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An azimuth thruster with counter rotating propellers is suitable for ships with a high-speed requirement, shallow draught or other purposes where a smaller propeller diameter is needed. This type of azimuth thruster can provide 360-degree alldirectional thrust for the vessel.When used as the main propulsion system for the vessel, it not only gives forward speed but also improves the vessel's maneuverability.
link:https://www.thrusterleader.net/counter-rotating-propeller-azimuth-thruster/
Counter Rotating Propeller Azimuth Thruster