cutless bearing

capricous · 2009-01-28 03:11:11

I was surpised to search posts and not see anything about a cutless bearing. Humm. Quick ? In thinking spring and eyeing the boat ,I notices some stress cracks around the strut that supports the prop shaft holding the bearing, where it attaches to the hull. Any thoughts,concerns?

Thanks

Dana Marblehead Ma

Capricous Hull #599
[You didn't find anything because every post I found (searching the term "bearing") uses the spelling "cutlass". Our search function isn't smart enough to find variant spellings the way Google does. I think "cutless" is correct, but even the people who make the things acknowledge the confusion and use both forms. - Admin]

Last edited by (2009-01-28 07:28:51)

carriden · 2009-01-28 04:08:00

Hi Dana,
It sounds like you are discussing two different issues here: the cutless bearing and the support strut for the prop shaft. Replacement of the cutless bearing is necessary once it is worn down enough to allow the prop shaft to wiggle about loosely within the support strut. Grasp the prop shaft right in front of, or right behind, the support strut and try to wiggle it around. If the movement is less than 1/16 of an inch, you are probably OK. DIY magazine has suggested that up to 3/16 of an inch is allowable, but I think that is excessive and other sources insist that 1/16 of an inch is the limit. I'd love to hear some more feedback on how much wiggle room is acceptable. The owner's manual is silent on the subject.

The other issue which you raise is "stress cracking" where the support strut is bedded into the hull. The support strut is cast bronze, in the shape of a "T". The top of the support strut is actually bolted into a moulded-in recess in the bottom of the hull. C&C bedded it with the same butyl rubber compound which they used for the hull-deck joint and for bedding the through-hulls. The base of the strut was then faired into the hull using a fairing compound, similar to the bondo used in autobody work (but marine-grade). The vibration of the engine running and the shaft turning, especially if the cutless bearing is worn or the shaft is out of alignment, can cause the fairing compound to crack. So, the burning question is: are the cracks in the fairing compound or in the gelcoat and fiberglass of the hull? If they are just in the fairing compound, then you can dig out the old compound and replace it with new stuff. I like the 3M Premium Filler because it cures quickly and is relatively easy to sand.

Alternatively, you can do what I did with my support strut. I filled in the gap around the base of the strut with 3M 4200 and then smoothed it out with a wet finger. This does not give as perfectly smooth a finish as a sanded filler would but you can come close. Its virtue is that the 4200 is able to absorb vibration without cracking. After 4 seasons, it is still perfectly sealed and unblemished.

If the cracks are actually into the gelcoat and fiberglass, you can open them up and repair them with epoxy, so long as they are not too deep, but you may want to seek a professional opinion first. I would like to point out that C&C's approach to the support strut is much more robust and maintainable than some of the currently manufactured boats, which actually embed the top of the support strut into the fiberglass of the hull at lay-up time. While this reduces manufacturing cost and presents a very smooth bottom when the boat is new, it presents a long-term nightmare in terms of allowing water into the actual fiberglass of the hull and rendering replacement or repair of the strut very difficult.

So, check your wiggle room and find out which material is actually cracking on your hull, then decide what needs to be fixed or replaced. Good luck!Marcus from Carriden
Mk III, Hull #847

capricous · 2009-01-28 07:20:42

Thanks Marcus

The prop shaft doesnt wiggle at all in the bearing,so hopefully some 4200 should suffice. Do you think I should dig out the crack area in a V then apply the 3M?

Dana

Capricous Hull #599

carriden · 2009-01-29 01:58:04

I would think that the most time- and cost-effective approach would be to dig out a deep V all around the perimeter of the top base of the support strut, then fill that with the 4200. Before you start filling, experiment with the smoothing technique on some scrap material. I cannot remember if I used plain water, soapy water or vinegar for moistening my finger. I would worry about the drawbacks of growing older, except that I keep forgetting them ... I do remember that I had a LOT of paper towels handy. As an aside, vinegar is an excellent, non-toxic way to clean up uncured polyester or epoxy resin, as well as cleaning up a host of other things. I always keep some on board.

I would make sure that the rest of the filler which is still bedded onto the top of the support strut is solid and securely attached, and that the V which you are filling is clear back to the gelcoat of the bottom.

Have fun, and remember: There is nothing so worth doing as simply messing about it boats.

Marcus from Carriden

Mk III, Hull #847
Oakville, Ontario

Last edited by (2009-01-29 01:59:11)

davidww1 · 2009-01-29 06:35:15

Tape around the "valley" that you're filling, then you can smear excess material onto the tape as you smooth the 4200. When you're satisfied, pull away the tape and clean up any little ridge lines with a moistened finger. Much less hassle than endless wiping with paper towels.

David Weatherston
Towser, Toronto
C&C 27 Mk IV

capricous · 2009-01-29 07:10:01

Will the 4200 accept paint?

Dana

Capricous Hull #599

davidww1 · 2009-01-29 07:41:01

Good question. A little Googling produces,

"-Some one part solvent-based Marine paints may not cure on top of cured Fast Cure 4200. It is strongly recommended to test paint of interest for suitability

-Fast Cure 4200 has an elongation much greater than most paints. Most paints will not elongate to this extent before cracking or losing adhesion to the sealant. If the sealant is used in an application where it will elongate or flex to a high degree, it is best not to paint."

3M TS Data Sheet 06560 06564 05260

Here's another option: West System G/Flex flexible epoxy.

David Weatherston
Towser, Toronto
C&C 27 Mk IV

carriden · 2009-01-29 09:12:30

I have had no problem overpainting with VC17. Can't make any claims about other bottom paint, though. In this particular location and usage, you are unlikely to encounter major elongation of the 4200. We aren't counting on it stretching, just accepting vibration.

Marcus from Carriden

Mk III, Hull #847
Oakville, Ontario

Last edited by (2009-01-29 09:14:13)

woodenr · 2009-01-29 13:18:16

Look to make sure that the support strut casting and the bolts that hold it (4 - 1/4 bolts with the nuts accessible from the port locker) are all solid with no movement between the strut and the hull. The flange on my strut was broken and I had to weld the strut... First warning was the cracked faring compound around the strut…
If it is solid, then I think you might have a balance problem or a bent shaft. There should not be much 9if any) movement between the strut and the hull. After I welded the cracked strut it broke next season in the body of the strut, probably due to vibration. I now have a new shaft, coupling, strut, cutlass bearing, and a factory rebuilt Martec prop... Smooth as silk now and no more cracking. I used standard fairing compound and then VC17 with the rest of the hull…

Bob Wooden - Rhapsody Mk 3 #466

capricous · 2009-01-31 01:44:39

Thanks for the reply Bob,although I dont like it as I did notice last season that at high rpm's the A 4 produced some vibration. I wish I new what was normal vibration? And is this from the prop,or the shaft and or maybe the engine isn't lined up correctly.

Dana

Marblehead

Capricous Hull #599

Brent · 2009-01-31 03:05:29

I guess normal depends on if you're Atomic powered or Yanmar. my 1GM10 has monster vibration at idol but disappears by nudging the throttle forward. Its the nature of the 1 lunger I think since my friends MkV has the same characteristics.

Brent D

C&C 27 MkV #15

davidww1 · 2009-01-31 07:55:54

My experience with an A4 is that they are very smooth. If there's irksome vibration, something is loose or something is mis-aligned. One way you can set a baseline for yourself about vibration is to disconnect the coupling and run the engine at various speeds, imprinting that level in your bones, as it were. Then you could just do the coupling up again and try the same thing. But at that point, you might as well check the alignment. Chances are, you'll find some adjustment necessary. One other thing I learned when my new diesel was installed was to make sure everything was tight (like, real tight, and set equally so with a torque wrench). I aligned my engine to what I thought was a satisfactory degree, then asked a mechanic to check my work because there still was considerable vibration. He told me my alignment was fine, but everything was far too loose. I will see if I can get some target numbers.

Edit: From mechanic friend: "For the coupler bolts 20 to 25 foot pounds. For the engine mount bolts 50 to 60 pounds or as tight as you can!!! Best to get a cheap open end wrench from Crappy Tire and bend/cut the wrench to get at the lower mount nuts for adjusting the alignment, I think it is 1 3/8" , but better check to be sure."

Other things to check in addition to things discussed previously:
- shaft straight? (Unfortunately it has to be pulled for an accurate check.)
- prop not bent, not nicked or otherwise damaged.

David Weatherston
Towser, Toronto
C&C 27 Mk IV

Last edited by (2009-01-31 10:18:46)

capricous · 2009-01-31 10:11:36

Thanks David

My prop doesn't look new ,so maybe I should go that route first. Perhaps the Indigo one?

Either that or get my old prop balanced.

Capricous Hull #599

Last edited by (2009-02-01 03:57:34)

davidww1 · 2009-02-02 00:27:31

Some fairly major vibration has damaged the filler around your p-bracket, but I wouldn't bother replacing the prop without some compelling reason. It is possible that the prop has damage that's not immediately apparent, but fixing it will probably be much less costly than replacing it. Can you get it off and to a prop shop without too much hassle? They will be able to check pitch, blade straightness, etc. and balance (seldom done on sailboat props, but should be).

You didn't say definitely that the p-bracket is secure on the hull (except for the filler) and but you did say the cutless bearing is tight to the shaft so I'll assume the p-bracket is secure. That really leaves alignment as the most likely culprit, so I'd check that after the hull has had a few days to regain its in-water shape.

Finally, if none of these produces a solution, I'd pull the shaft on next haulout and have a machine shop check it for trueness - but I'll wager that you've got an alignment problem.

David Weatherston
Towser, Toronto
C&C 27 Mk IV

capricous · 2009-02-03 07:04:07

Thanks David

I have a prop shop down the street ,and am trying to get the prop off as I write and will go that route,although youre probably right in that the alignment is the issure here. I don't think there would be that much vibration from just the prop

Capricous Hull #599

Last edited by (2009-02-08 02:17:52)

C-Wolf · 2009-03-06 13:51:31

I just replaced my cutlass bearing with a very costly Strut-Pro tool. This is a professional, robust and very heavy tool designed to replace a cutlass bearing without removing shaft - its worth every penny paid! It’s a two man job (thank you again Marcus for helping out on -16degC) due to space constraints and necessary alignment. Once we get it set-up it was a breeze replacing a cutlass bearing with new one. No stress or damage to P-bracket or shaft which was my goal. I will send picture to David and hopefully it can make its way to Black Arts...

C-Wolf

MKIII Hull # 718

Oakville, Ontario

[Now visible on the Propshaft page. Thank you. - Admin

Last edited by (2009-03-09 00:36:44)

windyday · 2009-03-06 19:44:16

Is there a Canadian source? What did it cost? Want to consider sharing for the price of shipping and a fee?
http://www.strutpro.com/

---------
"New" 1974 C&C 27 Mk II undergoing refit

C-Wolf · 2009-03-07 00:24:04

I am not aware of Canadian distributor. Tool with 7/8" sleeve only was $399US...on top of that there was of course charge for shipping (weights almost 30lbs) and Canadian duty. All together almost $700 CDN. Whereabouts are you?
C-Wolf

pablorusjan · 2010-03-24 12:43:14

Hello Dana,

Was the crack that you found something like this picture ?

How did you solve finally?
Some advice?

Thanks
Pablo

capricous · 2010-03-26 06:33:52

Hi Pablo
nice to keep in touch with people,
with the same interest
I wound up grinding out the cracks,mixing up some west apoxy with fairing powder,checking the tourk on the strut bolts,and everything seems fine.
Allways here
Dana
Capricious

Capricous Hull #599

GrayDoyle · 2010-11-13 16:18:44

Bob

I have the same problem were did you get the new shaft, support strut & cutless bearing?Graham Doyle Cygnes 1985

woodenr · 2010-11-21 03:23:12

Hi Graham,

I worked with Jerry Gravesen at Airmarine Inc./Propulsion Engineering in Chicago - http://www.therightprop.com/. I took him the strut, the shaft, the coupling, and the prop. He researched it all and could not matchup the stut. I found a casting shop (below) that could cast a new strut from the old one. Jerry had the strut cast and then machined it to match the original and fitted the cutless bearing. He made a new shaft (the old one was bent and scored) and sold me a used Martec folder really cheap which I had Martec rebuild. Martec did a great job, it is like new when they get done and that is a great way to get into a "new" prop cheap. As I recall the whole adventure was about $1,000 but when I was done everything was new from the back of the engine (coupling, shaft, strut, cutless, prop) and I have not had any issues since; smooth as can be. I installed everything and aligned as best I could with feeler gauges and very limited access.

The casting was great, the quality of the work Jerry and his crew did was also great.

Hope that helps, good luck!

Bob Wooden
Rhapsody, C&C 27 Mk 3
Waiting for spring in Racine Wisconsin

Mystic River Foundery - http://www.mysticriverfoundry.com/marine2-05.html

GrayDoyle · 2010-11-21 04:51:26

Bob

Thanks, Bob, very helpful.

I assumed all these things just came off the shelf. Would your strut (Mk 3) be the same as mine Mk 5, or would i have to get Mystic River to cast mine?

We got a new prop from Martec last year & it looks ok.
I think i will need a new shaft made.
The cutless bearing is a stock item surely?

Hardest part is the cramped quarters & getting the set scew out.

Graham Doyle C&C 27 Mk 5 hull #026Graham Doyle Cygnes 1985

C&C 27 Association Forum

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#1 2009-01-28 03:11:11

cutless bearing

#2 2009-01-28 04:08:00

Re: cutless bearing

#3 2009-01-28 07:20:42

Re: cutless bearing

#4 2009-01-29 01:58:04

Re: cutless bearing

#5 2009-01-29 06:35:15

Re: cutless bearing

#6 2009-01-29 07:10:01

Re: cutless bearing

#7 2009-01-29 07:41:01

Re: cutless bearing

#8 2009-01-29 09:12:30

Re: cutless bearing

#9 2009-01-29 13:18:16

Re: cutless bearing

#10 2009-01-31 01:44:39

Re: cutless bearing

#11 2009-01-31 03:05:29

Re: cutless bearing

#12 2009-01-31 07:55:54

Re: cutless bearing

#13 2009-01-31 10:11:36

Re: cutless bearing

#14 2009-02-02 00:27:31

Re: cutless bearing

#15 2009-02-03 07:04:07

Re: cutless bearing

#16 2009-03-06 13:51:31

Re: cutless bearing

#17 2009-03-06 19:44:16

Re: cutless bearing

#18 2009-03-07 00:24:04

Re: cutless bearing

#19 2010-03-24 12:43:14

Re: cutless bearing

#20 2010-03-26 06:33:52

Re: cutless bearing

#21 2010-11-13 16:18:44

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#23 2010-11-21 04:51:26

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