PSS Shaft seal maintenance time.

[JohnP]

Boat is hauled for Winter storage, I looked over the Pss shaft seals bellows and they look very good. But I don't know how old they are? Had the boat for about six years and looking in my manual binder I see no year when the Pss shaft seals were installed. They are not leaking the hose clamps look good. If it is not broke don't fix them? Or buy the maintenance kits and install them? What if the whole thing is original from 1996 with 3000 hours? Buy whole new Pss seals and change everything? I am really leaning toward getting a pair of Buck Algonac Bronze shaft logs new and install GFO packing and just go old school. So here are the choices, Do nothing, install pss maintenance kits, install complete pss seal systems, Or go old school and Keep it Simple. With Bronze stuffing boxes.

What do you guys think?

 

[lwarden]

I just put new bellows on mine in June, it had been about 6-7 years. I was surprised how much compression set was on the old ones vs. new. They didn't show any cracking but I did get some spraying at speed which I attributed to the compression. I resurfaced the SS collar and graphite seal surface on a glass plate with wet or dry 600 grit. I would recommend changing yours out, they are likely due or will be soon.

BTW, I'm not a big fan of these seals and would prefer a traditional packing arrangement but didn't see the need to replace these on my boat. If I were going all new I would not use PSS.

 

[O C Diver]

As mentioned, there is a rebuild kit that includes bellows, clamps, orings and set screws for the metal doughnut on the shaft. There are now 2 types of bellows (rubber and I believe silicone reinforced. I opted for the slightly more expensive silicone this fall, as it has about double the life.

As far as life, my original one had zero maintenance and ran almost 8 years, 6,000 hours 38,000 miles. Considering you have to remove the shaft from the transmission coupling, I decided to rebuild it at a time and place of my choosing as it requires being hauled out.

Ted

 

[Mambo42]

I have them installed as well, they told me 5 years would be the maximum, but I decided I will just wait and see how long they last. They are not going to explode and sink the boat. If they start to leak I have enough time to find the parts and exchange them (and that is when I can't fix the leakage)

 

[STB]

Mine were seemingly in the boat for about 20 years before I replaced them. There were no signs of cracking at all -- but they sure did lose the resistance to apply force and make a good seal.

I replaced them soon after buying the boat, but not on an emergency basis, but instead at a scheduled haul out.

 

[Hippocampus]

We removed the PSS on the current boat and replaced it with a tides. Had to grind off the PSS which was delicate as didn’t want to touch the shaft. Fortunately then close could split it and didn’t touch the shaft. The PSS was original to the boat (2007). I’ve had PSS on multiple boats. Only issues related to inadequate cooling water getting to them. Have had spray but no leaks of concern. Prefer the tides as all maintenance and replacement of the O ring can be done in the water. Also much less concern about sinking from catastrophic failure. To be honest if doing a blue water boat would spec old school stuffing box with the new stuffing material. Mid ocean would prefer to not be dependent upon two discs maintaining close proximity or an Oring.

 

[O C Diver]

For those with an issue removing the PSS stainless steel doughnut, I offer a pretty simple technique.

Remove all set screws, and then reinstall one with the set screw flush with the doughnut. Rotate the shaft till the other set screw hole is facing up. Fill the hole with your preferred liquid lubricant. Screw a bolt (I believe it's 5/16" course thread) into the set screw hole. Wipe some lubricant on the shaft before the doughnut.

The objective isn't to move the doughnut forward, but rotate it on the shaft. Basically the orings are dry and bound to the shaft. Once the doughnut rotates (orings become lubricated) the doughnut should slide forward relatively easily, provided there's lubricant on the shaft ahead of the doughnut.

I use dish washing soap like Dawn or Joy for lubricant as it's environmentally friendly. Obviously, light weight oils will work extremely well but will require much more effort to clean up.

I've done this more than 20 times with 100% success as my charter boat had a carrier bearing on the propeller shaft that was replaced annually.

Ted

 

[Comodave]

We had a conventional stuffing box in our last boat with Duramax packing. You can adjust the box so there are no leaks after the initial breakin period.

On our current boat it has a Norscot dripless stuffing boxes. They are 25 years old and it appears they had never been touched. One of them started leaking last summer. I called Norscot and the owner answered the phone and was great to work with.

 

[firehoser75]

John,
Personally, if it were me, I would install the maintenance kit from PSS using the newer, better, pro (model) bellows (more expensive but has a longer stated life).

These "devices" like most things require maintenance and/or have a working life. The manufacturer "may" for liability issues state an earlier replacement cycle than is absolutely needed. However, it really depends on a lot of factors such as exposure of the bellows and O rings to chemicals (oil, diesel, battery acid, etc.) and/or ozone, etc.

Other than contaminate damage, or deterioration like cracking, clamp issues, etc., the main issue is the diminishing of the bellows' ability to maintain the necessary compression. This does lessen over time. If it were me, I would add in the new "retention collar" available from PSS or some other method to help maintain the tension in the system (eg. a hose clamp tightened on to tape on the shaft forward of the PSS - right up against the metal collar).


Also, while doing this work, you might consider replacing your cutlass bearing(s), and having any prop work done that may be needed.


Personally, I believe in preventative maintenance, rather than waiting for problems to develop, but to each his own!!!

 

[JohnP]

For those with an issue removing the PSS stainless steel doughnut, I offer a pretty simple technique.

Remove all set screws, and then reinstall one with the set screw flush with the doughnut. Rotate the shaft till the other set screw hole is facing up. Fill the hole with your preferred liquid lubricant. Screw a bolt (I believe it's 5/16" course thread) into the set screw hole. Wipe some lubricant on the shaft before the doughnut.

The objective isn't to move the doughnut forward, but rotate it on the shaft. Basically the orings are dry and bound to the shaft. Once the doughnut rotates (orings become lubricated) the doughnut should slide forward relatively easily, provided there's lubricant on the shaft ahead of the doughnut.

I use dish washing soap like Dawn or Joy for lubricant as it's environmentally friendly. Obviously, light weight oils will work extremely well but will require much more effort to clean up.

I've done this more than 20 times with 100% success as my charter boat had a carrier bearing on the propeller shaft that was replaced annually.

Ted

Interesting, If I understand this I would be trying to rotate the collar to free it. The boat is on the hard so I could put some wood under the prop to prevent the shaft from turning. Could I use a strap wrench to try and turn the collar-- is the bolt sticking out to give the wrench a better hold? I understand the need to lube it. I guess the collar removal could be the most challenging part of the job. I did it maybe 7 or so years ago on my old boat. Don't remember it being that difficult, but I was younger!

 

[O C Diver]

Interesting, If I understand this I would be trying to rotate the collar to free it. The boat is on the hard so I could put some wood under the prop to prevent the shaft from turning. Could I use a strap wrench to try and turn the collar-- is the bolt sticking out to give the wrench a better hold? I understand the need to lube it. I guess the collar removal could be the most challenging part of the job. I did it maybe 7 or so years ago on my old boat. Don't remember it being that difficult, but I was younger!

I can't remember ever having to block the prop or use a strap wrench on the shaft. I think I just put a pipe over the bolt and pulled it back and forth once. When it breaks loose, it's all at once. My shaft is 2.5", and was easy to move once it broke free.

Ted

 

[Arc]

Many boats are running 1:1 gears on high speed engines . That means over 4,000 RPM. Under those conditions they easily last 1000 hours . That’s 240,000,000 revolutions.
Most of our boats have a shaft speed under well 1,000 rpm . That’s the difference of about 200,000,000 revs. I would not be too concerned.

 

[captmikem]

I actually replaced mine in the water a couple of months ago. It was leaking from a split in the bellows. I believe the original was not a PSS as the bellows was dramatically different. It was not that hard, only problem was separating the shaft from the shaft coupler which was VERY tight.

 

[JohnP]

So far so good, removed the starboard side seal. Was pretty easy. Actually the bellows looked pretty good not hard or cracked. The port side is another story, had to remove part of the exhaust, just to access the Shaft seal. Was thinking of using regular old style stuffing boxes but the access would be an issue if I felt I had to adjust them. I have been pretty happy with the dry bilges, so I have ordered the PSS maintance kits. So the boat work continues.

 

[Don L]

I have had the bellows rupture in the middle of the season before.

I finally replaced with a stuffing box with Ultra-X packing. I don't have it hand tight and it has been a couple hundred hours and doesn't drip with the engine off and so little while motoring I can not even see the drops (box doesn't get hot)

The stuffing box plus the packing was more expensive than a PSS seal, but it will not just fail.

 

[Hippocampus]

Going through my boat when it was bought noticed the PSS looked like it hadn’t been serviced in awhile. It didn’t leak or get hot but didn’t want a catastrophic failure so tried to service it. I couldn’t remove the collar. Tried the dawn trick with no joy. Tried to do the same with Blaster and no joy. Given we had the boat on the hard wanted this done before splash so got the yard involved. They tried the usual including heat and various solvents and wrenches with no joy. Eventually decided to grind it off with a cutting wheel. Issue was to not scar the shaft. Was told the nobility of most shafts is slightly different than the PSS and even if well zinced eventually they may bond. Don’t know the truth of that but do know I couldn’t get it off. It was cut leaving a paper thin residual. Then with a big flathead screwdriver and a few taps it snapped off. Had tried that with the set screws off before involving the yard. Replaced it with a Tides. Put a few additional O rings on the shaft before setting up the Tides in case it failed.
Take aways
Periodically remove the whole damn thing when on the hard even if it looks perfect. Don’t just remove and replace bellows and the two discs. O rings aside it may bond to the shaft and or shaft tube. Even with a packing gland or Tides removal and inspection periodically maybe justifiable.
Keep the shaft spotless. Think even a speck of dirt or dirty water near on in either of these devices may service as a connection. Don’t know why this happened as I had records prior owner was diligent about his zincs and there was no evidence of corrosion anywhere else on the boat. Only thing I can think of is there’s a thin film of water between the two discs which may serve as a connection and there’s no anode independently on the PSS. But don’t understand this as would think the anodes on the shaft would protect it. My shaft looked brand new and had no pitting or scratching.
A standard packing gland or a Tides maybe a better choice

 

[JohnP]

I do agree with the idea of pulling the whole thing apart every six years or so. I think it insures that things don't freeze up to the point of cutting off. In my case both stainless collars came off without issue. One shaft coupling was harder to pull off than the other I think because of less room to use the puller. Overall the project is not too bad. Probably will put project on hold while Winter weather makes things less interesting.

 

[twistedtree]

For all these reasons I used PSS shaft seals only once, and now am back to Tides.

 

[O C Diver]

Going through my boat when it was bought noticed the PSS looked like it hadn’t been serviced in awhile. It didn’t leak or get hot but didn’t want a catastrophic failure so tried to service it. I couldn’t remove the collar. Tried the dawn trick with no joy. Tried to do the same with Blaster and no joy. Given we had the boat on the hard wanted this done before splash so got the yard involved. They tried the usual including heat and various solvents and wrenches with no joy. Eventually decided to grind it off with a cutting wheel. Issue was to not scar the shaft. Was told the nobility of most shafts is slightly different than the PSS and even if well zinced eventually they may bond. Don’t know the truth of that but do know I couldn’t get it off. It was cut leaving a paper thin residual. Then with a big flathead screwdriver and a few taps it snapped off. Had tried that with the set screws off before involving the yard. Replaced it with a Tides. Put a few additional O rings on the shaft before setting up the Tides in case it failed.
Take aways
Periodically remove the whole damn thing when on the hard even if it looks perfect. Don’t just remove and replace bellows and the two discs. O rings aside it may bond to the shaft and or shaft tube. Even with a packing gland or Tides removal and inspection periodically maybe justifiable.
Keep the shaft spotless. Think even a speck of dirt or dirty water near on in either of these devices may service as a connection. Don’t know why this happened as I had records prior owner was diligent about his zincs and there was no evidence of corrosion anywhere else on the boat. Only thing I can think of is there’s a thin film of water between the two discs which may serve as a connection and there’s no anode independently on the PSS. But don’t understand this as would think the anodes on the shaft would protect it. My shaft looked brand new and had no pitting or scratching.
A standard packing gland or a Tides maybe a better choice

I find this hard to believe. First, there is an electrical bond between the PSS collar and the shaft in the form of 2 set screws in a dry area (sealed by orings). So no loss of continuity between anode (if one were on the shaft) and collar. Secondly, the clearance is sufficient without the orings that it can be rocked. The collar hole didn't shrink and the shaft diameter didn't grow to eliminate the clearance and make it a press fit.

Ted

 

[Hippocampus]

I find this hard to believe. First, there is an electrical bond between the PSS collar and the shaft in the form of 2 set screws in a dry area (sealed by orings). So no loss of continuity between anode (if one were on the shaft) and collar. Secondly, the clearance is sufficient without the orings that it can be rocked. The collar hole didn't shrink and the shaft diameter didn't grow to eliminate the clearance and make it a press fit.

Ted

Totally agree. As stated in the post I have no understanding how this occurred. But it did.

 

[O C Diver]

Totally agree. As stated in the post I have no understanding how this occurred. But it did.

I don't think it did.
Atleast not as a function of design. Maybe somebody buggered the shaft ahead of the collar or tried to move the collar without loosening one of the two set screws and raised a shoulder. The other reasons aren't plausible.

Ted

 

[Hippocampus]

Shaft was spotless without pitting or scratching as mentioned above. It did have some muck on it but just a wipe with a rag was sufficient to clean. No need for solvents nor abrasives. Just a wipe. As mentioned replaced with a Tides. That device requires a perfect shaft for its O ring to do its job. It’s been fine for >1000nm with no leaks. Wish I took pictures so maybe someone could explain this. My prior boats all had PSS except one (a tayana stuffing box) . None had any issues at all. Felt very confident with PSS until this event.

 

[O C Diver]

Shaft was spotless without pitting or scratching as mentioned above. It did have some muck on it but just a wipe with a rag was sufficient to clean. No need for solvents nor abrasives. Just a wipe. As mentioned replaced with a Tides. That device requires a perfect shaft for its O ring to do its job. It’s been fine for >1000nm with no leaks. Wish I took pictures so maybe someone could explain this. My prior boats all had PSS except one (a tayana stuffing box) . None had any issues at all. Felt very confident with PSS until this event.

I think your yard guys are spinning you a tale about what happened. No way the stainless collar stays in place without the set screws biting into the shaft. That's not were the Tides seal would ride, but there are going to be marks from the set screws.

Ted

 

[twistedtree]

My prior boats all had PSS except one (a tayana stuffing box) . None had any issues at all. Felt very confident with PSS until this event.

Lots of people are successful with them. I think I would describe them as finicky. When I had them they mostly worked, most of the time. But there was a lot of fussing, and a delicate balance to maintain that.

 

[twistedtree]

Shaft was spotless without pitting or scratching as mentioned above. It did have some muck on it but just a wipe with a rag was sufficient to clean. No need for solvents nor abrasives. Just a wipe. As mentioned replaced with a Tides. That device requires a perfect shaft for its O ring to do its job. It’s been fine for >1000nm with no leaks. Wish I took pictures so maybe someone could explain this. My prior boats all had PSS except one (a tayana stuffing box) . None had any issues at all. Felt very confident with PSS until this event.

Probably a silly question, but did you remove both set screws from each hole? PSS uses stacked set screws, one binding on the shaft, and the other on top of that to lock the first set screw in place.


I have seen this messed up both ways. People install the collar with just one set screw and fail to install the second locking set screw. The single screw works loose and the collar works forward releasing the bellows pressure and it starts to leak.


And on removal people don't realize there are stacked set screws, remove only the top one, then struggle to get the collar to move when it's still being held in place by the remaining screw.

 

[Hippocampus]

Yes all were removed. Yes small dimples where they were. Yes after set screws removed tried twisting, separating, tapping and light heat. No joy. Yes Tides positions differently.

My failures. Didn’t critical look at the gunk under. No idea what it was. Wonder if bilge water was high at some point in time . But saw no other evidence of this. However prior owner may have cleaned up any evidence of that.
Yard cut it off without me present. They did show it to me and I looked at it briefly. It was then thrown away. I should have kept it for a more detailed look. They didn’t cut all the way through. Just mostly then cracked it. That cut surface was unremarkable.
In retrospect wonder if the gunk was some oily substance and sufficient to act as an insulator. Wonder if the set screws had insufficient contact area for good electrical flow. Have no idea if the shaft was clean before installation. PO was a credit card captain and although we had a reasonable relationship after the sale had no useful insight. Know he put very few hours on the boat during his period of ownership. Know the fire extinguishers went off due to an inverter failure prior to my ownership . But inverter is at most forward starboard side of the ER and device most aft. Did clean airsept but no other evidence of residual in ER at time of purchase. Stuff in the filter was minimal and white. Both surveyor and engine surveyor said a non issue. The replacement was done to ABYC standards by an electrician according to the bill. Prior owner did give me his records.
We had a PSS on several sailboats. Unlike power with their small motors some were installed without a cooling water feed. On the Outbound I added one. On the NT we use an infrared thermometer and do check temperatures there as part of our engine room checks. It was never hot and the PSS seemed to function well. Have no evidence it ever ran hot in the past.
This whole thing started as just preventive maintenance. I remain uncertain why this occurred. I’m very happy with the NT and now think it’s a much better boat than it was at purchase. NTs are great boats. Feel mine is fully restored and Bristol fashion. I’m also very happy with the Tides and reassured if the O ring leaks I can replace it while in water. I also believe the Tides presents a lower risk of catastrophic failure than the PSS. I agree the risk of catastrophic failure for the PSS is extremely low if maintained.

 

[adornato]

I had two sailboats and a Krogen 42 with conventional drip drip stuffing boxes for a combined 27 year history without a problem.
Then I had a Sabre 42 with two PSS seals 12 y old which I had replaced at a cost of about 1500 in parts and labor. ( The Sabre in prev owners invoice collection had a bill for emergency haulout for leaking PSS)
Now I have a Mainship 30 with a PSS seal that was 18 years old which I had replaced at a cost of about 1200 due to extremely difficult access.
I think PSS seals are a costly and potentially dangerous solution for a non existent problem

 

[C lectric]

HIppocampus. But don’t understand this as would think the anodes on the shaft would protect it. My shaft looked brand new and had no pitting or scratching.



If there is enough distance between any anodes and the part you expect it to protect then the protection may fail to be effective. People make similar assumptions about their sea strainers and similar seawater exposed item but if the anodes are far enough away there will be little to no protection.

There is a minumum distance to meet between anodes and the parts to be protected.

 

[helm]

For those with an issue removing the PSS stainless steel doughnut, I offer a pretty simple technique.

Remove all set screws, and then reinstall one with the set screw flush with the doughnut. Rotate the shaft till the other set screw hole is facing up. Fill the hole with your preferred liquid lubricant. Screw a bolt (I believe it's 5/16" course thread) into the set screw hole. Wipe some lubricant on the shaft before the doughnut.

The objective isn't to move the doughnut forward, but rotate it on the shaft. Basically the orings are dry and bound to the shaft. Once the doughnut rotates (orings become lubricated) the doughnut should slide forward relatively easily, provided there's lubricant on the shaft ahead of the doughnut.

I use dish washing soap like Dawn or Joy for lubricant as it's environmentally friendly. Obviously, light weight oils will work extremely well but will require much more effort to clean up.

I've done this more than 20 times with 100% success as my charter boat had a carrier bearing on the propeller shaft that was replaced annually.

Ted

Ted I used your method on my stuck PSS shaft seal, worked like a charm.
Thank you so much
Eric