Mercruiser Sterndrive exhaust system with additional watermuffler and high gooseneck?

Discussion in 'Boat Design' started by an2reir, Jun 7, 2022.

  1. an2reir
    Joined: Sep 2001
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    Location: Bordeaux France

    an2reir fifty boat designs

    exhaust.jpg Hi There Greetings to all from France!

    Does the Mercruiser Diesel Sterndrive type of exhaust system eliminate the need for a high gooseneck and does the Mercruiser straight exhaust prevent syphoning and water going back to engine at various situations of water current coming from stern ?

    I would be inclined to design the exhaust system in a sport boat fitted with Diesel and tern Drive with an additional watermuffler and high gooseneck like the attached Vetus and image

    Thanks for your feedback on this one and I wish you a wonderful day! exhaust1.gif
    Last edited: Jun 7, 2022
  2. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Is it possible to have the engine connected to the outdrive leg with a Cardan shaft or universal shaft?
    As it looks like the engine will have to be a fair ways forward of the transom to accommodate the water trap, muffler and gooseneck shown in the above drawing.
  3. an2reir
    Joined: Sep 2001
    Posts: 645
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    Location: Bordeaux France

    an2reir fifty boat designs

    thumbnail_image006.jpg Hi Bajansailor thank you for your feedback !

    Mercruiser in their installation manual have writen the exhaust should be mounted as per the above .

    I think many aspects in regards Sterndrive Mercruiser Diesels water ingestion and walterlocking were discussed in a previous thread here onthe BoatDesign Forum

    Water Ingestion Into I/o Merc Engine

    One of the Boat Design forum members recommends problem can be fixed with Mercruiser exhaust spacers

    My understanding is water ingestion can happen due to following seas or due to
    the boat being launched at water from an inclined ramp

    Would it be safe and possible to add an additioanal and higher exhaust gooseneck + muffler to the Mercruiser QSD4.2ES320 w/ Bravo II ?

    The Mercuiser installation manual says:
    " All diesel models covered by this manual are now factory equipped with an exhaust tube to reduce the exhaust back pressure when using through‑propeller exhaust"

    Greetings from France
    Last edited: Jun 9, 2022

  4. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    The picture needs the static waterline drawn in.
    The diagram shown and the picture have nothing in common for comparison, however raising the spillover height at the exhaust exit from the motor is always the best solution.
    The water lock muffler is unneeded, and actually complicates the issue. It being below the waterline will retain water at all times.
    bajansailor likes this.
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