Anyone have any experience/comments about that clay-like material that molds to the inside of the stuffng box to create a shaft seal? Pretty pricey stuff (@$64 from Defender), but wonder if it may be worth it? Better than GTU packing?
Dripless Shaft Packing
- Thread starter Warren Milberg
- Start date
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Warren,
The posts that I recall reading were generally negative on that product, but that is an old geezer's memory which must be taken with a grain of salt and I don't wish to slander a product that I have never tried.
I went with an industrial version of the GTU on the prop shaft of our C-320 and the prop shaft and rudder post our Ski Nautique (cheaper to buy stuff like that in an industrial supply store than in chandleries) almost a decade ago and I love it. As with all 'thread fiber' packing, it must be adjusted regularly. However, that is an easy task on a C-320 and I adjust ours to be dripless when the shaft is not turning and to allow 1-2 drips per minute when turning. This assures adequate cooling and 'cleansing' and that small amount of water evaporates as it passes under the hot engine before it ever gets to the bilge.
I personally do not like mechanical seals on the principle that increased complexity increases the possibility of a catastrophic failure. Despite manufacturer's claims on the subject, when a vessel sinks in 400 fathoms with loss of all life, we seldom know precisely why. I would only observe thst my research also suggests (though hardly exhaustive or throrough) that the USCG may now be specifying GTU ffor shaft seals for maintenance of their vessels where formerly, they reportedly were specifying mechanical seals.
YMMV
The posts that I recall reading were generally negative on that product, but that is an old geezer's memory which must be taken with a grain of salt and I don't wish to slander a product that I have never tried.
I went with an industrial version of the GTU on the prop shaft of our C-320 and the prop shaft and rudder post our Ski Nautique (cheaper to buy stuff like that in an industrial supply store than in chandleries) almost a decade ago and I love it. As with all 'thread fiber' packing, it must be adjusted regularly. However, that is an easy task on a C-320 and I adjust ours to be dripless when the shaft is not turning and to allow 1-2 drips per minute when turning. This assures adequate cooling and 'cleansing' and that small amount of water evaporates as it passes under the hot engine before it ever gets to the bilge.
I personally do not like mechanical seals on the principle that increased complexity increases the possibility of a catastrophic failure. Despite manufacturer's claims on the subject, when a vessel sinks in 400 fathoms with loss of all life, we seldom know precisely why. I would only observe thst my research also suggests (though hardly exhaustive or throrough) that the USCG may now be specifying GTU ffor shaft seals for maintenance of their vessels where formerly, they reportedly were specifying mechanical seals.
YMMV
Warren, I used it for the past ten years successfully. I wrote the link below when I first did our stuffing box back in '99. In that is a link to Maine Sail's article on stuffing boxes, where he describes the downsides to it. I've switched to the Ultra, the green goop ran out after ten years.
http://www.c34.org/wiki/index.php?title=Stuffing_box_packing
there's also this recent discussion
http://forums.catalina.sailboatowners.com/showthread.php?p=1027243&highlight=flax
http://www.c34.org/wiki/index.php?title=Stuffing_box_packing
there's also this recent discussion
http://forums.catalina.sailboatowners.com/showthread.php?p=1027243&highlight=flax
Warren ............... in my experience, I believe the same drip free, dripless, or whatever you want to call it (I call it bone dry) packing can be had from at least teflon impregnated flax all the way up to high tech GTU packings and better.
In this modern world of teflon and super low friction materials, I think that allowing a stuffing box to drip is a hold over from the early 1900's. To me, a wet bilge from a dripping packing gland is a major detriment in a boat. It's no different than having a constant water level in the basement of your home. On our boat, the bilge is powder dry and a cool storage area for food while away from the dock. I've actually stored toilet paper in there from time to time.
The link below tells why dripping packing glands make no sense in 2013.
http://forums.sbo.sailboatowners.com/showthread.php?p=872589&highlight=need to leak
The shaft has a mirror polish after 1,700 hrs. and runs cold to the touch while running bone dry.
Imagine how long the packing could last using one of the modern high tech packings.
Ralph, thanks for that link, I remember it. I've added it to the Stuffing Box article I wrote and use to link whenever this subject comes up (like weekly).
So ......................... how are my royalties coming on that ? Any hope of early retirement :cry: ?
Ralph, that thinking is pretty foolish. Don't you realize that in 13,000 years your shaft is going to wear in two? You'll probably have to do something different in about 10,000 years to get the packing to seat though.
I too run teflon packing, and it does not drip. I'll buy a new shaft, packing, prop, whatever before I have a boat slinging salt water all over the backside of my transmission. I did this on my own accord without consulting anyone, simply to quell the outcry from "the drippers" about how I'm destroying the boat.
It doesn't seem that way.
I reach down occasionally and grab the box, and even now and then shoot it with the laser to reaffirm that it's not on fire. But no, my results look like yours. In about 7 or 8 thousand years from now, I'm going to start saving up for a new shaft.
Thanks Ralph and Stu again.
(Vindication by the experts).
I too run teflon packing, and it does not drip. I'll buy a new shaft, packing, prop, whatever before I have a boat slinging salt water all over the backside of my transmission. I did this on my own accord without consulting anyone, simply to quell the outcry from "the drippers" about how I'm destroying the boat.
It doesn't seem that way.
I reach down occasionally and grab the box, and even now and then shoot it with the laser to reaffirm that it's not on fire. But no, my results look like yours. In about 7 or 8 thousand years from now, I'm going to start saving up for a new shaft.
Thanks Ralph and Stu again.
(Vindication by the experts).
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Ralph,
Thank you for your research. I have used the same material and had a dry bilge. I was told that the shaft will be scored over time and the boat yard replaced it with traditional flax packing. Now it leaks constantly. On the next haul out, I will use the green Teflon, again.
Thank you for your research. I have used the same material and had a dry bilge. I was told that the shaft will be scored over time and the boat yard replaced it with traditional flax packing. Now it leaks constantly. On the next haul out, I will use the green Teflon, again.
I'm Not Even Going That $Exotic$ ...................
One of the tricks to watch, IMHO, is that the packing be the biggest possible which will fit into the gland. I use 1/4" in my 1" dia. box and it's a tight fit but requires almost no compression to get it to stop leaking. Most references to a 1" dia. shaft gland seem to recommend 3/16" which would be a very loose fit and require lots of axial compression to stop the leaking. I would suspect the packing would be hard after that much compression and possibly have high friction (high heat).
Fact remains that in this modern world of teflon and super low friction materials, packing glands on relatively low RPM shafts should not drip.
................... as the packing I've mentioned is teflon impregnated flax, and not the expensive green doughy material. Haven't had any experience with that material but I wouldn't doubt that it'll work just as well or better (bone dry). Just a little too expensive for my blood.
One of the tricks to watch, IMHO, is that the packing be the biggest possible which will fit into the gland. I use 1/4" in my 1" dia. box and it's a tight fit but requires almost no compression to get it to stop leaking. Most references to a 1" dia. shaft gland seem to recommend 3/16" which would be a very loose fit and require lots of axial compression to stop the leaking. I would suspect the packing would be hard after that much compression and possibly have high friction (high heat).
Fact remains that in this modern world of teflon and super low friction materials, packing glands on relatively low RPM shafts should not drip.
Ralph:
I began this thread as I was having the following problem with my packing gland, which I repacked with 4 rings of 3/16" GTU, about 2 years ago: it would not leak when the shaft was not turning. When I used the engine, it would leak a few drops per minute (per the "expected" tradition),but it would continue to leak at this rate after I shut the engine down. I would then adjust the compression nut one flat, and the leak would stop -- that is until the next time I used the boat. This cycle repeated itself each time I used the boat this season. Reading your posts about dripless packing and using the largest size packing as possible, I just repacked the gland with 1/4" packing per your suggestion. It was really hard to get the 1/4" packing into the compression nut, but it did finally fit. I have only used the boat once since repacking, and so far so good. No drips and the gland stays coolish during engine operation. We'll see if that (hopefully) continues.
Below is an image (not a good one I know) of 2 of the 4 rings of the 2 yr old GTU packing I just removed. I doubt this packing had 200 hrs of use on it, but it looks tired and burned to me. My shaft is not scored or otherwise presenting an irregular surface. Any thoughts?
I began this thread as I was having the following problem with my packing gland, which I repacked with 4 rings of 3/16" GTU, about 2 years ago: it would not leak when the shaft was not turning. When I used the engine, it would leak a few drops per minute (per the "expected" tradition),but it would continue to leak at this rate after I shut the engine down. I would then adjust the compression nut one flat, and the leak would stop -- that is until the next time I used the boat. This cycle repeated itself each time I used the boat this season. Reading your posts about dripless packing and using the largest size packing as possible, I just repacked the gland with 1/4" packing per your suggestion. It was really hard to get the 1/4" packing into the compression nut, but it did finally fit. I have only used the boat once since repacking, and so far so good. No drips and the gland stays coolish during engine operation. We'll see if that (hopefully) continues.
Below is an image (not a good one I know) of 2 of the 4 rings of the 2 yr old GTU packing I just removed. I doubt this packing had 200 hrs of use on it, but it looks tired and burned to me. My shaft is not scored or otherwise presenting an irregular surface. Any thoughts?
Attachments
The last two shaft assemblies that I have rebuilt have been one inch. On the first one, as per "instructions" that I must have ascertained from a seance or something, said 3/16". Not a chance in hell. By the time I shoved 4, maybe five rings in it, I nixed that train wreck. So, 1/4" teflon is the ticket. I use absolutely no "goo" whatsoever, as in my mind, and the last I heard, Teflon is still the slickest substance known to man. So what could you put ON it to make it any better?...
So, I have field trialed, (sea trial, shake-down whatever), them both with zero leaks. As Ralph said, the gland can be adjusted by hand, and maybe a slight tug on the lock ring to secure it. This works exponentially better if the box is out, (which also includes the boat and shaft), and glass bead the box of all the crap that generally ensues during their hard life. I know this is not an option if a man is just repacking under water, but it sure does make for a long service life if you can. And a brave man could kick the shaft back, bung the hole and proceed. But this would also require someone under the boat to push it back in. This time of year that would present little difficulty.
All the debate aside of which packing is better, this is not new technology. Sealing rotating shafts for pumps etc. has been done for a hundred years or so I guess. So don't make it any more complicated than it needs to be.
And I will stand by my opinion that a boat should not leak water. From any place whatsoever, period. If the shaft etc. is leaking, the boat is sinking,
albeit very slowly, but sinking nonetheless..
So, I have field trialed, (sea trial, shake-down whatever), them both with zero leaks. As Ralph said, the gland can be adjusted by hand, and maybe a slight tug on the lock ring to secure it. This works exponentially better if the box is out, (which also includes the boat and shaft), and glass bead the box of all the crap that generally ensues during their hard life. I know this is not an option if a man is just repacking under water, but it sure does make for a long service life if you can. And a brave man could kick the shaft back, bung the hole and proceed. But this would also require someone under the boat to push it back in. This time of year that would present little difficulty.
All the debate aside of which packing is better, this is not new technology. Sealing rotating shafts for pumps etc. has been done for a hundred years or so I guess. So don't make it any more complicated than it needs to be.
And I will stand by my opinion that a boat should not leak water. From any place whatsoever, period. If the shaft etc. is leaking, the boat is sinking,
albeit very slowly, but sinking nonetheless..
Four or five rings? Why so many? I've never put in more than 3 in any of the stuffing boxes I've had. (3 different boats.) So long as you reduce or mitigate the water flow while still keeping the stuffing box cool, that's all you are after.
If the packing is properly sized it should be snug but not inordinately difficult to insert. On my previous boat, a Catalina 30, I replaced the stuffing box as part of a prop shaft replacement. The shaft was 1". The previous box used 3/16" while the new box used 1/4". It all depends on the specific box. My current Ericson 26, with a little Yanmar 1GM, has only a 3/4" shaft and has a baby stuffing box that takes 1/8" packing! Prior to my buying this boat some genius mechanic managed to jam 3/16" packing in there and it created all kinds of problems before I removed it and put in the properly sized stuff.
All forms of packing--whether Goretex, Teflon, or conventional flax--require some flow of water to cool the shaft while rotating. A slight weep may be adequate for this, though several drips a minute are fine as well. It should not be bone dry while the shaft is in rotation or the box will overheat. The "sweet spot" would be a slight drip while running with the dripping stopped with the shaft at rest.
Why wait?
I'm very, very far from an expert on this or anything else related to sail boats. However, I've changed my packing two or three times and always did it when the boat was in the water. The first time, the packing was so hard it took me an hour or more to get it all out. Meanwhile, the water was coming in, but once I realized that my bilge pump could keep up with the inflow, I relaxed and did the job.
I suspect that is his point - the 3/16" was too small, which he figured out after the 4th or 5th ring not being sufficient. Moving up a size, to the 1/4", resulted in a properly stuffed box with fewer rings.
Nom,I suspect that is his point - the 3/16" was too small, which he figured out after the 4th or 5th ring not being sufficient. Moving up a size, to the 1/4", resulted in a properly stuffed box with fewer rings.
Yeah, I think you are right and I probably missed the point. But perhaps Chris can clarify: How many rings did you wind up with after you moved up to 1/4"?
Oh, I'm sorry. Sometimes I'm not very clear. Correct, in the first one, yes, 3/16" I ended up with the 4-5 rings, and by community dissention went with the 1/4" which looked perfect. On the first one I had three rings, and on the second one only two.
Note: I wouldn't tell anyone for the obvious reasons that they should use this size only, as yes, the box will be the determining factor, as opposed to, "The shaft is one inch, so it MUST be 1/4". Nay nay. Just these last two did.
Note: I wouldn't tell anyone for the obvious reasons that they should use this size only, as yes, the box will be the determining factor, as opposed to, "The shaft is one inch, so it MUST be 1/4". Nay nay. Just these last two did.
But They Just Don't Have to .......................
Also, note the comments by Western Pacific Trading with regards to their packing products.
http://www.wptinc.net/wpt_tech.html
Sorry to disagree, but you're simply parroting an old wife's tale which seems determined not die in this generation and maybe not even the next :naughty:.
................. as shown by the temperature on this running, bone dry stuffing box.
Also, note the comments by Western Pacific Trading with regards to their packing products.
http://www.wptinc.net/wpt_tech.html
Sorry to disagree, but you're simply parroting an old wife's tale which seems determined not die in this generation and maybe not even the next :naughty:.
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You are welcomed to disagree, but...
...allow me to "parrot" this e-mail for you that I received from Buck Algonquin tech support, the folks that actually make the stuffing boxes in many of our boats:
From: Steve Gaston
Sent: Saturday, May 08, 2010 9:57 AM
To: Alan Gomes
Subject: Re: Packing box issues
Dear Alan,
We have seen the variations in the packing sizes that you have described. 95% of my packing box questions revolve around the goretex graphite based packing. It is good packing. However, most people misinterpret the instructions and believe it is drip free. All three material (graphite, teflon, and flax) have their drawbacks.
Flax. low cost. temperarture tolerance minimum. abrasive. Does require water for cooling and lubrication.
Teflon. medium cost. High temperature tolearance (packing only). mildly abrasive. Does require water for cooling and lubrication.
Graphite. higher cost. High temperature tolerance. least abrasive. Does require water for cooling and lubrication.
The common theme here is they all require water for cooling. The temperature will vary with the amount of water drip through the packing and the shaft speed.
The other components have a reasonably high tolerance to heat. The packing box hose is made of the same materials as marine exhaust hose. The bronze and stainless are not a relative heat consideration.
The abrasion factor would be the other consideration. Since the goretex has the least abrasion impact, it would be the better choice.
I hope this helps.
Best Regards.
Steve
Steve Gaston
Buck Algonquin Co., Inc.
********
I guess someone needs to bring Buck Algonquin up to speed so they'll stop "parroting" these "old wives' tales."
...allow me to "parrot" this e-mail for you that I received from Buck Algonquin tech support, the folks that actually make the stuffing boxes in many of our boats:
From: Steve Gaston
Sent: Saturday, May 08, 2010 9:57 AM
To: Alan Gomes
Subject: Re: Packing box issues
Dear Alan,
We have seen the variations in the packing sizes that you have described. 95% of my packing box questions revolve around the goretex graphite based packing. It is good packing. However, most people misinterpret the instructions and believe it is drip free. All three material (graphite, teflon, and flax) have their drawbacks.
Flax. low cost. temperarture tolerance minimum. abrasive. Does require water for cooling and lubrication.
Teflon. medium cost. High temperature tolearance (packing only). mildly abrasive. Does require water for cooling and lubrication.
Graphite. higher cost. High temperature tolerance. least abrasive. Does require water for cooling and lubrication.
The common theme here is they all require water for cooling. The temperature will vary with the amount of water drip through the packing and the shaft speed.
The other components have a reasonably high tolerance to heat. The packing box hose is made of the same materials as marine exhaust hose. The bronze and stainless are not a relative heat consideration.
The abrasion factor would be the other consideration. Since the goretex has the least abrasion impact, it would be the better choice.
I hope this helps.
Best Regards.
Steve
Steve Gaston
Buck Algonquin Co., Inc.
********
I guess someone needs to bring Buck Algonquin up to speed so they'll stop "parroting" these "old wives' tales."
Please be VERY, VERY careful attempting to run a stuffing box completely dry or dripless not just drips-less. There is HUGE difference between bone dry, and water lubed but no "visible" dripping. This is a very, very tight margin to attain. I believe Ralph is also using Syntef grease in his box and this is easier to attain with a packing gland lubricant.
Also many boats are quite "air prone". This means they tend to trap air in the box and while cool now they may not remain cool once air gets trapped up in there and the air has no way to escape. We put piles of hours on our Syntef clay in our Catalina 36. It was working fine until one day it became air bound. I could smell it burning from the cockpit and when I reached out to touch the gland I got second degree burns.:cussing: This from a box that had run cool for many, many, many hours (in excess of 100 engine hours) before it smoked itself.
PSS/PYI learned all about this with their non-vented seals and now all seals are vented/plumbed. MANY Boats are quite prone to air entrapment in the shaft log and these packings will not run cool without water. I have had to convert numerous PSS sealed boats from non-vented to vented seals because even after burping they entrap air in the shaft log and the PSS runs dry. In a perfect world the shaft speed is low enough for this to not be an issue but PYI never counted on boats that are prone to air entrapment in the shaft log even after burping. Our Catalina 36 needed to be burped about every three to four weeks with a non-vented seal. I rough weather I burped it after each sail.
I have been testing packings now for well over two years and am in development of a new "non-galvanic" packing to compete directly with the highly galvanic graphite variants. This is an entirely new product that is head and shoulders above anything currently available and it will have NO GALVANIC issues and is electrically inert.. I am meeting with my manufacturer again on Wednesday to go over the latest testing data.. We have done extensive testing and there is no packing that will run cool at sailboat shaft speeds without water, none. To test for this we actually broke in packing with water then removed the water from the shaft area replicating a shaft that has become air entrapped. Temps immediately spike to the danger zone.
Just because it may not visibly drip it is still getting water lubed if it is running cool. There's no way around this. I've run every single packing on the market dry and they all exceed 200F quite quickly without water lubrication. The problem is that it is very easy to go from water lubed but not dripping to no dripping and no water lubrication. In some instances this margin is half of one nut flat....
I have also run a permanently installed temp sensor directly mounted to the bronze stuffing box nut and these temps can be anything but stable when you get close to the drip, no-drip line. Careful adjustment is critical but not always guaranteed..
There are many reasons to let the box drip some and one of those is crevice and pitting corrosion and this is becoming especially true with the graphite impregnated packings. We are seeing much more galvanic activity and oxygen starvation of shafting likely due to stagnant water in the shaft log. Again, not all boats will entrap air but stagnant ocean water can be a real problem for any boat that does not move some water through the log to expel old stagnated water.
Please be very, very careful and adjust very carefully. Also check temps frequently as a spot check can very often be misleading..
I have been running the box on our boat using a proprietary shaft grease and my new packing. It is set up for drips-less, and in actuality it does not drip, but it IS water lubed. I keep a microfiber rag under the box and it is always dry. Still this takes time and patience during break in to get right and is much easier to do with a packing lube/grease.
So, there is a difference between dry and dripless, please know that....
Also many boats are quite "air prone". This means they tend to trap air in the box and while cool now they may not remain cool once air gets trapped up in there and the air has no way to escape. We put piles of hours on our Syntef clay in our Catalina 36. It was working fine until one day it became air bound. I could smell it burning from the cockpit and when I reached out to touch the gland I got second degree burns.:cussing: This from a box that had run cool for many, many, many hours (in excess of 100 engine hours) before it smoked itself.
PSS/PYI learned all about this with their non-vented seals and now all seals are vented/plumbed. MANY Boats are quite prone to air entrapment in the shaft log and these packings will not run cool without water. I have had to convert numerous PSS sealed boats from non-vented to vented seals because even after burping they entrap air in the shaft log and the PSS runs dry. In a perfect world the shaft speed is low enough for this to not be an issue but PYI never counted on boats that are prone to air entrapment in the shaft log even after burping. Our Catalina 36 needed to be burped about every three to four weeks with a non-vented seal. I rough weather I burped it after each sail.
I have been testing packings now for well over two years and am in development of a new "non-galvanic" packing to compete directly with the highly galvanic graphite variants. This is an entirely new product that is head and shoulders above anything currently available and it will have NO GALVANIC issues and is electrically inert.. I am meeting with my manufacturer again on Wednesday to go over the latest testing data..
We have done extensive testing and there is no packing that will run cool at sailboat shaft speeds without water, none. To test for this we actually broke in packing with water then removed the water from the shaft area replicating a shaft that has become air entrapped. Temps immediately spike to the danger zone.Just because it may not visibly drip it is still getting water lubed if it is running cool. There's no way around this. I've run every single packing on the market dry and they all exceed 200F quite quickly without water lubrication. The problem is that it is very easy to go from water lubed but not dripping to no dripping and no water lubrication. In some instances this margin is half of one nut flat....
I have also run a permanently installed temp sensor directly mounted to the bronze stuffing box nut and these temps can be anything but stable when you get close to the drip, no-drip line. Careful adjustment is critical but not always guaranteed..
There are many reasons to let the box drip some and one of those is crevice and pitting corrosion and this is becoming especially true with the graphite impregnated packings. We are seeing much more galvanic activity and oxygen starvation of shafting likely due to stagnant water in the shaft log. Again, not all boats will entrap air but stagnant ocean water can be a real problem for any boat that does not move some water through the log to expel old stagnated water.
Please be very, very careful and adjust very carefully. Also check temps frequently as a spot check can very often be misleading..
I have been running the box on our boat using a proprietary shaft grease and my new packing. It is set up for drips-less, and in actuality it does not drip, but it IS water lubed. I keep a microfiber rag under the box and it is always dry. Still this takes time and patience during break in to get right and is much easier to do with a packing lube/grease.
So, there is a difference between dry and dripless, please know that....
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