Dripless shaft seals [Master Thread]

Hello All,
I'm in the process of R-n-R'ing the 5432 in my E38 with a used engine. In the process of removing the engine several other things are receiving attention.

I am considering installing a dripless shaft seal while the engine is out. Boats with dripless setups seem to have less corrosion issues on the coupling, etc. and keeping more water out can't be a bad thing.

Pro's & cons of installing one of these would be appreciated. I have looked at the PSS as well as the Lasdrop? I think Tides Marine also makes one? Also would like to know if they make aligning the shaft any easier or more difficult.

Thanks, RT

Rob,

I have a PSS dripless seal on Journey and am getting ready to change it out for a "old fashioned" stuffing box. I have had it for about nine years and have been happy until I read a recommendation that the bellows should be changed every five years because it can crack with age. If that happens it will be more difficult to stop the water flow than it would be with the old stuffing box ( you could stuff rags in the old style box and get home). I then talked to a local boat fixer and he showed me several PSSs that he had removed that had failed in various ways including chunks of the face seal breaking off.

While it is true that there is less corrision with the dripless seals; the new stuffing materials let you run with a tighter seal with no drips and no heating. A friend just repacked his stuffing box with the new material and has no drips and no heating. Also I have heard that the new PSS seals all require a cooling water line which adds to the installation requirements.


Ray Rhode
S/V Journey
E35-III, #189

Potential issues mentioned above. I have been a fan of these units but like anything on the boat they will require attention at some point. Bigger concern is can you actually fit one on the E-38? On my 1989 version there was not enough room between the coupling at the engine and the shaft log to fit anything other than the traditonal set up.

PSS - Bellows

I have spoken with a PYI rep about the safe "life" for their bellows, and was told to replace it as a preventative maintenance item at any routine haulout at about ten years. They can and do last longer without any problem.
**Their attorneys have more say so about the specs and recommendations the last several years than do their engineers.


(That's also why they finally stopped offering the version without the air bleed attachment -- too much liability concern that someone would buy and install one in a planing power boat, contrary to the instruction to use it only for motoring at under 12 kts.)

We did have the '95 bellows replaced at a haulout in '06 and it looked like new.

A dry bilge is a good thing. :nerd:

Be careful of the argument that whatever was used a hundred years ago is better than some new-fangled invention..... I recall that an engineer on the old YachtList once commented (in a similar thread about the PSS seal) that it was only new to recreational boaters, having an established history in the pulp industry sealing shafts.

Anyhow, I like ours a lot.

Loren

You may want to check this thread on SSCA: http://tinyurl.com/y9naerv

I'd planned on switching when we finally haul out but have now decided to stay with the traditional stuffing box.

Of course, our bilge is so deep that any drip is a non-issue.



-Sven

dripless shaft

I have one on our 38.
I have been very happy with it.
I think it actually stopped the boat from sinking once.
I put the boat in reverse and the shaft came disconnected from the transmission.
The collar on the seal stopped the shaft from pulling right out of the boat.

Sven said:

You may want to check this thread on SSCA: http://tinyurl.com/y9naerv
I'd planned on switching when we finally haul out but have now decided to stay with the traditional stuffing box.
Of course, our bilge is so deep that any drip is a non-issue.
-Sven

Click to expand...

Fun thread reference. Some of the info is good, altho a lot of it was hearsay.
Imagine that -- a thread with more heat than light?! (Sounds a bit like us Vikings at times.)


At least no one (yet) posted up a dire prediction that dacron sails will never catch on or that internal combustion engines are just a passing fad!

BTW, I had a brief visit aboard Jeremy's boat before he left to go cruising... he describes it as old, but in reality it is an 80's GibSea, IIRC. A very "modern" performance-cruiser design.

Best,
Loren

"internal combustion engines are just a passing fad!"

Loren, You know they are ;-).

Thanks for the input! The cheap way out would be to simply reuse the existing unit but repack it with GoreTex. The PSS is spendy but I do like the idea of NO water. Hmmmm.... I'll have to think about it. RT

Hi Loren,

Loren Beach said:

Fun thread reference. Some of the info is good, altho a lot of it was hearsay.

Click to expand...

It was the pointers to news stories about sinkings (mainly by Jeremy White) that made me really decide to put the conversion on hold until we had a real reason to switch.

I don't think any of the stories specifically mention PYI seals.



-Sven

> While it is true that there is less corrision with the dripless seals; the new stuffing materials let you run with a tighter seal with no drips and no heating.

I've had a Lasdrop shaft seal since 1995 and tend slightly towards the old-style stuffing box. The shaft seal has been acceptable but the shaft needs to be removed from the coupling to service it (replace the bellows or any of the moving parts). This is a huge job. The stuffing box has no moving parts and the shaft only needs to be removed if the rubber hose needs to be replaced.

Ray Rhode said:

While it is true that there is less corrision with the dripless seals; the new stuffing materials let you run with a tighter seal with no drips and no heating. A friend just repacked his stuffing box with the new material and has no drips and no heating.
Ray Rhode
S/V Journey
E35-III, #189

Click to expand...

Ray,

Be very, very careful trying to get a traditional stuffing box not to leak.

1) Gore GFO, Western Pacific Trading GTU, Duramax Ultra-X and the other Gore knock offs are not drip-less, it just drips less. It must drip some and they are clear to not say it is drip free in their instructions.

2) Having a stuffing box that never leaks or does not allow some movement through it, can wreak havoc on stainless shafts up inside the shaft log where you can't see. The PSS's are vented thus the salt water does not become oxygen deprived which leads to crevice corrosion. PSS's on sail boats do not need to be "plumbed" just vented well above the heeled waterline so the box does not become air bound.



It always amazes me when people speak of replacing the bellows on a dripless seal like it never needs to be done on a traditional stuffing box? CS Yachts, the makers of our current boat, recommended in the manual to replace the shaft log hose every few years, yet no one ever did. They to are not infallible.

I think Gore GFO is a decent alternative to a PSS, but it will not be dry if installed correctly, however will be a lot drier than can be achieved with a flax plant based packing. If you're going to stay with a traditional packing system the GORE GFO is by far the best packing you can buy. The imitators, GTU and Ultra-X, are not Gore GFO they are made with "Gore fibers" and may look similar but they are not the same quality as actual GFO. The white, Teflon impregnated plant based flax, is also not GFO. It's simply regular flax with PTFE instead of a paraffin based lubricant. GFO is blackish gray in color ans has the GFO logo on the braid. The teflon impregnated flax plant stuff is white to off white.

GFO Marine Instructions:

Quote:

GFO Instructions said:

AFTER THE LAST RING IS INSTALLED, take up bolts finger tight. Do not jam the packing
into place by excessive gland loading. Make sure gland bolts are taken up evenly. STOPPING
LEAKAGE ENTIRELY AT THIS POINT WILL CAUSE THE PACKING TO BURN UP. Run
the vessel for 5-10 hours and readjust packing to get desired leakage.

Click to expand...

Please note that it says "desired leakage", not "adjust for no drips" ...



I've now had a PSS on five different boats. Not one single problem. The USCG uses them too and we all know how tough getting a government approval for use is. The 55 foot sport fishing boat I worked on had two PSS seals and the bellows were changed at 7500 hours of run time, zero issues. BTW that is 75 years of sailboat usage at 100 engine hours per year, pretty reliable...

Winddancer

I installed a PSS in 2002 and is very satisfied with it, it is easy to maintain but as with any part on a boat, it need to be inspected, before the boat is launched and after it is in the water, no different than all the other hoses and hose clamps.

The PSS will fit but the cost compared to the benefit was always pretty small to me. Also, when I do have to work on the engine, from the aft side my feet are pretty much on top of the shaft. Having another vent hose, flexible bellows, face seal, etc. in my way and possibly leaking when I lean on it.... Well, that doesn't seem worth it in the long run. I can get Duramax Ultra X which is supposed to be the latest and greatest synthetic packing and that will go in the traditional stuffing box. Thanks all. RT

rwthomas1 said:

I can get Duramax Ultra X which is supposed to be the latest and greatest synthetic packing and that will go in the traditional stuffing box. Thanks all. RT

Click to expand...

Rob,

While the Johnson Durmax stuff is good it is a knock off of GFO and may not have the same performance. I have used Durmax (Hamilton sells it) and GFO and the GFO I find to be a better product, like Gore-Tex was to the knock offs.

Gore always saves the best for them selves then tends to license out bits and pieces. eMarine sells the real stuff and it's quite reasonable. I have Hamilton right out my door and still will mail order GFO if I need to.

Don't get me wrong the Ultrax -X will be leagues beyond a pure PTFE or flax packing but GFO has a 30 year proven track record in the industrial world where pumps run continuously 24/7 and very high shaft speeds.


From W.L. Gore:

"Some users have tried “trading off” GFO® packing performance for lower price. However, low-price competitive “look-alike” black PTFE fiber packings perform differently. Recently, some look-alike products have targeted one performance
criteria – thermal conductivity – suggesting that this attribute makes them “equivalent” to GFO® packings. Close inspection of some competitive products show that these products consist of
pure PTFE with a thermally conductive layer. The design is much like a wire: a thermally conductive interior surrounded by an insulator. The material
in contact with the rotating shaft is pure PTFE, known for its thermal expansion and shaft scoring behavior at higher service temperatures. This outer PTFE layer of the look-alikes also raises questions
about how efficiently this packing is able to provide lubrication during break-in and service of the packing."



This was a direct quote from Jack Lane (sp) at Western Pacific Trading about GTU packing:

"RC,

GTU packing is not the same as Gore GFO but it does use some Gore fibers in the construction. We are the only ones who sell this type of packing in small quantities. You can not get GFO in small quantities."



With all due respect to Jack you can buy small quantities of GFO through eMarine. 2 feet of it is $19.25. Two feet of GTU (imitation GFO is $15.99).

Ultra-X is only $6.00 for 2 feet, and local, but I still buy the real stuff... BTW two feet will last a long time..

Just some thoughts..

I've been using a Norscot, by Ibsenco, shaft seal for about 15 years. No drips, but you do have a small oil tank to mount, no bellows, just a hose like the traditional stuffing box.

Whats wrong with a few drips anyway? Its not like your ever going to stop some water from getting in the bilge through the mast anyway? Now if it were a deck stepped boat we were talking about I could see the expense of a PSS. Then you could actually achieve a totally dry bilge.

ted_reshetiloff said:

Whats wrong with a few drips anyway? Its not like your ever going to stop some water from getting in the bilge through the mast anyway? Now if it were a deck stepped boat we were talking about I could see the expense of a PSS. Then you could actually achieve a totally dry bilge.

Click to expand...

The problem I have is the occasional motorsailing. The shaft water doesn't always end up in its little "gutter". It likes to slosh around a bit and ends up under the battery box. Annoying and not a place I want water trapped, by my nice new fuel tank..... Think poultice corrosion.

RT

Maine Sail said:

Rob,

While the Johnson Durmax stuff is good it is a knock off of GFO and may not have the same performance. I have used Durmax (Hamilton sells it) and GFO and the GFO I find to be a better product, like Gore-Tex was to the knock offs.

Gore always saves the best for them selves then tends to license out bits and pieces. eMarine sells the real stuff and it's quite reasonable. I have Hamilton right out my door and still will mail order GFO if I need to.

Don't get me wrong the Ultrax -X will be leagues beyond a pure PTFE or flax packing but GFO has a 30 year proven track record in the industrial world where pumps run continuously 24/7 and very high shaft speeds.


From W.L. Gore:

"Some users have tried “trading off” GFO® packing performance for lower price. However, low-price competitive “look-alike” black PTFE fiber packings perform differently. Recently, some look-alike products have targeted one performance
criteria – thermal conductivity – suggesting that this attribute makes them “equivalent” to GFO® packings. Close inspection of some competitive products show that these products consist of
pure PTFE with a thermally conductive layer. The design is much like a wire: a thermally conductive interior surrounded by an insulator. The material
in contact with the rotating shaft is pure PTFE, known for its thermal expansion and shaft scoring behavior at higher service temperatures. This outer PTFE layer of the look-alikes also raises questions
about how efficiently this packing is able to provide lubrication during break-in and service of the packing."



This was a direct quote from Jack Lane (sp) at Western Pacific Trading about GTU packing:

"RC,

GTU packing is not the same as Gore GFO but it does use some Gore fibers in the construction. We are the only ones who sell this type of packing in small quantities. You can not get GFO in small quantities."



With all due respect to Jack you can buy small quantities of GFO through eMarine. 2 feet of it is $19.25. Two feet of GTU (imitation GFO is $15.99).

Ultra-X is only $6.00 for 2 feet, and local, but I still buy the real stuff... BTW two feet will last a long time..

Just some thoughts..

Click to expand...

Thanks for the heads up on the GFO/GTU stuff. I thought they were the same..... Will have to look into it.

RT

ted_reshetiloff said:

Whats wrong with a few drips anyway? Its not like your ever going to stop some water from getting in the bilge through the mast anyway? Now if it were a deck stepped boat we were talking about I could see the expense of a PSS. Then you could actually achieve a totally dry bilge.

Click to expand...

I would almost agree, being in fresh water. OTOH if it's salt I would prefer not to have any in the bilge.
To me, the water that enters from the inside of the spar is different -- fresh water, and forward in the boat and away from machinery. Other than during mid-winter rain storms when I sponge some rain water out each week, our bilge is bone dry.

Loren