[C320-list] noise at 1800

[jim brown]

Thanks Karl. I did have the prop treated. I had a similar issue with the two blade prob but it sounded less "screaming" than the sound I hear now-guess it might with another blade rotating around. I'll live with it unless the yard will haul for free to take a look since it wasn't there before the work was done. As an aside. we met Orlando in Oriental when he was poking around the yard where our boat was hauled. Had a nice chat. He very much enjoyed his stay and your hospitality. 

Once again membership in the Association has more that paid for itself. 

Jim Brown



________________________________
 From: Karl Mielenhausen <kmielen at suddenlink.net>
To: C320IA Discussion List <C320-List at catalina320.com> 
Sent: Monday, September 2, 2013 9:53 PM
Subject: Re: [C320-list] noise at 1800
 

Did you have any bottom paint or other anti-fouling treatment applied
to the prop?
When I did, I developed a similar sound which occurs only at specific rpms.
The problem usually is a result of a fine trailing edge on the blades.
There is past discussion here...
http://lists.catalina320.com/pipermail/c320-list-catalina320.com/2010-September/033709.html

Bottom line... there is no eminent mechanical failure, so you can live
with it until the next haulout.

BTW, an alignment issue could sound like you have a loose chain
rotating around the propshaft, wrapping against the hull.

Karl

On Mon, Sep 2, 2013 at 7:00 PM, jim brown <jbrown5093 at yahoo.com> wrote:
> Had the boat hauled while we were on vacation for a week to have the bottom cleaned and repainted. While it was out I had the two blade prop changed to a three blade (my wife is at the helm and wanted more reverse power-I know it's slower-she doesn't care), the cutlass bearing replaced (10 years on the original) and the stuffing gland redone with Gortex packing. When taking the boat back to our marina we noticed a high pitched screeching sound only at 1800 to 2200 rpm. Go below 1800 and above 2200 and no vibration and quiet. No noise at the dock in neutral throughout the rpm range. Can't really locate the noise except it doesn't seem to be coming from the transmission or the packing gland (and that is cool after half hour of motoring), and it seems a little louder in the aft lazarette.   Any suggestions? Is there an upper bearing in the stuffing box that might need attention?
>
> Jim Brown  Desafinado 973
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