Stern Gland

RivalRedwing said:
+1 the only challenge might be matching a Radice to you stern tube & shaft sizes but it's not insurmountable
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When I fitted the first Volvo seal to a GibSea 96 I had to machine up and epoxy a thinwall tube in place over the too small diameter stern tube. I made it from an aluminium scaffolding tube. Still working today, 14 years on, with the current owner still using the Volvo stuffing box I fitted then.

As you say, not insurmountable.
 
Graham376 said:
I've seen two boats hauled out this year just because of leaking "rubber or similar" stern glands, makes not known. I've had traditional stuffing boxes for 26 years and never had a problem adjusting them to be virtually drip free.
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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.
 
rotrax said:
The guy who wired up my plotter and radar on a previous boat was debating changing his Volvo stuffing box as he had been advised that they had a five year life.

His was drip free and working perfectly at 14 years since he fitted it.

Many other recorded instances of long life and conversly, very few stories of drastic failure.
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Like others, my current Volvo dripless seal is now 20 years old. I am going to replace it this winter not that it is leaking but as I feel that I should. The use has been on the west coast of Scotland so very clean water (no silt) and moored in Crinan Canal so fresh water. I’d imagine the silt content would make a difference.

Not thought about the alternatives to buying the Volvo but the Radice one looks interesting. Has anyone fitted it to a Sun Odyssey 342 or similar as I note the comment about the stern tube size?
 
Stemar said:
.....................Jissel's on a drying mooring, so I'd rather not have to burp the seal every time it dries out. I'm drawn to a face seal, rather than a lip seal, as I don't yet know what condition that bit of my propshaft is in, but it's for a 50 year old Snapdragon, so the ...............................................................budget is limited.
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You may not want a face seal then, £300 + here:

https://www.asap-supplies.com/prope...eller-shafts/pss-hi-speed-shaft-seal-808303-1
 
Graham376 said:
If they last that long, why do Volvo say - Important! The seal shall be replaced after 500
operating hours or at least every fifth year.?
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They would say that, wouldn't they? Just to be on the safe side. Similarly, they say their saildrive diaphragm needs replacing every 7 years, but there's no evidence of one having failed.
 
I'd have thpught it was pretty obvious that if a Volvo seal fails (splits) the vessel floods uncontrollably and is in a potential sinking condition if the pumps can't keep up until yhe boat is dried out or lifted, a tall order at short notice in many places.
An 'old fashioned' grease packed seal simply cannot do this and is consequently much safer, surely?
 
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I experienced a PSS face seal failure which flooded my mate's boat swiftly and uncontrollably. By luck, we were moored in Falmouth Harbour at the time and not halfway to France..... and by further luck the ILB was exercising nearby and got a salvage pump to us within 2 minutes of us speaking to Falmouth Coastguard. They overheard the call.

We discovered from yard foremen that they knew of several similar, and a web search discovered a dozen more.

There are those who insist they are 'the best thing since sliced bread' simply because their personal installation hasn't failed. Yet. I'm told that isn't a 'statistically significant sample' and, statistically speaking, it is insignificant. What is very significant is that, if the damn thing fails, the boat sinks..... unless you are very lucky, as we were.

Researching 'how come', I discovered you cannot inspect that they are installed properly while maintenance involves replacing some grub-screw parts where, again, there's nothing to show any incorrect installation.
 
I've got to change my deepwater seal arrangements too.
At present I have a bronze casting consisting of a mounting plate and turret with a traditional 2 nut grease-lubed stuffing-box.

There is only 105mm between the new engine's gearbox drive flange and the deadwood to fit a seal and the bronze one is 145mm. I can't make more room.

If I cut the turret down and either sleeved it over or machined it smooth a Volvo or similar seal would clamp over it and probably just go into the space available. Can I remove the packing and turn the old grease packed seal into a rubber-gaitered seal with the shaft floating in the old casting? Would this work?
 
Old Bumbulum said:
.................... Would this work?
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Can't see why not, though what I think you have is probably the system that is most unlikely to fail in respect of flooding the boat.

Your new system would rely on a bellows to keep water out, in a similar way all patent solutions ultimately place their faith in plastic and rubber seals etc. I had this type for years and it was fine but you do have to keep an eye on the gaiter, tho they are very robust.

You have probably seen Vyv Cox's pages:

http://coxeng.co.uk/stern-gear/
 
I have a traditional bronze stern gland that was easy to repack. Not hard to undo the housing from the nut with 2 plumpers pliers. I repacked with 5mm 'Rami teflon". After using the engine i just give one two pumps to the greaser and thats all. Under power i may have 1 small drop every 10-15'' but feels correct since gland gets luke warm. You you should look for stern glands that will fit your engine mounting. A volvo rubber stuffing box is not recommended for flexible engine coulpings
 
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zoidberg said:
I experienced a PSS face seal failure which flooded my mate's boat swiftly and uncontrollably. By luck, we were moored in Falmouth Harbour at the time and not halfway to France..... and by further luck the ILB was exercising nearby and got a salvage pump to us within 2 minutes of us speaking to Falmouth Coastguard. They overheard the call.

We discovered from yard foremen that they knew of several similar, and a web search discovered a dozen more.

There are those who insist they are 'the best thing since sliced bread' simply because their personal installation hasn't failed. Yet. I'm told that isn't a 'statistically significant sample' and, statistically speaking, it is insignificant. What is very significant is that, if the damn thing fails, the boat sinks..... unless you are very lucky, as we were.

Researching 'how come', I discovered you cannot inspect that they are installed properly while maintenance involves replacing some grub-screw parts where, again, there's nothing to show any incorrect installation.
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It would be interesting to hear specifically of Volvo/Radice seal catastrophic failures, and of traditional gland failures.

Re. the 'statistically significant v's catastrophic outcome argument - my old greaser was held on with a short section of rubber hose, plus a few clips. There were several points of potential failure, so it still had the possibility to be catastrophic.

Proper installation - the PSS is a bit more involved than the Volvo/Radice. So long as the shaft is clean and reasonably centred the Volvo/PSS should work, and even if it is not centred it will start dripping long before it falls apart.

For me, the benefits outweigh the risks, but each to his/her own.
 
Old Bumbulum said:
I'd have thpught it was pretty obvious that if a Volvo seal fails (splits) the vessel floods uncontrollably and is in a potential sinking condition if the pumps can't keep up until yhe boat is dried out or lifted, a tall order at short notice in many places.
An 'old fashioned' grease packed seal simply cannot do this and is consequently much safer, surely?
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Have you seen the cutaway photo of a Volvo seal on Vyv Cox's website? Here it is below. The rubber is incredibly thick and very tough; I can't see in what circumstances it's ever going to split. And a traditional gland connected with a rubber hose is just as unlikely to split. Something like the PSS seal is a different case entirely, and there have been cases of serious failure. But you'll struggle to find any tales of Volvo seals failing catastrophically.

DSC_6040a.jpg

Photo: Andy Gray, from Vyv Cox's website.
 
Thanks for all the replies - plenty to think about.

I understand the arguments about catastrophic failures in dripless seals, but think the same could be said for my setup with a stuffing box on a rubber tube. If the tube is dislodged or splits, you're no better off than if the same happens on a dripless job. Given my less than satisfactory experiences with a stuffing box, I think I'm going to go for a dripless one.

Of the lip seals, it seems the Radice has all the advantages of the more expensive ones, plus no burping, so I think that's favourite as long as my shaft is in good condition where it matters. If not, it's a toss-up whether a new shaft plus a Radice or a Deep Sea face seal would be better value for money.
 
Over the years there have been many tales of flooding from all sorts of stern gear, one bloke posted a photo of his Volvo seal split, there have been displaced units, inverted seals and lots of moaning about various oil lubricated jobbies and face seals.

Given that only a small proportion of a fraction of all problems are reported here - in the end you take a punt. Personally, if his propshaft is clean I think Stemar's proposed choice is fine. For what that's worth.
 
doug748 said:
... one bloke posted a photo of his Volvo seal split, ...
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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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