How do I grease this gland?

[bizzard]

You can buy an aerosol of silicon grease. pop the thin bit of tube to it, poke it down that greaser hole and push the aerosols trigger, best done whilst turning the prop shaft by hand.

[Tony Brooks]

Two points

 

1. The instructions for the Vetus dripless gland say that every xxx hours the gland should be slid up the shaft and any scale on the shaft removed. Maybe worth looking into.

 

2. That type of gland is usually matched with Cutless fluted rubber shaft bearings, probably just one on a narrow boat at the back of the tube. The shaft coupling forms the front support. This leads to two more points.

 

a. The rubber shaft bearing uses water to lubricate it, not the gland, so that hose is probably to allow water to enter the back of the bearing but which way the water gets in is not important as long as it does.

 

b. There are gaps between the flutes in the bearing, but they are comparatively small so when you take the gland off water will flow in, but probably not much more than what you get when you pull the packing out of a worn conventional stern gland if you don't use the greaser first. There should be loads of time to slide the gland forward while you clean the shaft.

[Tony1]

22 minutes ago, bizzard said:

You can buy an aerosol of silicon grease. pop the thin bit of tube to it, poke it down that greaser hole and push the aerosols trigger, best done whilst turning the prop shaft by hand.

 

Thanks Bizzard, I've got a can of GT85 somewhere.

So the aerosol silicone lubricant sprays can do a similar job to the silicone grease that comes in tubes? I think the problem might be there's loads of air and very little grease in one of those aerosol cans. 

There's a screwfix handy so I might save the aerosol for my bike, and get some stuff in a tube. 

[Ryeland]

I have a Volvo Penta seal very similar to the RMTA one, but no hose. Same as Jen-in-wellies. A cloth tied round the shaft stops enough water to allow the gland to be loosened, and the shaft to be inspected. I found the gland had worn grooves in the shaft, admittedly after several thousand hours.  A slight movement of the shaft in the coupling improved leakage temporarily. I ended up replacing the shaft, cutless bearing and gland on a one day slipway pull out at Stafford Boat Club. If the prop shaft can be slid back far enough without fouling the rudder, just the gland could easily be replaced with a cloth round the shaft. My new gland came with a sleeve to allow it to be easily slid onto the shaft without damaging the seal lips.

The silicone grease really needs injecting between the two seal lips. A very fine tube on a syringe with an angle cut on the end allows the end of the tube to be manoeuvred past the front seal lip. Probably not a problem on the RMTA gland with the grease access on the top.

Richard 

Edited January 27, 2023 by Ryeland

[Tony1]

24 minutes ago, Tony Brooks said:

Two points

 

1. The instructions for the Vetus dripless gland say that every xxx hours the gland should be slid up the shaft and any scale on the shaft removed. Maybe worth looking into.

 

2. That type of gland is usually matched with Cutless fluted rubber shaft bearings, probably just one on a narrow boat at the back of the tube. The shaft coupling forms the front support. This leads to two more points.

 

a. The rubber shaft bearing uses water to lubricate it, not the gland, so that hose is probably to allow water to enter the back of the bearing but which way the water gets in is not important as long as it does.

 

b. There are gaps between the flutes in the bearing, but they are comparatively small so when you take the gland off water will flow in, but probably not much more than what you get when you pull the packing out of a worn conventional stern gland if you don't use the greaser first. There should be loads of time to slide the gland forward while you clean the shaft.

 

Thanks Tony- I am sure the RMTA seals would benefit from the periodic checking for scale as per the vetus ones, but in reality anything that involves loosening that seal and moving it forwards means allowing the water in, and that is not something I personally am competent enough to do on a regular basis.

 

I think this is the one issue I have with the RMTA seals- they work well, but the requirement to replace them at 400 hours is a pain.

For some boaters that means twice a year, maybe more. 

They cost at least £100 each on eBay, and probably more than that from a waterways supplier. So for some people that's £200 per year, plus a labour charge if you dont feel confident enough to tackle it on the water. 

I know in theory you'll have time to replace the seal with a bag wrapped around the shaft at the exit point, but I bet there are loads of boaters who would be very hesitant to do this job in the water, and that means for many, a haul out charge is included in the overall bill. 

I bet in reality this is one of those items that is routinely used well past its formal replacement time by loads of boaters, and with minimal problems for most.  

 

 

[Tony1]

10 minutes ago, Ryeland said:

I have a Volvo Penta seal very similar to the RMTA one, but no hose. Same as Jen-in-wellies. A cloth tied round the shaft stops enough water to allow the gland to be loosened, and the shaft to be inspected. I found the gland had worn grooves in the shaft, admittedly after several thousand hours.  A slight movement of the shaft in the coupling improved leakage temporarily. I ended up replacing the shaft, cutless bearing and gland on a one day slipway pull out at Stafford Boat Club. If the prop shaft can be slid back far enough without fouling the rudder, just the gland could easily be replaced with a cloth round the shaft. My new gland came with a sleeve to allow it to be easily slid onto the shaft without damaging the seal lips.

The silicone grease really needs injecting between the two seal lips. A very fine tube on a syringe with an angle cut on the end allows the end of the tube to be manoeuvred past the front seal lip. Probably not a problem on the RMTA gland with the grease access on the top.

Richard 

 

Thanks Richard, as Brian also suggested, I think I'll try and get some grease in there, and also maybe jiggle the prop shaft a teeny bit, and see if it slows down the dripping. In theory it shouldn't but it cant hurt to try. 

 

 

 

 

[bizzard]

34 minutes ago, Tony1 said:

 

Thanks Bizzard, I've got a can of GT85 somewhere.

So the aerosol silicone lubricant sprays can do a similar job to the silicone grease that comes in tubes? I think the problem might be there's loads of air and very little grease in one of those aerosol cans. 

There's a screwfix handy so I might save the aerosol for my bike, and get some stuff in a tube. 

GT85 is a PTFE spray  and is not grease., similar to WD40.    lots of silicone grease aerosols,  Ebay, Amazon ect ect.

Edited January 27, 2023 by bizzard

[ditchcrawler]

1 hour ago, Tony1 said:

I bet in reality this is one of those items that is routinely used well past its formal replacement time by loads of boaters, and with minimal problems for most.  

 

 

I think you are right, I would. While it worked I would keep it.

[pearley]

15 hours ago, Tony1 said:

 

Thanks Brian- unfortunately they seem to have sold out- but that said, I'll see if Cheshire Marine (at Nantwich) are selling it separately from the full kit including the seal. Or they may know of a safe alternative, since they seem to be very keen on using these seals, according to their website.

I'm near Whitchurch so its a short train ride to Nantwich anyway, if they'll sell it.

As you say, its definitely worth trying some grease, even if as an interim measure till the summer. 

 

 

 

 

 

Got mine from Kings Lock Chandlery.

 

And my first one wasn't replaced until around 3000 hours. Volvo Penta though.

Edited January 28, 2023 by pearley

[magnetman]

Is the 400 hours for replacement real? That seems slightly ridiculous. Maybe they missed off a zero. 

 

 

[Tony Brooks]

12 minutes ago, magnetman said:

Is the 400 hours for replacement real? That seems slightly ridiculous. Maybe they missed off a zero. 

 

 

 

That may be for just the seal and not the whole assembly. I think that originally Vetus had a similar stipulation, but it seems to have been relaxed.

[Tony1]

45 minutes ago, magnetman said:

Is the 400 hours for replacement real? That seems slightly ridiculous. Maybe they missed off a zero. 

 

 

 

 

I dont know, maybe this is only one of the manufacturers, and perhaps there are others with different requirements? 

Brian posted the link to the Radiche maintenance PDF thing earlier:

 

https://sillette.co.uk/pdfs/radice-axial-seals-RMTA.pdf

 

This is from page 2: 

'The RMTA seal should be greased every 5/6 months with the specially provided grease and should be replaced after 400 hours of running or 4 years after fitting.'

 

I normally assume when I see both a time-based interval and a running hours interval, you need to go with whichever comes up first, so for most people it would be every 400 hours, except I suspect that in reality nobody is actually following that. 

Mine is just over 7 years old and I bet its not been replaced since new- and I suspect it wouldn't have needed replacing now if I hadn't trodden on it somehow.

 

 

Edited January 28, 2023 by Tony1

[magnetman]

You need to change the link. 

Lucky it was to something innocent. Look out !

[ditchcrawler]

24 minutes ago, magnetman said:

You need to change the link. 

Lucky it was to something innocent. Look out !

Which link, the one I posted earlier ?

 

[Tony1]

7 minutes ago, ditchcrawler said:

Which link, the one I posted earlier ?

 

 

Yes, I put in a link to an expansion vessel by mistake. 

Just as a quick aside, I was going to double check whether a 12 litre vessel might be too big in some way, since I don't have a very large calorifier?

Would there be any snags if my calorifier was say 50 or 60 litres, and the expansion vessel was 12 litres?

I had an idea that the expansion vessel should ideally be at least 10% of the calorifier size, problem is I dont know what size my calorifier is, so I guess oversizing the expansion vessel is preferable to having one that is too small. 

 

[rusty69]

10 minutes ago, Tony1 said:

 

Yes, I put in a link to an expansion vessel by mistake. 

Just as a quick aside, I was going to double check whether a 12 litre vessel might be too big in some way, since I don't have a very large calorifier?

Would there be any snags if my calorifier was say 50 or 60 litres, and the expansion vessel was 12 litres?

I had an idea that the expansion vessel should ideally be at least 10% of the calorifier size, problem is I dont know what size my calorifier is, so I guess oversizing the expansion vessel is preferable to having one that is too small. 

 

You should be able to work out the volume by measuring it.

πr²h

Edited January 28, 2023 by rusty69

[magnetman]

Less the insultation of course. 

Stick a pin in it double it and take away to get the diameter of the actual cylinder. 

[rusty69]

9 minutes ago, magnetman said:

Less the insultation of course. 

Stick a pin in it double it and take away to get the diameter of the actual cylinder. 

Well if your gonna be insulting, best take the thickness of the copper into account too.