Triple Outboard Mounting

Discussion in 'Boat Design' started by tkdchris, Mar 28, 2013.

  1. tkdchris
    Joined: Nov 2010
    Posts: 9
    Likes: 1, Points: 3, Legacy Rep: 14
    Location: Southampton

    tkdchris Engineer

    I'm working on the design of a high speed RIB that will have triple 350HP outboards. The center out board will be a 30" leg and the two outer engines 25" legs.

    To achieve the minimum freeboard required by the engine manufacturer I need to mount the center outboard 150mm higher than its optimum position.

    I have two possible solutions for adjusting the transom to allow the flow of water to meet the prop in an optimum fashion.

    The first solution is to put a triangular flat that merges into hte hull 3m forward of the transom.

    The other option is to stop the running surfaces 500mm in front of the transom and step the hull.

    Has anyone had any experience of either of these methods and the effects they have on the performance of the vessel. I should add the boat will be of aluminium construction.

    Many thanks
  2. michael pierzga
    Joined: Dec 2008
    Posts: 4,862
    Likes: 116, Points: 0, Legacy Rep: 1180
    Location: spain

    michael pierzga Senior Member

    Dont know much about speedboats. This triple is in the yard this week



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