wetted surface area of appendages

Discussion in 'Hydrodynamics and Aerodynamics' started by jake wilson, Aug 20, 2021.

  1. jake wilson
    Joined: Oct 2020
    Posts: 11
    Likes: 0, Points: 1
    Location: india

    jake wilson Junior Member

    Hello there. I'm currently working on an assignment in which I have to find the resistance of ships using the Holtrop Mennen method in excel. I would like to know how to find the wetted surface area of appendages with an approximation formula.
    And also is there any specific limit for the half-angle of the entrance of the ship?
    apart from this how can the power estimation be done? I have used the method given below.
    Effective POwer = total resistance*Ship's speed
    Seamargin = 1.15*effective power
    Pd = effective power/0.65
    Gear loss=1.05*Pd
    shaft loss power = Pd/0.98
    Brake power = shaft loss power /0.85
    I'm open to suggestions. I would like to know if there are any other methods to estimate the power for ships.
    Thanks in advance. It would be a great help.
     
  2. TANSL
    Joined: Sep 2011
    Posts: 6,880
    Likes: 518, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    The best way to obtain the wetted surface of the appendages is to calculate it yourself. It is not usually difficult.
    The towing power required is usually proportional to the speed squared. Review the formulas you are using.
     

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  3. jake wilson
    Joined: Oct 2020
    Posts: 11
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    Location: india

    jake wilson Junior Member

    thankyou so much sir. I will review it again. thanks alot
     
  4. jake wilson
    Joined: Oct 2020
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    Location: india

    jake wilson Junior Member

    is there any particular formula to find the wetted surface of appendages?
     
  5. TANSL
    Joined: Sep 2011
    Posts: 6,880
    Likes: 518, Points: 123, Legacy Rep: 300
    Location: Spain

    TANSL Senior Member

    It is not possible to give a general formula for the appendages. There are too many variables that determine their size, shape, surface ...
     

  6. jake wilson
    Joined: Oct 2020
    Posts: 11
    Likes: 0, Points: 1
    Location: india

    jake wilson Junior Member

    okay sir, Thank You.
     
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