Stern Gland

I am aware of very few PSS failures although none of these involved rupture of the hose. As ever, I would like to hear of case histories with photos.
The ones I know of involved movement of the rotating seal face when the grub screws were not tightened sufficiently. Some people put a hose clip against it as additional protection. Having said that my PSS has been installed for around 10 years with almost no problems, and that one was very minor. I know many other users with no problems after similar periods of time.
 
IIRC, the Patents have expired on the Volvo seal so now others can freely make and sell them.

I believe the ASAP Orbitrade version is from the company that actually manufactured the Radice and Volvo seals for those two companies.

I might have been given duff gen - a chandler and engine specialist told me this some years ago - but I believe it is correct.

Properly installed, a Volvo type stuffing box has the advantage over traditional stern glands, especially with the Radice/Orbitrade improvements of breather tube and grease point.

And, IMHO, none of the disadvantages.
 
Poey50 said:
I saw that photo and the accompanying post suggesting that Volvo seals can split in half and therefore fail catastrophically. I found the photo was copied from another post in which the author had cut an old seal in half to show the position of the lips. It is fake stern gland news.
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...and I thought the fakey news thingy was limited to the Brexit forum on here! :rolleyes:

Well all done for investigating, thanks.
 
Poey50 said:
I saw that photo and the accompanying post suggesting that Volvo seals can split in half and therefore fail catastrophically. I found the photo was copied from another post in which the author had cut an old seal in half to show the position of the lips. It is fake stern gland news.
Click to expand...

Posted by PSS or Deep Sea Seals? ;)

Poey50 said:
... unless you have a 1 inch shaft and a 1.75 inch stern tube in which case only Volvo part number 3819724 will do. Grrr ....
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I know I have a 25mm shaft but it was changed a few years before I got the boat and she's 50 years old, so I wouldn't be too surprised to find an imperial stern tube. Finding the right fitting could be interesting...

With a bit of luck it'll be something close enough to a standard metric size that I'll be able to persuade one to fit. ITSM that the shaft size is critical, but for fitting a rubber tube over a pipe and tightening down with a jubilee clip or two, the size is less critical.
 
I recently fitted new replacement DSS's, I know they're not particuarly well regarded, but it was a like for like replacement.
All I can say is one of the original sets started dripping and gradually got worse, I don't know the age of them as they were on the boat when we bought it.
The face of the static seal was very badly scored and grooved so its a surprise it was sealing as well as it was.
The only tricky part was removing the gearbox coupling off the shaft which was carried out by Kent Marine Services.
No need to burp the seal as it has a Y piece, one to vent, the other to supply water from the engine.
They also have an "emergency" fitting, basically a big hose clip (red tag) which compresses the fixed part of the seal onto the shaft, which, obviously you have to secure so it doesn't rotate.
The old rotating seal showed no sign of splitting but was far less elastic than the new one.

69844208_10217468227875155_4580870212194140160_n.jpg
 
rotrax said:
Properly installed, a Volvo type stuffing box has the advantage over traditional stern glands, especially with the Radice/Orbitrade improvements of breather tube and grease point.

And, IMHO, none of the disadvantages.
Click to expand...

You don't count a failure as potentially dangerous with loss of engine and the costs and trouble of having to lift out for repairs as disadvantages?

OTOH, a dripping traditional gland can just be nipped up or repacked afloat easily.
 
Graham376 said:
You don't count a failure as potentially dangerous with loss of engine and the costs and trouble of having to lift out for repairs as disadvantages?

OTOH, a dripping traditional gland can just be nipped up or repacked afloat easily.
Click to expand...

Volvo-type seals (Volvo, Orbitrade, Radice) don't fail catastrophically, they start by weeping slightly, giving adequate time to get them fixed.
 
vyv_cox said:
I am aware of very few PSS failures although none of these involved rupture of the hose. As ever, I would like to hear of case histories with photos.
The ones I know of involved movement of the rotating seal face when the grub screws were not tightened sufficiently. Some people put a hose clip against it as additional protection. Having said that my PSS has been installed for around 10 years with almost no problems, and that one was very minor. I know many other users with no problems after similar periods of time.
Click to expand...

i hear all the negative responses about the PSS but mine is fine for the last 5 years.
It can develop a slip if not installed properly as you have said Vyv. It needs checking and i take on maintenance of checking each layup. I will this year remove all grub screws and slide the faces apart then refit with new grub screws etc to the right tolerances.
 
pvb said:
Volvo-type seals (Volvo, Orbitrade, Radice) don't fail catastrophically, they start by weeping slightly, giving adequate time to get them fixed.
Click to expand...

But there's the hassle of the work and the cost of a new seal plus haul out and yard fees, as happened to Heckler a month or so ago as well as another guy I met in the same yard this year. Fortunately, they were both capable of doing the work themselves so no labour charges.
 
Graham376 said:
But there's the hassle of the work and the cost of a new seal plus haul out and yard fees, as happened to Heckler a month or so ago as well as another guy I met in the same yard this year. Fortunately, they were both capable of doing the work themselves so no labour charges.
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Which seals? Does not sound like Volvo type from your description.
 
Graham376 said:
You don't count a failure as potentially dangerous with loss of engine and the costs and trouble of having to lift out for repairs as disadvantages?

OTOH, a dripping traditional gland can just be nipped up or repacked afloat easily.
Click to expand...

After extensive research over several years I am unaware of any dangerous failures of the Volvo type seal.

So far, none on this post have reported any either.

As to your last sentence, look up post #17 - The traditional stern gland fitted to my current boat was unadjustable without chiseling the nuts with large and long screwdrivers.

Three seasons on my Orbitrade has been greased 3 times and is bone dry. It needs no burping after drying out and should be dry and reliable for many more years.

And it was not expensive.
 
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Heckler said:
Im still a fan of Volvo seals, my sudden liftout at Bruces last month was because the three year old Orbitrade look alike started leaking. Just doing a write up of the episode for PBO. Bottom line, the lip seals were badly worn or stretched, I cant quite make out which it is.
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Can you describe the quantity of leak/degree of urgency?

Any idea of the cause?
 
pvb said:
They don't need expensive maintenance, and they really are not prone to "sudden failure and sinking"! When you've actually experienced one, come back and tell people how good they are.
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I recently started athread re Volvo Penta's which is an engine installed on a Freedom 35 I have now purchased, and your advice on starting it was spot on, not having experienced one previously.

Following running the engine stern gland seal is leaking water which will be repaired.
I researched the gland type and this is the result:

The Volvo seal is entirely constructed from rubber, combining the hose that attaches to the stern tube with lip seals that prevent leakage of water into the boat. An internal bearing is water lubricated while the lip seals need to be greased occasionally from a small sachet available from the manufacturer. The lips run directly on the shaft, which needs to be smooth and damage free. Volvo seals are reliable and long-lasting, a life of 10 years being common.
The seal is not vented in any way. On immersing the seal, whether at first launch or after drying on a tide, air will accumulate in the bearing. Running the shaft in this condition will cause a squealing noise and rapid wear. It is necessary to ‘burp’ the seal, compressing it in the lips area by hand to allow air to be dispelled. A small amount of water should be allowed into the boat to ensure that no air remains.

A shaft seal would normally be replaced with the boat on the hard. It is possible to change a Volvo seal (or most other types) afloat, as this video shows. Not advisable without some experience of doing it in easier circumstances.

The video is private and doesn't run.

Mt question is, what does 'On immersing the seal' mean? Is it bad punctuation and should it read: On immersing, the seal' as surely the seal does not run immersed.
The boat is currently in the water with someone keeping an eye on it and the pump running until she is moved to a drying out berth very soon hopefully.
Mike
 
Freedom35 said:
Mt question is, what does 'On immersing the seal' mean? Is it bad punctuation and should it read: On immersing, the seal' as surely the seal does not run immersed.
The boat is currently in the water with someone keeping an eye on it and the pump running until she is moved to a drying out berth very soon hopefully.
Mike
Click to expand...

On launching, when water comes up the prop shaft tube, air will accumulate in the bearing......
 
Nauti Fox said:
I recently fitted new replacement DSS's, I know they're not particuarly well regarded, but it was a like for like replacement.
All I can say is one of the original sets started dripping and gradually got worse, I don't know the age of them as they were on the boat when we bought it.
The face of the static seal was very badly scored and grooved so its a surprise it was sealing as well as it was.
The only tricky part was removing the gearbox coupling off the shaft which was carried out by Kent Marine Services.
No need to burp the seal as it has a Y piece, one to vent, the other to supply water from the engine.
They also have an "emergency" fitting, basically a big hose clip (red tag) which compresses the fixed part of the seal onto the shaft, which, obviously you have to secure so it doesn't rotate.
The old rotating seal showed no sign of splitting but was far less elastic than the new one.

69844208_10217468227875155_4580870212194140160_n.jpg
Click to expand...

My Achilles 9m had a DSS which had been used for years by the previous owner on a deep swinging mooring. When I moved it to a “drying” deep mud half tide mooring, it lasted a further 3 years. I replaced like for like; stern tube incompatible with Volvo and Radiche. This one also lasted 3 years. Abrasive mud? Now conventional, barely dripping.
 
Pye_End said:
Can you describe the quantity of leak/degree of urgency?

Any idea of the cause?
Click to expand...
It started as a few minutes after burping then stop, then two and a half weeks later after, it got to be a drip every couple of seconds. Wasnt catastrophic but I was on my way to Albufeira for 9 months and as we arent resident all the time, discretion was the better part of valour and Bruces was nearby. I didnt do anything different cruising wise than I normally do. Interesting that the lip seals were about the same size as the shaft, so no stretch to grip the shaft. They seemed flexible enough so either worn or lost tension. I had a 5 years old vp one and that wasnt like it. The new vp definitely was a lot grippier.
 
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