PSS prop shaft seal

[snooks]

1. Take a large tot of single malt
1. Flog the PSS on e-bay
2. Buy and install a Volvo Penta rubber stuffing box, the only good value component sold unfer that brand name.
3. Burp it by squeezing every time when refloating after drying out.
4. Squeeze a tiny amount of grease in once per year.
5.Settle down and open a good bottle of wine, secure in the knowledge that your sern gland is good for a minimum of 5 years, even if the vessel is used daily (more like 20 years with normal recreational use)

Why waste money buying another seal when the PSS seal is a perfectly good bit of kit?

If you can't access your stern gland easily (like me) then a Volvo seal is a right pain in the whatsits.

We have PSS seal (not a PSS type seal) no faults, no drips, after the first 10 hours it leaves a black spatter from the carbon bedding in, since then nothing...

 

[Boo2]

Manecraft seals

Has anyone here come across the Manecraft seals ? They have the facility that you can close the seal if it fails thus avoiding sinking your boat.

Just wondered if anyone had any info on how good they are ?

Boo2

 

[Simondjuk]

If it's the same thing as the Deep Sea, I wouldn't go anywhere near it myself. The PSS is incredibly simple and just works, why use another?

 

[fuss]

Thank you all for your replies.

I will fit the PSS and see how well I will sleep.

Well I look at it like this, especially when its new...
Its well engineered... and if installed correctly....How catastrophically could it suddenly fail? At worse it would leak a bit wouldnt it, not let in gallons.

 

[rotrax]

I had a conversation with the guys on the Volvo stand at Southampton boat show re-burping. I can't see how it's done! The rubber is so stiff. I must admit that I've never been on a boat fitted with one and it wouldn't suit me anyway being on a drying mooring. They have the advantage of being simple and cheap and I prefer a lip seal to a face seal as it's more positive but for the moment I'm sticking with the old packed gland.

Ah-Burping! Our Volvo seal is in a very deep bilge. I must be at full stretch to reach it. I use a pipe grip with tape on the jaws to protect the rubber.The actual bits that do the sealing are not stiff. They are quite long, quite soft-in comparison to the body-and water pressure appears to be what keeps the flexible lips in place and sealing tight. I fitted one on our previous boat. I had to epoxy a thin sleeve to the stern tube to bring the diameter up to the Volvo size. It worked perfectly-and still is 5 years later. One of the first jobs I did on our current boat was to deep six the old stuffing box which had put a 1mm groove on the shaft. As with any seal the shaft alignment must be spot on. As another poster said, they are one of the few Volvo Penta marine spares for sensible money. They also work very well. For your situation there is a similar seal that has a bleed tube attatchment for drying moorings. No doubt another forumite who can remember the name will be along to tell us soon...........................

 

[Ruffles]

Has anyone here come across the Manecraft seals ? They have the facility that you can close the seal if it fails thus avoiding sinking your boat.

Just wondered if anyone had any info on how good they are ?

Boo2

Not that great really. Mine used to leak slightly with the engine at idle. It doesn't support the shaft and the engine idle speed seems to coincide with the shaft resonance (not the fault of the seal).

Clamping the rubber to the shaft is a problem as it will tend to creep back. A couple of jubilee clips on the shaft solve that. Also the seal faces tend to stick with verdigris if the boat isn't used for a while which is a bit worrying as the rubber is very soft.

Replaced it with the VP seal ages ago.

 

[hans]

Pss type shaft seal

We have had one of these for 10 years. Changed the rubber seal after 7 years as suggested by manufacture. Never had any problems. Needs burbing if you have been ashore, but not after "drying out" in mud berth. We have "dried out" like this several times in E Frisan islands and on UK E coast, no problem as long as yacht sinks into soft mud. The Volvo seal in addition to burbing apparantly formally wants greasing once a season - not an easy exercise and may require medical equipment (one of those intravenous syringes with plastic covering). Good luck with the seal!

Hans Valderhaug
S/Y Anna
Oslo

 

[catalac08]

To my mind something that is safety critical on a boat should not be capable of catastrophic failure causing a sinking even if badly fitted or abused in some way. This sort of shaft seal does not seem an improvement over a traditional stuffing box that at worst will have a constant drip. I think you are right to worry, so would I.
There are other things that are also a concern such as flimsy plastic through hull log fittings but there is not a lot of choice in this although I will remove mine at the fist convenient time!

 

[HunterWanderer]

What concerns me is the vent connection. Just jubilee clips round the hose and no seacock.
A friends new Beneteau 257 has a vent and the hose goes up behind the instrument panel. Guess what happens when you get in a lumpy sea!

 

[Simondjuk]

To my mind something that is safety critical on a boat should not be capable of catastrophic failure causing a sinking even if badly fitted or abused in some way. This sort of shaft seal does not seem an improvement over a traditional stuffing box that at worst will have a constant drip. I think you are right to worry, so would I.
There are other things that are also a concern such as flimsy plastic through hull log fittings but there is not a lot of choice in this although I will remove mine at the fist convenient time!

What's the catastrophic failure mode you envisage a PSS suffering?

 

[Simondjuk]

As with any seal the shaft alignment must be spot on. <snip> For your situation there is a similar seal that has a bleed tube attatchment for drying moorings. No doubt another forumite who can remember the name will be along to tell us soon...........................

The PSS will cope with more misalignment than any shaft/stern tube I've ever seen will allow. Regarding the second part, the PSS self-bleeds.

 

[Simondjuk]

What concerns me is the vent connection. Just jubilee clips round the hose and no seacock.
A friends new Beneteau 257 has a vent and the hose goes up behind the instrument panel. Guess what happens when you get in a lumpy sea!

At a guess, the vent barb has an ID of about 4 or 5mm. Your log is a vastly bigger hole with no seacock fitted. Do you lose sleep over that falling off for no good reason whilst away from your boat? What about a through hull or the rudder falling out? All are equally as unlikely to happen.

 

[HunterWanderer]

At a guess, the vent barb has an ID of about 4 or 5mm. Your log is a vastly bigger hole with no seacock fitted. Do you lose sleep over that falling off for no good reason whilst away from your boat? What about a through hull or the rudder falling out? All are equally as unlikely to happen.

But rubber hoses can deteriorate in a relatively short time. Worth checking regularly.

 

[Suttle]

Has anyone here come across the Manecraft seals ? They have the facility that you can close the seal if it fails thus avoiding sinking your boat.

Just wondered if anyone had any info on how good they are ?

Boo2

I have a Manecraft seal fitted five years ago and no leaks. Was not my first choice but the PSS was too long and a Volvo seal too big for the stern tube.

 

[Simondjuk]

But rubber hoses can deteriorate in a relatively short time. Worth checking regularly.

Just like every other below the waterline hose on a boat, all of them many times the cross sectional area of the vent hose.

On my last boat, I removed many 30 year old hoses, all in hardened but sturdy condition. You'd have struggled to damage any quite deliberately without shears or a hacksaw, let alone have them fail spontaneously.

The quality of hose used, and hence it's lifespan, is decided by the installer/owner, so bears no relation to the fitness of the seal for purpose. If really paranoid, change a couple of quids worth of hose every 7 years along with the bellows.