v8 super boat hull improvements

Discussion in 'Boat Design' started by stoog01, Mar 8, 2016.

  1. stoog01
    Joined: Mar 2016
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    stoog01 Junior Member

    hi all i am hoping to get some advice and or help on understanding and improving my race hull, these are small 4 mt ali race hulls designed and built in new Zealand, mine is a gen one so is approx 15+ years old, sides are 3 mm and hull is 4 mm , the delta is approx 20 mm , it has a scott jet unit and is powered by a 700 hp sbc , boat weight is approx 600 kgs, my design is a bit heavier than the newer competition and take more power to get same speed approx max 130 kmh but is does this in 3 sec and can turn 90 degs at full throttle,so are a very quick turning boat aided by the jet suction processing large amounts of water.
    i am looking at either widening the delta at the back and or maybe wider chines to help lift the hull in the water and reduce drag.
    i am hoping someone here might have some ideas.
    thanks.
     
  2. stoog01
    Joined: Mar 2016
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    stoog01 Junior Member

    How Can I Attach A Couple Of Pictures Of My Hull.
    Cheers
     
  3. Boat Design Net Moderator
    Joined: Feb 2010
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    Boat Design Net Moderator Moderator

    Welcome to the forum. Click on the blue Post Reply button or click on "Go Advanced" on the quick reply.

    Then click on Manage Attachments and you can select photos or attachments from your local drive to upload with a post.

    If you don't get a new window when you click manage attachments, make sure the new popup attachment window hasn't been blocked. After uploading, post your reply with the attachments.
     
  4. stoog01
    Joined: Mar 2016
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    Location: perth

    stoog01 Junior Member

    Thanks For That
     
  5. stoog01
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    stoog01 Junior Member

    Lower Hull Pics

    Just To Give You An Overall Of The Bottom And Yes I Was In It Lol

    12227019_10153375144964531_2839317403896825405_n.jpg
     
  6. stoog01
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    stoog01 Junior Member

    Close Up During Repairs

    another pic

    11046886_10153504515509531_1754337906676251138_n.jpg
     
  7. gtflash
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    gtflash Senior Member

    Hoed far off competition are you in terms of speed and weight? Can't the boat loose some weight?
     
  8. stoog01
    Joined: Mar 2016
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    stoog01 Junior Member

    Boat speed

    Hi thanks is for the reply boat is pretty good we are running first in group a over here this season but there are better handling later model ones , I find that it porpoises bad coming in from a high speed run into Hairpin's. Also always has been nose high have moved the engine forward 130mm and roll cage 40mm now I. Can run o trim but still a bit nose high
     
  9. gtflash
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    gtflash Senior Member

    Any pictures of it running. You lot are nuts :)
     
  10. stoog01
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    stoog01 Junior Member

    Hi if you suearch YouTube Stuart Latham there are a few videos there may help
     
  11. pogo
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    pogo ingenious dilletante

  12. ondarvr
    Joined: Dec 2005
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    Location: Monroe WA

    ondarvr Senior Member

    I see the design flaw, the intake grate should be below the waterline at full speed. It may need to be repositioned.
     
  13. stoog01
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    stoog01 Junior Member

    Intake grate

    I will check but I am pretty sure the intake is below the waterline, and I would expect it to cavitate badly but it is fine , I have another grate to install this week and has had every second bar taken out so only 6 left, I am hoping this will reduce suction pressure a bit allowing the stern to rise a bit .may have to adjust the trim a bit
     
  14. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    I would consider reducing the strake count from 6 to 4, which will reduce some drag and also consider changing their plan form to match the waterlines, rather than the buttocks. This will let you turn crisper and the slight decrease in drag will offer some top speed. You can also consider what Roger Mutimer is working on and aerate the bottom (shingle bottom).

    [​IMG]
    an example of the strake modification I mentioned.
     

  15. Mani Kandasa
    Joined: Mar 2016
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    Location: Iowa

    Mani Kandasa Junior Member

    I believe ondarvr was joking about the intake grate being above the waterline, from your too cool for school inverted boat pic :)
    Have you looked into interceptors for correcting your nose high trim?
     
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