Converting a dry exhaust to wet.

Discussion in 'Inboards' started by nikosts, May 21, 2009.

  1. nikosts
    Joined: May 2009
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    Location: Greece

    nikosts Junior Member

    Hi to everyone. This is my first post here, hope it's in the right place.

    I have an old greek boat (this type is called "koutoulo"). It's about 16 feet long and has an old air cooled one cylinder Lister ST1 engine (about 10 HP). The exhaust goes straight up on the deck. It is rather noisy and we have always to be careful not to touch it etc, so I am thinking of converting the exhaust to wet.
    There is an old belt driven raw water pump (visible on one photo) which will need a rebuild probably. I then also need a custom made mixing elbow, some meters of exhaust hoses, a water lift muffler, siphon break etc, a cost of about $150-$200.
    What do you think about this? Is there a chance of having back pressure problems?

    Thanks for any response, Nikos!
     

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  2. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    First the idea to go wet is good for security, noise and efficiency under certain conditions
    Of course back pressure will cost you HP and torque
    In fact you can go for any solution but No AVOID "water lift muffler", W.L.M is inefficient and dangerous as back pressure bring CO and CO² out of junctions (may be not dangerous in your personal case of open boat)

    Wet exhaust will make you gain torque and lower noise too by cooling down exhaust it makes it easier to pull it out, but you will get rust
    Water cooled exhaust manifold will do the same without oxidation but is this available for your lister, i doubt ?
     

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  3. nikosts
    Joined: May 2009
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    nikosts Junior Member

    Hi kistinie.
    I just want to ask, what should be the difference between the "Water cooled exhaust manifold " that you propose, and a hose pouring water just after the exhaust manifold? Sorry for asking but I 'm not sure that I understood what you wrote.
    Thanks again.

    P.S. About back pressure. I think that if I can regulate the amount of water going into the muffler it would be ok. My opinion though...
     
  4. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The easiest is to make a water sleeve. You make a pipe going around the exahust pipe but in never mixes with the gas. There is an exit hose for the hot water.
     
  5. kistinie
    Joined: Aug 2007
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    kistinie Hybrid corsair

    Water inside exhaust gaz is terrific and efficient but, it rust and it get difficult to send gas up else water returns to engine, which is very bad idea
    The Gonzo solution is great as it can be home maid and water stays out but a little less efficient. But again so much easier !

    Gonzo, what kind of pipe ?
    Coper pipe ?
    Should be great as it can be soldered (brazed) with 316L steel
     
  6. apex1

    apex1 Guest

    Hello Nikos, welcome aboard.

    You are already on the right path as your opening has proven. The parts you easily can buy at "Vetus" for example. Not the only supplier, but one who knows the business (largest supplier for the boatbuilding industry). No need for a custom made elbow.

    There are many Indian made "Lister" clones at the market, if you need parts or a new engine.

    The raw water pump you should fix anyway its your engines coolant provider.

    As long as you have about the same length of exhaust pipe and hose, you have no higher backpressure! But stay above waterline with the outlet!

    Torque or power do NOT increase (as our layman would tell you), a wet exh. usually is a little bit less efficient than a dry one. In this case your Lister will not notice, nor will you, if you loose 50Watt or so.

    A wet manifold is a nonsense on such a installation (raw water cooler), and not available at the market. Leave it.

    Do not use copper in the pipe material! Mild steel is the choice on the dry part (It has the advantage to corrode in a predictable and even manner, you can see long before it fails, that it will fail. Stainless brakes suddenly and unpredictable), exhaust hose is it between the steel and elbow, then you may use stainless for the through hull.

    Lookup the Vetus catalogue online, as I remember they even give a installation hint.
    Good luck!

    Soldering copper and steel on a seagoing boat was the joke of the week! (Layman)

    You must not feel sorry if you do´nt understand Kistinie! Nobody does!

    Regards
    Richard
     
  7. Lt. Holden
    Joined: Sep 2007
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    Location: Western Massachusetts

    Lt. Holden Senior Member

    Why not repair the coolant pump (which is necessary anyway) and put a stand off shield on the dry exhaust stack, I would attach a flapper type exhaust tip to keep out rainwater and stray cats.
     
  8. kistinie
    Joined: Aug 2007
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    kistinie Hybrid corsair

    Coming back on 316 L steel brazed on coper.
    I did this for outside use but not on a boat and it behaves well

    In a salted environment what happens ?
    Any picture to see ?
     
  9. apex1

    apex1 Guest

    Try to find a good shool to learn about the basics of physics instead of asking here for free education.
    Naturally no pictures! Who would be such a ***** to make that?

    Lt. Holden
    I agree, a "Truck type" arrangement would be the cheapest solution. But no wet exhaust.

    Regards
    Richard
     
  10. kistinie
    Joined: Aug 2007
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    kistinie Hybrid corsair


    A forum is for free education and knowledge sharing.
    Your general aggressive attitude and permanent sabotage is in total contradiction with the solidarity and fraternity sailors have shared for all eternity.
    I am rather surprised that nobody tell you to calm down, behave with more respect, and that recurrent insults is not a way to talk and express ideas.
    Do you suffer from a psychological disorder illness ?



    This being said
    What appends to coper tube brazed on 316L exposed to salt water ?
    Oxydo-reduction is one thing, but experience speaks more...
     
  11. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member

    Kistinie, I think certain people around here have lost their patients with you. I am ok with you, since you remind of my teenage son...

    One rule in engineering or making stuff in general. Don't mix materials unless you really know what your doing. Because that will be point of failure. Dissimilar metals will also corrode, crack, shrink or generally fail. On a boat vibration and salt air will destroy even 316ss if not done perfectly right.
     
  12. kistinie
    Joined: Aug 2007
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    kistinie Hybrid corsair

    You are always responsible for your own hanger and under no circumstance we can blame the others. It is our choice to be hungry not the other's choice.


    Back to metals, yes of course, but here on earth i do not get any problem with this 316/Cu mix used for architecture. (seen also in London in one of the queen castle)
     
  13. dobsong
    Joined: May 2009
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    Location: Australia

    dobsong Junior Member

    Love your boat!

    And a wet exhaust would make it even better! It would be very easy to convert to a quiet exhaust using a basic "wet" exhaust system - and heaps quieter.....
     
  14. kistinie
    Joined: Aug 2007
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    Location: france

    kistinie Hybrid corsair

    you can get a wet exhaust also with dual fuel
    When you run a diesel with butane or propane, added to the air inlet (like on a LPG car, exhaust will be producing water, do the test, it is surprising.
    Water cool the gaz and lower back pressure, increase torque

    This is not conventional, water produced may not be enough to cool down the pipe at high rpm and you need to manage 2 fuels...but it works great on slow motion
     

  15. apex1

    apex1 Guest

    Nikos,
    one thing I overlooked in your opening..........
    the Lister is NOT aircooled, as you mentioned yourself, there is a raw water pump!
    The whole installation is a pretty easy one and within your cost estimation. (I was impressed, that the "Truck type solution" is almost as expensive. I looked up at a highway truck shop.

    Forget about the statements above (post # 14), all nonsense! Stay with us, stay alive (no gas on a small fisherboat), and do not waste your time and money with such phantasies. A water cooled exh. does NOT increase torque or power! The opposite is the case in a perfect installation! But I mentioned that above, nuts!

    Regards
    Richard
     
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