Grinding Noise from Prop Shaft

[donradcliffe]

It sounds like you are doing a good job of isolating the problem. Did you grease just between the shaft and the stern rubber bearing, or does it look like the bearing has come loose and you also greased between the bearing and its housing?

Go under the boat again and try to move the propshaft from side to side. If it moves more than 2mm, the rubber inside of the stern bearing has failed completely and the grinding noise is metal-to metal contact. The grease would quiet that for a very short time, and continued operation would damage the propshaft. If the play is less than 2mm, everything is OK unless the bearing is locked to the shaft and turning in its housing.

From the HR manual http://www.hallberg-rassy.com/Download/Manual-Eng.PDF

The propeller shaft (HR 40 – HR 64)
Normally the engine’s anti-vibrators will subside a little during the first season. It is therefore important
to check the level between the engine and the propeller shaft and maybe adjust it. This should be done
by an expert.

The propeller shaft seals (HR 40 – HR 64)







The stern gland is water lubricated and requires little maintenance. However, if the boat has been lifted
out of the water the black rubber seal has to be squeezed, to be refilled with water (only valid on HR 40,
43 and 48). If forgotten it will run dry and quickly be damaged. HR 40-48: Grease once a year or after
200 hours, according to the engine manufacturer’s manual enclosed. The HR 54 and the HR 64 are
fitted with a seal that refills itself with water.
Press here according to instructions
Note !
Note ! 9
The outer propeller shaft bearing is maintenance free in general. However, in very bad water conditions
(sandy waters) there may be a need to replace the rubber bearing. In this case you have to dismount the
propeller and two retaining screws on the sides. After this the rubber bearing can be pulled out with a
suitable tool.

The propeller
Every propeller must be checked regularly, at least very 12 months, more frequently if the boat is
extensively used. You must check the nut and that there is no play. A sail propeller with movable blades
should be greased at least once every season. Check that the blades move freely. If you want to demount
the propeller, please notice that this should be done when the propeller is still wet directly out of the
water. If you let the propeller dry, it may be very tricky to demount it.

[Nicholson58]

Originally Posted by delmarrey

W/o pictures it's a bit difficult to tell what you have.

Grease may present more of a problem then a cure in a long run. Cutless bearings have longitudinal groves which allow water to pass thru, in turn lubricating and cooling the bearing.

If those get plugged, the bearing could over heat and cause even more wear on the parts. And I'm not sure grease would stay in a strut hung bearing for very long anyway.

And if it is a spinning cutless bearing it needs to be secured in place some how even if you have to drive tiny wedges/nails between the bearing and strut. Or like stated earlier, tighten the set screws, if it has them.

Can you explain in some detail what your drive consists of from the coupler aft?

OK - U lucky guy! sounds like it might just be the Cutlas Bearing. Ours became packed with som much marine growth in the water grooves that the deposits wore down the shaft diameter. I will attach a few photos. The replacement was easy. Use a hack saw at the top of the cutlas housing to cut nearly all through the bronze outer of the old bearing. Pictures show the bronze sleeve and rubber liner cut. This relieves the press-fit stress and allows you to use a bolt & washer or fitted wood or aluminum plug to drive/press the old one out. Some bearings are retained by set screw instead of press fit. Threaded rod & washers to draw the new one in. I used an engine cylinder hone in a drill to clean up the bore before I pressed in the new one. The whole job was less than an hour.


Make sure also that there is no damage to the hull where the shaft penetrates. and is stabilized.
I saw a boat lifted one end clear of the water once using a crane. Alternately, you could have them sling the boat and only lift the stern far enough to clear the cutlass.

My shaft was so worn at the cutlas and at the packing gland that I had to have it built up by plasma spray and then turned down to size. The total refit stopped my massive vibrations above 1200 rpm. (and packing leak) You can see the worn area under the cutlas and the photo showing the SS plasma build-up before I turned & polished it.

[Cheechako]

I sounds like you need to confirm if the Cutlass brg is loose in the boat. If it is, brass shim can be wrapped around it and drive it back in, underwater epoxy or other stuff would work also.....to get you by until haulout. BTW, if it's loose but wont actually come out, look for those set screws mentioned, sometimes they are filled in with bondo/bottom paint etc etc and you cant tell where they are.

[bobconnie]

Seem's to me that if you have any doubt about the safety of greaseing the shaft and bearing, you will pull the boat out and make sure the problems cured! Your to far from home to take a chance! the water your headed into is sorta motor nessasary! I would be very worryied about the damage that could happend when ya busted the line cutter !! Had to be a hell of a shock!! Just sayin, places to fix things out of the water are few and far between down there !!

[BoomBrake]

@Nicholson58: bloody great photos and excellent explanation, that should be a sticky. I was thinking about & really like the idea of lifting only stern out, as should minimise issues (& cost) when craning in a far flung remote area. Also agree with bobconnie's sentiments, better not to take chances there. Let us all now how you go.

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[jim_thomsen]

Wow, I never considered grease may be an issue!

Boombrake, if you get a chance please ask Darby. He checked our shaft (as did I) when they took Tenaya out of the water in May 2013. We did not notice any movement. That was probably 200 hours of motoring ago. I would love to have the bearing replaced, but Palau is sure not set up for taking a sailboat out of the water. The closest reasonable haul out is the Philippines, about 500 miles. I will have it replaced as soon as possible.
To explain our setup, from the gearbox, to a Centa Flexible Coupling to the stern tube and out the stern to the prop. There is no separate strut. By disconnecting the flexible coupling I was able to move the shaft back 5-7 cm and then put on Seldon waterproof grease and then moved the shaft back in.
Before I put on the grease I did move the shaft in and out a couple of time but the grinding continued until I put on the grease. I hope this doesn't cause a problem with the water cooling! Maybe it was marine growth between the bearing and the shaft. I had not put the motor in gear for 3-4 weeks. The bearing does not seem to turn when I turn the prop by hand, but of course I can't see it when the engine is turning the shaft.

[Nicholson58]

If you have marine growth in the cutlas it will be like spinning your shaft in sandpaper. Grease may make it hold dirt instead of flushing. Your observation with the grease tends to make me think the cutlas is the problem. Even if you only hoist the stern, pull the shaft clear, inspect and clean it out, you will be in better shape. We carry a spare cutlass. If you shaft is worn under on the diameter you may need to replace or rebuild it. Ours is 1984 and the variable pitch feature means the shaft has a coaxial push rod interior. The bronze hub is custom fitted as well. Our only choice was to fix it or pay a lot of boat bucks to replace. I suspect yours is around one inch and solid; less complex. It might even be possible to end-for-end with modifications.

Our worn cutlas was not evident from leaning on the shaft although a surveyor thought it might be dodgy.

[jim_thomsen]

Nicholson58,
Fantastic photos and information.
As far as I can see the cutlass bearing is not moving, but that is from just hand turning the shaft.
bob&Connie, I would love to haul out and do it right. But the best they can do here is a construction crane that has not lifted anything at our weight and the pull out area we need to go into at HW, giving us only a few inches, so just lifting the stern won't work. They have lifted a couple of sailboats, lighter than us, but this is a sideline to their construction work. They also don't have any stands, so we would have to find some construction braces to hold the boat.
Breaking the line cutter was a shock, but I didn't see any real damage to the stern tube. That was in even a more remote place, Papua New Guinea where I gave the village their only pair of pliers.

[BoomBrake]

Jim, I just spoke with the marina and Darby is off on Christmas holidays and not back until the New Year. Bluey is in Monday, so I'll give him a buzz and ask some questions. Yea, marine growth would be very active in that area, even after 3 weeks.

If it were me, I'd stay put until at least able to lift the stern out by crane and checking everything, removing grease and possibly replacing Cutlass Bearing. Wouldn't be risking reef eddies and so forth in case something seizes. I am being a bit over dramatic, but we don't know if combination of Cutlass Bearing plastics, petroleum based grease and high temperature friction can create a seized blob, or something more sinister. If the shaft seizes or seal gives and allows too much water into bilge, that won't be good especially mid-reef channel in a current. Will run all this by the marina guys and let you know their opinions.

Sent from my Nexus 7 using Cruisers Sailing Forum mobile app

[delmarrey]

Originally Posted by jim_thomsen

Wow, I never considered grease may be an issue!

Boombrake, if you get a chance please ask Darby. He checked our shaft (as did I) when they took Tenaya out of the water in May 2013. We did not notice any movement. That was probably 200 hours of motoring ago. I would love to have the bearing replaced, but Palau is sure not set up for taking a sailboat out of the water. The closest reasonable haul out is the Philippines, about 500 miles. I will have it replaced as soon as possible.
To explain our setup, from the gearbox, to a Centa Flexible Coupling to the stern tube and out the stern to the prop. There is no separate strut. By disconnecting the flexible coupling I was able to move the shaft back 5-7 cm and then put on Seldon waterproof grease and then moved the shaft back in.
Before I put on the grease I did move the shaft in and out a couple of time but the grinding continued until I put on the grease. I hope this doesn't cause a problem with the water cooling! Maybe it was marine growth between the bearing and the shaft. I had not put the motor in gear for 3-4 weeks. The bearing does not seem to turn when I turn the prop by hand, but of course I can't see it when the engine is turning the shaft.

So, if I read this right, you have an in hull cutless bearing similar to one of these pictures.
Next, does it have a support bracket on the end similar to the picture?

A big problem with these types is the water lubrication. Some times the water is injected in. Others there are holes on the sides to allow water to enter forward of the bearing.

[Bestathook]

I have changed out a thru hull fitting underwater, It is a bit scary, but not very much water came in.

One helper is inside with rags. One helper is in the water with a toilet plunger. Somebody is in charge of the pumps. You take out the through hull,or in your case shaft, and cover with the plunger. I don't know if your bottom's contours will allow this. The big question is replacement parts and access to work without dislodging the plugs.

I have read of replacing the cutlass bearing with hydraulic cement in an emergency. The guy who did it said he suffered no major shaft damage, even after several hours of gentle use, but I did not witness the event.

I guess it is a question of alternatives.

[Jimbo485]

Probably cheaper to buy a used25 HP outboard and have it ready for the inevitable outcome of Mr Murphy. And then go on to Philippines immediately.

[Jim Cate]

At this point I would be tempted to check the bellows setting on the PSS seal, and then put the engine in gear and run it at anchor for a while, first idling, and then (if you cah keep her anchored) at a slow cruise RPM. If nothing happens in a few hours of carefully monitored running, I'd then be inclined to trust it for minimal usage. If it fails this test, the outboard solution sounds a lot safer than a mickey-mouse crane op.

OH... what is the tidal range there? Is there any chance of careening or drying next to a wharf?

Jim

[NoTies]

Hi Jim,
Looking at the pics it seems you have a Volvo type lip seal on the shaft. If you decide to draw the shaft under water you simply need a piece of round stock (wood, nylon, whatever) to slide into the seal as the shaft comes out & secure in place. Voila, no water in the boat and a good seal whilst you sort the cutlass issue (if that is what it is). Having an offset shaft would acutally make this job a doddle and probably easier and cleaner than in a yard but if you need to drop the rudder it might be a bit different.

[jim_thomsen]

So I think we will follow a couple of suggestions. First, too late to learn the grease is not a good idea, but today we will pull the shaft out again and at least wipe any grease left on it off. I can't image there is much. Then hopefully it still runs quietly.
And then (Thanks Jim Cate) we will run it in gear at anchor. At least at low RPMs that should not be a problem and hopefully it continues to run fine. If all looks good we'll take a 30 mile or so trip in the Rock Islands. At least we can be towed back is we have a big issue.
Thank you EVERYONE for so many great ideas! And also just having people to talk to about the problem.