Marine exhausts???

Discussion in 'Diesel Engines' started by burt2, May 8, 2006.

  1. burt2
    Joined: Nov 2005
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    burt2 Junior Member

    Scary well ill try not to put into a situation like that lol but sometimes these thing just happen. I think the exhaust will look much nicer out the back, and I suppose the swim platform will also muffle it slightly.

    Ok so out the back on the starboard side above the waterline it is, well that was easy now I just got to do it which is much harder than talking about it. I’m going to build it in stainless to a plastic water lock then stainless up to the turbo, ill buy a pre-made through hull exhaust flange that looks nice.

    The next big project is building a hard top which I think ill build out of stainless tube with a fibre glass top and clears that drop down to the screen pretty standard but anything is better than a rag top, weather is very unpredictable here in New Zealand and putting those vinyl covers up in a squall sux.
     
  2. bilgeboy
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    bilgeboy Senior Member

    Hi Burt,

    I'm trying to visualize your exhaust system, and I can't see what you mean by a "water lock". Water locks are good if you are trying to brew beer.

    Since I am not sure what you mean, I just want to humbly offer that you might want to build a "riser" into the exhaust system, and then inject your cooling water after the rise. This will protect your turbo and possibly engine from any back flow of seawater or cooling water. Once the injection occurs, you can use reinforced muffler hose to the back of the boat. This should make a well designed system that has quality stainless components, but saves work and money by using muffler hose.

    Mike
     
  3. StianM
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    StianM Senior Member

    It eleminate vibration in the exhaust system where stressed point will be damaged. On a steel pipe you would nead a compensator, but I have changed a lot off them during my work hours so a hose like bilgeboy sugest is the bether option.
     
  4. burt2
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    burt2 Junior Member

    thanks a good point exhaust hose would keep vibration down I didn't think of that, so you guys would just run it from the riser straight out the back without any thing in between
     
  5. Ike
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    Ike Senior Member

    Run it out the stern but think about air flow. You don't want a large concentration of exhaust and Carbon Monoxide forming a cloud at the stern that literally gets sucked back into the boat. Take a long look at your boat and try to figure out where is the best place to put it on the stern so that airflow will take it away from the boat under most conditions, particularly when at idle or going slow downwind. Look at newer boats similar to yours and see where they put them.
     
  6. burt2
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    burt2 Junior Member

    thanks, yeah i had thought of that, the engine room air intakes are on both starboard and port sides right at the rear i was think of blanking the starboard one off and making the port vent bigger as the exhaust will come out pretty near the starboard vent
     
  7. StianM
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    StianM Senior Member

    let the steel pipe from the turbo go up as far as posible befour leting it go down. Place the coolig water outlet as low as posible befour the conection off the exhaust hose.

    The exhaust will be cooled and somehow cleaned by the water so it won't be mutch off a problem and just to pick a litle carbon monoxside is not a problem with diesels since they work with large excess air. A good combustion give close to zero carbon monoxside. I belive your thinking off Carbon dioxide.

    Carbon Monoxide is flammable and highly toxic while Carbon dioxide is not flammable and not toxic, but displace oxygen and can suffocate living creatures and put out flames. Just wanted to sort out anny misunderstanding.
     
  8. burt2
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    burt2 Junior Member

    The turbo will sit approximately 300mm above the water line, do you think I will need to extend the factory exhaust up higher; I will be using 2x check valves one in the exhaust through hull fitting and one in the plastic muffler.
     

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  9. StianM
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    StianM Senior Member

    Depends on how paranoid you want to be.
    We let the pipe bend up befour we go down on our coust gard vessels, but we don't have anny valves.
     
  10. burt2
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    burt2 Junior Member

    I know what you mean, there is no way of checking that the check valves are in good order but im sure 2x check valves and 300mm above water line and the exhaust and muffler to fill with water would be a pretty safe set up for a leisure cruiser more than the factory set could provide anyway.
     
  11. inchman
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    inchman New Member

    Hello, forgive my ignorrance but why is the waste cooling water always put out the exhaust?

    cheers Gary
     
  12. FAST FRED
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    FAST FRED Senior Member

    why is the waste cooling water always put out the exhaust?

    It serves to lower the temperature of the exhaust , making it easier to not catch the boat on fire.

    And it can reduce the noise from the exhaust a bit.

    On larger engines only a portion of the cooling water is used to cool the exhaust , as the cooling water volume would be too much for the exhaust .

    FAST FRED
     
  13. bilgeboy
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    bilgeboy Senior Member

    Hey Burt,

    How is the project coming? This thread got dredged up from the depths, thought we could get an update.

    I somehow missed the check valve thing before. I don't like check valves at all- they can't be trusted, and when they fail they put you in a world of hurt. Consider how they are discouraged from use in a bilge pump system, and you will not want them in the exhaust. I tried one once to keep my bilge a bit drier, it stuck closed after a month an burned up my bilge pump. Lessoned learned. Since that event I have read some pretty bright people warning to avoid such things.

    I'm still partial to the riser idea. Lots of protection, good flow, no check valves and small money.

    Mike
     
  14. ChrisF
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    ChrisF Junior Member

    Nobody has mentioned an exhaust water tell-tale, so I will. Tee off a little bit of the cooling water just after it exits the manifold and run it out high on the hull, wherever you can best see it from the helm. Then you just check that instead of peering over the transom. All you need is a big enough stream to see, say 3/8" pipe. This can also serve as a siphon break if you tee off at the highest point of the cooling water loop.
     

  15. chandler
    Joined: Mar 2004
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    chandler Senior Member

    It sounds like this all power boat stuff. How about a yawl? Could you run the exhaust up and out the mizzen mast?
     
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