Prop Shaft / Cutlass Bearing "Squeal"

Mar 22, 2009
360
Catalina 310 Gulfport Small Craft Harbor, MS
Happy New Years!!!

So the background: 2002 Catalina 310 pulled for bottom job and polishing/waxing in December. Planned to install new cutlass bearing by "tapping" out the old one with the prop shaft in place (prop removed). However, we quickly learned that technique wasn't going to work. Needed to either remove the prop shaft or take off the strut...and we hadn't planned on that so we didn't do the bearing change. Old bearing never gave me any issues and there was no play/slop with the shaft inside the bearing...so left the current one in place.

Prop shaft and prop came out of the water with a fairly good growth of barnacles but sand-blasting cleaned it perfectly...looked brand new. There was no prop shaft zinc...must have completely worn away (was installed in the Summer).

Installed 2 x football shaped shaft zincs. Pretty standard I think.

When we painted we put 2 coats of Micron 66 on the exposed prop shaft, the strut, and the prop itself.

Finally relaunched 9 days after pulling it out.

Problem: Now I get a fairly high pitched squeal at RPMs between 1300 and 1900. Idle is 1000-1200 and Max RPM is 2500 (my limit...engine will go to 28-2900).

Boat yard guy told us that sometimes the cutlass bearings "dry out" some and once it "re-soaks" for a while the squeal may go away. Been 2 weeks and still squeals.

Squeal only happens in forward...not in reverse. And squeal doesn't seem to happen if not moving forward...shifted from reverse to forward while moving in reverse at 3+ knots and powered up to 1500 RPM....no squeal while still drifting backwards and standing still. But once moving forward the squeal became apparent.

Do no feel or see any wobble on the prop shaft. Pretty sure it is not the stuffing box. I do get a reasonable stuffing box leak when prop spinning at 2000+ RPM so don't think it is dried out packing glands.

Suspect maybe that the shaft zincs are not properly balanced and causing a slight shaft wobble at those RPMs and squeal is shaft rubbing on cutlass bearing. Going to see if I can get my diving friend to remove the zincs and will see what that does for the situation.

Does anyone have any thoughts on what could be the issue or what might resolve this situation?

Sorry for the long-winded post.

Cheers,
Jim
 
Feb 26, 2011
1,428
Achilles SD-130 Alameda, CA
Suspect maybe that the shaft zincs are not properly balanced and causing a slight shaft wobble at those RPMs and squeal is shaft rubbing on cutlass bearing.
How can the zincs be "unbalanced"?

What seems more likely is that you damaged the cutless while attempting to remove it.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
I find the "no play/slop with the shaft inside the bearing" to be an odd statement. A 1/16 of an inch play is considered excessive.

I would tend to agree with Fast Bottoms that you might have damaged the bearing when you attempted to remove it. What exactly did you do?
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
If you bead blasted the prop it is possible you created too sharp of a tip/edge. This can result in prop singing. The edge of the prop is ideally pretty square to minimize this....
 
Apr 2, 2011
185
Catalina 27 Niceville, FL
Although rare, I have seen this happen on freshly painted props. Sounds like a drive belt slipping. The paint will not last long and the noise will go away.
 
Mar 22, 2009
360
Catalina 310 Gulfport Small Craft Harbor, MS
We did not really do anything to the bearing. We took out the set screws and saw that we had no way to tap it out. We never tapped on it. Don't think we damaged the cutlass bearing in any way.

Not sure about zincs being "out of balance"...just my muddled brain trying to think about possibilities. I thought I was pretty careful when putting them on...but I had never done that before so I thought I might have one not quite right.

The "no slop" statement might be a bit of an overstatement. The shaft felt pretty solid. Very, very, very little play when I tried to jiggle it back and forth. The bearing definitely did not feel like it was worn to the point where it would allow the shaft to wobble.

No idea about sharpness of blade edge. If that is a possibility then maybe it will wear down some and stop squealing...

And paint may be an issue...I am not sure and have no experience with that. Once again maybe the paint will wear off and the squealing will go away.

For now I will live with it and hope it solves itself.

Thanks for the inputs.

Cheers,
Jim
 
Sep 29, 2008
1,928
Catalina 310 #185 Quantico
Cutless Bearing Replacement

This is not all that hard of a job. You can buy this kit which has a lot of shizzle for $395 (http://www.strutpro.com/) or you can make your own out of some old hardwood, threaded rod and copper tubing, host clamps and assorted nuts and bolts. It would look similar to the attached picture but much cheaper.

Cut two 6" lengths of hardwood (old flooring is good). Center and drill a 1.25" hold in one (goes below the strut over the prop shaft on the side where you removed the prop).

Cut the other board lengthwise down the center and then cut a 1" hole in the center. Drill two holes and use threaded rod, nuts and washers to hold the two pieces back together (around the shaft). This will go above the strut and be connected around the shaft.

On both pieces you will need to drill holes and use threaded rod to connect the two boards on either side of the strut. Note your threaded rod will need to be the length of the strut plus 7-8" plus the width of the boards.

Cut two lengths of .75" copper pipe about 6" long. Then cut them in half lengthwise. Polish the cuts after cutting so they are smooth. Both pieces will need to be smooth to help slide. A slight flare on the end that faces away from the strut toward you upper piece of wood will help. Widen the first two pieces and lay them on the shaft above the strut, then take the next two pieces and widen them as well to lay over top of the first two pieces offset a little over the splits. This will make your copper pieces wide enough to contact the brass part of the bearing but slide inside the strut itself. Use a hose clamp to hold the copper pieces lightly together on the shaft but not tight enough they wont slide.

Start tightening the two boards pushing the copper pipe against the strut/bearing. If it gets read tight with no movement us a hammer to tag on the top side.

This worked for me. Except for the threaded rod, I had most of it sitting around in my garage. Oh yeah, don't forget to remove the set screws before you start. :D

If you have the skills and materials, you could make the one in the picture. I don't have that much skill or material. :doh:
 

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Dec 25, 2008
1,580
catalina 310 Elk River
When I did mine, I had the shaft out. No way was it going to push out, had to cut it out.
Since I had such a seriously misaligned strut, I chose to drill out the strut rather than digging it out of 4" of glass to shim. I than floated the new Cutlas Bearing in with epoxy in perfect alignment. I now just need a torch to remove. Heat destroys the epoxy and out it comes.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
When I did mine, I had the shaft out. No way was it going to push out, had to cut it out.
Since I had such a seriously misaligned strut, I chose to drill out the strut rather than digging it out of 4" of glass to shim. I than floated the new Cutlas Bearing in with epoxy in perfect alignment. I now just need a torch to remove. Heat destroys the epoxy and out it comes.
Did you do the alignment with the boat on the hard?

I just replaced my motor mounts, along with a new dampener plate, new shaft and new cutlass bearing. Hoping to finish the reinstall this weekend. I was thinking I couldn't do the final alignment until I was in the water due to hull deflection from sitting on the keel.
 
May 10, 2008
392
Catalina 355 Boston
Did you do the alignment with the boat on the hard? I just replaced my motor mounts, along with a new dampener plate, new shaft and new cutlass bearing. Hoping to finish the reinstall this weekend. I was thinking I couldn't do the final alignment until I was in the water due to hull deflection from sitting on the keel.
Jesse,
The boat should definitely be in the water and ideally you should bend your sails on and have your 'normal' cruising gear on board. Might as well start out as close to ideal as possible given all the new goodies...
 
Dec 25, 2008
1,580
catalina 310 Elk River
Did you do the alignment with the boat on the hard?

I just replaced my motor mounts, along with a new dampener plate, new shaft and new cutlass bearing. Hoping to finish the reinstall this weekend. I was thinking I couldn't do the final alignment until I was in the water due to hull deflection from sitting on the keel.
Yes the final engine alignment was done in the water. No real practicable way to do a strut/shaft-stern tube alignment in the water. Not sure I agree with the need to have all the gear aboard, what about the level of fuel and water and waist...,seems a bit over the top in the face that the mere torque of the the engine idling moves the engine considerable on the mounts and I have never heard of someone doing the alignment with the engine running, let alone when it is under full load when this deflection is max. The engine is trying to rotate on the mounts in the opposite direction that it is turning the prop. This rotation is not concentric due to gravity and thus causes this finely tuned alignment to change considerably.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Thanks.

Getting this alignment right is the part of the project I am most nervous about. I have never done most of the things I do to poor Smitty since I didn't grow up into engines or anything so I am used to working outside of my comfort zone. But for some reason I am very intimidated about doing the alignment.

The engine goes on the new mounts this weekend and probably the rough alignment. Hopeful all goes well.

Thanks again for all the help guys.
 
May 10, 2008
392
Catalina 355 Boston
Thanks.

Getting this alignment right is the part of the project I am most nervous about. I have never done most of the things I do to poor Smitty since I didn't grow up into engines or anything so I am used to working outside of my comfort zone. But for some reason I am very intimidated about doing the alignment.

The engine goes on the new mounts this weekend and probably the rough alignment. Hopeful all goes well.

Thanks again for all the help guys.
For some reason doing final alignment has caused me the same trepidation. I am of the same mindset as you--I never had any experience with engines/plumbing electrical etc., but one of the things that drew me to boat ownership was learning and doing. Over time I have come to understand what my limitations are as far as execution of certain projects (for example I will never take on a cosmetic gelcoat project because I am just not good at it--know how to do it, but the results, not so much).
I've had alignments done professionally half a dozen times while watching and taken on the effort myself an equal amount. The reason I remain intimidated is because I get too anal about it and it is a matter of patience as the practice itself is rather straightforward.
As for having your 'normal' cruising gear aboard and tanks not empty--learned this from both Nigel Calder's recommendations and the Yanmar guy who has done my engine alignments in the past. The engine does move, but the key is to get the face of the coupling aligned with the trans and then locked down so that the entire drive train moves when the engine is rumbling away.
My understanding is that getting the boat to a 'normal' cruising weight/balance is a best practice. Given you can get a sloppy CB with just a 1/16" of wear, I've always tried to get my alignment down as well as possible....good luck this weekend!