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Leaking stern gland issue


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I've recently purchased a wide steel hulled canal boat that was manufactured by Big Fish Boats who I understand have gone out of business. The stern gland has a significant leak that needs attention but I'm having difficulty in identifying what make and model has been fitted.

From what I can see, It would appear that it's a job that could potentially be tackled while the boat is still in the water because it looks like the propeller shaft could be detached from the coupling and slid towards the stern. That would allow the seal to be replaced, albeit with water escaping while the seal is being swapped.

So the key questions are these....

 

Does anyone recognise this stern gland from the picture and where a replacement seal can be bought?

Is there any way of contacting someone associated with Big Fish who would know what they used to fit to their boats?

And finally,,,,,, has anyone been brave/stupid enough to affect the replacement of a seal while the boat is still in the water?

 

Any help would be much appreciated.

 

 

Hopefully these photos will show enough detail to identify the stern tube.

 

preview 165868

preview 165869

IMG 20140424 WA0000

IMG 20140424 WA0001

 

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It's a Vetus stern gland. (Water lubricated - hence the lube pipe from the weedhatch to the gland)

 

These require lubricating (via the top allen bolt) every year with silicone grease. (Although I lube mine every few months)

 

Spares are (only) available from Vetus.com.

 

They are excellent glands, and will last for many years providing: the engine & prop shaft are properly aligned, there's no excessive vibration and they are lubricated.

 

 

Edited to add: Sorry - I forgot my manners - - - welcome to the Forum John

Edited by Grace & Favour
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Thank you so much, that's a huge help. So are you of the opinion that it's just short of grease then? As you can see from the closeup picture, there's a steady stream of water coming in.

Is there a particular silicone grease that you know the grade of?

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Thank you so much, that's a huge help. So are you of the opinion that it's just short of grease then? As you can see from the closeup picture, there's a steady stream of water coming in.

Is there a particular silicone grease that you know the grade of?

Some recommendations for grease type on here

http://www.canalworld.net/forums/index.php?s=615bc2a11676e9e1dc09e99ca7c08b69&showtopic=66088&hl=morris#entry1295455

K

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Thanks for that Kevin, there are a couple of suggestions there. I'll ask Vetus as well if they have a preference.

That thread seems to suggest that it's possible to replace the packing on stern tubes in situ but the Vetus one isn't an adjustable type. Does anyone know if it's possible to be done on the type I've shown in the picture? Since it's a water lubricated type, maybe you can't?

I was surprised to see that there wasn't a permanent way of inserting grease into that type of seal, I have no idea what the thread size is or where I can get an adaptor for a grease gun. How is it normally done, and does water erupt from the hole when the bolt is removed?

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The grease on a conventional gland is to lubricate the plain metal shaft bearings, not the packing. Your shaft (if its a 100% Vetus assembly) uses rubber water lubricated cutless bearings so needs no grease.

 

If you take the shaft coupling off and remove any key you should be able to slide the old seal off and a new one on. Some water will come in but how much depends upon the degree of wear in the shaft bearings but it is likely to be more than with a plain metal bearing. Likewise some water may come out when you take out the screw but in both cases I would expect the bilge pump to cope with it.

 

Vetus say that at fairly few running hours (for a canal boat) the seal should be removed and any scale taken off the shaft, then new grease be applied. I think it was at one time something like every 200 hours but they may have extended it to 500 hours. Look at the Vetus site for the instructions.

 

Because the rubber bearing allows the shaft to deflect in the bearing other things that may cause leaking are a worn bearing, bent shaft, and engine out of alignment with the shaft. All will allow the shaft to move in a radial direction and open one side of the seal.

 

 

PS I think the Vetus seal uses a special silicon grease, NOT normal stern tube grease.

Edited by Tony Brooks
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Adding more grease won't help with these glands, it's the seals that keep the water out, the grease just keeps the seals lubricated. Sounds to me like the seals need replacing.

 

It can be done with the boat in the water if you have the nerve, IIRC a boatyard will charge about £150 so there is some incentive to do it yourself. But you also need to get the alignment checked if this boat is new to you as, if that's the cause of the problem, replacing the seals will only be a temporary cure.

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We've had two boats fitted out by Big Fish here. They only fitted them out, the shells were made by others. I'm not sure if Big Fish installed the engines and running gear though but on one here the engine alignment was visibly wildly out of alignment in all directions which caused in a very short time from new to wear out the stern tube bearing, shake the tube loose in the sternpost collar causing a severe leak, we had to emergency dock it and renew it all, all except the shaft and realign properly. It had a conventional stern tube.The shell was a 12' 6'' wide Jonathan Wilson shell a horrible ugly monster.

The other Big fish W/B here has a shell built by someone else ''can't remember'' much more attractive than the Wilson monster, probably the same make as yours, which has the same Vetus rubber stern tube as yours, alignment is ok with no leaks.

I unbolt the seal carrier and slide it up the shaft a little to silicon grease the shaft behind properly rather than use the Allen bolt plug on the top. Only a little water should trickle in. I'd also check the engine alignment absolutely without a doubt.

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Probably too late now, but the vetus stern gear should be lubricated through where the Allen screw is, every 100 hours or annually. You must use the correct grease or it perish's the seals. Our vetus dealer supplied us with the Volvo penta marked tube of grease as it is identical but considerably cheaper, no vat. (Vetus added tax ).

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What a helpful and knowledgeable and friendly bunch you are! I can't thank you all enough, this information is exactly what I need to know.

I guess it will be obvious how out of line anything is when the coupling is undone and the propeller shaft is slid forward. From what you say it doesn't sound as if there will be an alarming amount of water coming out of the tube unless the bearing is badly worn. Even if it is, the new seal ought to keep the water out until such times as it can be taken out of the water.

There's no sign of any tube of grease in the bits and pieces I've inherited from the previous lady owner. It's entirely possible that she didn't appreciate that this needed regular if infrequent greasing, so it may just be that just the seal has been destroyed.

Looking at the Vetus web site, they sell the seal with gasket and grease for just under £100 delivered which sounds reasonable to me.

I just need to measure the shaft diameter and then it's decision time.They only seem to make the one style and in 5mm shaft increments so it ought to be easy enough to get the right part.

Once again, a big thank you to you all, it's very much appreciated.

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I know nothing about these inventions of a Dutch Devil, but shouldn't the blue tube be able to get water from below the water line?

The pictures show the tube connected towards the top of the weed hatch where there shouldn't be any water (if there is then the weed hatch doesn't comply with the BSS.

Even if there's a corresponding tube going down into the oggin, the Vetus gland can't such water, can it?

Perhaps that's why its leaking - no water lubrication.

 

I do know something about fresh water cooled engines (lovely!) - glad to see someone else with it!

 

 

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What a helpful and knowledgeable and friendly bunch you are! I can't thank you all enough, this information is exactly what I need to know.

I guess it will be obvious how out of line anything is when the coupling is undone and the propeller shaft is slid forward. From what you say it doesn't sound as if there will be an alarming amount of water coming out of the tube unless the bearing is badly worn. Even if it is, the new seal ought to keep the water out until such times as it can be taken out of the water.

There's no sign of any tube of grease in the bits and pieces I've inherited from the previous lady owner. It's entirely possible that she didn't appreciate that this needed regular if infrequent greasing, so it may just be that just the seal has been destroyed.

Looking at the Vetus web site, they sell the seal with gasket and grease for just under £100 delivered which sounds reasonable to me.

I just need to measure the shaft diameter and then it's decision time.They only seem to make the one style and in 5mm shaft increments so it ought to be easy enough to get the right part.

Once again, a big thank you to you all, it's very much appreciated.

Not necessarily.

 

If it is more than 3 thou out it needs re-aligning, you wouldn't be able to detect that with the naked eye.

 

I'm no expert - others will have more experience, but it can be a lengthy job to re-align an engine. One engineer I know said he allows half a day for it.

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I know nothing about these inventions of a Dutch Devil, but shouldn't the blue tube be able to get water from below the water line?

The pictures show the tube connected towards the top of the weed hatch where there shouldn't be any water (if there is then the weed hatch doesn't comply with the BSS.

Even if there's a corresponding tube going down into the oggin, the Vetus gland can't such water, can it?

Perhaps that's why its leaking - no water lubrication.

 

I do know something about fresh water cooled engines (lovely!) - glad to see someone else with it!

 

 

 

I think at canal speeds a tube like that above the waterline would allow water to flow through the flutes in the rubber bearing and push air out of the tube so the bearing stays lubricated. I also suspect that when many boats are running the centrifugal action of the prop will push a fair amount of water into the wed hatch and thus force water back down the tube.

 

I agree with the devil bit though.

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If you are concerned that a lot of water will come in when you dismantle the seal put a good dollop of ordinary grease on a plastic bag and , working through the weed hatch, wind it round the shaft outside the hull. That will form a temporary seal and slow the ingress of water, but remember to remove it once the inside seal is back in place.

 

N

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I think at canal speeds a tube like that above the waterline would allow water to flow through the flutes in the rubber bearing and push air out of the tube so the bearing stays lubricated. I also suspect that when many boats are running the centrifugal action of the prop will push a fair amount of water into the wed hatch and thus force water back down the tube.

 

I agree with the devil bit though.

Well my weedhatch is full while we go along and I am sure if I take the lid of while going along I will sink and I wouldn't be the first. Looking at the amount of water that comes through a faulty lid seal it looks as if there could be a reasonable pressure building up in the top there as well.

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I have the same set up and I'm sure when I investigated the workings of this type of seal, that the water for lubrication comes in along the prop shaft and the tube is to take the water away so there is always cool water flowing around the seal. If you have like myself and many others the bottom plate on the weed hatch lid will stop water filling the weed box and coming down the pipe

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I'm not sure how much flex there is in that coupling. It's not a simple matter to confirm the alignment to an accuracy of a few thou. I could take the coupling off completely and then clock round the engine shaft with a dial gauge on the propeller shaft I suppose. I have that sort of kit, being an engineer. That wouldn't tell if the axis of the engine was true to the shaft but it would give an indication as to whether it's miles out. I guess the most telling piece of evidence will be how much play there is in the propeller shaft bearing when it's detached. If there's precious little then I'll leave it as it is.

 

I think some rag wound round the shaft on the exposed end of the stern tube ought to stem the flow while the seal is being replaced. Hopefully that won't take long and it won't be necessary.

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I agree with most of what has been said:

Silicon grease (only) to lube the seal (cheap from plumbers merchants.)

If it is really peeing in I suspect the engine has gone out of alignment. Mine did exactly the same when an engine mount came loose.

I notice there is an R&D coupling fitted. This is unusual and has been known to cause problems with these seals (mine has an R&D fitted too, which I believe causes a slight leak when reversing.)

I once accidentally stood on the propshaft whilst working on the engine, and was amazed at the amount of water that spurted in around the seal, and for me this proves that the alignment is critical.

 

I suspect all units will have to be of the "greaserless" type one day; I understand they are already required on new builds in some countries.

Edited by Guest
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I have the same set up and I'm sure when I investigated the workings of this type of seal, that the water for lubrication comes in along the prop shaft and the tube is to take the water away so there is always cool water flowing around the seal. If you have like myself and many others the bottom plate on the weed hatch lid will stop water filling the weed box and coming down the pipe

Surely it's the other way round? As I understand it all these water cooled glands relay on water being forced in either by a tee off the raw water cooling system or by a dedicated pump. Isn't this the main reason they are not more popular in narrowboats? ie most boats are keel cooled, and an auxiliary pump is something else to go wrong. (There's also the issue of using gritty canal water.)

 

I don't really know enough about them, but if one of these is fitted relying on the siphon effect, or water being forced in from a weed hatch, doesn't that mean is isn't properly installed and that is the main defence offered by those who rave about these glands, they only go wrong when not fitted exactly as the manufacturers intended.

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Surely it's the other way round? As I understand it all these water cooled glands relay on water being forced in either by a tee off the raw water cooling system or by a dedicated pump. Isn't this the main reason they are not more popular in narrowboats? ie most boats are keel cooled, and an auxiliary pump is something else to go wrong. (There's also the issue of using gritty canal water.)

 

I don't really know enough about them, but if one of these is fitted relying on the siphon effect, or water being forced in from a weed hatch, doesn't that mean is isn't properly installed and that is the main defence offered by those who rave about these glands, they only go wrong when not fitted exactly as the manufacturers intended.

 

Yes or a scoop to force the water in. I've not had my boat out of the water yet (thats happening in about 3 weeks time) so I havent been able to see. And yes gritty water has been mentioned as a problem before, as canals are fairly shallow there is a lot of grit in the water the prop stirs up

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I have one of these glands on my boat. I haven't read the whole thread but if nobody else has suggested it, I know someone else who fixed a leak by simply moving the prop shaft a few mm (backwards or forwards), so that the seal was able to reseat itself on an unworn area of the shaft.

 

When I put silicone grease in my gland I don't bother with that little screw because it's too difficult to get thick grease down that small hole. I take all three allen screws off the front of the housing and slide the bronze housing cover up the shaft. Be careful not to break the fibre gasket as you separate the housing cover. Water will come in at the rate of about 1 litre/minute so be prepared. You can then carefully clean out any crap and shove a load of silicone grease in there before sliding the front of the housing back to the gland and retightening it. Tighten the 3 screws evenly.

Edited by blackrose
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Surely it's the other way round? As I understand it all these water cooled glands relay on water being forced in either by a tee off the raw water cooling system or by a dedicated pump. Isn't this the main reason they are not more popular in narrowboats? ie most boats are keel cooled, and an auxiliary pump is something else to go wrong. (There's also the issue of using gritty canal water.)

 

I don't really know enough about them, but if one of these is fitted relying on the siphon effect, or water being forced in from a weed hatch, doesn't that mean is isn't properly installed and that is the main defence offered by those who rave about these glands, they only go wrong when not fitted exactly as the manufacturers intended.

 

I think you're probably right. I've looked at the Vetus installation instructions and they don't show the commonly adopted canal boat method of plumbing them in from the weedhatch. They show a raw water scoop/skin fitting method and another method using raw water cooled engine water. So the weedhatch method is an adaptation.

 

I've taken the tube off the gland while the boat is stationary and water comes in from the gland. However, I've no idea which way around the water would flow while the boat is moving. I think this method of installation mainly relies on immersion of the gland and the relatively slow speeds of canal boats compared to other craft.

 

However, I don't think anyone's "raving" about water lubricated glands are they? I've never heard anyone raving about greasy glands either for that matter. They both work well enough and the water lubricated glands have been around long enough to know that the doom and gloom merchants who slagged them off initially were wrong. There are pros and cons of both water cooled and greasy glands. Having had a water cooled gland on my boat for over 9 years I wouldn't go back to a greasy gland, but that's just a personal preference.

I agree with most of what has been said:

Silicon grease (only) to lube the seal (cheap from plumbers merchants.)

If it is really peeing in I suspect the engine has gone out of alignment. Mine did exactly the same when an engine mount came loose.

I notice there is an R&D coupling fitted. This is unusual and has been known to cause problems with these seals (mine has an R&D fitted too, which I believe causes a slight leak when reversing.)

I once accidentally stood on the propshaft whilst working on the engine, and was amazed at the amount of water that spurted in around the seal, and for me this proves that the alignment is critical.

 

I suspect all units will have to be of the "greaserless" type one day; I understand they are already required on new builds in some countries.

 

I have a R&D coupling on mine - no problems as long as it's adjusted properly along with the engine mounts.

Edited by blackrose
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