PSS maintenance

[cosmo]

New to us in July..

Surveyor recommended having our PSS done in maintenance form. He didn't see anything egregious but not knowing its history, PSS recommends bellows and O rings addressed every 6 years.

We're currently 'on the hard' for the winter. The yard quoted me 10-14 hours for installing the maintenance kit on our twin shafts.

My mechanic (not yard affiliated) recommends bypassing maintenance kit and installing new PSS which is more than triple the cost of the maintenance kit. Hours on the boat are low but I agree the maintenance kit is warranted.

My mechanic and yard seem a high on their recommendations. Admittedly, I have never had PSS so perhaps it is me who is way off base. Do their recommendations seem on par?

 

[mvweebles]

Congrats on the new boat. Hope it's been fun so far.

To service or install a PSS, the shaft needs to be slid back and the coupler to the transmission removed which can sometimes be sticky. Having two workman for some of the work makes sense. It's a one day job so 10-14 hours is justifiable, though at upper end in my opinion.

As far as entire PSS vs maintenance kit (bellows and set screws), I would lean towards maintenance as long as the existing PSS looks clean, no leaks, etc. That said, I understand your mechanics point of view in this case - spending some extra for brand new parts lowers risk of having a leak which would require a haul to fix. Pretty expensive. But it's a judgement call.

I know PSS recommends 6 year service life. There are reports of these going much, much longer. Personally, I'd let overall condition of bellows as more of a determination than service interval, but going work PSS recommendation is a safe route.

As an observation, inspect your cutless bearings. Shaft would need to be pulled entirely so there's incremental cost and labor, but it's an appropriate time to do it since you're doing the PSS.

Peter

 

[Shrew]

I'd ask the yard why they think it should simply be serviced instead of being replaced.

I'd ask the mechanic why he thinks it should be replaced and not serviced.

I look for ulterior motive. What benefit does each party have in their proposed action?

Which requires more labor? Which requires more in parts? Who stands to benefit? IS anyone genuinely looking for my interest above their profit?

I've had many mechanics steer me toward the cheaper of the two solutions knowing it was the better choice for me, despite it costing them revenue. But the good will and trust fosters a long term business relationship, and that is worth more to some people.

 

[Ken E.]

You might ask the mechanic why he is recommending new rather than the 6 year maintenance to be performed. Does he propose to sell you the new PSS kit? Maybe it's the markup he's looking for.

 

[cosmo]

All good suggestions-thank you.

I know that if the mechanic touches a part, that part, likely just went up in price despite what I can buy it for.

I will act on the suggestions and report back…

 

[Comodave]

I would guess that the mechanic is steering you towards the new shaft log because it is a good time to go new and probably improved log. The incremental cost will be much less than doing it later if it starts leaking. I had a PSS in a previous boat but I don’t know the difference between the older and new ones. Maybe call PSS and ask their opinion and go that way. As to the labor hours, one of the PSS I put in was simple the other one was a screaming nightmare. It took me several days to get it installed due to a poorly machined coupler. I could not get it back on no matter what I did. Finally took it to a machine shop and they found out the bore on the coupler was not straight. I don’t know how it was ever installed in the first place. They bored it out straight and it went right back together. These type of things are an unknown when you start a job so the labor quote may be way out of line.

 

[Mambo42]

I just installed PSS seals on my boat and was told that they need to be inspected on a regular basis, also cleaned, but as long as they are not leaking there is no need to replace them. It was one of the main reasons why I wanted them. They are expensive, paid 960 euro (about same in USD) a piece for a 50 mm shaft.
Installation is indeed something. In my case the props and rudder need to come off, so when time comes I need to replace something I will immediately do maintenance on rudder and props + bearings as well. Otherwise it is just double cost if you do it separately.

 

[twistedtree]

How long until your next haul out? 2 years? Maybe 3? If they weren’t leaking, waiting until you next haul out I think would be fine if you want to space the work out.

 

[Bmarler]

How long until your next haul out? 2 years? Maybe 3? If they weren’t leaking, waiting until you next haul out I think would be fine if you want to space the work out.

I agree with this. If everything looks good you should be fine. I had one last 20 years or more with no intervention besides periodic cleaning. I finally replaced it just because of its age, not because it leaked.

 

[cosmo]

I called PSS and asked their opinion. They were very helpful. If there isn't any sign of leaking and bellows does not show any sign of aging, maintenance should be fine. In fact, he added that their stand on 6 year is because nothing lasts forever, especially in a hot environment. He said it could go many more years but recommend at 6 years. He can't commit to my scenario but gave good advice.

Thanks all!

 

[mvweebles]

If the OP decides to replace instead of service the PSS shaft seals, he may want to consider Tides Marine lip seal instead. The recommended service interval of 6-7 years is the same (and similarly, owners of both typically go much longer), however with Tides, a backup seal can be installed on the shaft ready to be placed in service upon failure. Not only does this double the service life, but allows you to comfortably get the last possible service out of the first seal without fear as there is a "warm standby" at the ready. With PSS, without a standby option, you have to be much more conservative about maintenance.

You have to take the manufacturers recommendation seriously. But if the plan is to replace bellows every 6 years with $2k labor/materials, I'd stick with conventional stuffing box with GPO packing.

Peter

 

[Pete Meisinger]

What is PSS?

pete

 

[mvweebles]

What is PSS?

pete

Packless Shaft Seal manufacturerd by PYI

https://www.pyiinc.com/pss-shaft-seal.html

Peter

 

[RT Firefly]

Greetings,
Mr. mv. " I'd stick with conventional stuffing box with GPO packing." EXACTLY! Why anyone would change a "traditional" stuffing box to a "dripless" system is beyond my comprehension. I'm sure there are thousands of dripless systems installed in a myriad of vessels but...they have the potential of failure which might sink said vessels.

The 2 trawlers we've owned with the traditional systems (3- one single, one twin) were virtually maintenance free for nigh on 30 years with the ONLY service being periodic adjustment (about a 10 minute/shaft job).

Yes, there was always a bit of water in the bilge but so what? I think IF we were to purchase another boat with a "dripless" system I would seriously look into converting to a packed stuffing box if that were even possible. Might even be a deal breaker if not possible.

 

[Shrew]

If the OP decides to replace instead of service the PSS shaft seals, he may want to consider Tides Marine lip seal instead. The recommended service interval of 6-7 years is the same (and similarly, owners of both typically go much longer), however with Tides, a backup seal can be installed on the shaft ready to be placed in service upon failure. Not only does this double the service life, but allows you to comfortably get the last possible service out of the first seal without fear as there is a "warm standby" at the ready. With PSS, without a standby option, you have to be much more conservative about maintenance.

You have to take the manufacturers recommendation seriously. But if the plan is to replace bellows every 6 years with $2k labor/materials, I'd stick with conventional stuffing box with GPO packing.

Peter

A few years ago I asked my yard to replace my dripless shaft seal. I asked to replace my Tides with a PSS. They politely turned down the opportunity to make more money and serviced the existing dripless and placed a second seal just in case.

They felt this was better security and less money.

 

[mvweebles]

A few years ago I asked my yard to replace my dripless shaft seal. I asked to replace my Tides with a PSS. They politely turned down the opportunity to make more money and serviced the existing dripless and placed a second seal just in case.

They felt this was better security and less money.

I'm in a similar camp. I actually ordered a PSS and decided not to install opting instead for Tides. When I thought about it, lip seals have been used reliably for years: traditionally in engines, a lip seal is used to seal the crankshaft-output at rear of engine. Like you, I bumped into a few old timey yard manager types who will only use Tides.

My guidance on these topics is less dogmatic than Mr. RT Firefly. Traditional packing gland is fine. But requires fairly frequent monitoring and adjustment. If the owner is unwilling, unskilled, or uncomfortable with maintenance, by all means go dripless. And I've seen a few vee-drive installs that bury the shaft coupling making maintenance damn near impossible.

For me, it was a tough decision. In Weebles, I've had a conventional packing gland for 25-years, though I did have to renew the original about 15-years ago. So why go dripless? I aspire to a 100% dry bilge to make it easier to spot early troubles. Yes, I was able to keep dry with a small Tupperware container beneath the packaing gland that rarely accumulated more than a quarter cup of water, but still, I am comfortable with lip seals.

Best of luck to the OP on whatever he decides. Honestly, TwistedTree's pearl of wisdom to "just wait" reinforced by PYI makes the most sense to me.

Peter

 

[tiltrider1]

Greetings,
Mr. mv. " I'd stick with conventional stuffing box with GPO packing." EXACTLY! Why anyone would change a "traditional" stuffing box to a "dripless" system is beyond my comprehension. I'm sure there are thousands of dripless systems installed in a myriad of vessels but...they have the potential of failure which might sink said vessels.

The 2 trawlers we've owned with the traditional systems (3- one single, one twin) were virtually maintenance free for nigh on 30 years with the ONLY service being periodic adjustment (about a 10 minute/shaft job).

Yes, there was always a bit of water in the bilge but so what? I think IF we were to purchase another boat with a "dripless" system I would seriously look into converting to a packed stuffing box if that were even possible. Might even be a deal breaker if not possible.

I am in agreement here. However, there are some boats that a PSS makes sense. These are usually racing sail boats that have no bilge. I have also seen boats were the bed had to be removed to adjust the stuffing box. Outside of these unusual cases I think a stuffing box is a better mouse trap.

 

[bshanafelt]

for what it's worth, when I bought my boat 20+ years ago, I was hot on the trail to change out the antiquated 'old' style packing gland with flax packing and bring this part into the new century.

The goal being to achieve a completely dusty bilge.

I waited until the first haulout 3 years later and replaced it with a 'dripless' unit.

It worked ok, but there were still occasional drips and spray which had to be cleaned up anyway.

Not bad but not as advertised either.

Mix in the fact that I subsequently read about catastrophic bellows failures and this encouraged me to return to the old ways.


At the next haulout, I switched back to the old style packing and this time used GFO packing. With a bit of fiddling it will run with a number of drips during a days operation and zero drips at rest.

I place a small plastic paint tray beneath the packing gland to capture these drips and empty it out every other day or so when cruising.

It doesn't hurt that the GFO never wears out, so once adjusted requires very little attention

In hindsight, I would have skipped the packing replacement entirely.


good luck

 

[sunchaser]

Back to the OP’s question:

For a “new” boat getting mechanicals to Zero is often a good idea. This includes servicing HXers, valves, belts, hoses, oils etc. as well as shaft seals and logs. Watch the PSS and when timely with a haul out I’d recommend a complete changeout.

The PSS systems require but a decent daily inspection ( All seals do) when cruising and insuring water flow. Shoot the unit regularly with an IR gun and you’ll be happy for the life of your boat.ownership.

 

[Arc]

PSS are good for 30,000 hours. Just call them . That’s what they will say. That time can be significantly reduced if there is vibration or poor alignment.

 

[mvweebles]

PSS are good for 30,000 hours. Just call them . That’s what they will say. That time can be significantly reduced if there is vibration or poor alignment.

Ummm.....do you have a reference for that? They clearly say 6-year service interval (HERE). 30k hours is a lot - average fulltime US worker logs under 2000 hours per year, so that would be a 15-year expected life if run 8-hours/work day. Average boat gets used under 100 engine hours per year. PSS is therefore good for 300 years?

Peter

 

[Arc]

There is a difference between service and replacement.

 

[Bmarler]

The pss is nothing more than a mechanical seal. Very old technology, and very dependable. A properly installed seal like that can easily last more than six years. Like I said before, I had one more than 20 years old still working perfectly.
A seal of this type will give warning when it starts to go bad, just like the fresh water pump on your engine, it will weep.

 

[mvweebles]

Back to the OP’s question:

For a “new” boat getting mechanicals to Zero is often a good idea. This includes servicing HXers, valves, belts, hoses, oils etc. as well as shaft seals and logs. Watch the PSS and when timely with a haul out I’d recommend a complete changeout.

The PSS systems require but a decent daily inspection ( All seals do) when cruising and insuring water flow. Shoot the unit regularly with an IR gun and you’ll be happy for the life of your boat.ownership.

I like this post - I like the terminology of "zero," to re-baseline. Before I took Weebles down the coast from San Francisco to Ensenada, she had sat unloved for many years. Because parts on a small Perkins 75hp are reasonably priced and my mechanic's time is not, was easier/better to just replace all the pumps vs rebuild them. It was still a pretty expensive refresh, but gave a lot of peace-of-mind.

Not sure the PSS will heat-up much - will likely drip or spray. But the IR temp gun is always a good idea. At some point, I'll put some dots on various places on my engine to 'shoot' at consistent points.

Peter

 

[Puffin_NT32]

After 17 years and 2,500 hours of service. I installed the PSS maintenance kit last year. I kept the original seal clean, wiped a light coat of lubricant on bellows (coconut oil, silicone grease, 303, etc), and the seal NEVER leaked. Installed the kit just because of seal's age. The original bellows was still flexible, and a little sanding and polishing of the SS rotor and carbon stator surfaces with 600 grit brought them back "like new". The only difference between the PSS maintenance kit and a new replacement seal is, the new package contains new rotor and stator. Regardless of maintenance or new, the installation process is the same. If seal is not leaking or not damaged, the mechanic wanting to replace entire seal is looking for extra dollars. The biggest installation problem is pulling the shaft coupler off. And a periodic fresh water engine flush can't hurt.

 

[cosmo]

Thank you!

 

[Hippocampus]

Last year replaced a PSS with Tides. The PSS had frozen to the shaft. Had to be ground off. Fortunately done without marring the shaft. Have had PSS on all prior boats except first. Some worked fine but some not so much. Issues have been inadequate water lubrication. Loss of bellows tension. Minor leak with spraying of surroundings. Never found burping them an issue of significance.
The PYI is basically two discs pushed together. One spins. One doesn’t. Surface tension prevents leaking. The Tides device is a simple O ring. The boat needs to be out of the water to safely service a PSS. You can place extra O rings on the shaft so you can replace them with the Tides device with the boat in the water. Although catastrophic failure of a PSS is extremely rare it does happen and you may not be able to mitigate. Tides you should be able to address if you put extra rings on the shaft.
Still feel a traditional stuffing box is safest and with current stuffing materials easiest to live with long term. Think which one you choose depends upon access to the installation, size and rpm of engine , pattern of boat use. Was on a Puffin(steel sailboat). Shaft was held by two bearings. One where it exited the interior. One where it exited the boat. Log was filled with grease. Service was to remove two nipples at the ends and pump new grease through. Seemed foolproof. Shaft log was longer than usual and extended into the boat. No leak and nothing attached to the shaft. Wonder if such a system could be used with grp boats?

 

[SteveK]

...........................

We're currently 'on the hard' for the winter. The yard quoted me 10-14 hours for installing the maintenance kit on our twin shafts.

..................

............... It's a one day job so 10-14 hours is justifiable, though at upper end in my opinion.

...........................

Peter

I must be the only one that thinks 10-14 hours is twice the time a layman can do it for. A mechanic, doing this work more than once should not take that long. JMO

I base this on replacing the dampers on two Lehman's which involved removing the trannies, pushing the shaft away to make room. And I did that job in about 6 hours, 3 per side.
So what am I missing?

 

[Comodave]

We had traditional shaft logs in our last boat. We used Duramax packing. After the initial break in period we adjusted them to where they didn’t leak either running or at rest. We checked the temperature of the log and they weren’t too hot. No maintenance after they were adjusted.

 

[mvweebles]

I must be the only one that thinks 10-14 hours is twice the time a layman can do it for. A mechanic, doing this work more than once should not take that long. JMO



I base this on replacing the dampers on two Lehman's which involved removing the trannies, pushing the shaft away to make room. And I did that job in about 6 hours, 3 per side.

So what am I missing?

First, good on you. Sounds like you must know what you're doing.

Second, I believe I gave a mild caveat that it was at the upper range of what I'd guess.

Third, in this thread, Hippocampus gave an example of having to grind off his PSS. Comodave gave another example of an obstinate coupling which I too had once. Not all goes well.

Finally, and most importantly - if a total stranger asked you to do the dempners on his boat, would you bid 6-hours? Would that compensate you for travel time? Setup time? Finding the right alignmnent tool? Time to resolve an unexpected but not uncommon issue like a seized bolt? Cleanup time? You get the idea. 6 hours of labor isn't always 6 hours.

Peter