Shaft gland packing or dripless shaft seal?

FastOlson · Apr 9, 2016

Ken13559 said:
Ok I've put on my helmet and riot gears.
I've shaft packing gland for last 14 years. Now I want a dry/drier bilge. So whats the pros and cons of dripless shaft seal, in partiucular PYI PSS.
I've heard a regular packing gland gives ample warning before failing completely whereas dripless seal fails misserably when it does and will sinks the boat.
Advise? Experience?

Sounds like: Troll bait... "sinks the boat"?? Really?

But if you are asking a serious question, the face seal device is long proven in industry and works fine for sailboats with no sudden failure if installed properly... similar to installing the packing correctly in the traditional stuffing box.
I have been using a PSS shaft seal since '95 and it works fine. No drips in any normal usage. We did replace the bellows after about a decade, just as a preventative measure.
You will get used to having a dry bilge.
If you stick with the newer-tech teflon packing you should be 90% as happy, based on owner comments I have heard for years.

Regards,
Loren

Meriachee · Apr 9, 2016

Pretty much answered your own question about being dry and there aren't too many here with first person knowledge of catastrophic failure. The thing is a nice product, the bilge is bone dry and just like anything lacking in maintenance, subject to failure.

Ron20324 · Apr 9, 2016

FastOlson said:
Sounds like: Troll bait... "sinks the boat"?? Really?...

Yes, really. This past Dec 24th a boat was found sunk in it's slip in my marina. Guess what failed and "sunk the boat"???

capta · Apr 9, 2016

I also had considered a dripless gland, but decided against it because it cannot be repaired in the water. As for an old style stuffing box/packing gland 'failure' I think one would have to go several miles beyond poor maintenance before that would happen, though I could see it happen with a dripless.

Ralph Johnstone · Apr 9, 2016

Ken13559 said:
I've heard a regular packing gland gives ample warning before failing completely whereas dripless seal fails misserably when it does and will sinks the boat.

Hi Ken,

I've run my packing for almost five years now (100 hr/year) with no leakage.

http://forums.sailboatowners.com/in...y-need-to-leak.136282/&highlight=need to leak

I will repack this year as I've noticed that the packing is starting to drip and is not as easy to stop each time. The nut adjustments are still in the order of 1/2 flat at each tightening. Over the five years, I have tightened about three times.

Lots of people for, and just as many against. Not interested in discussion as I know I'm staying as I have for the last 17 years.

A few things which are mandatory for a dry gland to work:

your shaft must have a mirror polish.
your packing material must go in snug when packing i.e. good axial force from the get go. You don't want to rely on the packing nut to jam the undersize packing against the shaft. By that time, it's already hard and will overheat if run dry.
the packing must be cut exactly to the correct length. Too long and the overlap will cause a bump and leak. Too short and and water leaks between the end crack. Not as easy as it sounds once you start forcing a snug fit in the box. It tends to grow by about 1/8" on a 1" shaft.

Can't remember who said it

but "your boat, your choice"

Gunni · Apr 10, 2016

There are dry seals other than the PSS. The Volvo lip shaft seal being one. Dry bilge, push a little marine grease into the lip every year and they provide years of trouble free service. It was the OEM seal in Beneteaus when they were building shaft drives.

Benny17441 · Apr 10, 2016

Ken13559 said:
I've heard a regular packing gland gives ample warning before failing completely whereas dripless seal fails misserably when it does and will sinks the boat.
Advise? Experience?

It is true and probably the only downside other than the work of switching from one to the other. Ironically enough we went to a dripless after a packing gland failure that went unnoticed until the stern of the boat started listing from a significant water intrusion. The boat was two years old at the time and the dripless has now been in service for the past 13 years. That was one case where the packing failed catastrophically spraying significant amount water under pressure without any warning. We had not checked it for maybe two weeks and it went from a regular drip to a large leak.

Bill Roosa · Apr 10, 2016

You might want to check your pocket book. A dry boat would appear to cost significantly more then a wet one.

heritage · Apr 10, 2016

One advantage of the PSS shaft seal is that there is nothing touching the prop shaft except for the two o-rings and set screws on the stainless steel rotor and they remain stationary. Nothing to cause grooving in the prop shaft or to trap water that might cause crevice corrosion on the shaft. If your prop shaft already has some damage, I have had good success treating the area with JB Weld, then fine grit wet sanding the area. Since the shaft rotor doesn't move, there are no abrading forces on the repair area.

Kind of on the same subject is this pic of what could be a very serious problem with either type of gland. This is the bronze fitting, or whats left of it, on my H27. Discovered it while replacing the original gland with a PSS. Good idea to loosen and slide the rubber hose forward and inspect what's happening under it.

Davidasailor26 · Apr 10, 2016

Does anyone have hard data on dripless seal failures vs catastrophic conventional packing failures? I know we've all heard anectdotes, but I'm curious as to whether the risk is really any higher.

uncledom · Apr 11, 2016

I don't think the hole you wind up with is much different between the two shaft seals. Either way it's good to have a working bilge pump or two.

kito · Apr 11, 2016

When I replaced my coupling, shaft and strut I debated between reusing my original stuffing box or an expensive dripless PSS type. I decided on just using the Teflon impregnated packing. Seems like to be best of both options for me. I didn't like the idea of having to remove the shaft coupling for maintenance either. I know there are thousands of happy customers with the PSS though.

woodster · Apr 11, 2016

i like the teflon packing as well ...the PSS system is nice but not $400.00 nice especially when the packing is under $10.00 and about two hours of my time

mauruuru · Apr 11, 2016

Current boat came with dripless from factory. Previous two boats were old gland type. Love the dry dripless packing. Boat is 5 years old and has been to caribbean and back with zero issues. All I do is inspect it periodically and make sure water is in the discharge line

Roland5048 · Apr 11, 2016

Have had a PSS dripless now for over eight years. Just replaced in Jan. when I was it the yard. PSS was actually OK, but had started dripping a bit recently. Not a failure of the PSS, but, most likely, a piece of debris that had gotten in between the faces of the bellows and the rotor. It apparently washed out and the dripping stopped. These are not maintenance free, nothing is, but is a lot easier than contorting myself like origami to repack the gland. I just make sure to inspect it every time I'm at the boat.

Justin_NSA · Apr 11, 2016

Here's the topic from a different perspective. If you are getting to be an old fart like me, going on 61, which way would you go? I stay pretty fit, but I want to sail and be able to maintain my boat for many more years. I look at every maintenance and modification from a longevity and accessibility view anymore.

kito · Apr 11, 2016

Justin_NSA said:
Here's the topic from a different perspective. If you are getting to be an old fart like me, going on 61, which way would you go? I stay pretty fit, but I want to sail and be able to maintain my boat for many more years. I look at every maintenance and modification from a longevity and accessibility view anymore.

I can replace packing very easily. Maybe not as easy with a dripless. I would have to disconnect the coupler from the tranny and then the p.i.t.a. to remove the coupler from the shaft. Last time I did that I failed miserably. That's why I have a new shaft. I spent 2 weeks trying to pull the shaft out of the coupler and finally gave up.

peacheykeen · Apr 11, 2016

Not to repeat all the previous replies After 30 years on multiple boats, Teflon packing in a stuffing box is foolproof, and the shaft, strut, rudder (?) don't have to be removed with a haul-out, to maintain it. You can replace two of three packing strands in the water.