Shaft Seal - PSS or Tides Marine Lip Seal ?

[Lennie]

Changing out my old packing gland this spring looking into PSS or the Tides Marine seals. Is one better than the other?

Leo

[duncan_ellison]

Leo,

I'd think about this decision and do some searching around the boards before you finally make your decision. I changed out a perfectly functional standard packing gland for a PSS and am probably going to change it back next season. Don't get me wrong, there's technically nothing at all wrong with the PSS, it does exactly what it says on the tin, no drips - not a one. Wasn't even particularly hard to fit.

It's just that in the end I'm kinda jittery about the whole bellows and rotating ring thing in the event of a crisis with the shaft like a coupler malfunction or bent shaft.

My prop shaft is pretty long between the coupling and the P bracket and although I realise it's not actually a real bearing, the standard packing gland was pretty sturdy and I'm sure was imparting some stability to the shaft.

At the very least I figure that a standard packing gland would remain watertight even if the shaft was detached from the coupling as long as it didn't slide out.

Another minor worry is the need for a 3/8" tube from the gland to provide a 'burping' tube for the bellows. Instructions clearly warn only to use a "below the waterline approved" tubing for this, however, I've been unable to locate and tubing that small with is definately certified for that use. Just one more thing then to go wrong and flood the boat.

Just my 2c - you mileage may vary especially if you have a hard to get to location for your stern gland and want to cut down on future maintenance.

Duncan & Joan
s/y TALISA
Currently parked in RI

[delmarrey]

Proper installation and maintenance!!!!!

No matter what you decide, it takes the above to prevent a failure. With any shaft packing, if there is a failure one can stuff rags into the shaft log until one gets to where it can be dealt with.

Each have their own pluses and minuses but it's up to ones technical knowledge and power system as to which one would pick. One of my neighbors just pulled out his (twin screw) tides marines and replaced them with PSS due to the discontinue of the old model. Tides Marine - Manufacturer of the SureSeal Shaft Seal

A lot of people are afraid to fly but more people die in auto accidents each year then do airplanes, about 200:1 per mile.

[Ocean Girl]

Very interesting Talisa you mentioned the "sea worthiness" of these packing glands. I was in a survival storm out in the Atlantic and we began to take on water from the stuffing box area, there was no way to fix this offshore, had to wait till port. I have no idea if it failed because of poor installation or even if it had anything to do PSS. The boat was violently pushed around and the prop cavitated at times (we were motoring to maintain steerage). I sailed offshore on that vessel over 4000 miles including many ICW motoring hours, this was the only time we had an issue with the PSS.
Erika

[why me?]

Hey Lennie... I have used PSS seals and your installation is very similar to a boat I had about 10 years ago. 1 1/2 inch shaft 3 metres. maybe my recollection will help.

The downsides.. Oceangirl, I had a scare with mine.. and I found out it had happened before on other boats. The grub screws locking on the rotor are not real hard steel.. so they don't tear up the surface of the shaft.. but they also can loosen and thats what happened to me. The rotor backed off and flooded the bilge. Fortunately not in rough weather but did submerge some low mounted electronics. Maybe yours backed off a little in the rough weather.

Also as Leo noted.. I found I needed support to take the place of the stuffing box. I had a cutlass bush installed in the log behind the seal which worked a treat until it didn't. As I was running a low rev installation I didn't need to use the cooling line model, until I put in the bush which restricted water to the seal which then heated. So I drilled a hole in the black plastic side and used marine tex (yank boat on the slipway had some.. good stuff, wish we could get it here) and installed a fitting and ran normal reinforced vinyl water hose, 12mm, from my raw water system behind the jabsco. Worked well.

I know it sounds fetly but in the end it did it's job. When it's right it doesn't leak a drop. They take horrible abuse and survive.. remember I mentioned I got it a little hot! Well maybe more than a little. To fix the grub screw problem I applied way more torque than I would have otherwise, and a ton of locktite. And just for a little insurance, I put a heavy stainless hose clamp on the shaft behind the rotor. Never needed it.

Peter

[Pete7]

Leo, have you thought about the volvo seal. We ripped out our old stuffing gland a year ago and replaced it with the volvo one. Superb, and about a 1/3rd of the cost of other types. The only down side was the stuffing gland had worn the shaft over 20 years so we needed a new one, but now have dry dusty bilges and no grease flying about either. UK cost was £50 so about $80.

Pete

[Ocean Girl]

Peter, there is nothing more fun than crawling back into the bowels of the stern while taking on water in the middle of the Atlantic Anyways, when I crawled back there, if I remember correctly, it seemed like the shaft and everything around it was being shoved back into the boat. Since it occurred during a bad storm, maybe it wasn't supported (installed) properly. I described it to the captain as "it is imploding". Nobody aboard was familiar with PSS, probably not very wise to go offshore not knowing our PSS but I flew by the seat of my pants back then.
E

[James S]

Originally Posted by duncan_ellison

Leo,

I'd think about this decision and do some searching around the boards before you finally make your decision. I changed out a perfectly functional standard packing gland for a PSS and am probably going to change it back next season. Don't get me wrong, there's technically nothing at all wrong with the PSS, it does exactly what it says on the tin, no drips - not a one. Wasn't even particularly hard to fit.

It's just that in the end I'm kinda jittery about the whole bellows and rotating ring thing in the event of a crisis with the shaft like a coupler malfunction or bent shaft.

My prop shaft is pretty long between the coupling and the P bracket and although I realise it's not actually a real bearing, the standard packing gland was pretty sturdy and I'm sure was imparting some stability to the shaft.

At the very least I figure that a standard packing gland would remain watertight even if the shaft was detached from the coupling as long as it didn't slide out.

Another minor worry is the need for a 3/8" tube from the gland to provide a 'burping' tube for the bellows. Instructions clearly warn only to use a "below the waterline approved" tubing for this, however, I've been unable to locate and tubing that small with is definately certified for that use. Just one more thing then to go wrong and flood the boat.

Just my 2c - you mileage may vary especially if you have a hard to get to location for your stern gland and want to cut down on future maintenance.

Duncan & Joan
s/y TALISA
Currently parked in RI

I'm with Duncan on this....

[why me?]

first of all I confused two posts.. so was thinking lennie was the one with the long shaft.. but was actually duncan ellison.. good post that!

Pete7's volvo seal sounds really good too.

Something else I tried was a home brew fix. My log was schedule 80 pipe so cut another piece about 250mm long and bored the inside to 2".. then put 2 lip seals on either end with a short section of cutlass bush in the middle to keep the shaft true for the seals.. then ran a tube off one side and filled with tranny fluid. Worked great for a short time then got hot. I ran out of time and patience and stuck on the PSS which was a lot of money then. The problem I found out later was... I used a bush made of latex rubber... which absorbed the oil and swelled up, thus heating. If I had used a nitrile rubber it would have worked... the idea was from a nigel caulder book. Too bad about the wrong rubber... the thing cost me about $50 to make and did dampen vibration some as well.

Hey Ocean Girl... that must have been scarry! but it does sound like it could have been the rotor backing off. On mine I didn't recognise what it was at first. It was already underwater and it looked OK until I understood that the bellows were maybe extended further than I remembered... then got my hand in there and felt that the bellows had no tension against the rotor. All this happened in calm conditions... not crossing the Atlantic in rough weather... whew!

Peter

[jdoe71]

Our new to us boat has a PSS in it without the "burping tube". The bellows on the PSS is 3 years beyond the recommended 6 year service life of that part. The keel stepped mast in this boat runs water into the bilge from various openings. The PO put an air conditioner in that the condenser dumps water into the bilge from (which is being taken out). There are some plumbing leaks that dump water into the bilge that are slowly being fixed. The bilge will never be dry from the mast alone, so why would I take a risk on a PSS with their attendant risk of catastrophic bellows failure when an old style stuffing box rarely, if ever, fails catastrophically. Makes no sense to me at all especially since I can buy a brand new stuffing box for the same price as a new PSS bellows. So the PSS is coming out and a stuffing box is going in. Just one man's reasoning.

[nhschneider]

I just installed the Lasdrop Gen II model and so far, I've been very happy with it. However, it's still brand new. I preferred this model as it doesn't use bellows.

Good luck.

Fair winds and calm seas.

[markpj23]

I also had the PSS Gen II on our previous boat. Once I understood it I came to like its simplicity. It was effective even when I had an loose engine coupling (unkown at the time) and the shaft was moving aft when I backed down. (Gee that sounds funny....) PSS was very helpful and responsive when I called their support line.

I had a yard owner tell me he would no longer install anything but the Tides seals because they are "bulletproof." (His words). This was in Texas at a yard that caters to sportfish boaters, so I took that into account.

I think this choice is kinda like the anchor threads. Pick one you like and go. They all work and have various benefits / risks.

[Maine Sail]

Originally Posted by markpj23

I also had the PSS Gen II on our previous boat. Once I understood it I came to like its simplicity. It was effective even when I had an loose engine coupling (unkown at the time) and the shaft was moving aft when I backed down. (Gee that sounds funny....) PSS was very helpful and responsive when I called their support line.

This is why in about 90% of the instances a solid coupling should not be re-used when you install a PSS or replace a shaft log hose. Re-using an old coupling or failing to have a new one properly fitted to the shaft then faced can potentially sink a boat or at the least ruin a shaft. Solid one piece couplings are fitted to a MAX variance between shaft and coupling of .001" per ABYC P-06 and SAE J756. Most shops will try for better than .001" which usually requires a light press or light tap fit. When you remove an old coupling the layer of rust that broke free is almost always more than .001"..

If a boat yard installs a PSS and does not also charge you for a new coupling and fit & face, and your coupling is a solid one, not split, please question this..


As for the PSS I now install Ruland split collars on every install. They are available from McMaster Carr and are cheap insurance.



Clamp Collar in use. Even if the set screws loosened up the stainless rotor is not going to slide up the shaft:



These set screws are a one time use item. If you need to adjust the stainless rotor and move it on the shaft you should also replace the set screws.

[Chief Engineer]

I would not use either....

I have seen way too many Tides Seals self destruct when the water inlet wasn't opened.

I would only install a PSS seal if maintaining a standard stuffing box was too awkward to get to.....Like in Vee Drives.

[David M]

I have been using PSS seals for many years on a twin screw work boat. No problems.