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-   -   Propeller Shaft Packing (https://www.cruisersforum.com/forums/f114/propeller-shaft-packing-33392.html)

gbendaly 24-11-2009 02:19

Propeller Shaft Packing
 
is there any secure way to reduce / eliminate the gap ( approx.1mm) between my propeller shaft (25mm) and the cutless bearing ?? I really don't want to haul the boat and replace the bearing, especially since there are no leaks .
I was thinking, maybe insert a .5mm copper cylindrical sheet...:confused: between the shaft and the bearing
any suggestions / recommendations and advice would be welcome
thanks
georges

sailvayu 24-11-2009 04:33

I think you are sort of stuck having to haul. You might be able to get a driver to do it but it is really not the kind of thing to do like that. Cutlass bearing are rubber not copper. If you put a copper sheet in there it is likely to heat up and stick to the shaft causing more damage. Honestly this is a job that requires hauling. Best just bite the bullet and do it right or you will end up with more damage.

Good Luck
Wayne Canning, AMS
projectboatzen.com

James S 24-11-2009 04:54

I think Wayne is right....you should haul her.
I don’t think you want to insert that piece of copper.

Is it vibrating?

b-rad 24-11-2009 05:21

I just changed one, Had the strut off the boat and had it at work with any tool imaginable and it tok about an hour and a half to cut it out of the the strut. I dont belive it could be done in the water.

tangaroa3 24-11-2009 06:01

DO NOT INSERT A PIECE OF METAL INTO YOUR CUTLASS BEARING!
You will likely score your shaft which will then tear your rubber cutlass bearing to shreads.
There is supposed to be some gap between your shaft and bearing to allow water to lubricate it. The cutlass bearing has nothing to do with leaking.
What exactly is the problem? Vibration?

scubasteve 24-11-2009 07:35

Quote:

Originally Posted by tangaroa3 (Post 364988)
DO NOT INSERT A PIECE OF METAL INTO YOUR CUTLASS BEARING!
You will likely score your shaft which will then tear your rubber cutlass bearing to shreads.
There is supposed to be some gap between your shaft and bearing to allow water to lubricate it. The cutlass bearing has nothing to do with leaking.
What exactly is the problem? Vibration?

Agree, NOT a good idea. Just replace it, any other alternative will end up costing you a lot more later down the road.

Depending on shaft size, for an approximately 1" diameter shaft, a wear limit of 1/32" (0.030") on the shaft to cutlass clearance is acceptable. Some have gone as high as 0.050" or 0.060" without issues but if I saw that much play, I would replace.

delmarrey 24-11-2009 08:50

The cutlass bearing is designed to allow water to pass threw it so it doesn’t get hot. It could be your shaft is worn also. A little rattle will not hurt much. Just run your motor at RPM’s that make the least amount of noise for long runs and do it right on your next haul-out.


Haul-outs should be on a regular schedule! During those one should check everything below the waterline and fix what is showing any hind of problem. Cheating on cost is only cheating yourself. :whistling:

Rex Delay 24-11-2009 20:32

Are we talking Cutless bearing or Stuffing Box here? Cutless bearing does not leak into the boat.

IceMan 24-11-2009 20:41

Rex Delay,
Cutlass bearings use water for their lubrication, hence the water intake at the top end of the cutlass bearing to assure proper lubrication and this will allow water through the bearing and up the prop shaft tube(forgot the proper name right at the moment) and up to your stuffing box. The stuffing box should leak 1 to 3 drops a minute when the engine is running and not leak when you are sitting static, unless you have a dripless stuffing box. I just replaced my cutlass this week and had my cutlass threaded and made a special tool to pull it. If done properly, and you have a fixed pitch prop that only has a nut and keyway, you can remove and reinstall the cutlass while the boat is in the water.
WD

gbendaly 24-11-2009 23:58

Hi james

my problem os vibrations at low RPM

gbendaly 25-11-2009 00:01

Quote:

Originally Posted by tangaroa3 (Post 364988)
DO NOT INSERT A PIECE OF METAL INTO YOUR CUTLASS BEARING!
You will likely score your shaft which will then tear your rubber cutlass bearing to shreads.
There is supposed to be some gap between your shaft and bearing to allow water to lubricate it. The cutlass bearing has nothing to do with leaking.
What exactly is the problem? Vibration?

the problem is vibrations at low RPM
no leaking from the shaft seal
wondering if a 1mm gap between shaft and bearing is excessive for lubrification
thanks

gbendaly 25-11-2009 00:03

Quote:

Originally Posted by delmarrey (Post 365037)
The cutlass bearing is designed to allow water to pass threw it so it doesn’t get hot. It could be your shaft is worn also. A little rattle will not hurt much. Just run your motor at RPM’s that make the least amount of noise for long runs and do it right on your next haul-out.




Haul-outs should be on a regular schedule! During those one should check everything below the waterline and fix what is showing any hind of problem. Cheating on cost is only cheating yourself. :whistling:

I guess you are right
I am planning to haul next april, changing the bearing will be on my list of priorities
thanks

gbendaly 25-11-2009 00:05

Quote:

Originally Posted by Rex Delay (Post 365334)
Are we talking Cutless bearing or Stuffing Box here? Cutless bearing does not leak into the boat.

suffing box is the volvo rubber seal type and it is fine , no leaks whatsoever, I was just wondering if the gap That I noticed is excessive and may lead to the leaking of the stuffing box ??

gbendaly 25-11-2009 00:09

Quote:

Originally Posted by IceMan (Post 365338)
Rex Delay,
Cutlass bearings use water for their lubrication, hence the water intake at the top end of the cutlass bearing to assure proper lubrication and this will allow water through the bearing and up the prop shaft tube(forgot the proper name right at the moment) and up to your stuffing box. The stuffing box should leak 1 to 3 drops a minute when the engine is running and not leak when you are sitting static, unless you have a dripless stuffing box. I just replaced my cutlass this week and had my cutlass threaded and made a special tool to pull it. If done properly, and you have a fixed pitch prop that only has a nut and keyway, you can remove and reinstall the cutlass while the boat is in the water.
WD

without removing the shaft ???

James S 25-11-2009 00:28

Actually technically speaking its correct that you may be able to replace the cutlass with out taking out the shaft.
It depends on how you can pull it out...how much of it can you get a hold of? how is it held in place? set screws?
I think if you had intimate knowledge of it you may be able to do it.

gbendaly 25-11-2009 00:55

Quote:

Originally Posted by James S (Post 365383)
Actually technically speaking its correct that you may be able to replace the cutlass with out taking out the shaft.
It depends on how you can pull it out...how much of it can you get a hold of? how is it held in place? set screws?
I think if you had intimate knowledge of it you may be able to do it.

I was under the impression that the removal of the bearing is done by introducing a hacksaw blade in the shaft passage and making a longitudinal cut though the copper shell allowing for its folding and withdrawal, how can I pull it out with the shaft in place ?/

James S 25-11-2009 04:38


I've never removed mine...but I have a spare and the previous owner said there are set screws in the hull, which I have seen, you loosen them, and drive it out from the inside.
When he did it the shaft was out.

jdoe71 25-11-2009 05:59

There is a special tool made to press out a cutlass bearing with the shaft still in place. Boat yards occasionally have it but most don't. After its removed you slide it off the end of the shaft and this tool will press a new one into place. You probably could do it in water but the tool is somewhat cumbersome to use, has several pieces to it that all have to be lined up correctly to work and in water that would be tough I think.

IceMan 25-11-2009 07:31

Quote:

without removing the shaft ???
Yes. With the shaft still in the stuffing box very little water will ingress into the boat. If I knew how to post the pictures, I would post a couple I just took. I'll try to learn how to post pictures. A couple of friends of mine made this tool and I contacted them and made one for myself. It is small and easily used and all in one piece. Like I said, having a prop that is easily removed is the key. I have a Maxi-Prop so I'll still have to haul to remove the cutlass.

Gbendaly,
I'll post a couple of pictures. It will not help you with this one you need to change, but will make the next one almost painless.
WD

motion30 25-11-2009 07:38

stern tube

delmarrey 25-11-2009 09:20

Here are some links for removal tools. I made my own that is a slide hammer style but it only fits 1" shafts and 1-1/4" OD bearings.

Strut Pro Cutless Bearing Replacement Tools

Cutless-Bearing Replacement

Replacing A Cutlass Bearing (Photo Heavy) - SailNet Community

IceMan 25-11-2009 12:07

Good looking tool. Nice write up also.
WD

lancelot9898 02-12-2009 15:32

Quote:

Originally Posted by IceMan (Post 365466)
. I have a Maxi-Prop so I'll still have to haul to remove the cutlass.


WD

I also have the max prop and it's easy to remove. In fact I routinely take it apart when hauled out just to relub the gears. The newer ones have grease fittings so taking it apart is not needed, but I fail to see how it's any more difficult to remove a max prop over the fixed prop. Actually if you're doing it in the water then...yes I would want to be hauled. :)

4HMainer 05-12-2009 14:33

Yes, on a 25.00mm shaft inside diameter of bearing will be between 25.16 and 25.26mm. Once a bearing starts to wear the wear accelerates as the contact area at start up reduces dramatically. When running there is very little wear as the shaft should be running on water, but in an oversized/worn bearing it may not support a water film to hold the shaft away from the bearing material.

These are figures for a fully composite bearing material known as Maritex. It wouldn't be possible to change these in the water as the preffered fitting is to bed on epoxy and you need to be able to heat the carrier to soften the epoxy. Tis does make them easy to remove and instal and gives a check on carrier alignment as you can spin the bearing in the carrier on the shaft.

In a nutshell, it needs changing, it needs to be done out of the water, but it will probably keep running with noise an vibration for a number of hours before it fails completely.

scooperfl 16-12-2009 12:26

In my younger, "broke sailing" days I learned a couple of tricks. In retrospect, neither is worth the effort unless you have no other choice.

IN A PINCH, you can raise the rear engine mounts slightly and re-align to the engine to the shaft in a higher position. This will slightly cock the shaft in the bearing, temporarily decreasing play. Of course, this will also affect the shaft's position in the stern tube which may may cause stuffing box leakage. Note that this will not work dripless seals.

I have also changed mine in the water. However, it did not fit super tight in the strut and there was plenty of room to work betweent the prop and rudder, your results will probably vary:
Remove prop
Loosen the set screws
Drill a hole in a hardwood block to match shaft size
Place new bearing in position behind old one
Use block to drive new bearing into the strut, pushing the old one out
Cut old one off the shaft with hacksaw
Replace set screws
Replace prop


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