cooling design preference

Discussion in 'Diesel Engines' started by rfleet1066, Mar 4, 2012.

  1. rfleet1066
    Joined: Feb 2012
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    rfleet1066 rfleet1066

    Pardon my ignorance, but I'm fitting a new built vessel with a diesel engine, type and horsepower yet to be determined. I'd like to be briefed on the costs/benefits of seawater cooling vs closed radiator systems.

    Ryland
     
  2. michael pierzga
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    michael pierzga Senior Member

    Workboat or yacht ? Closed engine room or open ? 20hp or 2000hp ?
     
  3. J Feenstra
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    J Feenstra Junior Member

    wet exhaust dry axhaust. What engine manufacturer?
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Seawater cooling is simple, but corrosive. Closed loop cooling is more complex, but your engine isn't drinking brine, which likes to eat iron. There are several types of systems, each has advantages and disadvantages to consider. For example, some engines are so stout, that you can pump the Red Sea through them and they'll have plenty of water jacket thickness to tolerate it. Other engines are set up for closed loop by the manufacture and are lighter built, so raw water cooling might just cause it a quick death. Your best advised to take the recommendation of the manufacture or marinizing outfit.
     
  5. rfleet1066
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    rfleet1066 rfleet1066

    cooling

    This will be a landing craft with 200 hp or less (diesel) I can construct the engine room to be open or closed.

    Ryland
     
  6. FAST FRED
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    The first question is weather the boat will be operated in freezing weather.

    To properly winterize a heat exchanger system with sea water used to cool and then dumped in the exhaust may take hours , after every use.

    Since this is hardly acceptable the best setup is keel cooling with a dry stack exhaust.

    As a work boat that will frequently be aground , the internal baffled setup is better thsn an external keel cooler.

    All the math and sizing is in Dave Geers books.

    FF
     
  7. CatBuilder

    CatBuilder Previous Member

    What is the internal baffle setup all about? How does that work? Any tips on making a dry exhaust nice and quiet?
     
  8. mydauphin
    Joined: Apr 2007
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    mydauphin Senior Member

    All the large landing crafts I have ever seen have seawater cooling.
     
  9. rfleet1066
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    rfleet1066 rfleet1066

    That's a very good point. It will be used in freezing weather. The closed system seems to be the best choice.

    Ryland
     
  10. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    What is the internal baffle setup all about? How does that work? Any tips on making a dry exhaust nice and quiet?

    The surface area and baffle design tips are in the Dave Gerr book.

    Google "Hospital Critical mufflers" , heavy and pricy , but really as quiet as a diesel exhaust can be done.

    FF
     
  11. michael pierzga
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    michael pierzga Senior Member

    A conventional marinized marine engine is the only way to go. Hybrids like keel cooled , dry exhaust , only make sense when fouling is a issue.
     
  12. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "only make sense when fouling is a issue."

    Unless FREEZING temperatures are part of the vessels life. Spain isn't Maine!

    A really huge advantage to dry stack ,,keel cooled is any marine engine probably came from a truck anyway.

    By using a truck (or tractor take out) the engine cost can be reduced by 1/2 to 9/10 with ease.

    A good rebuilt marine tranny (Twin Disc) can be has at modest cost.

    Why dump $25,000 to $40,000 into a drive package with the same engine, when $5,000 will get you underway?
     
  13. michael pierzga
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    michael pierzga Senior Member

    Fouling implies ice, weed, plastic...whatever.


    The key component in a marinized engine is the watercooled exhaust manifold. Dry exhaust will require the exhaust to be heavily packed with insulation to deal with this exhaust heat in the engine room. Insulation is always a big bulky mess that takes up precious space . If cost is the factor then go dry.
     

  14. FAST FRED
    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "The key component in a marinized engine is the watercooled exhaust manifold.
    Dry exhaust will require the exhaust to be heavily packed with insulation to deal with this exhaust heat in the engine room."

    Not at all, the "marine" water cooled manifold just requires a bit larger heat exchanger to dump the exhaust heat into the ocean.

    On our lobster boat with a 6-71 the exhaust manifold is water cooled and two std 21 ft lengths of 1 1/2 pipe outside work as cooler , Maine or Bahamas.

    A Thermostat in the heat exchanger return is REQUIRED to prevent over cooling , about $400 new.

    FF
     
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