Dripless shaft seal owners beware.

[a64pilot]

Unless I’m mistaken water injection is recommended for any boat that has the Cutless in the deadwood. I keep going back and forth about a dripless shaft seal myself, currently running I believe Gore Tex for the last at least two years and have no drips and haven’t had to adjust it yet.

[MicHughV]

I too got tired of the slow drip-drip from a standard stuffing box and opted for the PSS shaft seal at a haulout. Like a previous poster did, I also attached a zinc shaft collar in front of the PSS shaft seal collar as an added safety precaution.
That PSS seal was on there for around 15 years and never gave me a lick of problems nor did it ever drip a single drip.
At some time, I did replace the stainless steel clamps that held the PSS shaft seal to the shaft tube. As I recall there were two of them, so doing one at a time, I did it while the boat was in the water.
I believe the standard PSS shaft seal is rated for a shaft rotation speed of under 1000 rpm. More rpm than that one needs the PSS shaft seal with the added water cooling tube.
One last comment....when the engine is running and in forward gear....the engine tends to move forward slightly on it's rubber mounts..this will cause the bellows to expand incrementally...so the bellows need to accommodate this slight movement by compressing them a few millimeters more when at rest.

[mcarthur]

Originally Posted by GILow

Sorry David M, but I do not agree with this. According to the manufacturer, the PSS only requires forced water injection if the boat travels fast enough under power for the venturi effect of the passing water to suck air into the seal from the front. I cannot remember the speed, but at least 9 knots comes to mind.

Greater than 12 Knots .

[a64pilot]

Here is the instructions. Note #15 where it says displacement boats with a bearing in the shaft log must use the pressurized hose like a go fast boat.
https://www.shaftseal.com/pss-instal...tructions.html

[GILow]

Originally Posted by mcarthur

Greater than 12 Knots .

Well, I’m safe. [emoji853]

[GILow]

Originally Posted by a64pilot

Here is the instructions. Note #15 where it says displacement boats with a bearing in the shaft log must use the pressurized hose like a go fast boat.
https://www.shaftseal.com/pss-instal...tructions.html

I wonder which sort of bearing they mean?

I have a “typical” cutless bearing on a 1.5” shaft and the water flow past it feels practically unlimited. I cannot imagine a shortage of water to the PSS with my setup. (Which, incidentally, does not use a feed from the engine raw water pump. I am not sure if I missed that note in the instructions or if they have been added in the last four or five years.)

[carlwk3c]

Originally Posted by stromatolite

Although unlikely, failure of the corrugated rubber seal part of the PSS was a concern when I installed mine... unfortunately there was not enough room to consider the traditional stuffing box. For piece of mind (albeit possible overkill), I installed at the same time a length of wheel-barrow tire inner tube and fastened one end of it with hose clamps around the stern tube (ie just beyond the PSS connection to stern tube). It was cut long enough to extend towards the engine coupling. I then folded it back upon itself a couple of times until completely out of the way. Failure is presumably more likely under forces imposed from an operating engine and therefore I will be on the boat... so the plan would be to pull the inner tube piece forward over the leaking seal and fasten it with another hose clamp or two to the propeller shaft. In short, I have a rubber hose containment system pre-fastened at one end and ready for deployment to slow down water ingress while I think about the next step. Engine use may subsequently be out of the question but I might be able to hose clamp it to the non-rotating carbon part of the PSS seal housing to regain this. Regardless, the engine would also become useless after a foot or two of water.
As for the OP concern, on possibility is if the rubber seal was not compressed enough... I think for a 1" shaft the compression is supposed to be about 3/4". The two surfaces of carbon and steel rotor also have to 'wear' themselves together, so as noted if the shaft was not turned subsequent to repairs, a leak might be possible, that said, I suspect it would be a drip, not a pour.

EXCELLENT idea!

[saillr]

I am constantly amazed why people go for the so-called dripless system. Reading about all the problems with leaks, adjustments, sand and stuff getting into the seal, worries and more worries. It adds a degree of complication that is truly not necessary.
Just use white teflon packing in a standard stuffing box and forget it after one or two adjustments. I have an Island Packet 40 and for 22 years have sailed it extensively locally and offshore. I have no drips at all and have not tightened the stuffing box at all - maybe once about 10 years ago after a trip to Hawaii. My bilges are dry and the box always runs cool.
Others have reported the same results with white teflon packing. Make sailing easier, safer, and drier. Suggest getting rid of the complicated stuff and go back to the simple stuff-(ing)

[Seadaddler]

I do the very fine sand paper in between the stainless and carbon collar every other year.
Nick

[pcmm]

Originally Posted by MicHughV

I too got tired of the slow drip-drip from a standard stuffing box and opted for the PSS shaft seal at a haulout.

Sounds like you never adjusted your stuffing box. At rest a traditional stuffing box ( when properly adjusted) does not leak!! When under way the drip is very marginal. a drip every few seconds or so is plenty.

[a64pilot]

Originally Posted by GILow

I wonder which sort of bearing they mean?

I have a “typical” cutless bearing on a 1.5” shaft and the water flow past it feels practically unlimited. I cannot imagine a shortage of water to the PSS with my setup. (Which, incidentally, does not use a feed from the engine raw water pump. I am not sure if I missed that note in the instructions or if they have been added in the last four or five years.)

I’m sure they mean a cutlass bearing.
I keep tossing around the idea of a dripless myself, but like the guy with the IP40, I don’t have any leaks in my IP38 either, so I keep getting back to what’s to fix?
I have water in my bilge, not much but there is water, it gets there changing water maker filters etc.
I guess I could wet vac it out, but it causes no problem, doesn’t stink etc.

[model 10]

I must be lucky, I have a regular flax seal that does not seem to leak much. During the boating season, the bilge always has water in it for some reason or other but not much from just the seal. When I got back to the boat last year, after not being onboard for a while, the bilge was dry. What drips there are, evaporated. The water temp is about 86deg.

It's easy to get the drip rate about right on this boat. I could see that on some boats, you couldn't even see the packing nuts.

[MicHughV]

just as a quick note.....I built a homebuilt steel Roberts 38...so indeed, while at rest, the standard stuffing box did not leak....it did drip-drip ( as it should) while under power.
Owning a steel boat, even though thoroughly sand-blasted inside and out, and properly primed and painted, the thought of corrosive salt water dripping inside my boat was not comforting. Even armed with several bilge pumps, I would think the goal of any any seafarer is to keep the ocean on the outside of the hull.
When the PSS shaft seal hove into sight, I had to have it.
In the 15 or so years I had the boat ( with PSS shaft seal) I never had a lick of problem with it, nor any seawater "dripping" inside my boat.
The problem with these chat site forums, is that everybody has their own opinion, based on their experience.
My goal here is to offer " my" experience and not to sell anyone on the PSS shaft seal.
I loved it and think it's a great product !
In closure, I recently tracked down my old boat, and after some 45 years, the inside of the hull is as spotless as it was back then when i owned it.

[Wotname]

Originally Posted by saillr

I am constantly amazed why people go for the so-called dripless system. Reading about all the problems with leaks, adjustments, sand and stuff getting into the seal, worries and more worries. It adds a degree of complication that is truly not necessary.
Just use white teflon packing in a standard stuffing box and forget it after one or two adjustments. I have an Island Packet 40 and for 22 years have sailed it extensively locally and offshore. I have no drips at all and have not tightened the stuffing box at all - maybe once about 10 years ago after a trip to Hawaii. My bilges are dry and the box always runs cool.
Others have reported the same results with white teflon packing. Make sailing easier, safer, and drier. Suggest getting rid of the complicated stuff and go back to the simple stuff-(ing)

I could find a zillion posts on CF asking for help for their leaking hard to fix traditional stuffing boxes.

I have had one such problem box and replaced it a PSS, never touched again for many years, finally sold the boat. Later on another boat I fitted a PSS during an extensive refit and again never had a moments worry with it.

I guess the take away is both work well when properly installed .

Next boat (being tiny) will use the traditional box,

[Dev0n60]

I have been the very unlucky person to have the PSS nitrile bellows literally disintegrate. It was completely my fault..... at the time (1993-4) there was no concerted effort by PYI (the vendor) to tell people they sold the units to, how to maintain them.... I replaced the original Hypalon bellows in 1999 because the Hypalon developed what the manufacturer called 'memory' and no longer kept adequate pressure against the rotor.... leaking....
The newer Nitrile bellows was fine until one day after coming back to the boat after being away for a few months, I started the engine and put it in gear in the berth to charge the batts and load up the engine. Almost immediately my bilge alarm started shouting at me!
Inspection revealed that the nitrile bellows was shredded. Water was pouring in thru the stern tube! The one hole in a boat that one cannot stick a bung into.
Trying to not panic, I quickly grabbed some material I use for creating moulds: 'Poly Vinyl Siloxane Putty'..... I mixed the part A & part B together, grabbed my mask, hopped over the side and stuffed the putty around the shaft at the point where it entered the stern tube. Viola! The in rush of water completely stopped.
This worked so well that we motored across Auckland Harbour to Orams and hauled the boat without a drop coming through. It took a good 45minutes to dig the putty out once hauled. This putty comes in various consistencies and once set, is quite hard/robust.

So.... the problem I now understand and which PYI now clearly warns people of: after sitting for a prolonged period of time (???) the rotor and carbon ring will form a tight bond to each other. So tight that the action of putting the boat in gear without first breaking the bond can cause the nitrile to sustain a significant amount of torque and fall apart. DO NOT DO THIS!!! These days, if I do not run the engine for more than a week, I simply take a mallet and LIGHTLY tap the meeting point of the Rotor and the Carbon. This has always been enough to break the two apart from each other.

I have also noted the PYI have significantly 'beefed' up the spec/gauge on the nitrile they supply these days compared to earlier versions