Stern flaps and interceptors

Discussion in 'Boat Design' started by terhohalme, Feb 1, 2011.

  1. terhohalme
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    terhohalme BEng Boat Technology

    Any technical paper of these, dimensioning, generated force etc.?
     
  2. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    There was an article in Professional Boatbuilder a few years ago with some rules of thumb; I'll go and see if I can find someting in the sediments here....

    Also have some pprs on the use on cavitating and vetilated foils, but that may not be of interest for trim control; I'll be back!
     
  3. kerosene
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    kerosene Senior Member

    are you thinking of using such system in a rowboat?
     
  4. terhohalme
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    terhohalme BEng Boat Technology

    That's a good idea! Short, stern trim rowboats could have some advance...

    Sorry, this concerns my job. Just couldn't find anything suitable in our library or internet.
     
  5. MechaNik
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    MechaNik Senior Member

    Trim tabs are all about compromise, rules of thumb etc will apply pertaining to there dimensions.
    Interceptors are what it is all about for me with regards to yachts. The idea is to cover the entire transom to prevent bypass around the side of the blades and limit the amount of blade deployed. This helps to reduce associate wake from the blade which should already be less than that of a trim tab.
    The amount of lift generated would be nothing with zero drag ranging until too much at full deployment. There are a few manufacturers out there but they show little on the net. The biggest supplier for yachts would have to be the Proford boys in Sweden www.humphree.com
    They at least have some information/dimensions and references on their site, plus standard products.
     
  6. Commuter Boats
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    Commuter Boats Commuter Boats

    I hope you find this helpful...
     

    Attached Files:

  7. tom28571
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    tom28571 Senior Member

    All of this information is about interceptors that are mounted on the transom and act like trim tabs. All pretty easy to understand. What about interceptors that are mounted under the hull forward of the transom but aft of the spray area.
     
  8. MechaNik
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    MechaNik Senior Member

    Still interceptors just not on the transom. They need to be ventilated otherwise they are just a drag device.
     
  9. daiquiri
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    daiquiri Engineering and Design

    Tom, I know that a member of this forum, HJS (http://www.boatdesign.net/forums/profile/hjs.html), has experimented with that configuration and also wrote few technical reports about it. But I haven't seen him around for quite some time... Maybe you could try to PM him?
     
  10. terhohalme
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    terhohalme BEng Boat Technology

    Thanks MechaNik and Commuter Boats.

    Still seaching the way to calculate average pressure and effective area or estimated force created by interceptors.
     
  11. keysdisease
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    keysdisease Senior Member

  12. HJS
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    HJS Member

    It is complicated to calculate the efficiency of the interceptor.
    Because I don't know what is related to the interceptor in it self and what is related to the boats longitunal trim.

    I am still researching on this topic.

    js
     

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  13. terhohalme
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    terhohalme BEng Boat Technology

    Thanks JS
     
  14. tom28571
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    tom28571 Senior Member

    Of course, but operational and theoretical information is still a bit lacking.
     

  15. keysdisease
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    keysdisease Senior Member

    Are you researching this so you can size properly, or build appropriate structure to attach to, or what?

    Steve

     
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