chine height at the bow

Discussion in 'Boat Design' started by tonipu, Oct 20, 2021.

  1. tonipu
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    tonipu Senior Member

    I need a opinion on chine height in the first meter of the bow, what is better for less spray, keep it dow or rise it 10cm about
     

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  2. tonipu
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    tonipu Senior Member

    Larger picture
     

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  3. HJS
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    HJS Member

    Before you can get an adequate answer, more information is needed, preferably in the form of a line plan.
    JS
     
  4. gonzo
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    gonzo Senior Member

    It depends on the overall shape of the hull, operating speed and weather conditions.
     
  5. TANSL
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    TANSL Senior Member

    I would say that it is precisely the opposite, the behavior in the sea, the way to attack the waves, depends on that height of the chine.
     
  6. gonzo
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    gonzo Senior Member

    The height of the chine is part of the shape of the hull. How in any context is that the precise opposite?
     
  7. Mr Efficiency
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    Mr Efficiency Senior Member

    Being an alloy boat, it is a good candidate for a spray knocker to be easily added as experience reveals the need. I'd leave the current shape alone till then. I don't like plumb bows on planing boats, but this is pretty well locked in already.
     
    Barry and clmanges like this.
  8. tonipu
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    tonipu Senior Member

    Thank you for all your replies, it is very valuable to me
     
  9. TANSL
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    TANSL Senior Member

    When the OP asks for the height of the chine in the bow, we read the following
    I think it is precisely the opposite. The shapes of the hull depend on the shape we give to the chine.
    If you ever design one of these small boats, between 6 and 12 m, (I know this is not possible, but let me do this theoretical exercise that supports my reasoning), the first, very initial steps that you will take will be draw a longitudinal profile of the hull, the sheer line in elevation and plan, and at least the trace of the chine in the vertical plane. With those few lines you can start to define the shapes of the hull. From this assumption it is as it can be said that the chine defines the forms of the hull and not the other way around. You, who, I know well, are addicted to new technologies, who create 3D models to carry out the finite element analysis that you have shown us, will find the procedure that I have indicated very useful to define your triangular meshes.
     
  10. tonipu
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    tonipu Senior Member

    I know the chine defines practocle all the planing hull at least the under the chine, but at monehodrom hull practically 2/3 of the hull and chine remain the same, so i can vary the bow part of the hull and chine shape( witht and height)
     
  11. TANSL
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    TANSL Senior Member

    Of course, the same for any type of boat, monohull or multihull.
     
  12. Barry
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    Barry Senior Member

    We owned a Ranger Tug for about a year. While called a tug, it was really a planing hull, ie pretty constant deadrise from 1/3 back and with the "tug" bow profile that the picture suggests.

    In small waves, 2 - 3 feet with a wind blowing, quartering into the boat, the water was always coming over the front deck onto the windshield. It was the absolute wettest boat that we have ever owned. The windshield wipers were on almost constantly. Even without the wind blowing at about 20 knots, its cruising speed, the water would be pushed up and the boat would enter the spray

    Google the hull as on first sight of your picture, it appears similar. As Mr E states, " I don't like plumb bows on planing boats" ditto
     

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    Last edited: Oct 29, 2021
    bajansailor likes this.
  13. tonipu
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    tonipu Senior Member

    i know, even my 1:10 sea test in random wave provet that is wet boat, but here in adriatic boat excursion busines we have a epidemic of plumb pow and is very atractive for turist, so i know that boat with flare bow is much better but i must folow the fashion, that is what sales my excursion.

    i vary litlle bit the stern and when i have more bow up moment it was very good in following sea, 1 degree of boat down come wetness in to play

    i dont have time to fill al my sea trial
     
  14. tonipu
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    tonipu Senior Member

    i dont have time to film al my sea trial
     

  15. tonipu
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    tonipu Senior Member

    so, you dont answer, by your opinion is it better to rise a litle bit?
     
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