Engine exhaust outlet in roof - for/against?

[Neil2]

I've never been on a boat with a vertical exhaust stack but the boat I have now was designed with the exhaust coming up through the engine room deck and out of the cabin roof on the starboard side, about three foot or so from the back of the cabin, just forward of the sliding hatch.

 

I know this because I have seen old pictures of the boat, and there is still a cutout in the deck board.

 

At some point this arrangement has been replaced with a more conventional (starboard) side exit, so at the point where the pipe would have turned to head up through the roof, it now goes sideways out of the hull.

 

At some point I'm going to fit a hospital grade silencer as there is plenty of room down there, the reason being the exhaust exit is right under the steering position.

 

But I have a fancy to change it back to the way it was originally built. The hole in the roof has been covered with a mushroom vent, so it wouldn't take a lot of work. I presume the extra pipe length will assist noise reduction but will it be more intrusive being in front of the steerer?

This is outside my experience so I am wondering what other implications of this arrangement would be, and are there good reasons why someone decided to do away with the vertical pipe? I can see an obvious disadvantage to having an exhaust pipe in the aft cabin but I'd appreciate views from anyone that has this arrangement or has considered it.

 

BTW the engine is a Bukh DV24, which though it is a quiet running motor does have quite a bark to the exhaust note.

[Proper Job]

Traditionally the exit for the exhaust was in the roof. With an engine room forward of the cabin it's a reasonable distance from the steerer.

 

I would suspect this was put in both for ease and practical purposes.

[Athy]

As PJ implies, you probably wouldn't want an exhaust chimney too near to your steering position or you'd be getting facefuls of diesel fumes all the time. A chimney with a cutter reduces this problem but doesn't always take it away altogether, depending on wind direction. We have such a chimney, I like the look and the sound, and it's a good ten feet forward of the steering position so not too many facefuls!

[Edders]

As PJ implies, you probably wouldn't want an exhaust chimney too near to your steering position or you'd be getting facefuls of diesel fumes all the time. A chimney with a cutter reduces this problem but doesn't always take it away altogether, depending on wind direction. We have such a chimney, I like the look and the sound, and it's a good ten feet forward of the steering position so not too many facefuls!

The exhaust on my boat is offset to the left hand side of the roof, about 10 feet forward and I found the cutter tended to keep the fumes at head height unless there was a slight tailwind. I now use a tall pipe with no cutter and have no fume problems unless into a direct headwind, (I'm not worried about spiders, etc in tunnels!).

 

Tony

[Proper Job]

I don't have a cutter on Ocelot's JP for exactly the same reason. I find the exhaust gas clears better without one.

 

It's not only the tunnel spiders, but the acorns etc from over head branches can be the down side

[MtB]

With a chuffy engine the exhaust goes out the roof, with a buzzy engine it goes out through the side.

 

This is the law.

 

 

MtB

[RichardH]

I broke the law m'lord

 

Guilty as charged.

[alan_fincher]

I think I'm correct in saying that the much accredited Dave Harris actually refused "Wrigglefingers" having the exhaust through the engine room roof on Cobbett, even though the boat has the fine lines of a replica. It comes out the side, despite a dedicated engine room, forward of a back cabin.

 

I believe he thinks ingesting the fumes is not good for your health. (I'm happy to be corrected by Jill if I'm misquoting that).

 

I have to say I do have serious worries about how much of Sickle's exhaust we breath, although, in fairness, it is not the cleanest exhaust around, even for a Lister.

 

That said, at least the exhaust is ten or more feet from the steerer, unlike range chimney about a foot away, and with top at "nose height". Sometimes my eyes are streaming, and I think that is more range smoke than diesel fumes.

 

I'm not at all convinced either is healthy - perhaps the boat I love is sending me towards an early grave?

[Phil Ambrose]

My understanding is that diesel exhaust is loaded with particulates which are known to be carcinogenic, sure I've read that somewhere.

Phil

[John Williamson 1955]

My understanding is that diesel exhaust is loaded with particulates which are known to be carcinogenic, sure I've read that somewhere.

Phil

One of the safest ways to deal with those is to inject cooling water into the exhaust flow, which should carry the particles with the water. AKA a water cooled exhaust. Whether you can live with the intensely annoying bubbling sound (In my opinion, anyway) is up to you.

[Proper Job]

One of the safest ways to deal with those is to inject cooling water into the exhaust flow, which should carry the particles with the water. AKA a water cooled exhaust. Whether you can live with the intensely annoying bubbling sound (In my opinion, anyway) is up to you.

It makes it a bit damp with a roof exit exhaust as well

[John Williamson 1955]

It makes it a bit damp with a roof exit exhaust as well

A cooling shower in the Summer, if it ever arrives?

[hughc]

We have always used a roof mounted exhaust about 4' - 4' 6"long. It is hinged to fold flat against the roof when necessary. The pipe is raised and lowered by the steerer using a lightweight pole with a small boat hook on the end. The exhaust gas is thrown well clear of the steerer but if you are towing the butty steerer may compalin if the wind is in the wrong direction. Do not under any circumstances reverse through a bridge hole without first lowering the pipe. As a bonus a long pipe softens the exhaust note . Regards, HughC.

[Athy]

Do not under any circumstances reverse through a bridge hole without first lowering the pipe.

I shall not ask how you discovered this rule; perhaps in the same way that we discovered "do not go through Aynho bridge without removing your chimney".

[nb Innisfree]

Ideally, three outlets, left right and up.

 

Up for locks to direct fumes away from steerer and either left or right depending on where the boat is moored. Could be done with diverter valves.

 

I've often wished I had done that when fitting out.

[Neil2]

I shall not ask how you discovered this rule; perhaps in the same way that we discovered "do not go through Aynho bridge without removing your chimney".

I'm glad someone else has done that.

 

Blasting the detritus (and spiders) from tunnel roofs hadn't occurred to me I must admit, and though the old pictures of the boat show the stack fitted with a cutter I wasn't thinking of using one as it seems to me you want the fumes to head skywards.

 

Having more than one stack seems to be the answer and I was surprised to see how cheap they are.

 

What is expensive though is the roof collar - the one Midland Swindlers sell is anyway - is there more than one way, ie is there a cheaper way, of doing it?

Ideally, three outlets, left right and up.

 

Up for locks to direct fumes away from steerer and either left or right depending on where the boat is moored. Could be done with diverter valves.

 

I've often wished I had done that when fitting out.

Now that's a thought...

[BD3Bill]

I've never been on a boat with a vertical exhaust stack but the boat I have now was designed with the exhaust coming up through the engine room deck and out of the cabin roof on the starboard side, about three foot or so from the back of the cabin, just forward of the sliding hatch.

 

I know this because I have seen old pictures of the boat, and there is still a cutout in the deck board.

 

 

We have this arrangement as our engine room is the back cabin.

 

It is a bit of a love/hate thing.

 

I love the sound. I hate the fumes if the wind is the wrong way, but stepping over to the opposite steering position usually helps.

 

I get just as much fumes from the stove pipe at the front in such wind conditions.

 

As you already have the side exit why not convolute a change over system ( side OR up ) ?

 

Cheers Bill

[ditchcrawler]

It makes it a bit damp with a roof exit exhaust as well

You could inject some washing up liquid with it

[Timleech]

A side exhaust from an engine room does have the disadvantage that fumes will collect in lock chambers, somehow it seems worse when the exhaust is blasted at the lock wall than out of the back of the counter.

Mine has the advantage that the vertical exhaust is behind the steerer - but then it's not a narrow boat.

 

Tim

[pippawatson]

I think I'm correct in saying that the much accredited Dave Harris actually refused "Wrigglefingers" having the exhaust through the engine room roof on Cobbett, even though the boat has the fine lines of a replica. It comes out the side, despite a dedicated engine room, forward of a back cabin.

 

I believe he thinks ingesting the fumes is not good for your health. (I'm happy to be corrected by Jill if I'm misquoting that).

 

I have to say I do have serious worries about how much of Sickle's exhaust we breath, although, in fairness, it is not the cleanest exhaust around, even for a Lister.

 

That said, at least the exhaust is ten or more feet from the steerer, unlike range chimney about a foot away, and with top at "nose height". Sometimes my eyes are streaming, and I think that is more range smoke than diesel fumes.

 

I'm not at all convinced either is healthy - perhaps the boat I love is sending me towards an early grave?

 

It might be a misquote Alan (unless Dave wants me bumped off!). Dave was happy enough to put a roof exhaust on mine.

 

I use a straight pipe with no splitter to get the gases and soot particles as high as possible.

 

I know a Norton Canes owner who has had his boat built with a side exhaust but who has now converted it to a roof exhaust as he didn't like the fumes in locks.

[dor]

My first boat, with a RN DM2 in it, had an exhaust pipe coming out of the roof. However that was for show as it was actually blanked off with the real exhaust exiting on the side below the gunwale. It seemed to keep the purists happy whilst stopping me breathing smoke all day.

[J R ALSOP]

A Bukh 24 does not have a "bark", but a Bukh 2G105 with original supplied spark arrester does.

[peterboat]

My understanding is that diesel exhaust is loaded with particulates which are known to be carcinogenic, sure I've read that somewhere.

Phil

Yes Phil you are right they are so dangerous that an artical on radio 4 by a scientist said diesels should be banned!! Their are lots of stuff on the NET about it so for me it would be out of the side

 

Prter

[Neil2]

I'm intrigued now by the idea of having a vertical pipe in addition to the side exit but I don't know how you would divert the exhaust gases - presumably you need some sort of valve, can anyone point me in the right direction?

[Graham Davis]

If you Google "exhaust diverter valve" you should find something suitable.

They are sometimes used in the custom car world