Sam's is your source for Hatteras and Cabo Yacht parts.

Enter a part description OR part number to search the Hatteras/Cabo parts catalog:

Email Sam's or call 1-800-678-9230 to order parts.

PSS Shaft Seals

  • Thread starter Thread starter z28jimi
  • Start date Start date
  • Replies Replies 69
  • Views Views 25,993
Just to put this out there... McMaster-Carr sell a clamp that will work with this, I think it is stainless, the one in the photo might have come from them. But we used a hose clamp, on each side.

The instructions ARE clear. And when mine loosened, all four setscrews were in place. But the points wear off the setscrews, and I didn't check it like I ought to have done. Now, this spring, you can bet they will get checked.
 
DCMY #92 said:
Some timely information: My neighbor hauled his 43 Saber MY today (unplanned) to diagnose and repair a badly failed Lasdrop seal. Don't know what initiated the failure yet, but it wasn't loss of cooling water. The seal that failed is 15 months old with 120 hours on it. He previously had PSS seals. Went to Lasdrop because of a PSS failure 15 months ago.
Click to expand...

Correction of the previous preliminary information: My neighbor's Lasdrop seal failure was attributed to loss of cooling water after full investigation. The seal cooling water was acquired downstream of the main heat exchanger. Crud from the HE fouled the cooling water tube, starving the seal. The seal cooling water tap has been relocated to just downstream of the raw water pump on both engines.
 
Boatsb said:
Size matters. Whats the od of the tube and the shaft size. I may even know where some are.
Click to expand...

So crawled around and vacuumed out bilges yesterday and various other slave work. Shafts 2", Logs 3". I have a Duramax (20yrs?) on one and a Tides (10+ yr old) on the other. I want to install something new on both while out. Haven't decided to go stuffing box with duramax packing or go PSS or other mechanical seal. I'd like to get away from the need to have pressurized water to the seal...I think my gears can freewheel so I can run on 1 engine to save hours and fuel









......there's a joke in there.
 
Last edited:
If you want a recommendation, I would go with the PSS units. If you want regular packing glands, Buck-Algonquin would be your best bet. They are actually located here in MD. Groco may also make regular shaft-log/packing gland units, I can't recall, but they are up here, too.
 
krush said:
So crawled around and vacuumed out bilges yesterday and various other slave work. Shafts 2", Logs 3". I have a Duramax (20yrs?) on one and a Tides (10+ yr old) on the other. I want to install something new on both while out. Haven't decided to go stuffing box with duramax packing or go PSS or other mechanical seal. I'd like to get away from the need to have pressurized water to the seal...I think my gears can freewheel so I can run on 1 engine to save hours and fuel









......there's a joke in there.
Click to expand...


Wise ass. I almost dropped the phone when I read that.
 
Of the face seals (axial "mechanical seal") there are PSS, Lasdrop Gen II (must be genII model), and Duramax.

The Gen II and the Duramax both look to be built strong and better than PSS. LasDrop Gen II uses exhaust hose like a stuffing box. Duramax has ABS classification cert and a big spring inside it's "bellows". I got more info, I have a 10yr old tides seal and about a 10yr old duramax lol. I don't really think lip seals are the best solution in this case...I have really silty water where I run.

Also, though this is a marketing flyer, it does have general information on shaft sealing types: http://www.duramaxmarine.com/pdf/ShaftSeal.pdf
 
Last edited:
Since you already have one Duramax, you should probably just get a second one. Any spares you have to carry would fit both.
 
I can't see a reason to change from Duramax to anything else and agree that upgrading the other to match would seem to be the best approach.

I have to admit their drawing (page 6) is a bit confusing because the arrows that point to the seal ring and friction ring point to the same ring? The smaller diagram on the same page seems to back up my interpretation.
Then there is the sea gasket. I get it that the friction ring slides inside the adapter. But that sea gasket, if it is tight to the shaft, will prevent the supplied water from escaping the assembly? If that bellows fails you're still going to get a mess of water in the bilge but you could probably wrap it with "rescue tape".

It looks pretty much like Lasdrop Gen II except they mounted the spring on the rotating assembly thus making it susceptible to the hose collapsing beyond the ability of the spring to maintain seal pressure.

I like this one better than Lasdrop, but still have reservations if the shaft clamp is not stainless. My experience has me concerned that these will slip since they are not keyed. But then if they were, they could spin the whole assembly and make a real mess out of everything. The mating surfaces of the seal seized on ours and the shaft spun inside the clamp. Sounds really weird but trust me it happened. Salts or calcium caused the faces to lock to each other. I was able to bust it loose but it left me wondering just how much force a non metallic shaft clamp could supply.
 
Last edited:
Dan Mapes said:
I can't see a reason to change from Duramax to anything else and agree that upgrading the other to match would seem to be the best approach.

I have to admit their drawing (page 6) is a bit confusing because the arrows that point to the seal ring and friction ring point to the same ring?
Click to expand...

Once it gets above 10F, I'm going to go inspect the duramax on the boat closer, and give them a call to ask about renewal parts. After research and independent analysis, I think the duramax design is probably the most robust. It's the only one, as far as I can tell, that has ABS class rating--if they failed and sunk a lot of vessels, they wouldn't have this LOL.

As for how it works, it took me a couple minutes and looking at page 6 and 7 to fully understand it.

The "shaft clamp" rotates with the shaft and is two pieces. A nylon clamp is tightened on the shaft (instead of set screws like PSS). The "seal ring" is 316SS and is attached to the shaft clamp AXIALLY with 3 compression screws. The SS seal ring does not touch the shaft...it is insulated from the shaft with an o-ring. This reduces electrolysis problems.

The SS Seal Ring spins with the shaft and rides against the "friction ring" that is stationary and made out of "oil impregnated nylon" (instead of graphite/etc on PSS). Look at page 7 and you can see the friction ring is actually very long, almost looking like a cutless bearing shape. On the engine end, it seals against the rotating SS "seal ring". Pretty simple and just like other systems.

The difference is on the prop end, the friction ring has a "sea gasket" attached to it that connects to the "adapter ring" (adapter ring is attached to shaft log). What this means is that there IS NOT water inside the yellow bellows under normal situation. Very different than the other designs out there. If the "sea gasket" fails or the "friction ring" cracks in the body, it will leak water, but the yellow bellows will now be holding the sea water out, like the PSS bellows.

"The Duramax Main Seal Body has been
designed to eliminate the use of a rubber
bellows or spring-loaded hose. It employs
a rigid, spring-loaded, composite body
that cannot be knocked off the seal face.
The main seal body is attached to an
adapter ring by a neoprene sea gasket.
If this sea gasket were to fail, the seawater
would enter the sealed spring chamber.
This special design feature provides
a secondary seal to the main body seal
and would prevent the entry of seawater
into the vessel."
 
The drawing does not show that sea seal riding on the shaft. It mates with the friction seal assembly. There won't be water in the bellows but it will come all the way up to the friction/seal ring and Lasdrop has similar capability but the components are reversed.
 
Yes, water comes up too the interface of the friction ring (stationary) and seal ring (rotating).
 
Damn, this thd is growing. So I have the PSS in the boat, and the Duramax in the truck. I suspect that almost all systems will serve well and not sink the boat if we just occasionally open the hatch and eyeball using a flashlight.

Krush likes the duramax and provides much rational with many words to describe the system. I can describe the PSS system with fewer words I like simple on such devices. The stationary SS disc on the PSS is equiped with 2 o-rings, and the (4) set-screws we have spoken of earier. PSS does not require water-injection below 12 kts. I troll for hours and my shafts freewheel like crazy. I never worry about one-engine operation.

If shaft is pulled for any reason (last time was new cutless), o-rings and set screws are replaced. About $5 and next day in mail from PSS.

Earlier, Krush linked us to a cruisers forum where some guy had these huge stainless clamps installed as back-ups. Geez guys not everyone an engineer, I guess. Use those monsters as crab pot weights and just go with as $1.00 hose clamp! Would you believe a 747 (or whatever you got) has no system whatsoever that requires more than (2) safetys. So yep, if that locknut and safety-wire both fail, we are going down.

Gary
 
Took me a moment. Different Duramax...

I don't think the SS rotor is stationary on the PSS unit. It is locked to the shaft by the setscrews, and spins with it. The O-rings keep the water out, as well as the face seal between the rotor and the nose of the carbon-fiber housing that fronts the bellows.

I think any of these systems are quite reliable if you keep an eye on them and maintain them. A lot of it concerns having the room to get in there. I think the 41 convertible has more room back there than my boat does. No excuse, I freely admit.
 
Last edited:
GaryNW said:
PSS does not require water-injection below 12 kts. I troll for hours and my shafts freewheel like crazy. I never worry about one-engine operation.
Click to expand...

I believe most of them can run slowly with no water injection...provided there is water and not and air bubble around the seal. I think I read these same words on all the brands.

"In order for a mechanical face seal
to work correctly, a thin film of water
is required between the two seal faces.
This water film acts as a lubricant,
carries away frictional heat and maintains
the proper seal face temperature.
Every Duramax Shaft Seal System has
an air vent/water injection fitting that
provides adequate water lubrication at the
seal face. For a displacement hull (sailboat,
trawler, etc.) - the fitting is used to vent
or bleed off any air trapped at the seal face,
which could prevent water from reaching
the seal faces.
For high-speed hulls (approximately above
12 knots) - as the vessel reaches higher
speeds, a vacuum can occur on the stern
tube which draws the lubricating seawater
outboard and starves the seal faces.
In these types of installations, the fitting
is used to inject water to the seal faces."
 
I have heard one story where someone had to use acid to boil out the seals because of calcification.

I know Lasdrop recommends running fresh water through them if you intend to lay the boat up.
 
luckydave215 said:
When some a$$hat volunteers his unwanted opinion on motorcycles I can't resist telling them that I raced for 35+ years, 20 of them pro, and currently, at 60 years old (!) hold a land speed record on a 400hp motorcycle, and still race sports cars.
After the shock wears off they promptly accuse me of probably being a gun nut too (I live in California).
Small minds.......
Click to expand...
So you raced motorcycles, Good Stuff. I raced B-Class Motocross off and on most of my life. I know it's not the same as road racing motorcycles, but non the less a lot of people look at you strange when you tell them. All of them always ask aren't you afraid of getting hurt jumping those bikes around, that's dangerous ya know? Everyone always thinks the jumps are the scary part. That is untill you tell them how a start works. Where a full gate of 40 handle bar to handle bar riders are racing Full Throttle for a turn that's only wide enough for about 10 riders all come together at once. To me that first half a lap until everyone starts to spread out is always the most tense part of the race.

Tony
 
Where a full gate of 40 handle bar to handle bar riders are racing Full Throttle for a turn that's only wide enough for about 10 riders all come together at once. To me that first half a lap until everyone starts to spread out is always the most tense part of the race.
Click to expand...
Especially when it's open novice class :eek:
Experts and Pro's will do everything they can to take your line away and/or slam the door, but will give that tiny bit or room you need to stay upright. they know that if they tangle with you....they crash too.
Novices haven't figured that out yet.
 
Last edited:
Last week, got my first windows 10 machine. I assure you no shaft seal, or motorcycle will ever be the POS that windows 10 is. And I can't figure out how we morphed into bikes on the thd.

A tad bit more on the PSS setup. Yes, Jim, the stainless disc rotates with the shaft and is secured with 2 set screw positions, each to receive 2 setscrews. The 2nd being the locking device. So the locking function is our 1st safety and actually we have redundancy in that one setscrew could handle the load. I can compress the bellows 1" to specs with 2 thumbs. Then my hose clamp is the 2nd saftey. The stationary carbon disc has no contact with the shaft due to bore diameter. This insures shaft does not try to spin it or wear on it.

Here is what I look for (shaft seals, radars, engines and everything else. In order:
1) performance of intended function.
2) elegance of design
3) quality of build and materials
4) customer support. If the thing is 20 years old and I am the 4th owner, I want to get someone on the phone within 5 minutes who actually knows enuf to answer technical questions. Really good when that same person can sell and ship me parts.
5) safety would be up there but 2) and 3) cover it.

Gary
 
And I can't figure out how we morphed into bikes on the thd.
Click to expand...
Happens all the time. Boats, bikes, hotrods, and airplanes go hand in hand, there are many of us on this board that play with all of them.
My condolences on your Windoze 10 misery, it is indeed a POS
 
Spoke with guy at Duramax today on the phone. Lots of good info....he just warned be warned about our muddy/silty water with any face seal, not just theirs.
 
You must log in or register to reply here.

Forum statistics

Threads
38,156
Messages
448,753
Members
12,482
Latest member
UnaVida

Latest Posts

Trending content

Back
Top Bottom