I would suspect Catalina moved back to a traditional stuffing box because they are about 1/3 the cost of a PSS (based on wholesale pricing and Catalina pays less than I do I am sure).
The installation is also less costly for Catalina with a traditional gland not having to run an extra hose for the vent.
The PSS seals are extremely reliable and are used by the USCG and the world best builders. I know of some in commercial used with over 10k hours on them.
All the failures of PSS I have read of have been due to installer or owner error. The stainless rotors do not slip if properly & competently installed. I have seen 20 year old PSS seals still working perfectly. I have one customer who still has the old cloth covered bellows, this despite my very strong suggestion he replace it. I don't think PYI has made those bellows for about 15-20 years.
The term "properly installed" means the grub/set screws that contact the shaft are only ever tightened once. ONCE!!!! Tightened
are two different things. They also need to be tightened to the proper torque with the proper Allen key.. PSS ships the proper Allen key but I still see grub screws molested by using the wrong Allen key.
Often times installers mess up the adjustment or compression of the bellows. Sadly they think nothing of loosening the set screws and simply moving or re-adjusting the rotor and snugging up the set screws. PLEASE DO NOT DO THIS! If this is done it is no longer a proper
installation and you have just increased the risk of the rotor slipping and a leak. If you need to adjust the bellows you need to use brand new set screws.
These set screws can only be tightened once because the shaft, usually Aqualoy or Nitronic, is harder than the grub screw. These volcano head
screws rely on the initial "cut" or bite into the shaft for the grip. Loosen the screw and move the rotor, even 1/8" and you need new screws.
PYI Says this right in the installation instructions:
"Do not re-use the supplied cupped pointed sets screws."
What is a one time use? If you tighten the set screws onto the shaft even once, that is your use. For example if you are installing the PSS and adjust it, tighten the set screw then realize the adjustment was wrong you now need to use new set screws. This is installer error numero-uno with PSS seals....
For years I have installed PSS seals with "clamp collars" from McMaster Carr as added insurance. Hose clamps and zincs are really not the ideal solution but a clamp collar is designed for this:
Here's a better view:
PYI saw me using these and they now offer their own "clamp collars". IMHO all PSS seals should come standard with a clamp collar, and a bag of extra set screws, but I digress. It would virtually eliminate installer error and slipping rotors and help eliminate the "I had a PSS failure"
threads, which were really "installer error".
Both standard glands and PSS seals are reliable. I have however seen and know of plenty of sinkings related to traditional boxes. They are also highly prone to installer or user error. Hoses on traditional boxes also need to be changed so a traditional gland is not immune from hose replacement maintenance.
Despite misleading marketing messages by packing manufacturers traditional boxes should not be run "dry" or "dripless" but they can be "drips-less" than older plant based packings.. They, all PSS type or traditional glands, need to pass some water (traditional) or vent air (PSS type), or they can overheat. Trapped air or not passing of water can also lead to stagnation and corrosion of the shafting up inside the log.
This is what stagnant water on a traditional box set to not drip can do:
Some boats are more prone to trapped air in the log hence PYI's move to all vented/plumbed seals even on slow moving craft. "Burping" on some boats was more than just at launch time so vents make a lot of sense on all sailboats.
Newer packings can be pretty darn drips-less
but should not be 100% dripless.
it can be so minimal that engine warmth evaporates any drips before it accumulates.
Unfortunately I can't count the number of times an owner or yard mechanic has said to me "Yeah when I adjusted the PSS."
and I ask "Did you replace the set screws?"
and am treated with a blank stare? Scary stuff!
If a failure were to occur with a slipping rotor, in this scenario, it is installer error not the fault of PYI or the PSS seal.
I also very often see the vent holes plugged with brass or ss plugs. The vents should always be plumbed (power) or vented/used on sailboats. Metallic plugs should never, ever be used in the carbon rotor. There is a reason PYI uses a nylon hose barb and that is because the carbon is the most noble element in the galvanic scale and the differing expansion contraction characteristics between brass or SS and the carbon...
PYI says this in the instructions but many people choose not to read or heed them:
"Do not tighten or replace the installed nylon hose barb fitting with a metallic fitting (bronze or stainless steel). Metal hose barbs will damage the carbon and destroy the PSS."
Again, this type of failure, overheating of the seal, dissimilar metals corrosion or a split carbon would clearly get blamed on the PSS seal. Sadly on the "net" PSS takes the hit not the dolt who caused the failure by not following the installation instructions. These are examples of installer error not a failure on the part of the seal. I see the metallic plugs and set screw errors frequently.