[C320-list] Knock, knock, who's there?

[James Sweet]

We had the same issue and the ace mechanic said it was the rudder. Only manifests @ 2100 rpm so when we haul in sept they are going to buy the repair kit from Catalina & rebuild the rudder shaft tube-there are no bearings. I'll let everyone know how it works out next year. 

Jim Sweet
TGIF (Thank God It Floats) 903

Sent from my iPhone

> On Aug 16, 2015, at 6:46 PM, "B. Stumpp" <bstumpp at comcast.net> wrote:
> 
> Back in May I posted the following on the forum: 
> 
> 
> 
> "We went out for our first Spring sail this afternoon.  Everything worked 
> great BUT with the engine running and turning left I get a knocking sound 
> with what seems like every revolution of the prop shaft.  It does not make 
> the noise when going straight, turning right or in either direction in 
> reverse.     If I speed up the engine the noise  goes faster.  I stuck my 
> head in the engine compartment both in front of and behind the bulkhead, 
> the sound is emanating farther back towards the stern.  It's not  a real 
> loud knock but kind of like someone lightly tapping on the deck with a 
> hammer as a surveyor does when checking for moisture.   Before we launched 
> the cutlass bearing and strut all seemed fine.  Has anyone experienced this 
> before?" 
> 
> Following is the best I can offer right now on a cause and a plan going
> forward: 
> 
> 
> 
> Nothing totally conclusive on the cause of the knocking but we think it was
> wear in the cutlass bearing.  I had the engine aligned and it seemed to
> occasionally make the noise but it was not as bad as it had been.  We hauled
> the boat  - service hang on the crane straps - and there was some looseness
> in the bearing but not too bad.  Decision by the mechanic, marina service
> manager and myself was it was not bad enough to fix right then and there so
> we relaunched and have been using it over the summer.  Have not really heard
> the noise since so am thinking the realignment helped but the bearing needs
> to be addressed.  Plan is to replace the cutlass bearing and change to a
> stainless shaft over the off-season.         
> 
> Bruce Stumpp 
> Adventure, #647 
> Frog Mortar Creek, Maryland  
>