Advice requested: PSS bellows loose and leaking

twistedtree said:

Have you considered a Tides Marine dripless seal. They have a different design approach compared to PSS. I have had both, and did need to do some adjusting on one PSS, but that was because the yard never secured the set screws, so not PSS's fault.

Any other experience with Tides?

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Thanks. I looked into it. It appears to be more robust and I like that the mating surfaces are male and female. It eliminates the fear of someone or something bumping into it and causing a leak. When I was tightening the hose clamps on my PSS, I had a temporary gusher when the mating surfaces misaligned momentarily.

But because of my good experience with traditional stuffing box packed with Gore GFO, I think I will just stick with that set-up. Also, I can service it without a haulout.

"Since when is a dripless seal "dangerous"? Thousands of boats are using them including mine."

The thin wall rubber of the unit can fail, and if it does the water inflow is beyond most bilge pump setups.

It was an attempt in its day to stop the hassle of a dripping shaft seal when in port.

Its day (to me ) is LONG past , and in many boats a weak point that need not be tolerated.

With good PM ,,, change the rubber bellows often, it is less dangerous,but still a needless danger. .

RT Firefly said:

Greetings,
Mr. m. I am of the same opinion as yourself. "bulletproof" and "peace of mind". Personally I do NOT like PSS or similar style systems. They are "solutions" looking for a virtually non-existent problem IMO. I would much rather tolerate a bit of water in the bilge than trust a system that might cause a sinking. A "classic" stuffing box system can be readily re-packed while in the water and $$-wise, a few feet of GFO packing is far less expensive than hauling and replacing a complete "dripless" system every 5-8 years.

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Mr. RTF I agree with your opinion. When I refit my boat, I asked myself, can I fix this with parts I can get from a remote marinia with out delay waiting for parts. I went with traditional packing gland rather than PSS, standard fuel line and SS clamps rather than high pressure compression fittings, PEX over copper, all parts found in a hardware store. Fancy systems are great until they fail when you only have three days left on vacation and have to get back to somewhere.

PS, there are lots of videos on you tube of PSS failing. The CG mandates minimal packing gland flow rate, without any packing installed. I have removed the packing nut all the way off the shaft while in the water, changed the packing material, no problem.

OK, now you guys have me afraid to leave port or even start my engine!

Lots of failures can sink a boat so I'm wondering what the actual risk is. There are thousands of these seals out there and failures aren't making the news. The companies are still in business so somebody is buying them and I assume they are being installed in new boats (like mine was).

As for youtube, it's the Internet so anyone can put anything on there.

I do appreciate the warning and I'll check on mine and possibly have it replaced but I don't think I'll go to the trouble and expense of having it converted to the old type. It's actually a bit hard to get to so adjusting or repacking it would be a pain for a person my size and age.

aboatman said:

OK, now you guys have me afraid to leave port or even start my engine!

Lots of failures can sink a boat so I'm wondering what the actual risk is. There are thousands of these seals out there and failures aren't making the news. The companies are still in business so somebody is buying them and I assume they are being installed in new boats (like mine was).

As for youtube, it's the Internet so anyone can put anything on there.

I do appreciate the warning and I'll check on mine and possibly have it replaced but I don't think I'll go to the trouble and expense of having it converted to the old type. It's actually a bit hard to get to so adjusting or repacking it would be a pain for a person my size and age.

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Just ignore. As you say, lots and lots of people using them and loving them. Others have made the choice to stay with a packing gland which is just fine. And there are always people who will dump on whatever they don't have, or whatever is "new".

aboatman said:

Lots of failures can sink a boat so I'm wondering what the actual risk is. .

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The wonderment of TF is everything nautical related is a risk. For those really curious about product XYZ a talk with your favorite large yard pros, professional Captains and insurer can help clear the air.

The TF nautical worries for us neophytes, beyond dripless seals, is a very long list. Generally though, "if I don't have it", it is no good.

Now I feel better.

Mine is 18 years old and 2500 hours, looks like something on the list, good tip.

porman said:

The suggested replacement interval is 6 years. Our Mainship is now 15 years old and I'm sure they have never been replaced. Will take care of it at the next haulout.

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I suggest you phone them. I found their support excellent when I called.

I don't know what brand mine is but as far as I know, it's never been serviced and it doesn't leak. There's a spare seal on the shaft that hasn't been used.

I'll find out the brand and recommended service interval the next time I'm on the boat and decide what to do.

I’ve been using dripless seals for years and do the maintenance on them with my haul out and have never had a problem, so my question is how many of us have had a catastrophic problem if you had done the maintenance? Compared to a wet bilge and the constant adjusting of the two nuts that are never easy to get to I much prefer dripless.

This has been my first PSS seal I’ve owned. Been a charm. Replaced bellows and orings while changing shaft last winter. Replaced because when I bought the boat 3 years ago there was no indication of age. Now I know I have 5 more years until it needs anything.

One other comment rings true. If the dss seal is leaking it is likely from debris, seaweed or other physical junk in between the seal face and the stainless ring. A quick dislodge and flush into the bilge is all it takes to clear it up.

I have found that a rubber bellows will allow much more give with shaft whip than a packing gland. (Thus the new shaft last winter).

aboatman said:

Since when is a dripless seal "dangerous"? Thousands of boats are using them including mine.

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We had a sportfish sink within sight of our boat a couple of months ago. PSS shaft seal was the culprit. I don't know the age or anything. But, it was sad to see..

We have them on our boat, too. We have hose clamps on the shafts to keep the disc from migrating forward (we learned that trick on our sailboat with a PSS after the disc pulled that trick on us one day).

Here’s a little reading:

https://www.passagemaker.com/technical/dripless-shaft-seals

Dripless Shaft Seals – May be Dripless, But Not Maintenance Free

http://www.pyiinc.com/downloads/pss-shaft-seal/pss-type-a-installation-instructions.pdf

The Promise is having one installed. I’m looking forward to a dry bilge.

I have personally been involved in investigations of a few sinkings and floodings related to dripless seals. On some models the seal housing has a plastic bushing that keeps the shaft centered for the lip type seal to work. If cooling water is not flowing for some reason, the bushing heats up and melts, seizing to the shaft. Then shaft rotation rips the hose from the shaft log. Can be from towing or if the cooling line gets clogged.

Another casualty refers to a cooling water cross-over line which cools both seals even if running one engine. The problem was the boat used water lift mufflers which had the outlet higher than the turbo. So the guy fried a starter and had to come in on one engine. Got to the dock and a week later found the engine was completely full of water and needed an overhaul.

I have not been involved in investigating any PSS boot failures, but have seen many leak at the actual seal interface. Many times no leak dockside or at slow speed, but up at fast cruise, it was spraying. Cost one boat a gennie as it was mounted between the shaft seals and ingested the salt spray. Locally we fab spray deflectors on these if there is any critical equipment nearby. Spray deflectors kind of defeat the purpose!!

So when I built my boat, it was classic bronze packing gland with teflon coated packing. I can handle drips (almost none) but can not handle a large ingress from a ripped seal hose or boot. Not likely to get a gross failure of a bronze packing gland.

Be careful with these type seals!!

Have had both PSS and Tide. Replaced current boat with Tide marine System Three years ago, not one drop I know of sense and can replace in water with extra seals already installed on shaft , although I have not had to change the original seals ( twin screw, with two spares on each shaft) yet. PSS was always a constant maintenance trying to stop leaks with Salt water sling. One boat was brand new and the other one used when I purchase them. Much prefer tide system over PSS, although Traditional
Stuffing box with the new packing materials, such as Gore-Tex or Tefpack would be considered.

Thanks for your input Ski.

Is your stuffing box water cooled? Is water cooling needed if Gore or similar packing is used. BTW, the cost of a water cooled unit is around $600 vs. $140 for the non water cooled.

Regarding water cooling- I did not install a water tap on my ride, and I cruise 18-23kts when in the fast mode. Packing gland stays cool at that speed. I did make sure I could drill and tap the gland for cooling if it ran hot. But it runs cool.

When I first splashed it, it did get hot. Was getting all ready to drill and tap it, but magically it on a single day started running cool. I guess it was break-in. Took about 5hrs running time I guess. Been cool since and I have adjusted it like twice in the last 1000hrs or so.

If you are an 8kt boat, I can not see the need for cooling water on a standard packing gland.

Thanks Ski. I appreciate the help. Good to know that water cooling can be added to a non water cooled unit just in case.

sunchaser said:

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+1. Mine work fine.

Ski in NC said:

Regarding water cooling- I did not install a water tap on my ride, and I cruise 18-23kts when in the fast mode. Packing gland stays cool at that speed. I did make sure I could drill and tap the gland for cooling if it ran hot. But it runs cool.

When I first splashed it, it did get hot. Was getting all ready to drill and tap it, but magically it on a single day started running cool. I guess it was break-in. Took about 5hrs running time I guess. Been cool since and I have adjusted it like twice in the last 1000hrs or so.

If you are an 8kt boat, I can not see the need for cooling water on a standard packing gland.

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Ski, is the cooling water always to cool a packing gland? Mine has a cutless bearing just outboard of the pg—tight up against a cavity in the hull—that looks like it wouldn’t get much raw water flow without a water line feeding it. I don’t know if Mahal’s is built the same way or if, in fact, I’m citing the actual purpose of the water line.

"Cooling" tap can also be an advantage as described above if there is a lot of dead volume between the gland and the hull exit. Flushes water that might otherwise become oxygen deprived and thus create corrosion issues with the shaft. Depends on the boat. If a long tube, then I would put in a tap. Short tube, probably no need. Water is moving around in there and will exchange. On mine I have about a 4' FG tube with gland on one end and cutlass on the other. But bottom of tube has a few angle drilled flush ports exposed to water flow underside. So it flushes naturally.

Didn't mean to start a debate on whether dripless or packing gland is the right choice, but this conversation has been interesting regardless.

I ordered new set screws and o-rings from PYI, and will replace those next weekend, but will do the complete rebuild kit on the next haulout (this spring).

Keep going with this thread, this is informative!

angus99 said:

Ski, is the cooling water always to cool a packing gland? Mine has a cutless bearing just outboard of the pg—tight up against a cavity in the hull—that looks like it wouldn’t get much raw water flow without a water line feeding it. I don’t know if Mahal’s is built the same way or if, in fact, I’m citing the actual purpose of the water line.

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Thanks Angus. I'll look into how mine is set up.

Bigsfish said:

I’ve been using dripless seals for years and do the maintenance on them with my haul out and have never had a problem, so my question is how many of us have had a catastrophic problem if you had done the maintenance? Compared to a wet bilge and the constant adjusting of the two nuts that are never easy to get to I much prefer dripless.

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Constant adjusting?
You do maintenance on your dripless seal every haulout. I tightened my packing gland twice in 1000 hours. It was a two minute job each time. No dripping. What's not to like?

Its not that dripless seals are dangerous. Its just that a (rare) catastrophic failure results in lots of water inflow; enough to sink a boat. Properly maintained the chance is almost zero, but equipment is not always properly maintained (even when it has been "serviced")

That potential for a catastrophic failure on a traditional stuffing box is almost zero. At worst, perhaps a loose packing nut could unscrew completely, (extremely doubtful) but it could then be screws back on.

Ski in NC said:

"Cooling" tap can also be an advantage as described above if there is a lot of dead volume between the gland and the hull exit. Flushes water that might otherwise become oxygen deprived and thus create corrosion issues with the shaft. Depends on the boat. If a long tube, then I would put in a tap. Short tube, probably no need. Water is moving around in there and will exchange. On mine I have about a 4' FG tube with gland on one end and cutlass on the other. But bottom of tube has a few angle drilled flush ports exposed to water flow underside. So it flushes naturally.

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Thanks, Ski. Makes all kinds of sense.

angus99 said:

Thanks, Ski. Makes all kinds of sense.

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That sounds like a similar setup to my boat. My shipwright wants to have water flow to the forward cutlass bearing as well as the PSS.

Maerin is fitted with a PSS seal, and like many others I was long overdue for bellows replacement. The recommended 6 yr. replacement stretched out to more like 9, and that was from the time I acquired the boat. The PO had NO records, so who knows how long? A new bellows, new O-rings in 2015. I was diligent in facing the surface of the stainless collar, polished it on a platen and lapped the surface with compound.

Subsequent to that service, I was plagued with some irritating leakage. Nothing of consequence, just a few drops that it would sling out while underway. As some point I considered that I may have had the surface TOO polished, so I took a long strip of 600 wet/dry and slid it between the graphite collar and the stainless, grit side to the stainless. I kept it in place while the shaft ran a dozen or so rotations in idle, holding the end of the strip. Flushed it, and hasn't spit a drop since. Just FWIW for those servicing theirs.

And... a +1 regarding water flow. There have been cases of other Selene's that are very low hours/use with shaft crevice corrosion, so there is likely merit in water flow as relates to corrosion rather than strictly cooling.

After 13 seasons, 2,000 engine hours, I'll be installing a PSS maintenance kit on my seal before launch next month. Over the years, I've keep exterior of seal clean, wiped a little olive oil or 303 Protectant on bellows, and tightened clamps. Looks brand new. No spray, but I've seen some slight leaks (no more than 1/4 cup) over the last several years. I know that some of the water under the seal is from my hot water tank pressure valve hose carried into the bilge.

PSS rep at boat show says to periodically "burp" the seal, by rocking the carbon stator forward to flush any debris between stator and SS rotor. A "catastrophic failure" is usually a tear or split in the bellows, and I've placed a 4" x 5' roll of Flex Seal rescue tape near the seal in event of a failure. Wrapping the bellows in tape should get you back to port. Hope I never have to use it.