what type of shaft seal / stuffing box is this?

I have unscrewed the big nut (clean one) on the left and pushed it towards the engine. There was one layer of 1/4" packing there half of it was sticking out and easily removed. The small nut (just right of it on the second photo, and still threaded on (the first photo) is some sort of locking nut for the big nut. When I have removed all four hose clamps from the rubber bellow/hose (third photo) the threaded piece with a flange that touches the rubber hose/bellow is spinning but has moved only 1/8" left towards the engine so I am unable to see what is under the hose and whether there is in fact any packing to be replaced / renewed. The small brass tube 3/8"on the right is where the hose is connected supplying water from the raw water pump. I will access it from other side tomorrow to have more purchase in order to try and push it to left towards the engine.

This to me seems as if the system works similar to the PSS dripless shaft seal with the rubber hose/bellow acting as a sort of seal wrapping around the through hull cutlass bearing and that piece that is spinning but not moving backwards, and only one layer of 1/4" packing is used to seal it.

Anyone have any tips knowledge about this is much appreciated.

There is nothing under the hose other than your prop shaft. (and a hose coupling on either end). The sole purpose is just to hold the stuffing box in place and seal the gap between stuffing box and cutlass bearing.


You'd only need to remove the hose if the hose to change it out if its looking a bit dodgy. (soft or cracked). You can change the length of the hose if space allows, to allow the shaft packing to seal on a smoother part of the shaft. I recently added about 6" just to make the adjustment nut more accessible.


I am surprised you only found one layer of shaft packing. 3-4 layers is normal.

Thanks AusCan,
The hose/bellow seem to be original (1980) and on the Port engine it looks it was renewed. To replace it i would need to pull out the shaft (at least few inches to slide the new length in) which I did not plan for this haul out.

Would you know what make/model is this stuffing box?

The one layer of 1/4" packing was found around the shaft under the threaded pice that I am unable to move backward. On Hatteras forum one guy claims more layers of packing should be inside the big (shiny ) nut but from quick check this afternoon I could not see any. I guess i will have to check more closely and try extracting if there is more.

To replace the stern tube hose, you'd either need to slide the shaft back or slide the engine forward a few inches, (and remove the shaft coupling) giving you a gap to maneuver the hose out of/into. It is a job to do during the haul out.


I don't know the model, but it looks fairly standard.


I'd guess the only the top layer of packing has been replaced numerous times and the bottom 3 layers are the original 30 year old packing, which has been squeezed into a hard solid mass. It may now have a shiny surface looking like its part of the stuffing box.
If you dig it out and replace it all, you will require much less frequent adjustments to maintain the ideal compression and seal.

I have a similar packing setup. The big hollow nut ,Pic #2,is where the packing should go, inside the nut. Preferably two or three pieces. The big nut is then run down on the threaded spud and is compressed to seal on the shaft. The compression takes place between the end of the spud and the inside of the hollow nut.

There is a locknut that , once the packing is adjusted, is used to jam the big nut in place. Pic.#1

Mine is almost the same except for the EXTRA threaded nut at the back run down onto the log hose. It should not be needed.

I learned to not go past 3 packing pieces as they do not compress readily, there can be too many for proper compression, and wouldn't seal well. My experience. Also I use a piece of plastic pipe to gently work each packing piece into place. Not hard but use of a screwdriver will damage the stuff and then you may find it does not seal well.

These packing box styles are/were made by co. like Perko, Groco, Buck Algonquin, Spartan Marine, Wilcox Crittenden [ out of business now] and others.

They are sized by the shaft diam. and the connection to the shaft log. You will have to go on the sites and possibly contact them. Unless you are trying for a replacement part you may not have to 'match' exactly. Even so take a look.

Old Packing will be compressed now so you will need some picks. A small screwdriver some times works. Just be carefull to get all the remnant out. There are also packing removal tools which have flexible .spring shaft and a twisted wire end to bite into the old packing. Sometime a chandlery will have it but a good seal house/shop should also have them.

Flexible Packing Extractors & Sets by C.S. OSBORNE & CO.

3-4 layers is correct. Use GFO packing and you can run it dripless.

Look to see if the old packing has worn a groove in your shaft/s. If so, the next time you pull the boat replace the hoses with longer or shorter ones to move the packing to a smooth section of shaft. Also if you replace the hoses be sure you use the correct type. Regular marine exhaust/water hose is not made for stuffing box use.

You should clean and change the ends on those bonding wires while you are at it.

I would be really surprised if there is only one ring of packing. Get some dental pics and lay one up against the shaft while scraping out the inside of that deep cup nut. You can also use special corkscrew packing puller.
Only when you can scrape the inside of the tube nut and feel nothing but smooth metal have you gotten all the packing out.

Try this:

Re-Packing A Traditional Stuffing Box Photo Gallery by Compass Marine How To at pbase.com

Capt.Bill11 said:

3-4 layers is correct. Use GFO packing and you can run it dripless.

Look to see if the old packing has worn a groove in your shaft/s. If so, the next time you pull the boat replace the hoses with longer or shorter ones to move the packing to a smooth section of shaft. Also if you replace the hoses be sure you use the correct type. Regular marine exhaust/water hose is not made for stuffing box use.

Click to expand...

How much grooving on the shafts is too much? Or are we in the "any amount" category?

When I broke 2 packing puller corkscrews on old packing....I started using long decking screws to drive into the packing with a screwdriver and pulling with vicegrips.

They didn't break and worked great.

I leave a couple in the top tray of my tool box and they Co e in handy for a lot of things.

Capt.Bill11 said:

Look to see if the old packing has worn a groove in your shaft/s. If so, the next time you pull the boat replace the hoses with longer or shorter ones to move the packing to a smooth section of shaft.

Click to expand...

Thanks Capt.Bill!

Although, as obvious as this may seem, I hadn't thought of it. Great idea.

angus99 said:

How much grooving on the shafts is too much? Or are we in the "any amount" category?

Click to expand...

Well, packing can deal with minor grooving pretty well. But once it gets to a certain point, which is a bit if a judgement call, or the call of a prop/shaft shop, you should move the stuffing box so the packing rides on a smooth spot. One way you can tell if the grooving is to extreme is if the only way to get the stuffing box to stop dripping is to have to way over tighten it.

And the shaft can get so scored that you need to have it repaired or replaced because it could snap at the groove. Again, if you are uncertain how bad the grooving is, have a professional look at it.

Capt.Bill11 said:

Well, packing can deal with minor grooving pretty well. But once it gets to a certain point, which is a bit if a judgement call, or the call of a prop/shaft shop, you should move the stuffing box so the packing rides on a smooth spot. One way you can tell if the grooving is to extreme is if the only way to get the stuffing box to stop dripping is to have to way over tighten it.

And the shaft can get so scored that you need to have it repaired or replaced because it could snap at the groove. Again, if you are uncertain how bad the grooving is, have a professional look at it.

Click to expand...

Thanks, Cap. Don't think I can move mine, however. These are the heavy bronze stuffing boxes bolted to the hull. We're out of the water right now for exactly the inspection you're recommending.

Brico said:

I have unscrewed the big nut (clean one) on the left and pushed it towards the engine. There was one layer of 1/4" packing there half of it was sticking out and easily removed. The small nut (just right of it on the second photo, and still threaded on (the first photo) is some sort of locking nut for the big nut. When I have removed all four hose clamps from the rubber bellow/hose (third photo) the threaded piece with a flange that touches the rubber hose/bellow is spinning but has moved only 1/8" left towards the engine so I am unable to see what is under the hose and whether there is in fact any packing to be replaced / renewed. The small brass tube 3/8"on the right is where the hose is connected supplying water from the raw water pump. I will access it from other side tomorrow to have more purchase in order to try and push it to left towards the engine.

This to me seems as if the system works similar to the PSS dripless shaft seal with the rubber hose/bellow acting as a sort of seal wrapping around the through hull cutlass bearing and that piece that is spinning but not moving backwards, and only one layer of 1/4" packing is used to seal it.

Anyone have any tips knowledge about this is much appreciated.

Click to expand...

Just to be clear:

You have a very typical stuffing box. ALL of the packing will be inside the big nut - all the way back to the end. You should find at least 3 and most likely 4 layers of packing inside that nut. As was said, there is nothing really "serviceable" inside that hose. In fact unless you think it needs replacing, I would not disturb it.

There is a good pic here:

http://www.alberg30.org/maintenance/MechanicalPropulsion/StuffingBox/StuffingBox.png

Ken

Filled with envy at members ability to take pics of accessible stern glands. Mine are concealed under the HW tank one side and battery boxes the other. The answers here are very informative.

"Filled with envy at members ability to take pics of accessible stern glands. Mine are concealed under the HW tank one side and battery boxes the other."

Invite the boats designer and assembler to a party on board

, and DEEP 6 them!

Greetings,
A question for the group: We have exactly the same stuffing box as shown my Mr. 99 in post #14. In my haste to eliminate drips while running I overtightened my stuffing box. One heated up to about 150 degrees F and was "steaming" I backed off the flange causing both a cool down and a constant drip to be able to continue running. So, do I re-tighten to minimize/stop the dripping or have I compromised the packing material to the point where I will have to re-pack? I'm not able to leave the dock at the moment but don't want to leave the drip.
Thanks

RT Firefly said:

Greetings,
A question for the group: We have exactly the same stuffing box as shown my Mr. 99 in post #14. In my haste to eliminate drips while running I overtightened my stuffing box. One heated up to about 150 degrees F and was "steaming" I backed off the flange causing both a cool down and a constant drip to be able to continue running. So, do I re-tighten to minimize/stop the dripping or have I compromised the packing material to the point where I will have to re-pack? I'm not able to leave the dock at the moment but don't want to leave the drip.
Thanks

Click to expand...

It's hard to say if you damaged the packing without looking at it. If it was me and the stuffing boxes are fairly easy to get at, I'd repack them with GFO.

Greetings,
Mr. 11. Has GFO in there now.

RT Firefly said:

Greetings,
A question for the group: We have exactly the same stuffing box as shown my Mr. 99 in post #14. In my haste to eliminate drips while running I overtightened my stuffing box. One heated up to about 150 degrees F and was "steaming" I backed off the flange causing both a cool down and a constant drip to be able to continue running. So, do I re-tighten to minimize/stop the dripping or have I compromised the packing material to the point where I will have to re-pack? I'm not able to leave the dock at the moment but don't want to leave the drip.
Thanks

Click to expand...

Really hard to say.

What type of packing is in the tube?

I have seen where the standard Teflon impregnated stuff looked burnt and glazed like glass....which was leaking and tightening didnt help.

I have never gotten one hot enough to steam though.

Just saw your last post...based on rereading gfo packing info...you should be ok.....but like all risk assessments...what would you have to do to fix, where would you be, etc...etc...

Or is it just better to redo it now?

Mr RT, I have a similar problem in that I can't get a normal drip without over-tightening, which I have avoided. In my case, shaft misalignment is an issue. Also, I think the packing glands were over tightened by a PO and it scored the shafts. I run them deliberately loose and over-cool at this point, putting up with the extra water in the bilge. I'm worried that the scoring will prevent GFO from ever working as it should once the shafts are aligned properly.

Have you verified that you're using the right thickness of packing?

Also, that the shafts are centered in the logs? One of mine is so off-center that I could probably fit 5/8" packing on one side and 1/4" on the other. I'm using the 3/8" that's spec'd and it leaks like a mother.

Good luck and I'd appreciate knowing how it turns out for you.

Greetings,
Mr. 99. Ahhh....Alignment. I DO have a vibration at higher RPM and I just noticed this afternoon that at LEAST one of my engine mount studs nuts is loose. The last time the packing was done, the shaft seemed to be centered in the stuffing box and GFO was used. Prior to heading south this spring I noticed, what I took to be, excess drippage and subsequently adjusted the stuffing boxes en route, notified the Admiral and asked her to "shoot" the temperatures (twins) during her regular ER walk through. Within 2-3 hours, she reported elevated temperatures, on the stb'd side primarily, and I immediatly loosened off the adjustment nuts and allowed a fair drip to develop. So as to shaft scoring? Who knows but it couldn't have run "hot" for much more than 3 hours or so.
As a result of all of the valuable input, my plan of attack is to have the engines aligned and then inspect the stuffing material/shafts. I will effect a report when the work is completed and a sea trial is done. Thanks all. Oh, don't hesitate to offer other comments.

RT Firefly said:

I will effect a report when the work is completed and a sea trial is done. Thanks all. Oh, don't hesitate to offer other comments.

Click to expand...

I'll do the same. I'm having all of this work done in the next couple weeks (including rudder bearings/packing). Good luck!

RT Firefly said:

Greetings,
Mr. 99. Ahhh....Alignment. I DO have a vibration at higher RPM and I just noticed this afternoon that at LEAST one of my engine mount studs nuts is loose. The last time the packing was done, the shaft seemed to be centered in the stuffing box and GFO was used. Prior to heading south this spring I noticed, what I took to be, excess drippage and subsequently adjusted the stuffing boxes en route, notified the Admiral and asked her to "shoot" the temperatures (twins) during her regular ER walk through. Within 2-3 hours, she reported elevated temperatures, on the stb'd side primarily, and I immediatly loosened off the adjustment nuts and allowed a fair drip to develop. So as to shaft scoring? Who knows but it couldn't have run "hot" for much more than 3 hours or so.
As a result of all of the valuable input, my plan of attack is to have the engines aligned and then inspect the stuffing material/shafts. I will effect a report when the work is completed and a sea trial is done. Thanks all. Oh, don't hesitate to offer other comments.

Click to expand...

RT,
You might also want to check that your raw water supply is not clogged.

Is there a possibility of a bend in the propshaft? One of mine was chewing out packing fast and leaking, trickling actually, the other was fine 5 years after repack. Wore out the rear gearbox oil seal prematurely that side too. I learned of a mooring being picked up on that shaft by a PO, with nasty results, took advice, sure enough the shaft was bent.

Greetings,
Mr. R2G. Wow, the water feed had completely slipped my mind-Thanks!
Mr. BK. I don't think I have a bent shaft although it IS possible given that I do have a vibration at speed. I had assumed engine misalignment but it could be the shaft. I'll have that checked next haul out. I DO know I've got a shaft coupling on each shaft about 4' forward of the cutlass bearing. Used to know what it is called but forget. In other words I have a 2 piece shaft. Thanks.

RT Firefly said:

Greetings,
Mr. 99. Ahhh....Alignment. I DO have a vibration at higher RPM and I just noticed this afternoon that at LEAST one of my engine mount studs nuts is loose. The last time the packing was done, the shaft seemed to be centered in the stuffing box and GFO was used. Prior to heading south this spring I noticed, what I took to be, excess drippage and subsequently adjusted the stuffing boxes en route, notified the Admiral and asked her to "shoot" the temperatures (twins) during her regular ER walk through. Within 2-3 hours, she reported elevated temperatures, on the stb'd side primarily, and I immediatly loosened off the adjustment nuts and allowed a fair drip to develop. So as to shaft scoring? Who knows but it couldn't have run "hot" for much more than 3 hours or so.
As a result of all of the valuable input, my plan of attack is to have the engines aligned and then inspect the stuffing material/shafts. I will effect a report when the work is completed and a sea trial is done. Thanks all. Oh, don't hesitate to offer other comments.

Click to expand...

RT--Just went through this, noticed vibration at higher rpm's, asked my boatyard to check alignment etc. Told me everything looked good--maybe start with checking prop. Prop is off a little, ok true it. $1000. NEVER AGAIN WITH THESE CLOWNS!! Go out on two week trip; guess what.... shaft breaks inside coupling! Boat US rocks!! 5 hour tow from Patos Island to Anacortes, $1600 tow bill- no cost to me- cant say enough about this service!
Back to subject, my yard missed that the aft starboard engine mount lower nut had backed off and was out 1/2". I dont think this had just happened but they should have noticed it! No excuse for me not seeing myself but this boat was new to me and I had limited time to fix everything else,figure out how everything worked, etc etc.
That being said, the alignment is crucial. Next-- the solid coupling. there was a machined keyway slot, a roll pin bore, and two bores (dimples?) for the lock bolts, basically on the same plane (of weakness) On a 1 1/2" shaft diameter Im guessing there was probably 1/2 the meat that should have been there.
RT If your doing all this other work, take a look at your engine coupling at the same time especially if your boat / shaft/ coupling is 35 years old.

RT Firefly said:

I DO know I've got a shaft coupling on each shaft about 4' forward of the cutlass bearing. Used to know what it is called but forget. In other words I have a 2 piece shaft. Thanks.

Click to expand...

Maybe a jack shaft? My boat had Velvet drives originally. When one bit the bullet, it was replaced with a Twin Disc that has a shorter housing. To keep the same prop shaft, it was necessary to fill the "gap" with a jackshaft and an additional coupling. The engine also had to be raised 2 inches with spacers under the mounts.

RT Firefly said:

Greetings,
Mr. R2G. Wow, the water feed had completely slipped my mind-Thanks!
Mr. BK. I don't think I have a bent shaft although it IS possible given that I do have a vibration at speed. I had assumed engine misalignment but it could be the shaft. I'll have that checked next haul out.

Click to expand...

Last thing a guy wants is a bent shaft.