propeller shaft rattle

[wflowe2]

I have a new to me, 2008 Catalina 320. It was very lightly used before I bought it and had it delivered to the inland lake where I sail. The boat is great and out performs my expectations but when motoring, there is a very annoying clattering noise. It is not in the engine because it only happens when in gear. It sounds like it is coming from the area of the propeller. I've had the shaft aligned but that did not help. The marina thinks that maybe the prop may not be balanced. The boat moves well under power, it just sounds odd.

Anyone have any ideas?

Bill

 

[Ted]

Have you checked the cutlass bearing?

 

[timvg]

Have a diver take a look. On my previous boat, I had a loose zinc that made a lot of noise.

 

[Tom J]

What your are describing has been a source of discussion for many Catalina owners in the past. I have had the same rattle since I bought my 2003 310. The engine had 19 hours on it, and now has 980, and the rattle has always been there. The consensus seems to be that it is probably the damper plate. Last week, I had the aft bunk up to gain access to the tranny, and, with the engine running, I was pretty sure the rattle was coming from the tranny, which indicates the damper plate. I have , on occasion, heard a rumble from the hull, but aligning the shaft and replacing the cutless bearing took care of that. This issue was recently addressed in the Catalina 310 forum.

 

[Witzend]

Please see this thread if you have not already.
http://forums.catalina.sailboatowners.com/showthread.php?t=113844
This is how I understand the issues from my limited exposure. Others probably know more, so pipe in and correct me.
The fundamental problem is the light weight of the flywheel in conjunction with a minimal cylinder configuration. This causes torsional vibration because every time a cylinder fires the main crank accelerates. The weight of the fly wheel is suppose to smooth this out, but because it is light that moment is transferred to the gears in the transmission. This action causes wear on the gears so a damper plate is employed to try to smooth this torsional vibration out. There are a number of things that can go wrong with this approach.
1) If there is any play between the tranny input spline and the damper plates collar it will rattle, wear and eventually strip out also damaging the spline. The manufactured tolerance between the spline and collar has to be very precise and when you are dealing with different manufactures small differences can add up. If it is as tight as it should be assembly is made difficult.
2) If the damper plate is too stiff it will transmit the vibration through the tranny as if there was no damper to begin with. I'm not sure how to calculate this, but for my M25XP rated at 37 ft lb of torque: 37ftlb X 3200RPM/5252=23HP. Sachs recommends a plate with a max torque rating of 154mn (meter Newtons) which is = to 113.5ftlbs max, seems like even there recommended plate is stiff, but I'm sure it does not act in a linear fashion.
3) If the plate is to soft it can fail under load.
4) If during installation the plate is not mounted centered on the flywheel the runout will cause vibration and load and unload the input bearing with every revolution. The use of a deflection gauge is necessary. Also the center of rotation must also match. Forcing the bell housing in place during re-assembly probably means something is not centered.
5) From inspecting the design of the Sachs manufactured plates it is obvious to me why they rattle and eventually fail. This design involves springs that press against the edges of the plate. Every time it loads up from acceleration the contact area tends to wear because it is small and has no lubrication, the springs then become loose and eventually fall out causing plate separation.
5) Other manufactures have tried the address these design problems but with limited success. The R&D design I have seen uses a polyethylene strip molded around pins (it looks like a thick ribbon) that alternately mold around pins connected to each plate. The ribbon flexes with each loading dampening out the vibration. Eventually the ribbon fails.
This is a tough problem to solve with these light motors.

 

[nightowle]

blog to check out

witzend covered this pretty well, but if you want to read a similar saga of someone that was frustrated for a couple years on this with a brand new Catalina check out: http://catalina28.blogspot.com/

 

[Witzend]

Nightowle,
Was your failed plate a R&D, sure look like mine?

 

[Tom S]

Few questions. Does the noise only occur when its in gear and the engine rpm is low approx 800-1200 RPM's (like from idle to just above idle?). Does it go away or get less when you increase engine speed? Does it sound like a bunch of pebbles in a coffee can? If so its probably the Damper Plate.

Some of Universals they put in the Catalina's over the past 10 years had the "Sachs" Spring type damper plate that was very prone to rattle. I am not sure you have a Universal - it might be a Yanmar, but the same thing applies. Get a good (PYI R&D type polymer Damper plate) and it will greatly reduce the noise - It did for me. (also there are a few different types of Polymer Damper plate - pay a little more for the better design)

 

[Witzend]

TomS, In my case M25XP, Tranny is a ZF5 or 6 (not sure someone pull the serial number plate off), see http://forums.catalina.sailboatowners.com/showthread.php?t=113844
The rattle noise happened in neutral or in gear up to 1500RPM. IMHO the R&D 22B4 damper is a POS!

 

[Tom S]

Witzend -- if the noise happens in neutral also I am not so sure its the damper plate. The noise is usually only when its in gear (Unless something is really wrong with it) But your other description that it it goes away after 1500 RPM's does make it sound like the damper plate. It could be multiple things .

BTW why do you think the R&D Damper plate is a POS? It sounded like it broke on you. I would contact PYI and ask for Fred Hutchinson (VP of Operations - I met him at a boat show) and ask for a warrantee replacement. That shouldn't happen especially for a lower HP engine like yours . The RD22B4 is an older design and the RC22W4 (Hammer Head design) is recommended -- FYI same price too - $157

 

[Maine Sail]

Few questions. Does the noise only occur when its in gear and the engine rpm is low approx 800-1200 RPM's (like from idle to just above idle?). Does it go away or get less when you increase engine speed? Does it sound like a bunch of pebbles in a coffee can? If so its probably the Damper Plate.

Some of Universals they put in the Catalina's over the past 10 years had the "Sachs" Spring type damper plate that was very prone to rattle. I am not sure you have a Universal - it might be a Yanmar, but the same thing applies. Get a good (PYI R&D type polymer Damper plate) and it will greatly reduce the noise - It did for me. (also there are a few different types of Polymer Damper plate - pay a little more for the better design)

Tom,

Be cautious with these R&D dampers and they might even warrant periodic inspections.

On behalf of Witz I spoke with one of my inside connections at a very large Universal/Westerbeke distributor who will remain nameless based on the info I was given, in confidence, but suffice it to say they have had a significant amount of problems with the R&D dampers including ones like Witz' R&D. The replacement damper plate for Witz' engine is a Sachs damper according to the dist.

My OEM Sachs damper plate had 2878 hours on it when I replaced it. It still worked fine and did not rattle at all. I only replaced it because I "was already in there" doing other work. The Sachs dampers can be bought for about $70.00 if you don't buy through Universal/Westerbeke.


Seeing photos of how the R&D destroyed Witz's gear box input shaft, or vice verse, the C-28 damper issues and after speaking with the distributor, I would certainly use caution in installing an R&D and do you due diligence to make sure it is the right application....


The Catalina 28 owner the image below came from had gone through three transmissions in 650 hours of use?
R&D spline teeth from the Catalina 28 linked to above (Witz's were even worse):

Apparently this is a potentially problematic situation with the R&D dampers. Don't expect to get the straight dope out of the manufacturer or even Westerbeke until they deem this a recall which is about as likely as a bag of money falling from the sky. It may not be a problem too.

I do think we should begin cataloging all the Universal damper plate failures, including Sachs, and begin to track this..? Perhaps a separate thread containing links to any discussion involving damper plate failures on Universal engines would be a good way? it does seem there are way to many?


P.S. here's my Sachs damper splines at 2878 hours, no visible wear:

 

[Tom S]

Maine Sail. With all due respect are we sure the problem with that C28 Transmission was the fault of the Damper Plate?

Witzend issue/problems http://forums.catalina.sailboatowners.com/showthread.php?t=113844 with the stripped looking spline on the damper plate had questionable tranny in his boat (His engine should NOT have a ZF5 on his boat)

Thats one variable you have missed. and There are obviously a lot of variables to these issues - PLUS the wrong R&D Damper plate was admittedly put on his engine ( from Witzend "I had Jim at Federal Marine look it up and it does not have the correct Ft Lbs rating for my engine, way too stiff.") etc etc.

Also for all we know when they were mounted at the factory maybe they installed poorly (incorrect torque of bolts holding plate, bad alignment ??)

I don't doubt a distributor has probably seen his share of issues and thats his singular view. But - How many of those failures were the fault of not really bad R&D dampers but possibly someone installing the WRONG damper plate for the engine its installed on. For instance blaming R&D Dampers for Witzend problem is wrong - it was the people who installed the wrong tranny and Speced Damper Plate. Who knows maybe the factory had a bunch of the wrong ones on a certain batch of engines. -- You get the idea

The old style Sachs Damper plate I had was rattling like an "old Jalopy" after only 100 hours. I replaced it with an R&D Type that was specifically designed for my engine and the idle in gear and low RPM's is much smoother and quieter. Going on 600 hrs now.
I personally know ~dozens~ of C36 owners that have swaped out the rattly Spring Designed Sachs Damper Plate and have been VERY happy and not one failure or complaint . Who knows maybe its a factory installation problem

Not saying there might be issues with R&D Dampers but there are too many variables to blame just this one item. Especially with every failure I have seen refereced didn't have either the correct Tranny or Damper plate.

I would call Fred Hutchinson from R&D and see what they had to say

 

[Maine Sail]

Maine Sail. With all due respect are we sure the problem with that C28 Transmission was the fault of the Damper Plate?

No and I'm in no way saying that is what caused it. What I am saying is there seem to be an awful lot of damper plate issues with the M-25's. After speaking with my distributor I was rather taken back by his tone and what he said in regards to the R&D dampers.

What does not make any sense to me is how two engines, plus there are many more in this situation too according to my distributor, could have needed replacement gear boxes all under 600 hours?

Witzend issue/problems http://forums.catalina.sailboatowners.com/showthread.php?t=113844 with the stripped looking spline on the damper plate had questionable tranny in his boat (His engine should NOT have a ZF5 on his boat)

Mine had a HBW 50. According to Hurth the HBW 50 has been superseded by the ZF-5 so if an owner replaced it it was likely they could no longer get the HBW-50

Thats one variable you have missed. and There are obviously a lot of variables to these issues - PLUS the wrong R&D Damper plate was admittedly put on his engine ( from Witzend "I had Jim at Federal Marine look it up and it does not have the correct Ft Lbs rating for my engine, way too stiff.") etc etc.

I may be wrong but the model # of the R&D seemed to correspond with what Catalina was using on the M-25.

Also for all we know when they were mounted at the factory maybe they installed poorly (incorrect torque of bolts holding plate, bad alignment ??)

This is totally plausible. I would suspect that Westerbeke knows what they are doing but still anything can and does happen..

I don't doubt a distributor has probably seen his share of issues and thats his singular view. But - How many of those failures were the fault of not really bad R&D dampers but possibly someone installing the WRONG damper plate for the engine its installed on.

See my PM.

For instance blaming R&D Dampers for Witzend problem is wrong - it was the people who installed the wrong tranny and Speced Damper Plate. Who knows maybe the factory had a bunch of the wrong ones on a certain batch of engines. -- You get the idea

I hope I was careful enough not to "blame" the R&D just to throw caution out there and to try and suggest we catalog all M-25 damper plate failures as there seem to be way to many of them with both Sachs and the R&D..

The old style Sachs Damper plate I had was rattling like an "old Jalopy" after only 100 hours. I replaced it with an R&D Type that was specifically designed for my engine and the idle in gear and low RPM's is much smoother and quieter. Going on 600 hrs now.
I personally know ~dozens~ of C36 owners that have swaped out the rattly Spring Designed Sachs Damper Plate and have been VERY happy and not one failure or complaint . Who knows maybe its a factory installation problem

Again, we don't know what is causing this and apparently neither does the factory after three gear boxes in a C-28?

Not saying there might be issues with R&D Dampers but there are too many variables to blame just this one item. Especially with every failure I have seen refereced didn't have either the correct Tranny or Damper plate.

Please re-read my response carefully. I specifically tried to point out that we may need caution with the R&D's and that they might need periodic inspections. I tried to not "balme" it but rather open the discussion up to further investigation.

The Sachs plates will rattle when they get bad the R&D may not give any signs until it is too late. I just don't know, that is why after reading sooo many damper plate, "I have a rattle" stories that I suggested caution and possibly a database of damper plate discussions.

I would call Fred Hutchinson from R&D and see what they had to say

That is a good place to start. This issue seems far to wide spread to ignore any more and with transmission being chewed up, splines being ruined and damper plates failing, both Sachs and R&D, the problem needs to be addressed and collected so that an educated decision can possibly be made about how to correct this problem?

 

[Witzend]

Whether the transmission I have is a ZF5 or an HWB 50 is a moot point in my mind, they are basically the same. There is no plate on this tranny to be sure. Jim at Federal Marine had me measure the unit to help identify it. The input spline would be the same size anyway, also the ratio I have is correct for the prop because it moves the boat with a clean bottom thru ebb or flow tide at 5-5.5 knt at 2000rpm. I have called Fred, and sent him pictures, so far I have received no response. Understandably he took a rather defensive tone during our initial conversation.
I have developed my opin on their design based on the fact that the polyethylene ribbon cracked in multiple places. The idea of flexing plastic to absorb shock in my mind is a fundamentally flawed. The Sacs plates also have their issues with a small non-lubricated spring contact areas taking the rub with every cylinder fire. There are a lot of variables in the installation as I previously concure. Because of the cylinder configuration and relatively light fly wheel this is a very difficult problem to solve from and engineering stand point. Bottom line, don't idle your engine.