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Exhaust options.


Tigerr

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I am considering another boat, looking at one with a nice engine room this time. I am too now old to spend hours hanging upside down attending to the needs of a lump in an inconvenient under deck hole. Our old boat had a 90's Beta 43, (died when the front fell off which was a problem with their design when used to drive a power pack) that I replaced.  What was good about it was the huge silencer that reduced it to almost electric quiet, tucked away over the swim.

I was wondering if anyone with a Gardner for instance, instead of a traditional exhaust through the roof, takes the exhaust through a low level larger silencer and out above the waterline?

I know some love the engine noise, but I reckon I'd find it intrusive and I don't fancy those (carcinogenic) fumes when the wind blows wrong. 

Edited by Tigerr
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I would have thought many hospital and close to hospital silencers could be fitted vertically into the existing exhaust pipe. That would direct the sound upwards, so it may well be quiet except when in tunnels and under bridges. I had my conventional exhaust moved from side exit to rear exit when I had a near hospital silencer fitted and the difference to the noise when cruising was very noticeable except when in locks where the sound bounced back off the lock gate.

 

I can't see any reason not t fit a low level exhaust pipe as long as it is adequately swan necked, except the potential build up of condensation in the pipe. That should not be such a problem now we use low sulphur fuel. If possible I would make it a stern exit.

Edited by Tony Brooks
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Very helpful Tony. Thanks.

Is there a handy 'duffers guide to vintage engines' out there so I can get a better idea of what I am looking at with different makes and models? Pros and cons etc. 

The boat I am currently eying up is 70' with a Gardner 2LW - but in truth I don't know if that's a good setup other than it's very nicely shiny etc! I know that some engines are very 'highly regarded' and valuable, other less so. My chum had a lovely Russell Newbery that was a thing of beauty. 

 

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9 minutes ago, Tigerr said:

Very helpful Tony. Thanks.

Is there a handy 'duffers guide to vintage engines' out there so I can get a better idea of what I am looking at with different makes and models? Pros and cons etc. 

The boat I am currently eying up is 70' with a Gardner 2LW - but in truth I don't know if that's a good setup other than it's very nicely shiny etc! I know that some engines are very 'highly regarded' and valuable, other less so. My chum had a lovely Russell Newbery that was a thing of beauty. 

 

 

This is not helpful if anyone's heart is set on a particular vintage engine, but I would not touch one with a barge pole unless I were assured there were readily available spares at reasonable cost. If t starts easily from cold -most vintage engines should because they are direct injection -  and does not smoke, except for just a little at idle or low speed/power then should be in fair condition. Next it is just the oil pressure, and that can be low compared to moderns on some such engines in perfect condition, and ensuring adequate cooling for river work.

 

Gardners are and were always considered quality engines as long as you can put up with the bus engine jibes from pratts.

 

Where the engine came from also has a bearing. If it came from a sea boat and is direct raw water cooled could mean excessive internal corrosion.

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My boat had a huge gate valve which switched between a traditional roof stack and one straight out through the side. It's a Jp3m so fairly quiet anyway with the marine silencer. 

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50 minutes ago, BWM said:

My boat had a huge gate valve which switched between a traditional roof stack and one straight out through the side. It's a Jp3m so fairly quiet anyway with the marine silencer. 

I had wondered if that was an option too. Pleased to hear it is. 

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A suitably rated lever operated full flow ball valve would be a better bet than a slide valve, if only because it is quicker to operate, it is obvious which position it is in and it is  less likely to stick.  I have a 1 1/2 in version on the generator exhaust.

 

N

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24 minutes ago, Tigerr said:

I had wondered if that was an option too. Pleased to hear it is. 

I was given the impression that it was fitted in the early 70's when used as a camping boat but have no means of confirming this. My decision to remove it was done in an effort to smooth the flow of gases and simplify the system but i doubt it would make much difference in performance. 

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Whilst a silencer will moderate the exhaust noise there is still the noise from the engine itself. With an engine in a room part way along the boat there will be more noise throughout the boat than compared to an engine at the stern with some soundproofing. We have a 3LW  and it's far from quiet. If a quiet boat is the aim I would not consider a vintage engine in an engine room is a solution. 

 

Our exhaust is quite effective at reducing the exhaust note. We also have a comparatively long roof exhaust which is hinged to avoid breathing the fumes. This is very effective and I would judge it to be a better solution than a side or rear exhaust when in locks or other confined locations. 

Edited by jonesthenuke
Added last paragraph.
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