Exhaust change

[Mikexx]

The short pipe between the flange on the Bowman and flexible is seriously holed.

 

The whole of the exhaust is currently suspended from the rear. Although there are a couple of brackets connected to the Swim, they aren't actually used.

 

I would like to undo the exhaust, though it is of sufficient age that I am happy to remove and replace the lot.

 

I do have access to pipe threading vice and dies so tailoring to fit shouldn't be a big issue.

 

I have been able to make one thing move using Stilsons, the 45 angle fitting (in the last photo). However I suspect if I apply any further force it will fall apart.

 

Photo 4 is perhaps the most telling, it is where it passes through/past the fuel tank. Photo 5 is where the pipe emerges. The gunk appears to be mastic, but I can't see any fitting I can remove.

 

Is this setup standard? Any ideas on how to proceed to remove the exhaust attached around the fuel tank?

[Tony Brooks]

I doubt any boat exhaust, especially on a narrowboat is in any way "standard". Even on so called production narrowboats.

 

I would be removing paint/blacking from the outside of the hull around the exhaust exit to see if the pipe is welded to the hull or screwed through a threaded boss. If it is welded then I suspect much angle grinding will be required and possible the use of a jigsaw. If its screwed I would keep dosing the inside with proper penetrating oil (not WD40) like Plusgas. Then apply a hammer to the outside to try to shock the rusted thread. If it still wont undo I would apply an oxyacetylene torch to the outside of the hull/boss.

 

I do not like the way the pipe runs downhill all the way to the manifold. If you moored stern on to waves water might get into the engine. However I can not see from the photos how you could fit a swan neck in the pipe.

[pophops]

I can sympathise having just renewed the exhaust on Falcon. I had some badly seized joints to free and followed the advice I found on a here.

That advice was to wrap the joints in diesel-soaked rag for 24 hrs ( all wrapped in cling film) and then use some ​​serious ​heat and 2 pairs of stilsons to free them off. My exhaust was threaded into a skin fitting in the side of the boat and was just unscrewed. However, you don't seem to have that option where the exhaust exits through the tank. If this section of pipe seems sound you could just leave it in situ and renew the rest of the system.

[PaulJ]

If the end section is infact welded in then trim the pipe on the outside down to a few millimetres and use that as a guide for a 2 inch hole saw. Leaves a nice hole ready for rewelding.

[Mikexx]

 

I doubt any boat exhaust, especially on a narrowboat is in any way "standard". Even on so called production narrowboats.

 

I would be removing paint/blacking from the outside of the hull around the exhaust exit to see if the pipe is welded to the hull or screwed through a threaded boss. If it is welded then I suspect much angle grinding will be required and possible the use of a jigsaw. If its screwed I would keep dosing the inside with proper penetrating oil (not WD40) like Plusgas. Then apply a hammer to the outside to try to shock the rusted thread. If it still wont undo I would apply an oxyacetylene torch to the outside of the hull/boss.

 

I do not like the way the pipe runs downhill all the way to the manifold. If you moored stern on to waves water might get into the engine. However I can not see from the photos how you could fit a swan neck in the pipe.

 

 

I'll attack the hull around the exhaust pipe with an angle grinder at the weekend and report what I see. Access to the rear-most part, through the depth of the diesel tank, is very poor.

 

I don't see any alternative to the downhill run. To be honest the exhaust is quite high up on the hull, and only just below the rear deck floor level, so the risk of water ingress is quite low..

I can sympathise having just renewed the exhaust on Falcon. I had some badly seized joints to free and followed the advice I found on a here.

That advice was to wrap the joints in diesel-soaked rag for 24 hrs ( all wrapped in cling film) and then use some ​​serious ​heat and 2 pairs of stilsons to free them off. My exhaust was threaded into a skin fitting in the side of the boat and was just unscrewed. However, you don't seem to have that option where the exhaust exits through the tank. If this section of pipe seems sound you could just leave it in situ and renew the rest of the system.

 

That is a plan. However if threads need cleaning up or remaking in situ there isn't going to be enough room.

 

I've never been successful with heat with iron on iron.

If the end section is infact welded in then trim the pipe on the outside down to a few millimetres and use that as a guide for a 2 inch hole saw. Leaves a nice hole ready for rewelding.

 

I'm not sure how I can successfully use a hole saw on a pipe. It has got me thinking but I am wondering if a jig-saw or other reciprocating saw might be a way forward.

 

 

Thanks for all the ideas.

[WotEver]

I'm not sure how I can successfully use a hole saw on a pipe. It has got me thinking but I am wondering if a jig-saw or other reciprocating saw might be a way forward.

As I understood the suggestion the hole saw sat over the stub with that stub acting as a guide for the saw.

[Bee]

I think I would remove the lot, cap off the stub on the outside of the boat, I bet its 1.5" BSP, then weld an elbow on the steel flange on the Bowman and poke the exhaust out of the side of the boat.

[PaulJ]

As I understood the suggestion the hole saw sat over the stub with that stub acting as a guide for the saw.

Yep- spot on. ☺

[Tony Brooks]

I think I would remove the lot, cap off the stub on the outside of the boat, I bet its 1.5" BSP, then weld an elbow on the steel flange on the Bowman and poke the exhaust out of the side of the boat.

 

And then have the noise bounce back at you from the bank, piling etc.

 

I would keep it out of the stern.

 

 

 

[Mikexx]

 

And then have the noise bounce back at you from the bank, piling etc.

 

I would keep it out of the stern.

 

I was reticent of moving the exhaust exit, this argument has me convinced!

[Dave Payne]

 

And then have the noise bounce back at you from the bank, piling etc.

 

I would keep it out of the stern.

 

 

 

Agreed, mine does this, and it leaves horrible black crap on the piling!

[Mikexx]

As I understood the suggestion the hole saw sat over the stub with that stub acting as a guide for the saw.

 

Yep- spot on. ☺

 

I see the idea, I will think about this a bit more. I've no idea how long the stub is, but the idea of having a tube former the hole drill can sit over sounds a good idea of centring a hole-saw.

 

I think some measuring if the actual pipe size is in order. I suspect it's either 1.25" or 1.5" BSP pipe.

[ditchcrawler]

 

And then have the noise bounce back at you from the bank, piling etc.

 

I would keep it out of the stern.

 

 

 

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