Does a hull need to be specially designed for surface drive.

Discussion in 'Surface Drives' started by tom kane, Aug 4, 2015.

  1. tom kane
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    tom kane Senior Member

    Some say any boat hull is suitable for surface drive, some say a hull should be designed to suit a surface drive.
    From long-tail drive for canoes to fast ferries does hull design matter?
     

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    Last edited: Aug 4, 2015
  2. PAR
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    PAR Yacht Designer/Builder

    The short answer is no. The long answer is it depends on what you want.
     
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  3. tom kane
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    tom kane Senior Member

    The boat on the left could probably termed a displacement boat with that deep V and the surface of the water would be very deep and only when the boat moves forward.

    Quite a lot of dragging appendages on image 2 loosing benefit of surface drive.

    Image 3 props would need to be dropped to a very steep angle to gain any thrust.
     
  4. PAR
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    PAR Yacht Designer/Builder

    The boat on the left doesn't appear to be a displacement boat. Surface drives can be used in slow moving applications, though a costly way to get propulsion. Who know what they're trying to do in image two, but speed or efficency isn't very high up the list. The right most image seems a reasonable arrangement for rakers.
     
  5. powerabout
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    powerabout Senior Member

    If a boat was optimised for sterndrives you are going to get a different result with surface drives as they cant do the same job
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    I'm amazed Tom thinks the boat on the left is some kind of displacement hull. It appears to be a deep-V planing hull of around 24-25 degrees deadrise angle.
     
  7. PAR
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    PAR Yacht Designer/Builder

    Surface drives can perform the same role as outdrives, but the speed range will change, with possable hull mods being necessary, to address some condisional issues.
     
  8. powerabout
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    powerabout Senior Member

    and the first day you are in a tight marina with the wind blowing you will wish you had your sterndrives back
     
  9. tom kane
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    tom kane Senior Member

    Does a hull need to be specially designed for surface drive

    what I think does not really matter we have expert guidance for free everywhere.
     

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  10. tom kane
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    tom kane Senior Member

    Does a hull need to be specially designed for surface drive

    Optimizing a hull for stern drives surely means the hull is specially designed for stern drives.
     
  11. tom kane
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    tom kane Senior Member

    Number 2 image is a micro-hull,so I suppose there is a little artistic leeway allowed.
     
  12. tom kane
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    tom kane Senior Member

    Does a hull need to be specially designed for surface drive

    Not if you have retractable and adjustable propeller operating depth.
    If you have expensive surface drives you probably can afford bow thrusters and other bells and whistles,
     
  13. Ad Hoc
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    Ad Hoc Naval Architect

    Well, it makes a big difference if your cut-n-paste expert does not even know the difference between a "ton" and a "tonne".

    Hardly inspires confidence...but hey it's free, so you seem to be happy :p
     
  14. tom kane
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    tom kane Senior Member

    The difference between a "ton" and a 'tonne" is just a measure and is not relevant,
    the definition remains the same in any language.
     

  15. Ad Hoc
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    Ad Hoc Naval Architect

    For someone that is constantly seeking clear/exact explanations of hydrodynamics etc that you are unaware off, whereas others are (and still dismiss them), thus always wanting the replies to be of an clear/exact nature - so YOU can understand the reply - to define your question 'correctly, as you see it, that is a very lax and lame reply! Definitions are everything in engineering..
     
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