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Outdrive, Prop where next?-gctid821071

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    Outdrive, Prop where next?-gctid821071

    Hi Guys,

    Bayliner 6858 Ciera Flybridge

    Weight approx 6000lbs

    The Engine

    6.5 General Motors Diesel

    non turbo poss 165 - 180 bhp

    New injectors and pipes Injector pump rebuilt and fuel

    Increased by 5%

    Engine runs and sounds really well.

    No overheating issues.

    Outdrive - Sterndrive

    Bravo 3 2:1 to 1 Ratio

    The engine runs at 3800 rpm with no load

    I have run her with 20" pitch props she run at 3100 rpm achieved 10 knots engine run at 85c

    I have also run her with 28" pitch props she run at 2100 rpm acheiving 11 knots she run at 80c slightly cooler.

    Question is would the speed increase if the outleg had one prop instead of a duo poss Bravo 2 ?

    or would it be better to drop the gearing to 1:35 to 1 from 2:1 to 1

    Prop calcs dont seem to make sense on this one.

    Can anyone give some ideas to help sort out issue?

    All the best