Jump to content

Water Has Been Dripping In A Lot!


Featured Posts

Hi

My narrow boat has been leaking water from the stern gear by where it comes through the boat. The tube looks like its threaded through the hull and the drips are coming up the threads. I put about 20 or so turns of grease in there and it's totally stopped.

My question is, is it through lack of greasing or lack of adjustment on my part? It was re packed 4 years ago and only covered 400 or so miles. I must add I've only recently adjusted it up a turn on each nut. I usually turn the grease a turn when I moor up.

 

Am I doing things correctly or is something amiss??

 

Many thanks

Link to comment
Share on other sites

You seem to be saying it is leaking at the point the stern tube actually passed through the back of the boat?

 

If so, a common arrangement is that a threaded steel boss is welded into the back of the boat, and then the (usually brass) stern tube is threaded to screw into this.

 

A leak at that point would indicate the screwed joint has loosened, and I must admit in that case to being a bit surprised if putting a lot of grease in via the greaser has completely stopped it.

 

I would not be at all surprised if it starts to leak again fairly quickly the next time you have the prop turning, and that grease gets disturbed.

 

 

 

If however you mean that the leak is at the inboard end of the stern tube, where the prop-shaft enters it, and the adjustable gland is, then ignore al the above!

Usually though if they leak at the back end it will need a proper fix eventually, although I held one a long while using a coating of silicone, with plumbers hemp wound into it.

Link to comment
Share on other sites

I had this happen, when the weld that held the stern tube to the hull partially failed, however, no amount of turning on the greaser would stop the flow, so I suspect that is not your problem.

The repair involved a lift-out, removal of the prop, shaft and bearing, then re-welding the tube (apparently the original weld had two small blow holes in it that had remained sealed by blacking etc. until I bought the boat and began working it hard).

It wasn't cheap, but when they put it back together, they vastly improved the route of the greaser tube, and the engine bilge has been bone dry for the 2 years since it was done.

 

A friend recently had a problem with a newish boat from a VERY reputable builder, where the stern tube had been welded incorrectly, such that the bearing didn't tighten full up when the fixing bolts were aligned. With a bit of trickery, the repairer drilled new holes for the fixing bolts that allowed the bearing to be screwed fully home. This only manifested itself after several years hard use, although a small amount of water was always evident around the bearing, but could never be pin-pointed until it got seriously wet.

Link to comment
Share on other sites

I think the most likely explanation is it is leaking down the screw thread, because either the stern tube is not tigtened in to the boss enough, or that whateber has been put into the joint to seal it is no longer doing its job.

 

I have heard of people being able to disconnect the inboard end, then using Stilsons to further twist the threaded stern tube into the outer boss, enough to seal it.

 

This may then involve drilling new holes such that the inner gland is no longer attached with its bolts horizontal.

 

The correct solution is doubtless to dock it, take it all apart, and remake it properly, which is something I decided to have done whenwe had the problem.

Link to comment
Share on other sites

the stern tube boss is welded into the steelwork the tube is then screwed in. it has come loose (happened once to me) just keep it tight enough to stop the dripping and then when you pull her out take the whole assembly apart and apply some thread seal and reassemble. the reason for the loosening is the fact that the engine sits higher than the stern tube (the reason for the 2 heavy duty flexible joints (UJ's) this results in a small amount of vibration (don't forget to check the 8 bolts on each UJ every 6 months as they do come loose as well

as for the tube packing this will wear down and again every 3 - 4 months its worth a quarter turn on each nut, repack when you get down to 4mm gap (if I re call correctly you can put 2 strips in at that distance

 

 

kev

and just to reassure you she will float perfectly even with a foot of water in her!! yes I found out the hard way!! luckily no floor had been laid at the time!

Link to comment
Share on other sites

What is the danger of it unwinding when in reverse, if any?

None, if the packing gland at the other end is bolted down as it should be.

 

The stern tube is firmly captive between the two ends, even if free to move slightly on its threads.

 

(Incidentally, whether forward or reverse might otherwise equate to "unscrew" of course depends on whether the boat has a left hand or right hand prop!)

Link to comment
Share on other sites

If water is wiring in through the tube to collar thread which does happen occasionally and its removed when docking, you or whoever does the job needs to take great pains to clean the steel collars internal thread, these threads get rusty when water leaks through. Clean it with an L shaped pricker chasing around the thread, small wire brush, stiff toothbrush ect, blowing out dirt and rust afterwards. If this is not done its doubtful if you'll tighten the tube completely right home and solid. When threads are cleaned have a dry run with penetrating oil on the threads screwing in the tube before finally tightening it right up with sealant.

Link to comment
Share on other sites

as Alan says there is a plate welded across the swim that the whole assembly bolts into, from memory it isn't that tight and the tube can wander about 3 mm forward/back and leaks if fully forward against the packing gland

Hi

 

Just been to boat and had close look. It's not coming from threads!! It looks like a hole 10mm from threads on the bottom. It doesn't look like its worn like that, almost like a perfect circle! When I grease it, it comes out the side of this hole. There appears to be a filler smeared under the bottom? Perhaps a old repair??

I can't upload pictures on here to show you :-(

Link to comment
Share on other sites

Hi

Just been to boat and had close look. It's not coming from threads!! It looks like a hole 10mm from threads on the bottom. It doesn't look like its worn like that, almost like a perfect circle! When I grease it, it comes out the side of this hole. There appears to be a filler smeared under the bottom? Perhaps a old repair?? I can't upload pictures on here to show you :-(

The hole is in the stern tube not the hull :-) just incase anyone thought otherwise

the stern tube boss is welded into the steelwork the tube is then screwed in. it has come loose (happened once to me) just keep it tight enough to stop the dripping and then when you pull her out take the whole assembly apart and apply some thread seal and reassemble. the reason for the loosening is the fact that the engine sits higher than the stern tube (the reason for the 2 heavy duty flexible joints (UJ's) this results in a small amount of vibration (don't forget to check the 8 bolts on each UJ every 6 months as they do come loose as wellas for the tube packing this will wear down and again every 3 - 4 months its worth a quarter turn on each nut, repack when you get down to 4mm gap (if I re call correctly you can put 2 strips in at that distancekev and just to reassure you she will float perfectly even with a foot of water in her!! yes I found out the hard way!! luckily no floor had been laid at the time!

Did you have a foot if water throughout the boat or to the engine room baulkhead?

Link to comment
Share on other sites

If you're worried about the short term until Sept then fit a float switch to your bilge pump if you don't already have one. This is most useful for if you.forget to tighten the greaser - I discovered !

Link to comment
Share on other sites

Hi

 

Just been to boat and had close look. It's not coming from threads!! It looks like a hole 10mm from threads on the bottom. It doesn't look like its worn like that, almost like a perfect circle! When I grease it, it comes out the side of this hole. There appears to be a filler smeared under the bottom? Perhaps a old repair??

I can't upload pictures on here to show you :-(

This is the remains of the peg ( basically some bearing metal) which stops the bearing rotating in the stern tube. Mine did this some years ago and has been fine since I did exactly what Tony suggests. It will get properly sorted next time I am on dock.

 

N

Link to comment
Share on other sites

What is the danger of it unwinding when in reverse, if any?

none it can only move 3-4mm due to being short

Hi

 

Just been to boat and had close look. It's not coming from threads!! It looks like a hole 10mm from threads on the bottom. It doesn't look like its worn like that, almost like a perfect circle! When I grease it, it comes out the side of this hole. There appears to be a filler smeared under the bottom? Perhaps a old repair??

I can't upload pictures on here to show you :-(

thanks Richard I got the pictures definitely a new tube needed as I said in text earlier looks like its corroded through wrap it with a greasy oily rag and secure that should see you through to dry dock

as for water yes right through to engineroom front bulkhead was about an inch from going over the door step!! it had rained very heavily that week and the hold (where the triangular cabin is now) was open to the elements.

This is the remains of the peg ( basically some bearing metal) which stops the bearing rotating in the stern tube. Mine did this some years ago and has been fine since I did exactly what Tony suggests. It will get properly sorted next time I am on dock.

 

N

you could be right, I cant recall wether there was one or not!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.