Shaft Seal - What is This?

[Albin]

Hi Folks,

I'm in the process of releasing the coupling on my shaft seal so I can slide the prop shaft back a few inches to remove my transmission so I can replace my damper plate. I had to cut a hole in the floor of the aft head but that gave me great access to the shaft seal. Why the designers of my Albin 40 didn't build in a hatch for this purpose is a mystery to me. My question is, what are the screws for on either side of the stern tube? I haven't seen this before on other seal/stern tube arrangements. The prop shaft is obviously rotating inside that tube so the screws can't be touching the shaft itself.

A second question is why does my shaft seal have two water feeds? One seems to be much more common. One is obviously cooling/lubricating the face seal and the other doing the same in the stern tube which seems like a good idea but most other boats don't have both. Just wondering.


Thanks to all who reply.
Cheers, Jeff

 

[Gdavid]

If your boat doesn't have a strut, I'm guessing that the water cooled cutless bearing is housed within this casting and the two screws lock it in place. They are safety wired so I'm assuming it is pretty important. I'll also guess that the water line in the bottom of the picture is original and the upper one was added when a dripless packing gland was added. If the boat doesn't have a dripless gland, they frequently don't have any hose for water flow but yours had one originally to provide adequate flow through the cutless bearing.

 

[psneeld]

The hatch to get to mine is under the aft sink

Water to PSS and cutless at top of shaft tube..

 

[Albin]

Thanks Dave, that makes perfect sense. While I'm at it I might as well remove the stern tube, slide it off the shaft and inspect and clean it up. I'll know then what the screws are doing but I suspect it's to hold the bearing in place as you have suggested.

 

[Albin]

Sorry, I just realized David is probably your last name. I didn't want my first reply to sound disrespectful. Thanks again for your help.

 

[Gdavid]

Sorry, I just realized David is probably your last name. I didn't want my first reply to sound disrespectful. Thanks again for your help.

No offense taken at all, my fault for having two first names, happens all the time and doesn't bother me in the least.

 

[OldDan1943]

May I suggest David is correct?
Could be worse. A second name of David resulting in GDavidDavid TEASE
I shall return you to the subject of this section.

 

[jleonard]

I originally had the copper tube feeding water, but when I installed the dripless I eliminated that and used hose. So just one source feeding the system.

 

[Albin]

Thanks Jay, good to hear from you. I removed those screws yesterday on either side of the stern tube just to clean them up because they were so corroded. I assume they are there to snug in against the bearing inside the tube. Do you have any idea how tight they should be when they go back in? I would like to remove the whole stern tube section to clean and inspect it but there is no way that will easily come out without destroying part of that stringer.

 

[rgano]

So back to the original photo. It appears there are two water cooling inputs to this shaft sealing system. The forward portion with the bellows is part of a dripless system, and the vinyl hose is the required water input to what may be a face seal up there. The copper tubing at the aft end looks to be an original installation by the boat builder to cool the stern tube cutless bearing. Are they both connected to a water source such as the engine seawater cooling system?

 

[Comodave]

I would replace the vinyl hose with a better quality hose too.

 

[Albin]

So back to the original photo. It appears there are two water cooling inputs to this shaft sealing system. The forward portion with the bellows is part of a dripless system, and the vinyl hose is the required water input to what may be a face seal up there. The copper tubing at the aft end looks to be an original installation by the boat builder to cool the stern tube cutless bearing. Are they both connected to a water source such as the engine seawater cooling system?

Yes, both lines split off from the same supply. I'm sure now it's just as you have suggested. The dripless seal is not original and that required it's own water source when it was added sometime later which explains the two lines.

 

[Albin]

I would replace the vinyl hose with a better quality hose too.

Good advice considering that seal is such a critical component.

 

[psneeld]

I originally had the copper tube feeding water, but when I installed the dripless I eliminated that and used hose. So just one source feeding the system.

I agree with this method.....

Not sure what replacement vinyl hose is better than what is on there...considering it is an important feed but far from critical.

 

[jleonard]

I agree with this method.....

Not sure what replacement vinyl hose is better than what is on there...considering it is an important feed but far from critical.

That's the same kind of hose I had on mine for 14 years and it was still working.

 

[McDan]

Hi Folks,

I'm in the process of releasing the coupling on my shaft seal so I can slide the prop shaft back a few inches to remove my transmission so I can replace my damper plate. I had to cut a hole in the floor of the aft head but that gave me great access to the shaft seal. Why the designers of my Albin 40 didn't build in a hatch for this purpose is a mystery to me. My question is, what are the screws for on either side of the stern tube? I haven't seen this before on other seal/stern tube arrangements. The prop shaft is obviously rotating inside that tube so the screws can't be touching the shaft itself.

A second question is why does my shaft seal have two water feeds? One seems to be much more common. One is obviously cooling/lubricating the face seal and the other doing the same in the stern tube which seems like a good idea but most other boats don't have both. Just wondering.


Thanks to all who reply.
Cheers, Jeff

Have you considered replacing that PSS while everything is apart?

 

[Albin]

Have you considered replacing that PSS while everything is apart?

Yes, that was the plan but once I got everything off the prop shaft (including that housing at the beginning of the stern tube that houses a cutlass bearing) I decided to keep what I have because it was actually all in very good condition. I'll just replace the o-rings in the rotor and clean everything up then I'm good to go. The cutlass bearing was also in good shape, presumably because it has been well lubricated by that secondary water feed.