Silencer recommendations for a twin pot lister

[Trevorleach]

Need a silencer for a twin pot lister in an open steel boat.
Local motor factors reckon a hospital silencer is 350 quid! I do not want that posh, just enough silencing to take the bark out of the exhaust note for the operator and nearby boat yards not to moan at the noise.
Ebay is nuts, thousands of listings mainly posh ends caps and bling.

Was thinking an old style vertical slip on tractor silencer, but they look a bit small/delicate.
The engine is a 10 foot pipe run from where the silencer will be fitted, main run will be 2 inch stainless flexi (not my choice but that is what they bought) we are using a scaffold tube (48.3mm) for the main vertical exhaust.

Any ideas preferably cheap welcomed.

 

[brightspark]

i had a pattern one of a grey fergy on mine same as on my stockcar . cheap as chips

 

[tom2207]

how about two lorry silencers in series ,,, in a box

or three , or what ever comes to hand it wont really matter .

 

[jenki]

Tractor dealers? I well remember the markup on anything called 'Marine'

 

[Morrisman]

Have a browse, lots of options. None anywhere near £350

Silencers - Round - Page 1 - Profusion Exhausts LTD

www.profusionexhausts.com

 

[zzr1200]

Can't you exit the exhaust under the water???

 

[GRW]

Can't you exit the exhaust under the water???

You have to think about exhaust back pressure a bit.
They used to run Lister exhausts through a water tank though (bit like a heat exchanger) to mute donkeys years ago

 

[zzr1200]

Surely back pressure will only be caused by how deep the exit is under the water surfave, having a 10ft long exhaust pipe wont help?

Provided the exhaust manifolds/valves are above the water level there shouldn't be aproblem.

 

[KemppiFrog]

Installed a few Lister aircooled gensets. Usually dug a trench, lined it and put baffles made out of concrete tiles. Very effective, but not much help to you
How about, if water cooled, copying the water lift boxes from Vetus and use rubber pipe. Or, just two of the cheepy tubular silencers off the local motor factor. Only prob with those, might not last long in the salt air.

I fixed a problem on a Swan. two engine rebuilds after water got back. The supplied water lock was too small to keep the water in the back pipe from surging when sailing into a head sea.
Found some extra room a bit lower down and made a new unit in GRP to fit, with three times the capacity. Work well.
Edit: This was with the engine below the waterline.

 

[Trevorleach]

Can't you exit the exhaust under the water???

We want to but due to machinery hanging off the back and down the sides there is simply no room, plus as we are not sure how it will sit in the water with all the mods we would be guessing on the exhaust route.
I would prefer it out the rear just below the waterline to help with smoke and noise.

 

[Trevorleach]

You have to think about exhaust back pressure a bit.
They used to run Lister exhausts through a water tank though (bit like a heat exchanger) to mute donkeys years ago

Still do that with many boats, my boat has the same, but then of course you need a water pump.

 

[tom2207]

if you can get away with a dry system thats exactly what I would be doing ,,, steam pipe lagging is cheap and effective ,,,

 

[mr haynes]

Cheapest poxhaul/ford box an option?

 

[Barking Mat]

Cheapest poxhaul/ford box an option?

I went to the lorry scrap yard, and stuck something of a similar size on my truck.

Probably a million reasons why this is not the correct thing to do, but hey.

 

[Trevorleach]

Well shiny Massey silencer fitted today, pretty impressed how quiet it made the exhaust note.