If the stuffing box fails ?

Sven

Seglare
The horror stories about failing stuffing boxes and huge leaks are a bit scary.

I'm curious how the leak can be so large if the shaft is properly sized and only a couple of feet below the surface ? The equivalent hole ought to be a fraction of a square inch unless there are roller bearings in there ? Maybe it is only a major leak while running the engine ?

I'm asking to get a feel for what size pump would be appropriate for a hard-to-repair-under-way failed stuffing box. A failed hose can be fixed and even a hull breach can in some cases be temporarily fixed, but a stuffing box is a bit more of a problem so I would not assume that it could be fixed under way.

Thanks,



-Sven
 

mherrcat

Contributing Partner
Just my observation from having my stuffing box refurbished, repacked and the pedro hose replaced...

Unless you completely ignore your stuffing box for many years I doubt you would experience a "catastrophic" failure due to normal operation. The hose on mine was so deteriorated from exposure to a fuel tank leak that it was near complete failure and constantly dripping; as was the packing. This caused the bilge to always have water in it, but not enough that a 500 GPH Rule pump could not keep it at a manageable level without running constantly. The worst I could see happening would be to somehow tear the hose, and the only way I could see that happening would be for the stuffing box itself to somehow seize on the prop shaft and turn with the shaft, thereby ripping the hose from the shaft log. How that could happen I can't imagine, unless the boat sat for years with the shaft and stuffing box somehow corroding together. Otherwise, with at least some packing still in place and the adjusting nut secure there seems to be very little room for water to come gushing in through the stuffing box itself.

After having mine serviced there is almost no water in the bilge from the stuffing box and I inspect it every time I am in there to replace the heat exchanger zinc, which seems to be about every six months.
 
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Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author

Stu Jackson

C34IA Secretary
The number of times I've read of recommendations that the boat MUST be taken out of the water to repack the stuffing box is amazing. Most likely from folks who haven't done it. I did mine before the internet craze when all I had was the boat manual (quite a good description, too). I bought the stuff, figured out how to take the old stuff out (drywall screw - the piglet pigtail things don't work on my box, they're too big) and spent an hour or two upside down on my head with water leaking it all the time. The boat remained afloat. Even if my bilge pump was broken, or if the batteries were dead, there simply wasn't enough water to worry about.

Catastrophic failures would, however, occur with a PSS shaft seal.

However, your boat, your choice.

Failures of stuffing boxes? Unless the thread go wonky, which I've never heard of happening, if your packing is gone, throw a shoelace in until you buy some more packing.

It can be fixed "under way" but you'd want the engine in neutral or off to stop the shaft from spinning. Can be done anywhere on the water, not necessarily at your dock.
 
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Sven

Seglare
Loren,

I believe that ours might keep up with what water would come in around the shaft, if the big nut on the stuffing box ever backed off.
Pictured in reply 15 in this thread: http://www.ericsonyachts.org/infoexchange/showthread.php?1974-bilge-pump-recommendations&highlight=jabsco
Comforting thought and what I was hoping to hear.


Stu,

The boat remained afloat. Even if my bilge pump was broken, or if the batteries were dead, there simply wasn't enough water to worry about.
Glad to get that confirmation.

Any leaking water is worrisome but it didn't seem like there could be enough to actually be a threat.



-Sven
 

Martin King

Sustaining Member
It's not the stuffing box I'm worried about

I am aware of at least 1 failure of a shaft log on an Ericson-you know, that fiberglass tube "bonded" in with polyester resin your stuffing box clamps on to. If that sucker goes, it aint going to be just
a trickle of water. On a related note, I would suggest that every owner of a boat with inboard rudder check the bond between the rudder tube and the inner hull. That has been known to fail as well. DAMHIKT.

Martin
 
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Maine Sail

Member III
The number of times I've read of recommendations that the boat MUST be taken out of the water to repack the stuffing box is amazing. Most likely from folks who haven't done it. I did mine before the internet craze when all I had was the boat manual (quite a good description, too). I bought the stuff, figured out how to take the old stuff out (drywall screw - the piglet pigtail things don't work on my box, they're too big) and spent an hour or two upside down on my head with water leaking it all the time. The boat remained afloat. Even if my bilge pump was broken, or if the batteries were dead, there simply wasn't enough water to worry about.

Catastrophic failures would, however, occur with a PSS shaft seal.

However, your boat, your choice.

Failures of stuffing boxes? Unless the thread go wonky, which I've never heard of happening, if your packing is gone, throw a shoelace in until you buy some more packing.

It can be fixed "under way" but you'd want the engine in neutral or off to stop the shaft from spinning. Can be done anywhere on the water, not necessarily at your dock.
Stu,

I've "done it", on perhaps hundreds of different vessels, power and sail.... You really need to work on more of a variety of vessels to make broad statements like that. There are plenty of boats that I simply won't re-pack in the water as it is just not safe to do so, and I am darn comfortable doing re-packs.

Take the Sabre 34 MKI for example, did three this spring and hated every second of every one of them.. On the boats with port side shafting, most of them, this is a 1 handed re-pack where the nut does not even have room to move forward the 1/4" thickness of the packing. It is physically impossible to get two hands in there to re-pack unless your a Cirque De Soleil "little person" who can contort themselves into a shoe box...:) It can take a few hours to re-pack these boats and water coming in would just make it take longer and make for a real PITA of an install. I would turn down that job if an owner asked me to do so in-water.. This is further compounded on the S 34 MKI by an engine sump that is isolated from the rest of the bilge, and they have no pump in there, to prevent spilled oil from being evacuated. Bristol 35.5's, Cape Dory's, many older CCA boats. etc. etc... Many boats can be easily re-packed in water but many are like going to Vegas, are you feelin' lucky.....

Even the late 80's Ericson 34's have a stuffing nut that barely moves forward a 1/4" but there is enough access to do these in-water, if you know what you're doing....

Just because it can be done in-water on many boats does not mean it can on all and there are many older CCA type Ericson's out there where this may be uncomfortable for most owners to tackle. This should not be based on anyone's comfort level but the person re-packing the box. I would not advise anyone not comfortable in their skill level to try this on all but the most simple to access boxes.

The other problem is that some of these older stuffing box hoses are so rotted out that I would not touch them with wrenches, in the water, to break the nuts free for fear of tearing the hose. This has happened to me, but luckily only on the hard.. I really would not want that to happen in-water... Also many builders, Catalina included, used sub standard non-stuffing box hose which is very, very thin compared to the proper hose. Most Ericson's I've worked on have the substantially thicker hose made specifically for stuffing boxes.

That being said catastrophic failures are VERY rare in traditional or PSS seals and if you replace the hose every ten or so years (6-7 with PSS), with the right stuff, it will likely never happen. The one failure I do see related to stuffing boxes is shaft log failures. Some builders bonded bronze shaft logs to the fiberglass hull, Mariner did this, and the bond eventually fails. I have seen Cape Dory's with a similar failure. These failures are usually a trickle though before it becomes catastrophic.

I see a lot more seacock failures than stuffing boxes. Had a Marelon valve about six weeks ago week with a broken handle that was leaking around the handle stem. The most common packing box "failure" I see is improperly tightened locking nuts and the stuffing nut backs off. I have seen boats sink due to this because the pump keeps up while the owner is still on-board but it quickly kills the batts once they leave.

Replace the hose every so often, use T-Band or AWAB hose clamps, properly tighten the locking nut, and this is really a non-issue, unless your boat catches on fire and the hose melts but then you have other issues more pressing.......:)
 
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tenders

Innocent Bystander
Superb insight from Mainesail as usual.

I've had a Lasdrop shaft seal for many years, which is similar to the PSS seal, and have never really loved it. Three years ago it suffered catastrophic failure when a pinhole leak from the fuel tank caused gasoline to pool around the bellows of the seal, destroying the rubber and integrity of the seal. Fortunately, the boat was out of the water. I replaced the bellows, and a few additional parts like the friction ring, as well as the fuel tank, but I'm not putting that seal back again the next time I take it out.

As long as there is at least mediocre access to the shaft, I think the stuffing box relies on much more readily-available parts and is less likely to suffer catastrophic failure. Once you understand how the flax packing works on a shaft seal -- or better, the Gore-Tex packing which didn't exist when I installed the Lasdrop seal -- repacking even in the water is a job that runs about 3/10 in terms of complexity or nailbiting.
 

Stu Jackson

C34IA Secretary
We are truly "blessed" that the access to our stuffing box is excellent, if not the best in the industry.

Of course, as Nigel Calder pointed out in his book Boatowners Mechanical & Electrical, if the stuffing box cannot be moved forward, and/or if the access is impossible, then all bets are off.

I was simply responding to the question about doing it in the water IF you can get to it and the boat design is proper to allow the whole arrangement to actually be used as intended.
 

Glyn Judson

Moderator
Moderator
Engine/transmission too long.

All, Before we got her, our boat had an upgraded engine replacement from a Yanmar 2QM15 to a Yanmar 3GMF which, with the addition of an extra piston in the engine block, moved everything aft. I couldn't gain access to the flax packing because the cup couldn't move forward far enough before hitting the coupling so my fix was to cut 1 1/2" off the shaft log which solved the problem. For any of you facing the same problem, consider doing that next time you're out of the water. All this assumes that there's enough of the shaft log protruding into the boat to successfully do so. Off topic, as with Marty, I too am aware of two E31's that experienced failure at the shaft log joint. They were hulls #28 and #19. In the case of hull #28, it occurred fairly well off San Diego, such that bailing and getting back home for 12+ hours was touch and go. In the case of hull #19, it was spotted on the hard and fixed then and there. Glyn Judson, E31 hull #55, Marina del Rey, CA
 

mherrcat

Contributing Partner
The other problem is that some of these older stuffing box hoses are so rotted out that I would not touch them with wrenches, in the water, to break the nuts free for fear of tearing the hose.
Pretty good description of what my hose looked like before replacement...not to mention the rusted solid shaft coupling...

The most common packing box "failure" I see is improperly tightened locking nuts and the stuffing nut backs off.
When you say, "improperly," do you mean not tightened enough or is there some tightening technique I am not aware of?
 
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Glyn Judson

Moderator
Moderator
Improper tightening of the stuffing box nut.

Mark and all, I once "improperly" adjusted the nut down onto the cup which means that in the cramped space afforded me to access the stuffing box, I didn't give the nut that final "umph" and after about two hours of motoring, I heard the bilge pump go on. I knew immediately the problem I'd created, shut down the engine, asked my wife to take the helm and got in there with my two large Channel Lock pliers and this time, did the job the right way. That was years ago and to the best of my recollection, I've not touched the thing since. I am sold on the old tried and true designs and methods but am still willing to accept the latest innovations such as cutting edge flax composition. That said, I've not had to use the newest (to me) Gore brand yet. From what I read on this thread earlier, it seems to be a real improvement. Cheers, Glyn Judson, E31 hull #55, Marina del Rey, CA
 

mherrcat

Contributing Partner
Thanks. I just readjusted my packing nut last weekend. I should try the Channel Lock pliers as I have been using a large (really large) Crescent wrench which is rather unwieldy and one of these adjustable plumbing wrenches:
Slip_nut_wrench2.jpg

The jaws of the wrench are angled, so I had to file them flat so they wouldn't keep slipping off of the lock nut.
 
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