bottom. We took advantage of the situation and ordered a cutless bearing replacement. According to the yard, they replaced it without pulling the shaft but using a hydraulic press. According to them, everything went well. I didn't see the cutless bearing on the hard this time. The boat went back to the water this weekend. I motored for 1 hour. Once again, I could not sense any vibration; however, a subtle (metal?) sound could be heard at around 1300-1500 rpm. The sound disappears above 1500 rpm.

I wonder if this could be the new cutless bearing temporarily adjusting to the shaft? Has anyone had a similar experience with new cutless bearings? Did the sound go away eventually? Or should I worry about something else?

Thanks,

Juan

[Ron Hill]

Juan : You shouldn't have a "METAL/grinding" sound.  You might have a squeaking sound from the cutless rubber, which should go away after an hour or two of running.
What was the condition of the drive shaft inside the old cutless?  

[C Martinson]

You shouldn't hear a grinding sound....something that isn't always mentioned is realigning your engine (check the engine mounts) after replacing the cutlass bearing........worth checking. 

Chris
More Therapy
Hull 945

[Juan]

Thanks Ron. It might not be a metal sound, but something like a high pitch. I was told that is not unusual for a new cutless being to "sing" a bit during it's break in period.

On the other hand, an engine alignment was not included as part of the bearing replacement. In my case, the shaft was left installed and the bearing simply pressed out and replaced, so nothing changed in the drive train other than the bearing.

I am trying to see if this is only a temporary sound that will go away or I should worry about the engine realignment. I guess I can motor some more time and wait to see if the sound will go away before doing anything else.

J

[John Sheehan]

Juan, 

Another source of the singing noise could be your propeller.  After I have cleaned our propeller it tends to sing until some crud starts to build up.  I have noticed this on other boats with real clean propellers.

John

[tonywright]

I think that I would have the alignment checked. When a cutlass bearing wears out, there is a reason for it. Could be poor alignment. It doesn't always manifest itself in a noticeable vibration. If the alignment is not good you could have some binding occuring on the new bearing?

(BTW a metallic sound normally would indicate a worn or missing cutlass bearing.)

Tony

[Juan]

John, I indeed cleaned the propeller which was full of stuff. So, hopefully your theory is right and I just need to sit back and wait for the crud to come back.

My question to Tony is this: let's assume that the alignment has been bad for a while. Why I dind't hear this sound with the old bearing and hear it now with the new one?

Thanks to both for your insights!

Juan

[Ron Hill]

Juan : I believe that the new noise is just what it is - a new noise from the new bearing. 
It would be prudent to have the engine alignment checked.  Out of alignment could have been a factor in the wearout of the old curless.  A thought

[tonywright]

Here is a list by David Pascoe of problems that could be caused by poor alignment:

Rapid cutlass bearing wear.
Misaligned strut galls shaft, requiring shaft replacement.
Causes stuffing boxes to wear out and leak, not infrequently sinking the boat.
Bent or broken shafts
Drive system vibration that can damage transmissions, engine mounts and the boat hull itself.
Vibration causes  damage to other systems.
Transmission failure caused by increased stress on the rear output shaft bearings and gears.
Loosening of struts, causing leaking and possible sinking.
Oscillating propeller shaft causing stuffing box clamps to loosen and work free, flooding or sinking the boat.

He has really good info and diagrams on his web site: http://www.yachtsurvey.com/Alignment2.htm

Tony

[Juan]

Ron, Tony, thanks a lot!

Juan

[Michael Shaner]

Tony...informative link...good find...