Stuffing box , seizing ?

[paulg222]

Here is a link to a short 10s video of my stuffing box shown while the engine is running: https://streamable.com/f8i4hi

During the video, you'll see 2 incidents of what I'm talking about. The first is about 3-4 seconds in, the second at around 8s.

Both times you'll be able to see a slight rotation of the stuffing box. It sort of quickly rotates counter clockwise and then back (I think). Small rotation. Also there is a noise when this happens (which is what alerted me to it).

Note this was just after I launched the boat this Spring. I did not service the box before launching.

What level of concern should I have about this? Is it normal, does it need immediate attention?

It does not happen all the time. After noticing this it seemed to stop and I did end up motoring for about an hour and did not hear that noise.

[AA3JY]

The whole stern tube is partially moving..!?!

[paulg222]

Originally Posted by AA3JY

The whole stern tube is partially moving..!?!

I can't really tell, but I suppose if the stuffing box is rotating slightly, then whatever is attached to it is also rotating slightly. It rotates just a few degrees then returns to original position.

I don't know much about the stern tube attachment. Sometimes these are somewhat flexible right? What typically happens if a stuffing box has too much friction?

[Wotname]

Originally Posted by paulg222

........

Note this was just after I launched the boat this Spring. I did not service the box before launching.

What level of concern should I have about this? Is it normal, does it need immediate attention?

It does not happen all the time. After noticing this it seemed to stop and I did end up motoring for about an hour and did not hear that noise.

It is not normal.
If it was me, I would have a high level of concern!
Perhaps not immediate attention as it hasn't let go in the previous hour but it won't fix itself, it will only get worse.

Do you have any details of the type of stern tube or pictures of where it exits the hull?

Can you move it by hand?

[paulg222]

Originally Posted by Wotname

...
Do you have any details of the type of stern tube or pictures of where it exits the hull?

Can you move it by hand?

No pictures of that right now. I'll have to do some more inspection when I'm at the boat next.

[AA3JY]

Originally Posted by paulg222

I can't really tell, but I suppose if the stuffing box is rotating slightly, then whatever is attached to it is also rotating slightly. It rotates just a few degrees then returns to original position.

I don't know much about the stern tube attachment. Sometimes these are somewhat flexible right? What typically happens if a stuffing box has too much friction?

No the stern tube should not move...I’d pull the vessel if it’s still in the waster and inspect..

[Allied39]

Funnily enough there was a recent post from a fellow who had no stuffing box experience and asked for help.
What amazes me is that it would appear that everyone is freaked out about doing such a simple job.
My point; that stuffing box requires servicing.
It needs cleaning up externally, lubrication, disassembly, removal of all old packing, cleaning, lubrication and then instalation of new packing.
All that can be done in water with no need to haul and no need to dive in the water and stuff bags, or even your socks anywhere.
That is the most obvious first step, do that and see what the result is.
I posted the complete process to do said maintenance on the other post so am not doing it again.
So simple, so easy, so quick and for so little money.

[Cheechako]

I would say it's the rubber tube flexing/twisting because your prop shaft/packing has way too much friction. Possible reason is the shaft is corroded inside the packing. I had one like that which wouldn't stop dripping too fast. I had to replace the shaft. It was so corroded it looked like little worm tracks in the SS gnawing away at the packing.
If a boat sits too long with trapped salt water in there, the SS gets corroded from low oxygen.
But your's could just be a build up of surface corrosion too.

I would get the boat out of the water and pull the shaft enough to clean it up or replace it.

[glcalahan]

Paulg222,


Was curious to see your video. I have completely rebuilt my boat and installed a new shaft and packing gland and had some issues. Hence...I am curious.


Glc

[SV__Grace]

Are you getting any leaking? If so, exactly where?

Is the stern tube moving or just the stuffing box?

The stern tube is typically glassed in and shouldn't move or leak. Mine has developed a small leak because the seal between the bronze stern tube and the fiberglass is starting to loosen.

[Boatyarddog]

Originally Posted by paulg222

Here is a link to a short 10s video of my stuffing box shown while the engine is running: https://streamable.com/f8i4hi

During the video, you'll see 2 incidents of what I'm talking about. The first is about 3-4 seconds in, the second at around 8s.

Both times you'll be able to see a slight rotation of the stuffing box. It sort of quickly rotates counter clockwise and then back (I think). Small rotation. Also there is a noise when this happens (which is what alerted me to it).

Note this was just after I launched the boat this Spring. I did not service the box before launching.

What level of concern should I have about this? Is it normal, does it need immediate attention?

It does not happen all the time. After noticing this it seemed to stop and I did end up motoring for about an hour and did not hear that noise.

Looking at the condition of your packing gland, you would benefit greatly by removing corrosion and repacking.
The challenge might be loosening the lock nut, and removing the packing rings to replace them.
It's dried out the rings, and needs a repack at least, I might suggest you inspect the gland to tube hose and clamps as well.
You can use a couple of dry wall screws to remove the rings, clean the shaft first, to get the crust off.
Loosen the packing nut and back it off, screw a drywall screw into the flax packing on both sides and use side cutters to lever them out.
Cut new rings using PTFE impregnated packing of the proper size, looks like 1/4" but?
Be sure to check the gland hose it may have softened up, and now twists easily.
The video wasn't great quality, so kinda hard to see everything.
I'd say it's an immediate concern, as the hose can be compromised, and water will flow in quickly. Cause an emergency haul, or worse.
I don't believe the tube is moving, you'd have water coming in.
SV Cloud Duster

[Michael Pope]

This seems to me to be a stupid suggestion from me but maybe the man-- you do not know that when you are using a "NoDrip" stuffing box the seal that keeps the water where it should be is a lapped face between two lowfriction flat surfaces ( Ceramic to Carbon ---- many choices) this seal needs water to cool it and microscopically lubricate it.
When you launch the boat you need to push back the face to allow the air trapped in there around the shaft out in to the boat until water appears and then let it close. This provides the cooling and lubrication of the seal. If you launched and failed to do this it would be doing exactly as you described.
If you leave it like it is it will slowly degrade the seal face or even seize( unlikely but does happen)
If this happens you are left with a hard to seal opening. Cheers Mike Pope

[Boatyarddog]

Originally Posted by Michael Pope

This seems to me to be a stupid suggestion from me but maybe the man-- you do not know that when you are using a "NoDrip" stuffing box the seal that keeps the water where it should be is a lapped face between two lowfriction flat surfaces ( Ceramic to Carbon ---- many choices) this seal needs water to cool it and microscopically lubricate it.
When you launch the boat you need to push back the face to allow the air trapped in there around the shaft out in to the boat until water appears and then let it close. This provides the cooling and lubrication of the seal. If you launched and failed to do this it would be doing exactly as you described.
If you leave it like it is it will slowly degrade the seal face or even seize( unlikely but does happen)
If this happens you are left with a hard to seal opening. Cheers Mike Pope

True enough, Mike.
If it were a dripless setup.
This doesn't appear to be that type.
SV Cloud Duster

[foufou]

I had a similar situation a few years ago. Like you my immediate reaction was panic. After watching my stuffing box rotate I came to the conclusion that my stern tube was loose. For peace of mind I attached a line to the stuffing box with a hose clamp and with a turning block on the rudder post I tensioned it so all would stay in place. A sister ship had nearly sunk with a similar problem. When I eventually hauled out I found that in fact the threads on the stern tube were loose. In spite of the fact that the treads were in good condition I opted to replace the stainless steel tube of unknown alloy with a G10 tube which I bought from McMaster Carr. The original tube was threaded into the cutlass bearing housing which I assumed was bronze. I had the threads removed from that piece and machined it to fit the G10 tube which I glued in with 5200. Now I sleep better, and while I was at it I replaced the stuffing box with a dripless shaft seal as the stuffing box was in a very awkward spot deep into the keel area where wrenches were near impossible to adjust the packing gland nuts. All is good now and no more drips. F

[stormalong]

I would be very worried. Every time that stuffing box twists it is putting a lot of stress on the hose between the stuffing box and the shaft log. The hose was not designed to take this kind of stress and it may fail without warning.

I suggest that you redo the packing immediately and at the next haulout replace the hose. Now is the time to explore a dripless packing system or at least go to Teflon packing.