This presentation will focus on the topic of Ship Underactuation in ocean-going vessels. The subtopics of this presentation consist of Propeller-Rudder-Bow Thruster Powered Vessel, Ship Navigation Calm Waters, Surge Acceleration & Velocity, Ship Resistance in the Surge Direction, Constant Surge Velocity, Ship Resistance on the Surge Velocity, Slightly Higher Propeller Thrust, Incoming Waves & Wave Resistance Force, Decomposition of Wave Resistance Force, Summation in Surge Direction Ship Resistance, Sway Acceleration, Birth of Sway Velocity, Ship Resistance in the Sway Direction, Summation of Sway Direction Ship Resistance, Course-Speed Vector, Yaw Moment, Yaw (Angular) Acceleration, Yaw Rate (Angular Velocity), Vessel Controllability, Rudder-Propeller Actuation, Bow thruster Actuation, Net Force in the in the Surge Direction, Net Force in the Sway Direction, Constant Course-Speed Vector, Net Moment in the in the Yaw Direction, Resulted Ship Motion, Realistic Ship Motions, Fully Actuation in Slow Maneuvers & Clam Weather, Ship Navigation in Moderate Speed & Weather, Adequate Yaw Moment, Inadequate Sway Force, Ship Underactuation.