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Smaller diameter water pipe leading into the stern tube..?

Gordon Chesterman

By Gordon Chesterman
in Boat Equipment

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Gordon Chesterman Contributor

Gordon Chesterman

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The stern tube on my Liverpool Boat (about six years old) has a small diameter hose going into it with a lever on a valve where it joins the stern tube. The other end of the small tube goes out through the hull below the waterline.

Which way should this lever be pointing? Either in line with the small tube or at right angles - ie should water be allowed to flow into it, or not?

I haven't a clue what it is there for, no one explained when I acquired the boat secondhand.

Your advice please would be appreciated.

Thanks,

Gordon in Ely

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the grinch Experienced

the grinch

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sounds like something is wrong here! the small tube going into the top of the stern tube should be a greaser the other end should be attached to a brass or metal 1.5 - 2" tubular barrel with a handle on the top. this is to grease the stern tube and stop any leakage.

 

a photo or 2 may help us to help you.

 

kev

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blackrose Veteran II

blackrose

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Yes it's a water-lubricated stern gland and the lever should be in the open (in line) position so that water can flow through the gland.

 

However, the arrangement you have is an unusual one for a Liverpool Boat. The other end of the tube on my boat goes into the side of the weed hatch but it's above the waterline.

 

Where exactly does the other end of your pipe go? If it really is below the waterline then there's nothing to worry about, in fact I think Vetus specifies one method of installation with an underwater scoop - the usual Liverpool Boats installations like mine were somewhat unorthodox.

 

Periodically (about once a year), you should close the valve, take out the allen key screw on top of the bronze stern gland housing and push a blob of silicone grease in the hole (not ordinary grease and definitely not silicone sealant!) I actually took off the front of the bronze housing to clean it out by removing the 3 screws and at the same time I was able to get a decent amount of silicone grease in. If you do that be gentle as there's a gasket - water will also come in at a rate of about a litre a minute. To be honest it was very clean so there's no need to do that, at least not until the boat comes out the water for blacking.

Edited by blackrose
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by'eck Veteran

by'eck

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The stern tube on my Liverpool Boat (about six years old) has a small diameter hose going into it with a lever on a valve where it joins the stern tube. The other end of the small tube goes out through the hull below the waterline.

Which way should this lever be pointing? Either in line with the small tube or at right angles - ie should water be allowed to flow into it, or not?

I haven't a clue what it is there for, no one explained when I acquired the boat secondhand.

Your advice please would be appreciated.

Thanks,

Gordon in Ely

 

Yes as previously mentioned you have water lubricated stern gland. The water pickup outside hull below water line should be forward facing to provide slight positive pressure as boat moves forward. The valve (usually washing machine type) should be set on with lever in line with pipe. Might be worth turning it off if leaving boat unattended for some time whilst in water, with suitable note to turn on before you next move.

 

My last boat had such with two valves, one ball valve on through hull fitting & a washing machine one where the hose connected to stern gland. This allows hose to be replaced without water coming in from either end.

Edited by richardhula
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Guest

Guest

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I concur. Lever on valve in line with pipe. My boat has connection into weed hatch above waterline too (not a Liverpool shell.) I apply silicone grease through grease point every engine oil change these days(so that I remember. Probably overkill.) SILICONE GREASE ONLY! available in plastic tubs from plumber's merchants for around a fiver; inject with a plastic syringe and is a five minute job. Vetus silicone grease is many times the price of the plumber's merchant.

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blackrose Veteran II

blackrose

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On most installations Liverpool Boats fitted it with the tube at the weedhatch above the waterline, but when I asked Vetus about this arrangement they said that water could go through the gland either way but they weren't sure about this type of installation, so it was something LB had come up with.

 

I've taken the tube off the valve while stationery and in gear, and then opened the valve to check that water is coming through. So far so good, but I still haven't done the same with someone steering the boat moving forward.

 

Other people have toldd me that the water pressure in the top of the weed hatch will force the water to go the other way and exit out the gland. I'm not sure there's any way to check the thing is actually working on Liverpool Boats other than take the prop shaft out and have a look at the condition when the boat's out the water?

 

I guess there are enough LB around that someone would have had problems if the stern gland wasn't being lubricated.

Edited by blackrose
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I suppose the advantage of an inlet above the waterline in weedhatch is not having to turn valve off when working on the seal or leaving boat for long time?

This has puzzled me for some years, but has worked OK on my boat. The most convincing explanation was by a boat builder who uses these units,; he claims that the pipe is merely a vent to let air out of the tube. The slotted neoprene cutlass bearing allos water in for lube.

 

I remember one member on here, who's installation went to a blank coupling on the weedhatch, not having been drilled through!

 

It seems that greasers are not allowed in some parts of the world, and if we follow suit (likely), I think this type of stern tube will be the norm.

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blackrose Veteran II

blackrose

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Mine only has a valve above the gland, but I've seen other LBs with a valve on the weed hatch too. I'm thinking about what you said, but I'm still not sure if a valve above the waterline does anything?

 

Yes, I think the LB installations just rely on the gland being immersed in water and the pipe just relieves any positive pressure in the gland.

 

Sorry, I'm doing this on my phone. First part of my reply was to Innisfree and second to Richard.

Edited by blackrose
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Guest

Guest

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On most installations Liverpool Boats fitted it with the tube at the weedhatch above the waterline, but when I asked Vetus about this arrangement they said that water could go through the gland either way but they weren't sure about this type of installation, so it was something LB had come up with.

 

I've taken the tube off the valve while stationery and in gear, and then opened the valve to check that water is coming through. So far so good, but I still haven't done the same with someone steering the boat moving forward.

 

Other people have toldd me that the water pressure in the top of the weed hatch will force the water to go the other way and exit out the gland. I'm not sure there's any way to check the thing is actually working on Liverpool Boats other than take the prop shaft out and have a look at the condition when the boat's out the water?

 

I guess there are enough LB around that someone would have had problems if the stern gland wasn't being lubricated.

Never tried taking the pipe off (you have given me an idea ;)), but my installation is OK after 2000 hrs, 7 years. The neoprene outboard bearing has lost the first 6mm owing to nylon rope around the propshaft underwater, but this is a very small proportion of the bearing, which is around 150mm long. I would imagine fishing line could have a similar effect, but then again I have seen traditional installations damaged by same.

 

Not had to do it yet, but am told that the inboard seal can be changed afloat, with the aid of a silcone greased rag stuffed between the shaft and tube. The seals are however expensive to buy (no surprise there.) The outer bearing will obviously be a dry dock job, and from what i am told is a swine to get out of the tube. I suspect a slide hammer might be the thing.

Edited by Guest
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