I own a Nonsuch 26 Ultra and am considering replacing the stuffing box with a dripless PPS shaft seal. Has anyone else done this? And if so is it something you would recommend?
Appreciate any advice you can offer. Thanks, Dan
Dan: You will find lots of owners that like PSS seal systems. Personally, my concern is if they fail they can sink a boat. The standard packing system can leak but not sink a boat under normal conditions. Also, after hauling and re-launching, they need attention. If there is a problem with packing, it can be replaced with the boat in the water. Not so with the PSS.
Joe
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Dan,
I always think twice before taking opposite sides with Dan, because he’s one very knowledgeable guy.
However, I’ve had PSS shaft systems on several of my boats, including my current 26C. I’ve never had a problem, and consider them quite safe.
I have less-than-fond memories of repacking stuffing boxes in engine compartments that had more wiggle room than a 26, in days when I was younger and didn’t need the wiggle room quite as much.
My personal preference is always for well-installed devices with lower maintenance requirements. I’m a good enough person to do something right once, but not good enough of a person to regularly maintain every item in an awkward location. Someone with my proclivities is better protected in practice by opting for safe-enough with low-maintenance over absolute safest but higher-maintenance.
Joe’s correct that the worst-case scenario is worse than a leaky shaft packing. It’s equivalent to the packing nut coming off your stuffing box and the packing coming loose. Again, proper installation is key with any critical system.
If you can do, or have someone do, an installation that you have confidence in, I’d say go for it. I’ve had stuffing boxes and I’ve had shaft seals, and I far prefer shaft seals.
– Bob
Solar Wind
Nonsuch 26C, #143
Check the clearances needed between the transmission flange and the shaft … on my 26 there was not enough space to install a PPS as the bellows is rather long. You definitely need the model with the vented loop as un-vented the water will drain and air lock from time to time…
Joe,
Thanks for your input. Much appreciated.
Dan
Bob,
Thanks. I think you and I are a lot alike insofar as I’m not as young and agile as I used to be. I’m leaning towards the PPS solution.
Dan
Hi Thor,
Thanks. I’ve been wondering about that very issue. I only have eight inches from the coupling to the aft end of the existing stuffing box. I can’t seem to find the dimensions of the PPS online. Guess I’ll have to find a dealer and measure one myself. If I decide to change it I’ll try and do it myself with a knowledgeable boatyard staff member/friend as back up.
Dan
I absolutely love my PSS vs traditional stuffing box with one exception. Aligning the shaft is a miserable experience and guess and hope work at best.
Adagio is on the hard at the moment for a prop replacement. Decided to check the shaft alignment while it was out since the only way to see it is to remove the PSS. We pulled the shaft, pulled the seal, put the shaft back in place and discovered it had been riding on the bottom of the stern tube all this time. After centering it and fighting to get the engine re aligned with it in the proper place we then had to pull the shaft again, reinstall the PSS and bolt it all down. Once in the water we’ll have to check the engine alignment once again. That’s where the real rub is. If it is out there is no way that we’ve discovered to ensure the shaft stays centered while we adjust the engine since we can’t see it. A traditional stuffing box, because of its stiffness, will hold the shaft somewhat centered. A PSS doesn’t have that stiffness so the shaft just sinks back to the bottom of the the tube.
So there’s a con. But I love the dry bilge and 0 maintenance. Just have to check on it periodically which is super easy with our V drives.
Kevin Wilson
“Adagio”, NS30U #475
Biloxi, MS
You need about 6 inches as I recall. As well like a stuffing box you need to plan on replacing wear parts every 6 years or so…
Thanks Kevin. I’ve decided to go ahead with the PSS. I’ll be mindful of the alignment issue. Hopefully I won’t experience the sort of problems you had. Since my Nonsuch is a 26 I’m hoping the it’s a shorter shaft than the 30 and therefore easier to centre in the stern tube.
Dan
Thanks, Thor. I have about 8 inches from the coupling to the aft end of the current stuffing box. So it looks like it’ll work. I’ve ordered the new PSS shaft seal. Fingers crossed it all works out.
Dan
Hi Dan,
Approx. 11 years ago I replaced the stuffing box in my NS30U with a dripless PSS seal while replacing the oil pan and engine mounts on my Westerbeke 27A. The method I used would be applicable for you, and probably less effort since your engine is already closer to its final alignment than what I had to do. I started with the engine in what I thought was it’s approximate proper location (primariIy determined by the mounts after I had replaced them). Yours would be in that location already. Then, I cut a 1 gallon plastic milk jug into long strips and used the strips as shims between the shaft and shaft log (tube) to hold the shaft roughly centered in the log (with the strips protruding out the back). I slipped the hub onto the end of the shaft and turned the shaft (and prop) by hand to make sure it turned smoothly and effortlessly feeling no binding from possible misalignment with the cutlass bearing. It turned easily by hand so, confident that the shaft would turn smoothly when centered, I slid the shaft outward, installed the PSS seal parts, slid the shaft back into place at the transmission, shimmed the shaft back to being centered in the log, reinstalled the shaft hub, turned it once more by hand as a last check, and aligned the engine to mate with the hub. When finished, don’t forget to pull the plastic shims out from between the shaft and log under the boat.
Since I was doing it by myself, I had to climb in and out of the boat a couple of times, but it wasn’t all that much effort.
Dave Easley
1987 30U #420 BIG EASY
Port Charlotte, FL
Hi Dave,
Thank you very much. Much appreciated. When it comes time to pull the shaft and install the new PSS seal I’ll certainly follow your advice. Best, Dan
Anyone else who runs into this thread while considering a PSS shaft seal might be interested in looking at their FAQ oages:
https://www.shaftseal.com/pss-faq.html#1
– Bob
Solar Wind
Nonsuch 26C, #143