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

[Rick Sulewski]

Mike, Good catch! I would also advise owners to check the hose section
nearest the fridge compressor shelf, as I had an issue a few years ago with
the exhaust hose wearing thru to the metal wire at that friction point.
Ended up replacing the hose as it was beginning to also show evidence of
dry-out type  cracking in several areas after 17 years of use as the hose
had also been flexing for over 1,000 hours. Securing the hose with rubber
insulation and with some robust screw to surface zip ties helped secure the
hose to the shelf and limited it from moving (thumbing) as well as laying an
old rubber mat under the hose where it moved about against the hull as water
& exhaust pulsed toward the exhaust exit.
Rick hull #277

-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Michael Rauh
Sent: Monday, August 17, 2015 1:18 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Knock, knock, who's there?

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
>>