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Calculating the thrust required to turn a submarine deep in the water

  1. Feb 14, 2014 #1
    Dear All,

    I am designing a AUV and trying putting a bow thruster in the front. I am kinda confused that how much power do I need to turn my AUV by a steady angular velocity. Could anyone pls help me with this.

  2. jcsd
  3. Feb 15, 2014 #2


    User Avatar
    Gold Member

    Working blind here.
    Power could be any value. I am guessing it should be about 0.1 HP.

    Firstly, briefly describe your AUV - weight, size, power consumption, duration of underwater expedition, desired time to make a turn, etc. That might cog someone with experience with a similar problem or knowledge of underwater vehicles to offer aid.

    You must at least have some idea of what your desired goal is.
    And how much knowledge you have on this subject would not hurt either.
  4. Feb 15, 2014 #3
    I am looking for the formulas or the procedure to calculate the drag while turning for any typical AUV of any size.
  5. Feb 15, 2014 #4


    Staff: Mentor

    I would guess that drag is small compared to the forces caused by currents impinging at angles such as 45 degrees.

    Here is a way to guess. Calculate, or fiind by experiment, how much primary propulsion power is needed to hold the vessel stationary against X knots of current bow-on. The power needed by the thruster and rudder to hold constant angle against X knots at 45 degrees is comparable within a factor of two.

    Your biggest job is to decide how much X to design for. Unless you are in a swimming pool, X is seldom zero.

    Good luck
  6. Feb 15, 2014 #5
    Ah, Cant do experiments. Anything mathematically
  7. Feb 15, 2014 #6


    Staff: Mentor

    Can you make the primary propulsion in pods that rotate 360 degrees? Modern ships do that. One pod fore, one aft and you have it. No separate thruster needed.
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