High pitch drive noise??

Jun 13, 2009
82
Catalina C320 mk 2 Australia
Perhaps someone has experienced this. Catalina 320 mk2. Sailing in neutral the noise starts around 4 kn and continues with more speed. Motoring noise is 1100 to 1200 and 2200 to 2300 (basically double rpm) but only when boat is up to speed. Cant replicate the noise at the dock in forward ot reverse. I have changed tranny oil. No hot spots on tranny and runs 50 60 deg. Replaced engine mounts and aligned. Replaced stuffing box packing , removed calcification from shaft. Checked couplings/set screws etc. Checked cutlass on a quick lift and pulled shaft aft and cleaned calcification on bush area. Checked anode and shaft log. Shaft is central. Checked prop nut etc. Everything is clean and undamaged. No noises rotating prop shaft by hand. The prop has a good coating of propspeed. Still got my noise !!! Any ideas? Singing prop? Cheers.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
High pitch noise under sail with engine running and in neutral?
 
Jun 13, 2009
82
Catalina C320 mk 2 Australia
Fair question. Pretty sure yes. But I will reconfirm that today as we have a 20 mile sail back to our marina if we can find enough breeze?
 
Jul 29, 2017
169
Catalina 380 Los Angeles
In Neutral the prop may be spinning due to hydrodynamic forces acting upon it. It would happen with or without the engine operating.
 

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
It's with i) the engine running, the boat sailing foward, and iii) the Transmission in Neutral?

IF you put the engine in gear, going forward with just the transmission engaged, at about the same speed, does it make noise?

If you are sailing at 4 knots, with the engine OFF, but the prop freewheeling does it make the noise?

Now, if you put a rag or whatever around the prop and some vice grips (i.e., stop the prop from freewheeling) and sail at 4 knots (or whatever) -- does it make the noise?

If you're sailing at 4 knots in your C320, you're heeled over? Is the noise different if you're on a flatter angle of heel?

If you're motor sailing at 4 knots (with the engine engaged), but you adjust the prop so that it's not driving the boat as much (i.e., let the sails do the work), does the noise change?

You have a stuffing box, or a drip less shaft seal?
 
Jun 13, 2009
82
Catalina C320 mk 2 Australia
Ran engine in neutral at various RPM whilst sailing today. No change. Sailing in neutral under 4.5 kn or over 6.5kn no noise. Push boat hard on engine no noise. Propshaft brake on obviously no noise. Not dripless seal. Motor sail pushing hard noise appears when sail power takes load off engine.When we get back to the dock I will try to load a video clip.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
I am suspicious of the transmission bearings and gear lash. Use the shaft brake when in neutral and monitor. Expect you will see it get noisier and reach a point where you are truly annoyed, at which point you can schedule a haul and have the trans pulled.
 
Jun 13, 2009
82
Catalina C320 mk 2 Australia
Annoying all right. Thats why I made a shaft brake. The silence is bliss. The noise when motoring is easily controllable with RPM. My background is heavy industrial mechanical and I have 2 separate marine mechanics have a listen unfortunatly no new suggestions. Thanks for the interest.
 

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
May I ask, what the make and model of the gear (transmission) is? I wonder why you went through the trouble of installing a "shaft brake" when simply putting the gear in reverse would stop the prop rotating. Unless, of course, you are running the engine to charge batteries or make hot water as you are sailing.
 

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Though I used to use reverse, Yanmar specifically says don't put the engine in reverse as a prop break. If he has a compromised transmission, I'm not sure that wouldn't further challenge it.
 

jviss

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Feb 5, 2004
6,745
Tartan 3800 20 Westport, MA
Yanmar specifically says don't put the engine in reverse as a prop break
Which is why I asked what make and model gear he has; Hirth recommends putting the lever in reverse when sailing.
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
It would be nice if someone would produce a factual statement from a reliable source instead of memory or opinion. Such as "I have the manual here, and it says..."
 
Last edited:

SG

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Feb 11, 2017
1,670
J/Boat J/160 Annapolis
Ron:

The standard Catalina engine, for both the 320 and 320 Mk I is a Yanmar? The cites were from publications that showed that standard?

Then, the owner of the boat confirmed that it's a Kanzaki transmission which is what Yanmar uses for that engine? The 'KM' is for Kanzaki. Example: https://www.yumpu.com/en/document/view/3934823/marine-transmission-yanmar/2 If you doubt that, you can search Kanzaki and Yanmar.

;^)))

P.S. -- Have you put the Beneteau to bed for the season yet?
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
...The standard Catalina engine, for both the 320 and 320 Mk I is a Yanmar? The cites were from publications that showed that standard? P.S. -- Have you put the Beneteau to bed for the season yet?
Well, we don't know, as it has not been specified. Post 11 asks for that info. If you've been on the SBO a while, then maybe you've seen the ongoing debate about in or out of gear and/or reverse or forward. Someone came up with the OFFICIAL Yanmar response, which may or may not have a KM tranny. Both engines and trannies can be change during the course of a production run, so the safest bet is for any OP to tell us what he KNOWS he has. It isn't until post 13 that he give any indication of his unit, and even then, he does not actually say he has it, but that is what the inference is.
Ron:p.S. -- Have you put the Beneteau to bed for the season yet?[/QUOTE] The boat is still ready for fair weather, but I'm going to have to take today and tomorrow to winterize so I can get on with other projects.