[C320-list] A High Pitched Whine Noise /// Restoring the flat edge on the prop blades eliminated prop whine

[jim brown]

I had the same whine. Thought it was the cutlass bearing but the yard said it was a very common noise with props that had a fine edge. When hauled they put a flat edge on the prop blades and no more whine. Cutlass bearing was fine. 

--- On Fri, 9/10/10, Rick Sulewski <rsulewski at bex.net> wrote:

From: Rick Sulewski <rsulewski at bex.net>
Subject: [C320-list] A High Pitched Whine Noise /// Restoring the flat edge on the prop blades eliminated prop whine
To: C320-List at Catalina320.com
Date: Friday, September 10, 2010, 11:26 PM

Dave,

 

I had a similar prop whine situation some 12 years ago after I cleaned up
the prop with some light sand paper. What I did not realize is that cleaning
up the two blade prop took some of the hard (flat - 90 degree) edge off only
a small portion of the prop blades.

 

For the entire season after cleaning up the prop we experienced that same
annoying prop whine whenever we left and returned to the marina, or
operating at speeds between 1,500- 2,000 RPM. 

 

The following spring I put a distinct flat edge on the prop blades with a
file, and that solved the "prop whine" problem. Now, I avoid removing any
material from the surface of the blades and only clean the prop with a damp
solvent (paint thinner) rag to dissolve any residue left on the prop. I also
check to make sure the hard (90 degree flat) edge is present on all of the
blades and touch up the hard edge as needed. 

 

All I know is that the flat edge remedy worked for me and I will leave it up
to others to explain why.

 

If I had to do it over again, I would address the problem when the water
temperature is comfortable and put on the flippers &  mask, tie a line to
the winch, then dive a couple of times to file the edge back on the prop
rather than endure the prop whine for an entire season.

 

 

Rick

My-Ria Hull 277

 

............................................................................
...........................................

 

Date: Fri, 10 Sep 2010 14:24:17 -0400

From: Chris Burti <clburti at gmail.com>

To: C320-List at catalina320.com

Subject: Re: [C320-list] A High Pitched Whine Noise

Message-ID:

      <AANLkTinR6xd6TG4ZVU599u_bsGjtyHLpzcWDaFjthdgf at mail.gmail.com>

Content-Type: text/plain; charset=ISO-8859-1

 

Your symptom sounds very much like prop harmonics. While there does

not seem to be any rationale in it appearing after a simple cleaning,

I have heard of it happening in one other instance and a light

flattening/rounding of the leading edge cured the whine.

 

While alignment is more likely to cause vibration than whine, accepted

wisdom is that alignment should be done after every haul out and

particularly after a land delivery

 

On Fri, Sep 10, 2010 at 12:57 PM, Utility Email <kswanson123 at comcast.net>
wrote:

> We after trucking out C320 all the way from San Diego to Seattle, spending
a week in the Seattle boatyard repainting the bottom, waxing the hull, and
inspection restepping the rig, our beautiful boat is back in the cool waters
of Puget Sound.

> 

> However, we also have a new sound...

> 

> When motoring between, say 1800 and 2200 RPM, there is a high pitched
whining sound coming from the shaft area. ?The noise is more like a high
pitched whistling or whining sound. The sound is very high pitched and sharp
in tone.

> 

> After doing a list-server search, I read somewhere that it could possibly
be a high pitched harmonic with our stock 3-bladed propellor and a "fix"
could be to "dull" the leading edges of the blades. I'm not sure that I buy
this explanation/fix without other input, but I am at a loss for another
rational explanation. ?Hence, this is why I am inquiring through our C320
list server.

> 

> We never heard this sound before in our C320 after operating the boat for
the last year, or any other boat we have had. ?Has anyone else experienced
this type of noise coming from the drive train area?

> 

> A couple of other facts about some basic changes to the boat from San
Diego to Seattle:

> 

> 1. We cleaned the prop and applied 3 coats of Petit (barnacle buster) zinc
paint to the brightly cleaned bronze 3-bladed prop during our
recommissioning in Seattle. The prop was cleaned with vinegar and a wire
brush to a bright metal finish, no filing or edges of the prop were
sharpened in the cleaning process.

> 

> 2. ?I cleaned out the stock flax shaft packing and installed 2 rings of
new 1/4" Gore Tex GFO packing. I adjusted the drip rate to about 3 drips per
minute under power, and we still get high pitched sound.

> 

> 3. ?I have not checked the engine and shaft alignment yet. I am thinking
of hiring a mechanic to check and realign the shaft to the engine since the
boat was transported from SAN to SEA by truck. ?Do others agree that the
engine and shaft should be aligned after overland trucking of the boat?

> 

> 4. ?New zincs are installed on the propellor shaft and strut. I doubt this
has any affect.

> 

> 5. ?Yesterday we motored for about 5 hours to transit the boat from the
Seattle-based boatyard to our home marina. The high pitched sound was
present when we started and also when we arrived at our marina.

> 

> 6. ?The engine has about 100 hours on it and it has been well taken care
or and services regularly.

> 

> If the sound doesn't indicate that there is nothing mechanically wrong
with the boat or drivetrain, then it is just an annoying sound that I will
avoid while operating the engine. ?If not, then I would like to learn about
what I should do to fix it.

> 

> Any and all comments, advice, and/or a fix would be appreciated. ?Please
weigh in with your experience.

> 

> Thanks!

> 

> Dave Swanson

> S/V Emily Ann

> 2007 C320 MK II, No. 1107

> Mukilteo, WA

> 

>