I considered retrofitting to a PSS shaft seal when I repowered a few years back. I heard some reliability problems with the item and decided to go with the more traditional packing gland. When traditional packing fails, the problem develops slowly and can be dealt with. When the PSS seal fails, the result can be quite dangerous. Just a month ago, a boat at my club had a failure with his PSS shaft seal which resulted in flooding. I’m not sure exactly what failed, but I was told that the seal requires water to provide lubrication and the water flow failed. This caused the seal to burn up and flood the bilge.

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Paul,
AFIK, there is no maintenance functions required on the PSS, except to
inspect it periodically. Make sure the hose clamps are not getting
corroded. The most important thing is to bleed the seal after a haulout,
before getting underway.
Sorry, I don’t know the OD of the pilot tube. In any case I wouldn’t use
the dimension on another boat. I suspect it will vary slightly from boat
to boat.
If you are concerned about whether the bellows is compressed enough, send a
pic and I’ll compare it to mine.
Actually I found a pic of my shaft seal (
http://www.svsarah.com/Sarah/Images/Hatch1%20005.JPG).

Regards,
John Stevenson
http://www.svsarah.com
Sarah’s Blog

On Thu, Oct 9, 2014 at 11:27 AM, pma_foyl via maillist <
> wrote:

Hi All,
So I’m inspecting my PSS dripless shaft seal (of which I know NOTHING) and
thinking about doing the recommended maintenance at my next haulout. I’ve
got a couple questions for those who have these.

1. I know our shafts are 1.5″. Can you please tell me what the Stern Tube
measurement is (so I can order the right PSS bellows)?

2. Also, it doesn’t look like my current PSS bellows is compressed
significantly (is this a concern?).

3. AND, while the rotor/bellows are well attached to the shaft, I don’t
see the “extra set screws” the manufacture recommends for the rotor (ie.
the ones ON TOP of the others, to prevent loosening). Anyone have first
hand experience/knowledge about this? Should I be concerned?

4. Is there any kinda annual maintenance required by the PSS?? I want to
be sure I’m not neglecting anything.

Thank you all for staying focused on my questions. I know we have a
tendency to expand to “related” topics, but I really would love to get
clear answers to the questions above. Again, I appreciate all your help.
Best,
Paul

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You know, expanding to “related” topics reminds me of a looong
but very funny story I once heard, but for you to fully
appreciate the story I first have to give you a brief history of
the seven people involved…

(Just kidding.) I have a PSS dripless shaft seal and your query
reminds me that it’s high time I check it over. It’s so efficient
one tends to forget it’s there. I can’t answer all your
questions, but can urge you to compress the bellows a bit since
that’s what holds the sealing ring against its counterpart. No
bellows compression, no firm setting of the graphite rings. And
be sure both ends of the bellows are double-hose-clamped.

I’d also encourage you to do as the manufacturer suggests and put
in the second set of set screws. Pull one and buy several to
match, or just order them from the factory. If the inside set
ever vibrates lose it will be a big (and avoidable) problem for
you at the worst possible moment. Holding them in place with the
back-up set, perhaps adding a drop of Loc-Tite for extra
insurance, seems a wise precaution.

You might want to download the owner/service manual for it. I
imagine the maker has a PDF version on their site. That will
answer all your questions correctly except for the size of the
stern tube, which is about 3″, but somebody else here will know
for sure.

Tor

Must have hit the wrong button and send this before I was finished. Here’s the rest.

The traditional packing gland I have leaks while underway as most do. You’re supposed to adjust them until the leak is just a drip every few seconds but it won’t stay that way. I readjust the thing when it becomes a nuisance. Some commercial boats put a grease fitting in the packing nut to allow grease to be injected in the gland.

https://www.youtube.com/watch?v=nlkfRXaWlB4
http://www.passagemaker.com/articles/technical/running-gear/dripless-shaft-seals/

Rich

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Rich,
That failure may have been do to not bleeding the bellows after haulout,
but I doubt it would generate enough heat on our boats to burn up the
bellows. More likely this was a power boat. PSS offers a water attachment
for high speed props. If the failure flooded the boat it was likely that
water attachment that did it rather than water coming in through the pilot
tube, which most bilge pumps can handle.
I agree that the PSS shaft seal is an unnecessary modification. When I
converted to the PSS I was trying to dry out the bilge and thought the
original stuffing box was the problem. I found it very difficult to
tightened the gland or to re-pack it. So i went with PSS. Since then I’ve
added a hatch over the drive train and I now have full access to the pilot
tube and seal (as shown in the picture in my previous post). When the PSS
gets to the point where a replacement is needed I’ll probably go back to
the old stuffing box.
Tides Marine also makes a dripless shaft seal which may be a little more
robust than the PSS. I think that one carries a spare bellows on the shaft
should the primary one fail.

Regards,
John Stevenson
http://www.svsarah.com
Sarah’s Blog

On Thu, Oct 9, 2014 at 1:08 PM, re.carter— via maillist <
> wrote:

Rich,

I would be very interested to hear a confirmed version of that
story. I don’t think it’s possible for “the water flow to fail,”
it being an open stern tube with the seal rings at one end and
the ocean at the other. Other things could cause the boat to
flood, however, such as the bearing ring slipping apart because
the set screws jiggled loose (because the guy didn’t put in the
back-up set of screws with a drop of Loctite, as the manufacturer
recommends), or the rubber bellows tearing from very, very old
age, or simply coming lose because the hose clamps failed from
being left to rust for 5 or 10 years. I used the PSS on my
previous cruising boat for 30,000 miles, and on Silverheels for
some many thousands more and (knock on wood) have never had a
problem with it. I suspect that ultimately your club mate is to
blame for the failure on his boat.

Tor

Thanks John and Tor,
I appreciate your clear (and on-topic) responses. Very good advice.

Regarding the “bleeding” post-haul out? Can you please describe the procedure? I’ve had my boat out twice, and to the best of my knowledge, this has never been done. I can’t see any damage or deterioriation, but would like to do the procedure anyway. Can I do it while the boat is in the water? Does the bleeding pose any threat (ie. if the parts don’t reassemble properly)?

Right now my PSS does not leak/drip at all (so seems okay).
Thanks again for your clear help. I do appreciate it tremendousl;y.
Best,

paul

On Thursday, October 9, 2014 10:32 AM, Silverheels via maillist wrote:

Rich,

I would be very interested to hear a confirmed version of that
story. I don’t think it’s possible for “the water flow to fail,”
it being an open stern tube with the seal rings at one end and
the ocean at the other. Other things could cause the boat to
flood, however, such as the bearing ring slipping apart because
the set screws jiggled loose (because the guy didn’t put in the
back-up set of screws with a drop of Loctite, as the manufacturer
recommends), or the rubber bellows tearing from very, very old
age, or simply coming lose because the hose clamps failed from
being left to rust for 5 or 10 years. I used the PSS on my
previous cruising boat for 30,000 miles, and on Silverheels for
some many thousands more and (knock on wood) have never had a
problem with it. I suspect that ultimately your club mate is to
blame for the failure on his boat.

Tor

Paul,
To bleed the bellows, just push it aft on the shaft to separate if from
collar on the shaft. Allow water to flow for a few seconds then release
the bellows and it should seal against the collar. This just gets rid of
any air that may be trapped in the bellows and insures water is in contact
with all of the internal parts.

Here is a link to the Tides Marine product:
https://www.tidesmarine.com/sureseals. It’s not the bellows that is spared
on the shaft but the lip seal.

Regards,
John Stevenson
http://www.svsarah.com
Sarah’s Blog

On Thu, Oct 9, 2014 at 1:39 PM, Paul Audi via maillist <
> wrote:

I think there is a bleed hose on the PSS shaft seal. If you run a vent hose up high in the boat, perhaps to a vent fitting in the cockpit, it’s supposed to self-bleed. I don’t have one of these, but that’s what I remember.

Tidesmarine makes a competitive product. It looks like you’re supposed to supply water to the stern tube. I have a tidesmarine tidestrack mainsail track and its well made. It helps with the mainsail adjustment but I’m not sure it works as well as I expected. Perhaps the 424 main is a bit too big for it. Dropping the main is much easier, but adjusting halyard tension while it’s under load is still a problem. Raising the main has always been an issue because the darn thing weighs a ton. I’m not sure the track helps much there. It added $1500 to the cost of my new main last winter. Previously, I lubricated the main track with spray dry-lube each spring.

Rich

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John,

I got a rejection notice from my last email to the group, too,
but like yours it actually did get through.

Tor

I was taught and have since believed that a packing gland is
properly adjusted when it drips about once every 30 seconds while
the shaft is spinning, and not at all when sitting still. That
guarantees the wetting necessary with the least amount of water
accumulation in the bilge. Of course, there’s no real harm to
letting it drip more than that other than having to pump the
bilge a bit more often.

Hi Paul,
The stern tube on my boat is/was 2 3/4″ and I think the tolerance is
pretty wide for it fitting. Here is the kit I purchased….
http://www.ebay.com/itm/PSS-Shaft-Seal-07-112-234R-Maintenance-Kit-1-1-2-Shaft-2-3-4-Tube-/321477639559?pt=Boat_Parts_Accessories_Gear&vxp=mtr&hash=item4ad98f7d87

It went on with no problems!

My old bellows (I was upgrading, also as the PO had installed one 9 years
earlier) was also measuring quite a bit less than what I had read for
dimensions. It was not cracked or looking bad and there was no sign of
water leaking but I felt…what the hell let’s replace it while I’m
replacing the shaft too.

The set screws are visible in two places on the rotor. What you don’t see,
is that “under” those set screws are additional set screws that actually
make contact with the propeller shaft. The ones you “see” are the backups
and only tighten up onto the top of the important ones. Be
reminded….these set screws that make contact with the shaft are a “one”
time use only!!!! If you tighten them to the shaft and then find you didn’t
get the proper compression for the bellows and want to try again, replace
the set screws. They(new set screws) have a sharp cup on the contact end
and when tightened to a shaft are somewhat damaged especially if you have a
stainless shaft.

I think the only maintenance on these is possibly after a few years (half
of recommended life/3 or 4 years) if hauled out why not replace the set
screws and add a half inch of compression. But I’m just guessing on that
one from my own …”what can I do to keep it safe perspective”? I think the
directions only call for visual and replace every 7 or 8 years.

I also have an added zinc firmly attached forward of the rotor…..just in
case!

Ken

On Thu, Oct 9, 2014 at 11:27 AM, pma_foyl via maillist <
> wrote:

Hi All,
So I’m inspecting my PSS dripless shaft seal (of which I know NOTHING) and
thinking about doing the recommended maintenance at my next haulout. I’ve
got a couple questions for those who have these.

1. I know our shafts are 1.5″. Can you please tell me what the Stern Tube
measurement is (so I can order the right PSS bellows)?

2. Also, it doesn’t look like my current PSS bellows is compressed
significantly (is this a concern?).

3. AND, while the rotor/bellows are well attached to the shaft, I don’t
see the “extra set screws” the manufacture recommends for the rotor (ie.
the ones ON TOP of the others, to prevent loosening). Anyone have first
hand experience/knowledge about this? Should I be concerned?

4. Is there any kinda annual maintenance required by the PSS?? I want to
be sure I’m not neglecting anything.

Thank you all for staying focused on my questions. I know we have a
tendency to expand to “related” topics, but I really would love to get
clear answers to the questions above. Again, I appreciate all your help.
Best,
Paul

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