Replacement of Stuffing Box with Dripless Seal

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hunter323

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The time has come to replace the old stuffing box and greaser with a dripless seal on my Moody 29 - I had originally thought of a volvo rubber seal but now understand that if you have a flexible coupling then this product is not suitable. I would be grateful for suggestions and experiences of other dripless seals from forum members
 
No problem, although Volvo do advise against using with flexible couplings - but many installations do. Usually the major snag is having a suitable diameter stern tube to attach it to as it is only made in one size for each diameter shaft. The key dimension is on the spec sheet. You also need a completely clear shaft as the lip seals don't like grooves.
 
I fitted a PSS 5 years ago, and although I check it every year it has never needed any attention and has never let in a drop of water. Also does not need "burping" after drying out. Like you I had orignally intended to fit the Volvo seal, but they are not made to fit my combination of shaft/stern tube sizes. PSS is a well engineered bit of kit available from ASAP Supplies.
 
I wanted to use a Volvo seal on my Moody 31 but the stern tube/shaft dimensions weren't right. I used a Tides Marine Seal - you have to organise a pressurised water feed but it works just great. Lots of info on the MOA website.

shaftseal.jpg
 
Look at the Eliche Radice shaft seals here (scroll down) as they are similar to Volvo, but have a greasing point and a water vent attachment, and are cheaper. Like Volvo there is a limited range of stern tube diameter to shaft size combinations, but if you are in luck they look a good alternative.

For a motorboat you might need to use a pressurised water feed, but I am told that for a yacht all you need is to run a tube with an open end to a point well above the water line, no need to "burp" them apparantly.
 
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My vote for PSS, good kit, simple to install and very reliable. I threw my Tides Marine Seal away after just 20 months as it failed to give me a sudden and very significant leak!!!!!
 
I'd also go with the PSS, which tends to be slightly cheaper than the Volvo, is simpler, works as well and made in a greater range of sizings.
Trade gossip condemns the Deep Sea seal.
I've had a PSS fitted for about 6000hrs on motor and 18 years and found it far better and more reliable than the Bukh and Halyard lipped seals I had previously.
 
cindersailor said:
I fitted a PSS 5 years ago, and although I check it every year it has never needed any attention and has never let in a drop of water. Also does not need "burping" after drying out. Like you I had orignally intended to fit the Volvo seal, but they are not made to fit my combination of shaft/stern tube sizes. PSS is a well engineered bit of kit available from ASAP Supplies.
Click to expand...

Ditto - Moody 31

Also had to sort out a friends Tides Marine which leaked badly - had worn a groove in the shaft which a PSS will not do.
 
charles_reed said:
I'd also go with the PSS, which tends to be slightly cheaper than the Volvo, is simpler, works as well and made in a greater range of sizings.
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Hardly simpler than a Volvo which is a simple one piece moulding rather than a complicated assembly that needs setting up correctly if it is to work properly. And certainly not cheaper - exactly the opposite at twice the price.

Currrent UK prices for 1" shafts which is what the OP needs PSS £181, Tides Marine £192, Volvo £80 and Radice (but only for metric shafts) 25mm £67
 
stuffing box blues

I had a conventional stuffing box and wanted to replace it with a Volvo seal. I made the mistake of purchasing the seal prior to dismantling the old one. On dismantling I discovered the prop shaft tube had a lip on it which the new seal is not designed for.

I thought about removing the lip on the tube using a pipe cutter but this would leave too short a length for the new seal to fit on to.

However I also noticed the prop shaft was worn - it had ridges where the old stuffing gland sat.

So I chatted to an engineer about the problem - he said short of replacing both the shaft and seal, a new seal would never work because the length of new seal would not be long enough to extend beyond the ridges to 'fresh' shaft. He advised carrying on using a conventional stuffing box (albeit a new one) but using a slightly longer length of flexible tube so that the new box would sit on the 'fresh' shaft.

I've learnt from the experience! And I've also got a Volvo seal for sale - see my listing on the 'for sale' section of this forum (plug plug!!)

Best of luck with yours!!!
 
maxi said:
My vote for PSS, good kit, simple to install and very reliable. I threw my Tides Marine Seal away after just 20 months as it failed to give me a sudden and very significant leak!!!!!
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That's my concern with all these 'fit and forget' types. At least with a packed gland you can tighten it up a bit if it starts leaking at sea especially if you are days away from shore. The slight drip into the bilge is annoying but not life threatening.
 
Sorry to spoil the party but any installation has three points of connection engine mounts shaft coupling and inboard bearing one must be solid otherwise it is out of control and excessive movement will occur.
 
i have no dog in this fight, but....

a hunter owner on the sailboat owners forum in the USS posted this about his PSS which was OEM on the hunter 41 boat:


PSS Shaft Seal-Big Trouble waiting to happen
My Hunter 410 came equiped with a PSS Shaft Seal, you know the one that is maintance free, as per PYI, Inc. I have under 300 hours on my engine and use my boat quite regularly through out the year. This past weekend the PSS shaft seal ruptured, actual tears in the rubber seal, with water pouring in at a good rate. When H & S Yacht Sales called PYI, INC they said they were not aware of this problem but would replace under warranty, then they called Hunter Marine and they said they don't use PSS Shaft Seal and where told they stopped using PSS Shaft Seals about 1 year ago because of the same problem, nice of them to notify all Hunter owners right? Be aware of this potentional problem if your boat is equiped with a PSS Shaft Seal, I replaced mine with the old style packing gland.
 
My take on that is that tears in the rubber can only occur if sufficient torque is applied to it. This implies that the seal faces had to be dry for any torque to be present. When the seal is operating correctly, with water between the faces, the torque is so low that it is immeasurable. PSS are very clear that the faces should be separated to allow a small amount of water onto the faces when the shaft has not turned for some time, I think a month? It sounds like this advice was not followed.

One problem I am aware of with the PSS is pitting of the stainless steel face. I know of three cases, one of which was mine. I think it occurred over winter, ashore, perhaps due to increased concentration of chlorides between the faces on evaporation of the seawater. I now flush with fresh water after haul out and have not had a recurrence.
 
Tranona said:
Hardly simpler than a Volvo which is a simple one piece moulding rather than a complicated assembly that needs setting up correctly if it is to work properly. And certainly not cheaper - exactly the opposite at twice the price.

Currrent UK prices for 1" shafts which is what the OP needs PSS £181, Tides Marine £192, Volvo £80 and Radice (but only for metric shafts) 25mm £67
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Perhaps you should look at the GA drawing of both PSS and Volvo seals - there are 5 main components with each and I'd still maintain a simple face seal is less complex than a lip-seal.
And, in my experience, far less trouble.

PS I bought my seal direct from the US - $68. Perhaps shopping in the wrong place is the problem with your comparison.
 
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charles_reed said:
Perhaps you should look at the GA drawing of both PSS and Volvo seals - there are 5 main components with each and I'd still maintain a simple face seal is less complex than a lip-seal.
And, in my experience, far less trouble.

PS I bought my seal direct from the US - $68. Perhaps shopping in the wrong place is the problem with your comparison.
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Volvo seal - 5 main components? Mine has just one, or three if you count the two jubilee clips!
 
charles_reed said:
Perhaps you should look at the GA drawing of both PSS and Volvo seals - there are 5 main components with each and I'd still maintain a simple face seal is less complex than a lip-seal.
And, in my experience, far less trouble.

PS I bought my seal direct from the US - $68. Perhaps shopping in the wrong place is the problem with your comparison.
Click to expand...

You clearly have a very strange view of "simplicity". Multiple materials, moving parts, requirement for a water feed or vent and a critical set up regime compared with no moving parts and 2 screws to do up.

Bully for you buying many years ago in the US. That choice is not available to everyone. The prices quoted are the current official dealer prices in the UK including VAT. The current US retail price is $204, roughly £125 plus £30 postage, plus VAT - long way away from your $68!

By all means recommend the product if you are happy with it, but don't suggest it has characteristics that it does not.
 
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