Two Stern Thrusters next to each other

Discussion in 'Hydrodynamics and Aerodynamics' started by Lewardsail, Feb 27, 2015.

  1. Lewardsail
    Joined: Feb 2015
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    Lewardsail New Member

    Has there been and testing of two stern thrusters close together and what if any effects this causes.
    I know some bow thrusters have two counter rotating props, does this make it more efficient?
    Any information would be helpfull.

  2. DCockey
    Joined: Oct 2009
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    DCockey Senior Member

    Counter-rotating concentric props can (if properly designed) improve efficiency by reducing swirl in the water stream exiting the props. With a single propeller the water stream exiting the prop is swirling and the swirl does not contribute to thrust.

    The propellers must be counter-roatating, concentric and properly designed to reduce the swirl and improve efficiency. Otherwise efficiency may be worse than with a single propeller.
  3. powerabout
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    powerabout Senior Member

    Do you mean 2 tunnels or 2 azimuthing thrusters?
    I think the other advantage of duo props is small diameter to equal the thrust of a larger diameter
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