How easy to replace stern gland packing?

[davethedog]

Thanks for all the replies and think I will repack it when out the water then, as hopefully does not look that bad then.

May think about getting a dripless seal put in at a later stage, a few years time maybe as when our boat is out the water not many engineers want to travel away from their own yards to do the work so will have to get her to them and then lifted out at a later date.

 

[Poignard]

I much prefer the arrangement where the stuffing box screws direct to the stern tube.
Relying on a piece of rubber hose, although high spec, seems risky to me..

Me too.

Advice to OP is he will need calipers to measure the prop shaft and internal size of housing.

No he won't. Just take 3/16", 1/4", 5/16" drill bits and see which one just goes into the gap.

 

[Tranona]

So what happens if that big rubber thing gets a split in it? Is there another seal? I have no doubt, by the way, that modern seals have their advantages and can work well, but I have not yet seen one I would care to have in a position (mine) where access is completely impossible.

Suggest actually look at one and then tell us, given how it is used, how it could possibly split. Difficult enough to physically cut with a hacksaw.

The only thing that wears are the lips, and even then only if you forget to lubricate them. The one I have replaced ran without any leakage from 1996 to 2010 and was only replaced to get the benefit of the additional Radice features which will actually solve your problem. Adding grease once a year is even easier than adjusting your stuffing box. As near perfect a low maintenance long lasting solution.

 

[JumbleDuck]

Suggest actually look at one and then tell us, given how it is used, how it could possibly split. Difficult enough to physically cut with a hacksaw.

Offhand I can think of three ways. Which is why I would only fit anything like this if I had ready access to it in case of problems. I am sure your solution works for you.

 

[Tranona]

Offhand I can think of three ways. Which is why I would only fit anything like this if I had ready access to it in case of problems. I am sure your solution works for you.

Would be interested in hearing about your "3 ways" Plus of course any evidence that any of these things have actually happened.

Not trying to persuade you to change, just curious about your seemingly implausible reasons.

 

[JumbleDuck]

Would be interested in hearing about your "3 ways" Plus of course any evidence that any of these things have actually happened.

Not trying to persuade you to change, just curious about your seemingly implausible reasons.

If you are absolutely certain, to the extent of betting your life on it, that your stern could never under any circumstances fail, good luck. Would you like to buy a bridge?

PS I have just thought of a fourth way.

 

[Tranona]

If you are absolutely certain, to the extent of betting your life on it, that your stern could never under any circumstances fail, good luck. Would you like to buy a bridge?

PS I have just thought of a fourth way.

You are avoiding the question. I asked how is the seal likely to burst or split which is what you are claiming, but refusing to explain or illustrate with examples.

 

[JumbleDuck]

You are avoiding the question. I asked how is the seal likely to burst or split which is what you are claiming, but refusing to explain or illustrate with examples.

I cannot help with your lack of imagination. If you would rather not think about the possibilities, fine. You may well get away with it. I prefer to take a slightly more proactive approach to safety afloat.

 

[Bobc]

I cannot help with your lack of imagination. If you would rather not think about the possibilities, fine. You may well get away with it. I prefer to take a slightly more proactive approach to safety afloat.

I assume that also means that you don't have any gas or petrol on-board, that you don't have any skin fittings and just use a bucket, and that you don't go outside of the marina just incase a metorite hits you and you sink

Get a grip.

 

[RichardS]

I assume that also means that you don't have any gas or petrol on-board, that you don't have any skin fittings and just use a bucket, and that you don't go outside of the marina just incase a metorite hits you and you sink

Get a grip.

A very gentle grip ..... in case something breaks.

Richard

 

[JumbleDuck]

I assume that also means that you don't have any gas or petrol on-board, that you don't have any skin fittings and just use a bucket, and that you don't go outside of the marina just incase a metorite hits you and you sink

Get a grip.

Oh dear. I thought I'd tried to make my point simply, but perhaps it wasn't made simply enough.

The reason I decided against a modern seal is that I have no practical way of getting at the stern tube while afloat. I have therefore chosen to keep my stuffing gland because their failure mode is almost invariably progressive rather than catastrophic. If I had easy access to it then I may well have gone for something else.

Gas? Yes, and fire extinguishers. Petrol? No. Skin fittings? Yes, and they are all easily accessible - I had the engine cooling water intake moved last winter for just this reason - and I have considered what I would do if any one of them broke off. I don't keep my boat in a marina and I don't consider meteorite strikes to be a risk worth preparing for. I do, however, carry flares, an EPIRB and a DSC radio for the statistically very low chance that the boat should be at risk.

Perhaps you haven't done much risk assessment? Once you have established what the risks are, you avoid those you can, reduce those you can't and make plans for what you would do by way of mitigation if one of them occurred. I don't feel happy about having a potentially catastrophic leak on my boat which, in the admittedly unlikely event of it occurring, would be impossible to mitigate.

Hope this clears things up.

 

[Poey50]

The reason I decided against a modern seal is that I have no practical way of getting at the stern tube while afloat. I have therefore chosen to keep my stuffing gland because their failure mode is almost invariably progressive rather than catastrophic. If I had easy access to it then I may well have gone for something else.

You need to differentiate between lip-type seals which fail progressively and face-type seals that can fail catastrophically if not maintained or fitted properly.

 

[JumbleDuck]

You need to differentiate between lip-type seals which fail progressively and face-type seals that can fail catastrophically if not maintained or fitted properly.

Definitely a useful thing to bear in mind, but for those whose heads are not too firmly in the sand, this should give some pause for thought:

Remember, please, that I would probably have one of these if I could actually get at it.

 

[Poey50]

Definitely a useful thing to bear in mind, but for those whose heads are not too firmly in the sand, this should give some pause for thought:

Erm ... it would be an unusual failure to have a lip seal neatly bisected. Vyv Cox may be able to confirm as it comes from his site but that looks like a worn seal cut in half to show the construction.

 

[vyv_cox]

I assume that also means that you don't have any gas or petrol on-board, that you don't have any skin fittings and just use a bucket, and that you don't go outside of the marina just incase a metorite hits you and you sink

Get a grip.

And that his car has its radiator solidly connected to the engine, no steering joint gaiters, exhaust firmly welded to the chassis, etc., etc. Rubber in a huge variety of forms is widely used in many engineering applications, where provided it has been designed correctly it will be perfectly reliable. These days there seems to be a whole army of people concerning themselves with the possibility, or even likelihood, of failure of items that exist in their thousands with no history of unreliability.

 

[Minchsailor]

And that his car has its radiator solidly connected to the engine, no steering joint gaiters, exhaust firmly welded to the chassis, etc., etc. Rubber in a huge variety of forms is widely used in many engineering applications, where provided it has been designed correctly it will be perfectly reliable. These days there seems to be a whole army of people concerning themselves with the possibility, or even likelihood, of failure of items that exist in their thousands with no history of unreliability.

I agree. There is a difference between what is 'possible', and what is 'probable'. I check the rubber hose the stern gland annually for deterioration. Preventative replacement.

 

[davethedog]

Anyway, back on track....will replace the flax in dec when the boat is out the water!

 

[NormanS]

Anyway, back on track....will replace the flax in dec when the boat is out the water!

Good decision!

 

[Kurphy]

Sorry but can someone let me know how many is “several”? I have a 1 1/2 Inch shaft to pack. Just pulled out a big single mass of packing so couldn’t count the layers. Thanks !

 

[NormanS]

Minimum would be three, but it depends on the depth of the stuffing box.