Tham khảo tài liệu 'practical ship hydrodynamics episode 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 5 Ship manoeuvring Introduction Ship manoeuvring comprises course keeping this concerns only the direction of the ship s longitudinal axis course changing track keeping important in restricted waters speed changing especially stopping Manoeuvring requirements are a standard part of the contract between shipyard and shipowner. IMO regulations specify minimum requirements for all ships but shipowners may introduce additional or more severe requirements for certain ship types . tugs ferries dredgers exploration ships. Important questions for the specification of ship manoeuvrability may include Does the ship keep a reasonably straight course in autopilot or manual mode Under what conditions current wind can the ship berth without tug assistance Up to what ratio of wind speed to ship speed can the ship still be kept on all courses Can the ship lay rudder in acceptable time from one side to the other Ship manoeuvrability is described by the following main characteristics initial turning ability ability to initiate a turn rather quickly sustained turning ability ability for sustained rather high turning speed yaw checking ability ability to stop turning motion rather quickly stopping ability ability to stop in rather short distance and time yaw stability ability to move straight ahead in the absence of external disturbances . wind at one rudder angle so-called neutral rudder angle The sustained turning ability appears to be the least important since it describes the ship behaviour only for a time long after initiating a manoeuvre. The stopping ability is of interest only for slow speeds. For avoiding obstacles at high ship speed it is far more effective to change course than to stop. Course changes require less distance than stopping manoeuvres for full speed. 151 152 Practical Ship Hydrodynamics Understanding ship manoeuvring and the related numerical and experimental tools is important for the designer for the choice of manoeuvring equipment of a ship. Items
