Cutlass Bearing Query

[whatever]

I hope this is a really stupid question, is it at all possible for a composite material cutless bearing sliding down a shaft? Or can a sleeve insert of a metal type come loose and slide down? Thanks for any legit answers...as I said, I really hope this is a stupid query

[Artif]

Yes on both counts, unlikely but it can happen.

[Pete the Cat]

Yes happened to my boat. But it was after picking up a hunk of polypropylene line in the prop that popped it out. I never heard of one spontaneously ejecting itself. Set screws that are set in a dimple should hold it in the strut. Some yards skip drilling the dimple. Not good.

[delmarrey]

Originally Posted by Pete the Cat

Yes happened to my boat. But it was after picking up a hunk of polypropylene line in the prop that popped it out. I never heard of one spontaneously ejecting itself. Set screws that are set in a dimple should hold it in the strut. Some yards skip drilling the dimple. Not good.

If you drill all the way thru, tap it and use bronze machine screws it'll stay in place. Just do it with the shaft out. I used two, fore and aft. Only aft one showing here.
And cut the screw so it only gets into the metal, not the rubber.

[whatever]

Ok, Thanks for those responses. Another one, is there possibly a rubber boot or thin rubber encasing a shaft that would slide from where the shaft comes out from the boat, that could slide toward the strut? This is about 9" long, thin rubber material, my husband found it while scraping the screws and shaft. He had never seen it before, but it has been about 2 yrs since he had actually dived on our own boat. But the previous crew that was scraping never mentioned seeing it. Thanks

[delmarrey]

Originally Posted by whatever

Ok, Thanks for those responses. Another one, is there possibly a rubber boot or thin rubber encasing a shaft that would slide from where the shaft comes out from the boat, that could slide toward the strut? This is about 9" long, thin rubber material, my husband found it while scraping the screws and shaft. He had never seen it before, but it has been about 2 yrs since he had actually dived on our own boat. But the previous crew that was scraping never mentioned seeing it. Thanks

A Stern Tube.
Someone may have installed a rubber liner of some sort. But the problem with a liner (either a support or anti-chatter) is if one has a stuffing box/PSS that is not plumbed with a water line, from the water pump">raw water pump, then the stuffing box/PSS can become hot from the lack of circulating water.

Some pictures would help.

[whatever]

We do have the water fed stuffing box, will this thing slide back in? We do not have an underwater camera, unfortunately

[delmarrey]

Originally Posted by whatever

We do have the water fed stuffing box, will this thing slide back in? We do not have an underwater camera, unfortunately

The question is; what held it in place? Is it loose on the shaft, or in the stern tube?

I'm Guessing but most likely was epoxied in the tube. If so, then a haul out may be in order.

Or can the boat function w/o it? Then just remove it. How does the shaft run at hull speed?

[whatever]

All good questions! We don't know the answer to any of those. We have not run the boat except to move from one slip to another since about March. We don't know how long it has been like that, we are mostly in fresh water now, so the need just arose to ck the bottom, hence scraping the running gear, and then he found this thing. He didn't finish cleaning the shaft around this sleeve well enough to try to see if it slides up and down on the shaft, and obviously that is the next step. He will go down tomorrow to complete that job, and I guess we'll see. The last time we moved the boat, there was no vibration, no seemingly noticeable problem, but then who knows when this occurred. Just trying to get a sense of "what" it might be, because it is getting to be that time when we want to start going to anchor out and make little trips to do some major fishing.

[whatever]

I do know the answer to one of those questions, it is on the shaft, away from but not sure how far, from the stern tube

[Artif]

Sounds like the rubber sleeve from the cutless bearing in the stern tube, especially since you have water cooled stern tube. Will need replacing soon as possible.

[whatever]

Should we not be having a leak, if that is what it is?

[sabray]

no the rubber is a bearing that is water lubricated. the water is stopped inside where the shaft enters the bilge. the stuffing box several types of these a common variant needs water up the shaft log to that seal/stuffing box to keep ir cool. Often it is needed that this leaks a tad so water is flowing and cooling the packing in the stuffing box. You need some sort of bearing down by the prop so the shaft does not go all wobbley.

[Artif]

No, the cutless bearing will probably be the same as in your p bracket and is fitted in from the outside of the boat.The bearing is a support not a seal, the water fed into your stuffing box is the water that lubricates the bearing. The p bracket doesn't need a forced feed as its fed form the water entering the forward end of the p bracket when under way.

[whatever]

So why does this need to be replaced as soon as possible? And I suppose that is a haul out job, as well?