Do hydrofoils work?

Discussion in 'Propulsion' started by nine mile, May 11, 2014.

  1. nine mile
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    nine mile Junior Member

    Anyone familar with Stingray or other brands of hydrofoils?
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    Getting worried about your transom "excavation" ? You do hear some nasty stories about some of them, like boats nearly flipping, not sure what the problem is there, but maybe the permatrim type is a safer proposition.
     
  3. nine mile
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    nine mile Junior Member

    Yea, I have large stationary trimtabs now,huh?
     

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  4. nine mile
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    nine mile Junior Member

    Those permatrims look like they could run very shallow, as though ventilation would be nearly impossible.
     
  5. Ike
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    Ike Senior Member

    I had a friend who was a naval architect. Unfortunately he is no longer with us. He used to say that if you have to add trim tabs or hydroplanes to get the boat to perform correctly, then the design was flawed from the beginning.

    Do they work. In some instances. But mostly they just add more drag.
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    Well, if the boat needs trim tabs at 'normal' speed in 'normal' conditions, and under 'normal' loading, it probably is a flawed design, but tabs give extra flexibility to operate effectively when the situation is outside what is usually encountered. Not to mention the control you get over lateral trim, like cross-wind lean correction. It isn't that expensive to fit them, for the convenience of having the extra control you get.
     

  7. daiquiri
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    daiquiri Engineering and Design

    IMO, not always so, Ike. Think of them as of the spoilers on cars. Most cars don't need them in most of situations. But they can give a better handling in some situations, especially at high speeds. One cannot say that a particular car was badly designed if a spoiler improves some of its characteristics in certain moments. It merely gives something more to the vehicle's characteristics when the basic body cannot be shaped to behave optimally throughout the whole range of road and speed conditions.
    Cheers
     
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