PSS maintenance

[SteveK]

Peter, I work on my bike, my boat and my house. It is like a hobby that takes my mind off work. Both of our cars go to get oil changes just cause I find that boring. So total stranger is out of luck, a friend may get an assist.

I was expecting a picture of the OP shafts and then maybe the hours are justified, but not justified as expect to pay for 10-14 man hours of labor.

From now on I will tell my wife how many hours it took me including cleanup, travel time etc to impress her further.

 

[koliver]

Peter, I work on my bike, my boat and my house. It is like a hobby that takes my mind off work. Both of our cars go to get oil changes just cause I find that boring. So total stranger is out of luck, a friend may get an assist.

I was expecting a picture of the OP shafts and then maybe the hours are justified, but not justified as expect to pay for 10-14 man hours of labor.

From now on I will tell my wife how many hours it took me including cleanup, travel time etc to impress her further.

Those time estimates remind me of a task I had to do on my car. I got the book standard time estimate from the dealer, at 11 hrs labour. I researched You Tube for amateur videos and found direction there. I completed the job myself at no cost, in under 1 hour. I am as Steve, a hobbyist, not a pro.

I do, however, always allow an afternoon for a 5 minute job.

 

[mvweebles]

.....

I do, however, always allow an afternoon for a 5 minute job.

Yes, and a trip to Home Depot for a propane bottle because your wife used last of your torch making Creme Brulee over Christmas (not that I'm complaining).

What marina are you guys in? 99 times out of 100 something takes me longer than I thought. I wanna get some tips.

Peter

 

[cosmo]

I have no issue turning a wrench. It's the tricks or potential issues that arise when separating coupling. I've watched some videos on doing it and things I am unaware of, like a stubborn coupling, I would probably give it love when I see that a puller going slow is the method. Those are the things that scare me off. I also don't know how to align when re-connecting.

Perhaps I am overthinking and it might go smooth? Then I again, I don't do things easily which I can now admit and 'tap out' when it's the right thing to do-for me.

 

[mvweebles]

There is no alignment needed. Just bolt it back together. The only challenge is getting the coupler off the shaft.....sometimes. PB Blaster and a torch and a strong mallet. If you get stumped, you're in the yard anyway and you can call in reinforcements.

Seriously, I'd wait. As SteveK said, pics would help with an evaluation.

Good luck.

Peter

 

[SteveK]

Those time estimates remind me of a task I had to do on my car. I got the book standard time estimate from the dealer, at 11 hrs labour. I researched You Tube for amateur videos and found direction there. I completed the job myself at no cost, in under 1 hour. I am as Steve, a hobbyist, not a pro.

I do, however, always allow an afternoon for a 5 minute job.

I learned various trade stuff by watching someone do it. Youtube is great to understand what it looks like to do some job you have never done, or even to brush up. There are videos on how to do this PSS install. Of course they have a mock up all nice and clean on the bench, yet it shows the process with tips.
My friend who was a mechanic most of his life would relate tales of going to work for eight hours, working on 3 vehicles and noticed they were charging the 3 customers some 8 or more hours labor each. It is the world we live in.

 

[firehoser75]

Cosmo,
As others have stated, PSS (PYI) list a 6 year maintenance schedule that is most likely "overkill". However, the bellows is a "rubber" like product that could be subject to exposure to many products (eg. diesel, oil, battery acid, ozone, etc.) as well as the fact that just age alone can affect the elasticity of the belllows. Also, a total failure could sink the boat! As another issue, as this was listed by your surveyor, it may be a requirement of your insurance company to do this work to ensure coverage should you need it???? Not a situation you want to test out "after the fact"? Pau Hana would know more.
Put in their "upgraded" 10 year bellows as the cost increase is minimal. Add in a "shaft retention collar" to ensure the bellows stays compressed for extra "insurance" against a total failure.
I also agree with the poster who suggested replacing the cutlass bearings. Not alot of additional labour and the parts are "cheap" on a boating scale.

I think your labour estimates are a bit high, but not so much so for 2 shafts especially if the cutlass bearings were also being done. As far as I know, you will need an alignment after this work, as the faces joining together at the transmission will almost for sure not be at exactly the same locations as they were (at least my boat did). For me, the mechanic even had to come back and sea trial to get the alignment just right (no extra charge for this).
I found the PSS seal to work well, and had no issues. I did IR gun it regularly to ensure no overheating (cooling water could be interupted under certain conditions).
Good luck.

 

[RT Firefly]

Greetings,
Mr. f. You raise an interesting point regarding bellows "aging/degradation". Some have mentioned putting an extra rubber bellows on the shaft as a backup. I would think that spare might be subject to the same environment and be of questionable condition should it need be replaced.

 

[Mambo42]

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.

The reason I changed to PSS is that my old system, with the gland, did not allow me to run on one engine. With the PSS I have the option to run on one engine when I want to and ultimately that saves a lot of fuel, giving me more range with the boat. I can increase my range from 1200 to almost 2000 nm and that is pretty impressive.
That was basically the only reason why I switched to PSS.

 

[Hippocampus]

Please explain this M42. Wouldn’t a shaft break allow single engine use? Also why does a stuffing box prevent single engine use?

 

[Mambo42]

Please explain this M42. Wouldn’t a shaft break allow single engine use? Also why does a stuffing box prevent single engine use?

In order to be able to use one engine only there are a few things you need to consider.
First is the oil pump in the gearbox. If that one does not function when the prop is freewheeling you have a problem. Of course you could just do it, but find out your gearbox will be damaged after prolonged periods of use.

The second is the gland itself. The outer part which is closest to the water will always be wet and when the boat is stationary the rest of the gland will also be wet. But when the boat is underway there is an under pressure in the area of the stuffing box, which means the inner part of the gland does not remain wet and may actually run completely dry, damaging the gland and over time causing heavier leakages than just the required drips. Of course this is not the case if you have to run the boat on one engine in case of emergency, but when you do this on a daily basis it does become a problem. The prop shaft generates heat while turning and thereby slowly 'burning' the gland, the water is required as a lubricant and cooling.
On my boat i had a water supply line running from the heat exchanger to the stuffing box, making sure the gland remained wet while the engine was running. Each engine had it's own water supply line. Of course I could make a system where copper pipes run through the bilge area, with switching valves etc, but I did not want to go that way. Only need to step on that pipe once and you could be in for a surprise.
So after some thought I decided to go for the PSS system, where I don't need to worry about the gland remaining wet. Since the engines were out of the boat, which meant the prop shaft was also out, this was the best time to change them. Otherwise I don't think I would have done it at this time. Taking out the boat, yard time, removing rudder, prop, shaft etc just to install a PSS is a bit over the top. Would have cost a fortune.

Now the total cost is about 2500 euro (around 2600 USD), which I will earn back in about 1300 liters of fuel, which is about 220 hours sailing on one engine. We do about 500 - 600 hours per year, so we earn it back in a couple of months.
I understand that our case is a specific case, won't apply to everyone and if I would have needed to take out the boat specifically for installing PSS seals it would have been around 8000 euro (or 8800 USD). Kind of ridiculous.

 

[Arc]

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?

Tides is not an o ring it is a lip seal. It is also very very difficult to replace while in the water and more then a few boats had to get rushed to the travel lift. Taking out the old seal is quite easy. Sliding down the new seal and getting it in the carrier is a different story. They sometimes need to be pressed in on a bench then re-installed. Also you can’t clean the shaft area that the seal fits while you are sinking. I have done more then 20 and will not do it in the water. Some will go right in, some will turn into a fire drill.

 

[Hippocampus]

Good to know. Th.

 

[Hippocampus]

Tides v PSS Was a thread I started earlier with good information. Went with TTs choice after misting issues in the past.

 

[Mambo42]

Tides v PSS Was a thread I started earlier with good information. Went with TTs choice after misting issues in the past.

I did not see that thread and at the moment I cannot go back anymore, but I have to admit I did not know the Tides at the time I had to take the decision.

Took a quick look at the Tides, but it does require the cross over line and that is exactly what I did not want to have. The risk of damaging that line and causing the boat to flood is too big of a risk for me. Our engine room is large, but is not stand up, so lots of 'crawling' around on your knees and thereby the chance to step on a line or kick it with your feet. And one thing I did not want to do it drill holes in the stringers.

 

[twistedtree]

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

This is what I’d do too. No a fan of PSS, and prefer Tides. So if taking it all apart…..

 

[rpackard]

I replaced the PSS after 30 years even though there was no need to. However it is not a difficult job on my sailboat. Drop the spade rudder, pull the shaft and replace.

Remember the golden rule of boating (and life in general): Better is the enemy of good".

 

[AndreHuizing]

We just replaced ours on single engine 3" shaft after 14 years 3500 hours. Had the maintenance kit so only belows and some stuff. Inspected the below and it was still in good shape. Could not find any cracks etc. Imho would have been good for many more years. However while the composite stator was still as new, the ss rotor had some bad pitting in it. As usual SS submerged in salt water will pit where it's deprived of oxygen. Hence where it's touching a seal or in this case the stator. Got it milled back until pitting was gone.
This experience made me decide not to change the smaller one on our emergency engine as it has nearly zero hours and from the outside there is nothing wrong with it.
Cheers, André