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

[Michael Rauh]

The next time you run your engine listen for the knock when the transmission is in neutral.  If you still hear the knock it is probably coming from the exhaust hose banging against the hull.

If that is the case:
Open your port side aft lazarette and you might be able to see the hose thrashing about.  I corrected this problem on my boat by installing an additional hose hold-down plastic strap.  I bought a plastic strap intended for holding plastic electrical conduit from Home Depot. 

Mike - On Your Mark
# 408

Sent from my iPhone

> On Aug 16, 2015, at 19:08, James Sweet <jamesweet at frontiernet.net> wrote:
> 
> 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  
>>